bluuebunny/crossref_metadata_2025 huggingface dataset:
Research on space microwave energy reception technology based on electromagnetic-thermal-DC conversion
Authors: Qiu Zhuoyue , Wang Xinfa , Qin Zihao , Wang Xiaoshun , Fang Jinyong
Published: December 2021

A new microwave energy reception method is proposed for the wireless energy transmission needs of lunar rovers combined with the lunar environment, i.e. collecting thermal energy through microwave absorbing materials, and then converting thermal energy into direct current by using temperature difference power generation devices. The article analyses the two conversion processes, microwave-thermal and thermal-DC, separately. Under the approximate condition that the temperature at both ends of the absorbing material is regarded as equal, the two conversion processes are linked by energy conservation, which theoretically leads to the temperature and total efficiency of the system at steady state. The temperature and total efficiency of the system are initially obtained by numerical simulation with respect to the thickness of the absorbing material, the receiving area and the input power density by selecting the parameters of the carbon and iron composite material at 10 GHz. The results show that there is an optimum thickness of absorbing material for a certain input power density and receiving area, which results in the highest system efficiency. The larger the receiving area and input power density in a certain range, the higher the efficiency, but beyond a certain range the system efficiency shows a decreasing trend. Also the theory and the actual will produce a large deviation when temperature is high. The article concludes that this energy receiving method has great potential for application in the space environment based on the excellent wave absorbing materials and thermoelectric components but further research is needed.
Effect of laser deweighting on properties of ZL205A aluminum alloy
Authors: Li Guang , Wei Zhipeng , Wang Junlong , Zhang Yangyang , Wang Chen , Wu Xinping , Wang Xiaohua
Published: December 2021

In this paper, a nanosecond fiber pulse laser is used to carry out the experimental study on laser weight removal of ZL205A aluminum alloy gyro rotor. By optimizing the process parameters of laser weight removal, better surface morphology was obtained. The effects of surface roughness, metallographic structure and hardness of samples before and after laser deweighting were analyzed. The experimental results show that the laser weight removal does not affect the matrix properties of ZL205A aluminum alloy. The laser de-weight technology is suitable for the balance of ZL205A aluminum alloy gyro rotor.
Development of spring torsion bar type negative stiffness damping device and applied research
Authors: Song XinKe , Chen DeMin , Long QingMing , Qu BaoHua
Published: December 2021

Mini-tiller is the most commonly used machine for agricultural production in hilly areas of our country the traditional micro-tiller will produce strong vibration during the working process, which will cause physical injury to the operator while reducing the reliability of the micro-tiller. In response to this problem, a technical solution for arranging a spring torsion bar type negative stiffness vibration damping device on the tiller was proposed, and a spring torsion bar type vibration damping device with stable mechanical performance, economical and practical, and negative stiffness characteristics was developed. A mathematical model of the vibration source of the micro-tiller was established to analyze the vibration parameters of the micro-tiller. On this basis, SolidWorks is used to carry out three-dimensional modeling of the tiller and the vibration reduction device, and Adams is used for vibration simulation analysis. The vibration parameter curve before and after the addition of the vibration reduction device at the handle of the tiller is collected and mathematically analyzed. The results show that the spring torsion bar type negative stiffness damping device has a good damping effect, and the damping rate for displacement in the x, y, and z directions are all above 30%.
Research on Path Planning Algorithm of Bidirectional Rapidly Exploring Random Tree Improved by Artificial Potential Field
Authors: Xu Jinli , Xiao Haoran , Huang Fengyun
Published: December 2021

Aiming at the defects of path planning in rapidly exploring random tree(RRT) algorithm, such as low efficiency, strong randomness and slow convergence rate, a new algorithm based on artificial potential field was proposed in this paper. The algorithm used the scheme of bidirectional growth of exploration tree to make two growth trees explore and expand outwards from the starting point and the end point at the same time to accelerate the convergence speed of the algorithm. In the early stage, growth pretreatment was added to make the two growing trees take their respective endpoints as the target points and pass through the obstacle free area rapidly at one time. Artificial potential field method was used to modify the growth tree touching the obstacle and guide the path to grow towards the end. The adaptive change probability was used to select different target points as the growth directions in different periods with different probabilities to accelerate the meeting of two growing trees. After a lot of simulation experiments and data analysis, the improved bidirectional RRT algorithm has higher search efficiency, better growth path and fewer sampling points.
Fusing image feature and title semantic regularization with adversarial networks for cross-modal retrieval
Authors: Zhou Kai
Published: December 2021

With the improvement of living standard, people pay more and more attention to their health. Food is the foundation of human life, modern society places more emphasis on a balanced diet, which controls fat, protein, carbohydrate and vitamin intake. So food computing is more and more important. Food retrieval is one of the important research directions in food computing. On the basis of food retrieval, we can predict ingredients and instructions in each dish, according to the ingredients and instructions to speculate on the visual effect of cooking, which can guide human reasonable diet, analyse human diet structure and diet culture and so on. In this paper, we focus on cross-modal retrieval between food image and recipe. Firstly, we analyze the problems existing in the present method. Based on the problems existing in the existing method, a fusion image feature and title regularization with adversarial network is proposed, which uses the idea of generative adversarial to align the modes, fuses the local features and global features of the image, and adds the semantic regularity of title to improve the accuracy of the retrieval.
Core looseness fault identification model based on Mel spectrogram-CNN
Authors: He Ping , Li Yong , Chen Shoulong , Xu Hoghua , Zhu Lei , Wang Lingyan
Published: December 2021

In order to realize transformer voