bluuebunny/crossref_metadata_2025 huggingface dataset:
Effect of structure parameters of catalyst substrate on the performance of diesel particulate filter
Authors: Tan Piqiang , Li Yunpeng , Cao Chenyang , Lou Diming , Hu Zhiyuan
Published: May 2022

The filtration efficiencies of the particulate matter and the particulate number in DPF, the no-load pressure drop of DPF, and the load pressure drop of DPF were selected as key performance parameters of DPF. The influence of the cell density and the wall thickness of the DPF on these key performance parameters of DPF was studied in detail. Firstly, a calculation model of DPF was established, and the compensation mathematical model was added. Secondly, the key performance parameters of DPF were defined. Finally, based on the model, the key performance parameters are numerically investigated under different cell density and wall thickness of the DPF. Consequently, with the increase of cell density of DPF, the filtration efficiency of DPF increases, the load pressure drop of DPF decreases, but the no-load pressure drop of DPF increases. With the decrease of the wall thickness of the DPF, the no-load pressure drop of the DPF decreases, the load pressure drop of the DPF decreases, but the filtration efficiency of the DPF decreases. The most suitable combination scheme is a cell density of 200-300 CPSI and a wall thickness of 11-16 mil.
Kinematic Simulation of Automatic Conveying and Stamping Machine based on UGNX
Authors: Liang Wenyue , Zhan Xianghui
Published: May 2022

This paper designed a kind of automatic conveying and stamping machine, which was mainly used for drawing thin sheet metal. UGNX software was used to design the motion law of the mechanism and the simulation mechanism. The time displacement diagram obtained by theoretical calculation and simulation was compared to verify the correctness of theoretical analysis and the rationality of the design. The comparison shows that the device meets the requirements of theoretical calculation. The device has the characteristics of simple structure, high efficiency and easy operation, which provides a reference for the subsequent realization of conveying and stamping devices with different requirements.
Research status and prospect of dissimilar light alloy welding technology
Authors: He Xiaohui , Liu Bin , Zhou Xiong , Li Cheng , Zhang Xuhui , Chang Junjie
Published: May 2022

Magnesium alloys, aluminum alloys and titanium alloys are currently widely used light alloy materials with good prospects. The welding of Mg/Al/Ti dissimilar light alloys has a wide range of application requirements in aerospace, automobile manufacturing, electronic information and other fields, and is a hot topic of current research. This article summarizes the welding research results of Mg/Al/Ti dissimilar light alloys in recent years, outlines the current research status of welding technology of Mg/Al/Ti dissimilar light alloys, analyzes the common problems and solutions in welding, and proposes further Carry out the research of Mg/Al/Ti welding technology and basic theory, look forward to the effective ways to improve the welding performance of Mg/Al/Ti dissimilar light alloys and future research directions, and promote the promotion of Mg/Al/Ti dissimilar light alloy joints The practicality of it is of great significance.
Finite Element Simulation of Graphene Thermal Conductivity Framework
Authors: Yang Jun
Published: May 2022

With the rapid development of electronic devices towards miniaturization and high integration, the problem of overheating and heat dissipation forces people to find thermal conductive materials with good comprehensive properties to meet the needs of development. Inspired by the three-dimensional boron nitride network, this paper creatively proposed the construction of a composite thermal conductive material with 3D graphene network structure and PDMS as filling matrix, and carried out finite element analysis and simulation with COMSOL. The results show that the thermal conductivity of the composite thermal conductive material with graphene 3D network structure is significantly better than that of the single thermal conductive material without graphene and the thermal conductive material with random distribution of graphene, and most of the heat flow forms a connected thermal conductive path along the heat transfer direction in the graphene of 3D network composite. It can be seen that the prepared composites with 3D thermal conduction network structure have excellent thermal conductivity, and will have broad market prospects in the fields of heat dissipation materials, computers, smart phones, laser weapons and so on.
Solid solution behavior of Cu-1.0Cr-0.1Zr alloy
Authors: Ma Yuxia , Chen Huiqin , Li Hui , Dang Shue
Published: May 2022

Solid solution treatment on Cu-1.0Cr-0.1Zr alloy was performed at different temperatures and holding times to study the impact on solid solution behavior. At low temperatures, the results show that solid solutions do not form in the Cr-rich phase, but they start to form when temperatures rise above 900 °C. The dissolution rate first increases and then decreases, as temperatures approach higher values. At 950 °C, substantial solid solution forms, and as the holding time extends, the dissolution rate gradually decreases until the formation of solid solution completed. The pinning of dislocations by the Cr-rich phase leads to fine grain generation in the structure to further enhance the strength and lower the conductivity. Formation of solid solution completes when held at 950 °C for 120 min. The strength is 63.7 HB and conductivity is 34.5% IACS. Solid solution increases strength and resistivity by 43.91% and 63.59%, respectively.
Truly a hyperparasite, or simply an epibiont on a parasite? The case of Cyclocotyla bellones (Monogenea, Diclidophoridae)
Authors: Bouguerche Chahinez , Tazerouti Fadila , Justine Jean-Lou
Published: May 2022

Cyclocotyla bellones Otto, 1823 (Monogenea, Diclidophoridae) is one of the few monogenean species reported as hyperparasitic: the worms dwell on cymothoid isopods, themselves parasites of the buccal cavity of fishes. We present here observations based on newly collected monogenean specimens from Ceratothoa parallela (Otto, 1828), an isopod parasite of Boops boops off Algeria and also investigated its diet to address whether Cy. bellones is indeed a hyperparasite, i.e., whether it feeds on the isopod. We also compared the body shape of various monogeneans belonging to the same family as Cy. bellones, the Diclidophoridae, including Choricotyle cf. chrysophryi Van Beneden & Hesse, 1863, collected from Pagellus acarne off Algeria. No morphological character of the anterior organs suggested any special adaptation in Cy. bellones to the perforation of the crustacean cuticle. The wall of the oesophagus and of the intestine of Cy. bellones was lined with a dark pigment similar to what is usually observed in haematophagous polyopisthocotyleans, and which is derived from ingested fish blood. We noticed that an anterior elongate stem exists only in diclidophorids dwelling on parasitic isopods and never in those attached to the gills. We hypothesize that the anterior stem of the body of Cy. bellones is an anatomical adaptation for the monogenean to feed on the fish while dwelling on the isopod. We thus consider that Cy. bellones is an epibiont of the parasitic crustacean, as it uses it merely as an attachment substrate, and is not a true hyperparasite.
Patients partenaires en éducation thérapeutique : quels ressentis et besoins à la suite de leurs activités ?
Authors: Borie Constance , Cherillat Marie-Sophie , Leroux Marie-Christine , Berland Pauline , Robello Aurélie , Gerbaud Laurent
Published: May 2022

Introduction:Alors que les patients partenaires sont de plus en plus impliqués en ETP, leurs expériences à la suite de leurs pratiques ont peu été explorées.Objectif :Comprendre comment les patients partenaires évaluent leurs activités et rôles en ETP, en Auvergne (France).Méthodes :Une étude quantitative d’une durée d’un mois a été proposée à vingt patients partenaires d’Auvergne. Les données qualitatives ont été exploitées par catégorisation thématique, en respectant une triangulation de méthodes et d’analyse.Résultats :Onze patients partenaires ont participé à l’ensemble de l’étude. Un total de 107 catégories de vécues ont été décrites dont la majorité était à connotation positive (76,6 %). Les patients partenaires ont mentionné 90 verbatim décrivant des aptitudes et compétences nécessaires à leurs activités, principalement relationnelles et pédagogiques (37 %) puis intrapersonnelles (31 %). Ces données recueillies s’accompagnaient de besoins d’échanges sur leurs rôles et leurs postures ainsi que d’acquisition de nouvelles compétences.Discussion :Les patients partenaires réalisent des activités et formations multiples en lien avec l’ETP et ont un statut particulier. Ceci leur permet d’acquérir et mobiliser de nombreuses compétences, mais engendre aussi une difficulté de reconnaissance et d’identification auprès des institutions. Des besoins d’échanges entre pairs, structurés, stables et en groupe, apparaissent.Conclusion :Les patients partenaires possèdent une curiosité intellectuelle salutogénique les poussant à se former et à développer leurs activités. Cependant, ces élans et investissements doivent être soutenus au niveau régional, voire national, afin d’en assurer la pérennité.
Rosette-Forming Glioneuronal Tumor at Septum Pellucidum: Insights Gained from a Common Tumor at Rare Location
Authors: Nandan Maruti , Patnaik Ashish , Sahu Rabi Narayan , Singh Yashveer , Maurya Ved P. , Das Kuntal K. , Behari Sanjay
Published: May 2022

The rosette-forming glioneuronal tumor (RGNT) is an uncommon entity and carries a special character because of its mixed glial and neuronal composition in the histomorphological appearance. These lesions have a benign character and carry a good outcome if undergoes gross total resection. Over the past 15 years, there have been a significant change in their nomenclature depending upon the location to histological composition. Herein, we report an interesting case of a 26-year-old lady who was diagnosed to have the lesion at the septum pellucidum with significant symptoms in the form of headache and seizure episodes. A gross total resection was achieved and she made an uneventful recovery. We discuss the literature on the incidence, location, and histological characteristics of the RGNT in various age groups.
Spectral statistics of Dirac ensembles
Authors: Khalkhali Masoud , Pagliaroli Nathan
Published: May 2022

In this paper, we find spectral properties in the large N limit of Dirac operators that come from random finite noncommutative geometries. In particular, for a Gaussian potential, the limiting eigenvalue spectrum is shown to be universal, regardless of the geometry, and is given by the convolution of the semicircle law with itself. For simple non-Gaussian models, this convolution property is also evident. In order to prove these results, we show that a wide class of multi-trace multimatrix models have a genus expansion.
Dynamics of two unequal-sized drops coalescence at a liquid–liquid interface
Authors: Singh Swati , Saha Arun K.
Published: May 2022

The secondary droplets formed during the coalescence of two drops have an important role in many applications, including raindrop formation in clouds and emulsions coarsening. The process of secondary drop generation at the liquid–liquid interface is numerically investigated using a coupled level set and volume of fluid method during the coalescence of two drops of different parent drop size ratios. The coalescence dynamics has been found to depend on the five-dimensionless parameters, namely, the Ohnesorge numbers for liquid-1 and 2, the Bond number, the Atwood number, and the diameter ratio of the two drops. As a function of these non-dimensional parameters, different pinch-off regimes, namely, first-, second-, and no pinch-off, are studied. The result shows that the local neck curvatures at the onset of pinch-off play a key role in the appearance of various pinch-off regimes. The second-stage pinch-off occurs primarily within the Ohnesorge number range from 0.002 to 0.01, i.e., inertio-capillary regime range. Above this range, a direct transition from the first-stage pinch-off to no pinch-off occurs with the increasing Ohnesorge number. Within the inertio-capillary regime, the pinch-off mechanism in both the first and second-stage pinch-off regime is found to be almost independent of the Atwood number and the parent drop size ratio. Capillary waves produced at the contact region of two drops have also been observed to influence the pinch-off process. A large parent size ratio induces the higher curvature near the neck zone, resulting in stronger capillary waves. Strong viscous forces, however, dampen the propagation of capillary waves at a large Ohnesorge number. The critical Ohnesorge number is obtained for both the first and second-stage pinch-off regimes above which the strong viscous forces hinder a secondary drop pinch-off.
Coupled surface and bulk diffusion in crystals
Authors: Kosolobov S. S.
Published: May 2022

We analyze point defect bulk and surface diffusion near the crystal–vacuum interface and show that bulk diffusion is coupled with surface diffusion via the atomic processes in the intermediate subsurface layer. A set of self-contained differential equations describing the interaction of self-interstitials and bulk vacancies with the surface of crystal is proposed. The results show the existence of the fundamental relation between the equilibrium concentrations of the point defects in bulk and at the surface of the crystal. For the case of silicon, the energy barrier differences that restrict the point defect fluxes between the bulk and surface of the crystal are estimated.
Patterns of livestock depredation by snow leopards and effects of intervention strategies: lessons from the Nepalese Himalaya
Authors: Filla Marc , Lama Rinzin Phunjok , Filla Tim , Heurich Marco , Balkenhol Niko , Waltert Matthias , Khorozyan Igor
Published: May 2022

Context Large carnivores are increasingly threatened by anthropogenic activities, and their protection is among the main goals of biodiversity conservation. The snow leopard (Panthera uncia) inhabits high-mountain landscapes where livestock depredation drives it into conflicts with local people and poses an obstacle for its conservation. Aims The aim of this study was to identify the livestock groups most vulnerable to depredation, target them in implementation of practical interventions, and assess the effectiveness of intervention strategies for conflict mitigation. We present a novel attempt to evaluate intervention strategies for particularly vulnerable species, age groups, time, and seasons. Methods In 2020, we conducted questionnaire surveys in two regions of the Annapurna Conservation Area, Nepal (Manang, n = 146 respondents and Upper Mustang, n = 183). We applied sample comparison testing, Jacobs’ selectivity index, and generalised linear models (GLMs) to assess rates and spatio-temporal heterogeneity of depredation, reveal vulnerable livestock groups, analyse potential effects of applied intervention strategies, and identify husbandry factors relevant to depredation. Key results Snow leopard predation was a major cause of livestock mortality in both regions (25.4–39.8%), resulting in an estimated annual loss of 3.2–3.6% of all livestock. The main intervention strategies (e.g. corrals during night-time and herding during daytime) were applied inconsistently and not associated with decreases in reported livestock losses. In contrast, we found some evidence that dogs, deterrents (light, music playing, flapping tape, and dung burning), and the use of multiple interventions were associated with a reduction in reported night-time depredation of yaks. Conclusions and implications We suggest conducting controlled randomised experiments for quantitative assessment of the effectiveness of dogs, deterrents, and the use of multiple interventions, and widely applying the most effective ones in local communities. This would benefit the long-term co-existence of snow leopards and humans in the Annapurna region and beyond.
Phones as a semiotic disadvantage
Authors: Dryden Stephanie
Published: May 2022

While previous studies have outlined the advantages of semiotic resources for meaning making and relationship
building, not all semiotic resources are equal in their ability to enhance these features. Using linguistic ethnographic
interviews and focus group discussions, this article examines whether mobile phones provide sufficient semiotic resources for
English as a Foreign Language (EFL) migrants to effectively communicate, particularly for service situations regarding finances
where they often have to speak in English with unknown interlocutors. Two important elements are uncovered regarding EFL migrants’
difficulty in using phones as a semiotic resource – (1) linguistic superiority, where they are judged by their English-speaking
interlocutor as engaging in inferior English practices, and (2) paralinguistic insufficiency, where the lack of gestures and
facial expressions takes away their ability to make meaning. These elements combined make telephone conversations difficult for
many EFL migrants, affecting their expressiveness and ability to effectively communicate, leading to negative outcomes such as
avoidance behaviors, and feelings of anxiety and disempowerment. Such difficulties lead to the finding that EFL migrants must be
better accommodated when engaging in service transactions, with other, semiotically richer resources required to better aid their
understanding and ease feelings of anxiety.
Laser melting deposition of aluminium 7050 alloy: Heat treatment, microstructure and mechanical properties
Authors: Li Jianan , Zhao Hongjin , Deng Shenghua , Liu Xu , Ojo Olanrewaju A. , Zhang Lina , Li Weirong
Published: May 2022

In this study, the microstructure and mechanical properties of laser melting deposited 7050 aluminium alloy are investigated. An anisotropic microstructure is observed in the alloy: the columnar-grained structure on the building plane and a fine equiaxial structure on the scanning plane. Pores are the main metallurgical defects found but a higher energy input can significantly reduce large pores. The mechanical properties can be significantly improved with heat treatment. After being subjected to multiple solution and aging treatments, the hardness, ultimate tensile strength and elongation at break of the printed alloy increase by 58.6%, 14.06% and 27.8%, respectively. This research offers a reference for the formation technique of large and complex 7xxx series aluminium alloy parts by additive manufacturing.
Regulated targeting of the monotopic hairpin membrane protein Erg1 requires the GET pathway
Authors: Farkas Ákos , Urlaub Henning , Bohnsack Katherine E. , Schwappach Blanche
Published: May 2022

The guided entry of tail-anchored proteins (GET) pathway targets C-terminally anchored transmembrane proteins and protects cells from lipotoxicity. Here, we reveal perturbed ergosterol production in ∆get3 cells and demonstrate the sensitivity of GET pathway mutants to the sterol synthesis inhibiting drug terbinafine. Our data uncover a key enzyme of sterol synthesis, the hairpin membrane protein squalene monooxygenase (Erg1), as a non-canonical GET pathway client, thus rationalizing the lipotoxicity phenotypes of GET pathway mutants. Get3 recognizes the hairpin targeting element of Erg1 via its classical client-binding pocket. Intriguingly, we find that the GET pathway is especially important for the acute upregulation of Erg1 induced by low sterol conditions. We further identify several other proteins anchored to the endoplasmic reticulum (ER) membrane exclusively via a hairpin as putative clients of the GET pathway. Our findings emphasize the necessity of dedicated targeting pathways for high-efficiency targeting of particular clients during dynamic cellular adaptation and highlight hairpin proteins as a potential novel class of GET clients.
Seebeck-driven transverse thermoelectric generation in on-chip devices
Authors: Zhou Weinan , Hirai Takamasa , Uchida Ken-ichi , Sakuraba Yuya
Published: May 2022

An unconventional approach to enhance the transverse thermopower by combining magnetic and thermoelectric materials, namely the Seebeck-driven transverse thermoelectric generation (STTG), has been proposed and demonstrated recently. Here, we improve on the previously used sample structure and achieve large transverse thermopower over 40 μV K−1 due to STTG in on-chip devices. We deposited polycrystalline Fe–Ga alloy films directly on n-type Si substrates, where Fe–Ga and Si serve as the magnetic and thermoelectric materials, respectively. Using microfabrication, contact holes were created through the SiO
x
layer at the top of Si to electrically connect the Fe–Ga film with the Si substrate. These thin devices with simple structure clearly exhibited enhancement of transverse thermopower due to STTG, and the obtained values agreed well with the estimation over a wide range of the size ratio between the Fe–Ga film and the Si substrate.
Chemical-free exfoliation of hexagonal boron nitride via cavitation-bubble plasma in water
Authors: Goto Taku , Hatakeyama Kazuto , Ito Tsuyohito , Inoue Kenichi , Hakuta Yukiya , Shimizu Yoshiki , Terashima Kazuo
Published: May 2022

Hexagonal boron nitride (h-BN) sheets have numerous applications, but current low-cost, environmentally friendly techniques for h-BN exfoliation yield undesirably small sheet sizes. We have developed a novel chemical-free method to prepare large h-BN nanosheets (BNNSs) by the exfoliation of h-BN using plasma with cavitation bubbles in water, named here as cavitation-bubble plasma. Unlike ordinary liquid exfoliation methods, which reduce the sheet size of BNNSs compared with that of the starting h-BN, the cavitation-bubble plasma process exfoliated h-BN without reducing the sheet size. Furthermore, the plasma dramatically improved the exfoliation yield.
Distributional health impacts of electricity imports in the United States
Authors: Hennessy Eleanor M , de Chalendar Jacques A , Benson Sally M , Azevedo Inês M L
Published: May 2022

The electric grid is evolving rapidly in response to climate change. As renewables are incorporated, more interconnection of the grid is expected. Exposure to fine particulate matter (PM2.5) from fossil-fuel generation causes adverse health impacts, including thousands of premature deaths each year in the United States. It is well understood that PM2.5 exposure can occur at great distances from pollutant sources, but insufficient work has been done to understand the role of grid interconnection and trade in causing pollution-related mortality. Regions with clean generation can import electricity from regions with highly polluting generation sources, allowing them to benefit from the electricity consumption while people in other regions suffer the associated health damages. We use flow tracing and consumption-based accounting to characterize the health damages from exposure to PM2.5 from electricity imports. We find that 8% of our estimated premature deaths from electricity consumption in the United States are due to electricity imports. There is large geographic heterogeneity, with the most impacts occurring in the Midwest. While the West Coast has much cleaner generation and lower impacts overall, in many West Coast Balancing Areas, more than 50% of the estimated premature mortality associated with electricity consumption is caused by electricity imports, with some groups experiencing larger impacts than others.
Energy requirement for implementing unitary gates on energy-unbounded systems
Authors: Yang Yuxiang , Renner Renato , Chiribella Giulio
Published: May 2022

The processing of quantum information always has a cost in terms of physical resources such as energy or time. Determining the resource requirements is not only an indispensable step in the design of practical devices—the resources need to be actually provided—but may also yield fundamental constraints on the class of processes that are physically possible. Here we study how much energy is required to implement a desired unitary gate on a quantum system with a non-trivial energy spectrum. We derive a general lower bound on the energy requirement, extending the main result of Chiribella et al (2021 Phys. Rev. X 11 021014) from finite dimensional systems to systems with unbounded Hamiltonians. Such an extension has immediate applications in quantum information processing with optical systems, and allows us to provide bounds on the energy requirement of continuous variable quantum gates, such as displacement and squeezing gates.
Actuation of ionic polymer-metal composites with alkali metal counterions—a molecular dynamics study
Authors: Truszkowska A , Porfiri M
Published: May 2022

Ionic polymer-metal composites (IPMCs) are soft, electroactive materials with unique actuation properties that have attracted the interest of physicists, chemists, and engineers for over two decades. Despite significant progress in our understanding of the phenomenology of their actuation, we are yet to fully elucidate the physics at the nanoscale that underlies their macroscopic actuation. Previous experiments have shown that IPMC actuation depends on the type of counterions that is used to neutralize the acidic polymeric backbone. Some continuum theories have attempted to explain such a modulatory effect, but a complete understanding of the physics at the nanoscale level is lacking. Here, we employ classical molecular dynamics to fill this gap in knowledge. Building upon recent developments in the field, we investigate the response of three IPMC membranes with different metallic counterions that have been considered in earlier experimental research. While we do not detect variations in the axial stress, the examination of the spatial distribution of the through-the-thickness stress components in the three membranes reveals important differences. We show that these differences are well explained in terms of variations in water content as it relates to the type of counterions, challenging existing continuum models of IPMCs that mostly overlooked these factors. Overall, our work brings to light new physics within active materials, inspiring new efforts in material design and engineering, as well as multiscale modeling of soft matter.
C1 THE ROLE OF ATRIAL ELECTRO–MECHANICAL COUPLING AS PREDICTOR OF CATHETER ABLATION EFFICIENCY
Authors: Barletta V , Spatafora D , Gentile F , Parollo M , Mazzocchetti L , Zucchelli G , Bongiorni M
Published: May 2022

Background

Atrial fibrillation (AF) results in electrical and structural remodeling of the atria, and the extent of remodeling has already been found to be associated with higher AF recurrence rate after catheter ablation (CA). Recently, a novel echocardiographic parameter derived from tissue Doppler imaging (TDI), called PA–TDI, has been introduced to assess the total atrial activation time, as a non–invasive surrogate of fibrosis and atrial cardiomyopathy. The aim of the study was to investigate the role of PA–TDI interval as predictor of AF ablation efficacy.

Methods

Consecutive patients with persistent or paroxysmal symptomatic AF referred to our Center to perform radiofrequency ablation or cryoablation procedures were prospectively enrolled. In these patients, a complete transthoracic echocardiographic examination was performed before and after the ablation procedure, including assessment of the PA–TDI interval.

Results

From October 2018 to May 2020, 221 consecutive patients (mean age 61 ± 9 years, 74% male, mean BMI 26.5 ± 3.6, mean Ejection Fraction 61 ± 6%) symptomatic for AF, undergoing the procedure ablation (first procedure or re–do) were enrolled. Out of the blanking period, 25% of patients experienced recurrence of arrhythmia during follow–up (mean 16 months). Compared to patients who did not relapse, patients with AF recurrence have a generally longer post–procedural PA–TDI interval (139.6 ± 22.1 msec vs 153.9 ± 33 msec, respectively). In the multivariable analysis only post–procedure PA–TDI and re–do interventions were found to be independent predictors of AF recurrence. A PA–TDI cut–off> 144msec identifies patients at risk of post ablation AF recurrence with sensitivity 58.7% and specificity 73.5% (AUC 0.697).

Conclusions

The PA–TDI interval is an independent predictor of AF recurrence after catheter ablation. This echocardiographic parameter is easily obtainable, low–cost, reproducible, and accessible even in peripheral centers.
C6 IN VIVO CHIARI NETWORK REMOVAL. COMPLICATION OR INNOCENT SURPRISE
Authors: Lupo A , Bacchiega E , Zerbo F , Sacca‘ S
Published: May 2022

A 78 years old man was admitted to our hospital because of a syncope and evidence of complete AV– block, low ventricular rate and suitable for definitive PM implantation. He had no other pathologies or previous surgical interventions. A transthoracic echocardiography was performed and any particular structural anomaly was detected and the left ventricular ejection fraction was normal. In the electrophysiology laboratory, a vascular access through the left axillary vein was used to insert a passive fixation catheter for the right ventricular using a 9 F sheath. When the ventricular lead reached the right atrium it was impossible to advance it farther into the right ventricle; the lead was blocked near tricuspid anulus without any possibility to move it towards any direction despite many and vigorous manual traction maneuvers were attempted. Immediately, a transesophageal echocardiography was performed and it showed the lead entrapment into a mobile structure, likely a Chiari network.The patient needed a PM implantation as soon as possible and also a temporary PM could further complicate the procedure. Since the hospital did not have a cardiac surgery department and our crew was not familiar with lead extractions, an expert hemodynamist, who suggested to remove the lead by using a snare, was consulted. The tip of the lead was stuck in the atrial wall so it was impossible to capture it as expected. So, from right femoral vein access, a 6F pig–tail catheter was inserted through a a 45 cm– 8 F Terumo Destination sheath in order to give more stability to the pig–tail catheter until it hooked the lead. A 0.035 mm normal hydrophilic Terumo wire was later passed into the pig–tail catheter, snared and externalized with an AndraSnare 25 catheter inserted through another 6F introducer. A vigorous traction was performed simultaneously pulling both the ends of the wire from the bottom and the lead from the top. After a few seconds, the lead was unstuck and removed from the axillary vein [Fig. 1a,b]. At the external examination, the tines of the lead were found attached to a net–like structure that was actually the Chiari network that had been completely removed from the atrium [Fig 2–3]. A transthoracic echocardiogram ruled out any pericardial effusion. The anatomical finding was sent to tissue analysis and was confirmed to be the tendon material. After that the patient was immediately implanted with a VDD PM without any complications, and dismissed after 2 days.
C12 MANAGING CARDIAC ARREST SECONDARY TO SPONTANEOUS CORONARY ARTERY DISSECTION: SHOULD WE ROUTINELY CONSIDER ICD IMPLANTATION? INSIGHTS FROM PARMA SCAD REGISTRY
Authors: Giacalone R , Toselli M , Pelà G , Cattabiani M , Vezzani A , Benatti G , Tadonio I , Ferretti M , Gurgoglione F , Noni M , Niccoli G , Ardissino D , Vignali L , Solinas E
Published: May 2022

Background

Cardiac arrest secondary to a spontaneous coronary artery dissection (SCAD) represents a challenging scenario. It deserves specific considerations due to the dramatic presentation and the need for secondary sudden cardiac death prevention.

Methods

We collected clinical data of four women admitted during the last two years in the Coronary Care Unit of Parma University Hospital, whose presentation of SCAD were cardiac arrest due to ventricular fibrillation (Table1).

Results

Three patients survived the acute phases. One patient, being considered at high risk of SCAD recurrence, received a subcutaneous implantable cardioverter–defibrillator (S–ICD). Acute management of cardiac arrest related to SCAD deserves specific considerations. Our case series illustrates the importance of prompt resuscitation manoeuvres and early defibrillation. We propose a flow chart of management of cardiac arrest in patient with suspect of SCAD (Figure 2 A). Evaluating risk of SCAD recurrence and sudden cardiac death. The management of SCAD patients complicated by malignant ventricular arrhythmias and cardiac arrest is challenging. Looking at published registries, it appears that SCAD patients are more likely to suffer from ventricular arrythmia or sudden cardiac death than non–SCAD MI patients. The risk–benefit ratio of ICD implantation in these patients remain uncertain . Evaluation of scar burden with CMR can help stratify the global arrhythmic risk, especially as extensive myocardial scar with a residual impaired LVEF increases the risk of future arrhythmic events (Figure 2 B). In our series, only one patient underwent S–ICD implantation, and the decision was mainly driven by the finding of underlying arteriopathy affecting other vascular territories, suggesting a potentially higher rate of SCAD recurrence. For this particular subset of patients, we propose an algorithm that combines predisposing factors and myocardial injury quantification data (Figure 2 B) that could be useful for the estimate of the risk of malignant arrythmias, as well as the risk of recurrence of SCAD, but needs to be validated in larger case studies.

Conclusions

The acute management of cardiac arrest related to SCAD deserves specific consideration. The residual myocardial damage, predisposing and precipitants factors should be evaluated in order to estimate the SCAD recurrence and sudden cardiac death risks.
C16 PROPENSITY SCORE COMPARISON OF ELASTIN–BASED AND COLLAGEN–BASED MECHANICAL PROPERTIES OF AORTIC WALL IN BICUSPID VS TRICUSPID AORTIC VALVE PATIENTS UNDERGOING AORTIC SURGERY
Authors: Totaro P , Scocozza F , Morganti S , Auricchio F , Pelenghi S
Published: May 2022

Objective

Several studies addressed characteristics of aortic wall in patients with bicuspid aortic valve (BAV) compared to those with tricuspid aortic valve (TAV). Different patients population and lack of randomization were the main limitations in many of such studies, focused furthermore, only on ultimate properties (at rupture). In this study we compared mechanical properties in BAV and TAV patients undergoing aortic surgery using propensity score analysis to obtain two homogeneous groups of patients. We also focused on both elastin–based and collagen–based mechanical properties.

Methods

Among 87 overall patients undergoing surgery of ascending aorta, 26 were selected, following propensity score analysis, and divided in 2 groups according the type of native aortic valve (13 BAV and 13 TAV). Mechanical tests were completed following circumferential and longitudinal force application. 137 cumulative tests were accepted (93 from anterior aortic wall). Aortic wall strain (marker of elasticity) and aortic wall stress (marker of strength) were measured either in the Elastin–based (initial) distension and in the Collagen–based ultimate distension (until rupture).

Results

Cumulative comparison of specimens thickness confirmed that anterior aortic wall is thinner in BAV patients. Aortic wall thickness, however was not correlated to any of mechanical tests in Elastin–based or Collagen–based distensions. Aortic wall elasticity and strength (applying either longitudinal and circumferential force) were not different in BAV compared to TAV patients. Initial and ultimate elasticity were significantly correlated either applying circumferential and longitudinal force. Direct correlation between initial and ultimate strength, on other hands, was showed only in BAV patients when a longitudinal force was applied.

Conclusions

We clearly showed that, in dilated aorta, anterior wall is thinner in case of BAV compared to TAV. Our study, furthermore, confirms that mechanical properties of aortic wall in BAV patients are no impaired, compared to an homogeneous group of TAV patients, neither in initial or ultimate tests. Elastin–based and collagen–based aortic wall mechanical properties (under circumferential force) are directly correlated regardless BAV presence. Lack of correlation between initial and ultimate strenght in TAV patients, under a longitudinal force, needs further evaluation as it could be related to an increased frailty of aortic wall in such conditions.
C20 IMPACT OF TELEMEDICINE SERVICES DURING THE COVID–19 PANDEMIC
Authors: Nodari S , Fioretti F , Glisenti F , Bollani G , Gabbrielli F
Published: May 2022

During the Italian national lockdown (11/3 to 4/5/2020), the COVID–19 epidemic caused a shift of hospital resources towards the management of the COVID+ patient; hospitals saw a progressive drop of admissions for acute myocardial infarction and arrhythmias. In order to verify the role of Telemedicine in this context, we compared 6104 ECGs recorded by 5000 pharmacies, with the 17280 ECGs of the same period of 2019, evaluated and stored in the telemedicine platform of Health Telematic Network (HTN), in collaboration with the Department of Cardiology of the University of Brescia, Federfarma and Istituto Superiore di Sanità. Chest pain was the reason for examination in 298 patients (4.88%) vs 402 (2.33%) in 2019 (+109.86%). Of these, 118 were in Lombardy, (39.50% of the total), 36 in the province of Brescia (30.50%) and 28 in the province of Bergamo (23.73%). 8 ECGs showed a STEMI picture, (2.68%), compared with 7 STEMIs (1.74%) detected in 2019 (+ 54.17%). All of these patients were referred urgently to the emergency department. We detected Atrial Fibrillation in 344 patients (5.64%), vs 393 (2.27%) in 2019, (+ 40.25%); 32 cases of Atrial Flutter (0.52%), vs 25 (0.14%) detected in 2019 (+ 26.92%). Finally, we found paroxysmal supraventricular tachycardia in 8 cases (0.13%), vs 6 cases (0.03%) detected in 2019(+ 23.07%). During the lockdown period, 384 patients (6.29%) were referred to the emergency department for symptomatic tachyarrhythmia, vs 424 patients (3.47%) in 2019(+ 55.16%). In Lombardy, 194 cases of tachyarrhythmia were reported in territorial pharmacies (about 50.52% of the total in Italy), 93 in the Brescia area (47.94%), 50 in the Bergamo area (25.77%). Conclusions: a high number of patients with cardiovascular symptoms preferred to refer to territorial pharmacies during the COVID–19 blast. Telemedicine allowed patients with STEMI to access hospitals quickly, avoiding a serious diagnostic delay; a significant proportion of accesses to local pharmacies for chest pain occurred in the region most affected by the COVID–19 outbreak; the service also allowed to refer to the hospital only patients with clinically relevant tachyarrhythmias, avoiding delay of care and inappropriate accesses. This underlines how the telemedicine network provided by pharmacies can become an important resoruce for the citizen, supporting the services of the Italian National Health System.
C25 PREDICTION OF ALL–CAUSE MORTALITY FOLLOWING PERCUTANEOUS CORONARY INTERVENTION IN BIFURCATION LESIONS USING MACHINE LEARNING ALGORITHMS – THE RAIN–ML PREDICTION MODEL
Authors: Gallone G , Burrello J , Burrello A , Iannaccone M , De Luca L , Patti G , Cerrato E , Venuti G , De Filippo O , Mattesini A , Muscoli S , Trabattoni D , Giammaria M , Truffa A , Cortese B , Conrotto F , Mulatero P , Monticone S , Escaned J , Usmiani T , D‘ascenzo F , De Ferrari G , Breviario S
Published: May 2022

Aims

Stratifying prognosis following coronary bifurcation percutaneous coronary intervention (PCI) is an unmet need. Machine learning (ML) may identify patterns from multidimensional, non–linear relationships to make outcome predictions. We sought to develop a ML–based risk stratification model built on clinical, anatomical and procedural features to predict all–cause mortality following contemporary bifurcation PCI.

Methods and Results

Multiple ML models to predict all–cause mortality were tested on a cohort of 2,393 patients (training, n = 1,795; internal validation, n = 598) undergoing bifurcation PCI with contemporary stents from the real–world RAIN (veRy thin stents for patients with left mAIn or bifurcatioN in real life) registry. Among 38 commonly available features, 25 (13 patient–related, 12 lesion–related) were selected to train ML models. The best performing model (the RAIN–ML prediction model) was validated in an external validation cohort of 1,701 patients undergoing bifurcation PCI from the DUTCH PEERS (DUrable polymer–based sTent CHallenge of Promus ElemEnt versus ReSolute integrity: TWENTE II) trial and the BIO–RESORT trial cohorts. The area under the receiver operating characteristic curves for the prediction of 2–year mortality was 0.786 (0.74–0.83) in the overall population, 0.736 (0.72–0.847) at internal validation and 0.706 (0.6919–0.794) at external validation. Performance at risk ranking analysis, k–center cross validation, and with continual learning confirmed the generalizability of the models, available also as an online interface.

Conclusions

The RAIN–ML prediction model represents the first tool combining clinical, anatomical and procedural features to predict all–cause mortality among patients undergoing contemporary bifurcation PCI with a good discriminative performance.
C26 COMPLETE REVASCULARISATION IMPROVES SURVIVAL OF PATIENTS RESUSCITATED AFTER AN OUT–OF–HOSPITAL CARDIAC ARREST
Authors: Kajana V , Primi R , Gentile F , Compagnoni S , Baldi E , Mandurino Mirizzi A , Repetto A , Ferrario M , Ferlini M , Marinoni B , Bendotti S , Currao A , Oltrona Visconti L , Savastano S
Published: May 2022

Background

Sudden cardiac death is a major issue in industrialised countries and survival of patients after out–of–hospital cardiac arrest (OHCA) remains low. Acute myocardial infarction (AMI) is the principal cause of OHCA and myocardial revascularisation plays a positive role on survival. In this setting little is known about the role of complete (CR) versus culprit–only revascularisation (IR) on survival.

Purpose

The aim of this study was to assess whether CR could lead to a better one–year survival as compared to IR. Methods. Among patients prospectively enrolled in the Lombardia CARe OHCA registry from January 1 2015 to May 1 2021, who underwent a coronary angiography (CAG) at the Fondazione IRCCS Policlinico San Matteo were enrolled in this study. CAGs were retrospectively reviewed by two interventional cardiologists. Prehospital and survival data were retrieved from the registry.

Results

We enrolled 239 patients [mean age 63.7±12.4 years; male 79.9%; shockable presenting rhythm 84.1%; AMI at post ROSC ECG 67.9%; ejection fraction 37% (30–45), circulatory support with ECMO 10.9%]. Among the 119 (50%) patients with multi–vessel disease, 82 (69%) received IR whereas 37 (31%) received CR [8 during the first procedure, 29 in a second procedure with a median time after OHCA of 5 (2.5–10) days]. This latter group showed significantly higher one–year survival (54.9% vs 16.2%, p < 0.001). At univariable logistic regression only a shockable presenting rhythm and the presence of chronic total occlusion (CTO) were significantly associated with the probability of receiving a CR [OR 5.1 (95%CI 1.1–22), p = 0.03; OR 0.37 (95%CI 0.16–0.85), p = 0.02 respectively]. However, at multivariable regression analysis only CTO was significantly associated with the probability of receiving a CR [OR 0.36 (95%CI 0.15–0.9), p = 0.007]. At Cox multivariable regression model cardiac arrest duration (longer that the median value of 24 min) and CR were independently associated with the probability of death [HR 3.6 (95%CI 1.9–6.9), p < 0.001; HR 0.2 (95%CI 0.1–0.9), p = 0.02]. Similarly, cardiac arrest duration, CR and a shockable presenting rhythm were associated with the probability of death or poor neurologic outcome [HR 3.3 (95%CI 1.8–6), p < 0.001; HR 0.5 (95%CI 0.3–0.9), p = 0.03 and HR 0.2 (95%CI 0.1–0.5), p < 0.001].

Conclusions

Complete revascularisation is independently associated with a better one–year survival in patients resuscitated from an out–of–hospital cardiac arrest.
C28 THE FINANCIAL BURDEN OF NEWER GENERATION TAVI DEVICES: RESULTS FROM THE ITALIAN OBSERVANT STUDIES
Authors: D‘Errigo P , Marcellusi A , Barbanti M , Biancari F , Tarantini G , Baglio G , Tamburino C , Rosato S , Seccareccia F
Published: May 2022

Objectives

To estimate the financial burden of using newer generation transcatheter aortic valve implantation (TAVI) devices compared with older generation devices.

Background

TAVI is becoming the standard treatment for severe aortic stenosis in symptomatic elderly patients and is increasingly offered also to younger and lower risk patients. Resource utilization in performing TAVI has become an important focus due to the high likelihood of hospital readmissions, but it is unclear whether readmissions after TAVI contribute to a significant proportion of overall costs of TAVI to the healthcare system at mid–term follow up.

Methods

A probabilistic Markov model was developed in order to estimate the cost consequence of introducing newer generation TAVI devices were calculated as the absolute deterministic difference between a cohort of 6,000 patients treated with the newer TAVI devices (TAVI–new scenario) and the same cohort treated with old TAVI devices (TAVI–old scenario). Transition probability and hospitalization costs were retrieved among patients enrolled in the OBSERVANT I and OBSERVANT II studies; 1898 patients treated with older generation TAVI devices and 1417 patients treated with new generation TAVI devices were compared. Outcomes were adjusted using propensity score matching.

Results

Propensity score matching resulted in 853 pairs, whose baseline risk factors were well balanced. The mean EuroSCORE II (6.6 vs. 6.8; p = 0.76) and the mean age (82.0 vs 82.1; p = 0.62) of older generation TAVI patients and newer generation TAVI patients were similar. The use of newer generation TAVI devices determined a significant reduction of re–hospitalizations (–30.5% re–intervention, –25.2% major re–hospitalization and –30.8% minor re–hospitalization) and mortality (–20%). These reductions were associated with significant cost savings over a 1–year period (−€4.1 million in terms of direct costs and −€19.7 million considering the additional cost of the devices). The main cost–reduction was estimated for re–hospitalization that cover 79% of the overall cost reduction in the economic analysis without the costs of the devices.

Conclusions

After adjusting for baseline characteristics, patients undergoing TAVI with newer generation devices had lower risk of all–cause death and re–hospitalization. These reductions are leading to significant cost savings at 1 year, mainly due to the reduction in re–hospitalization costs.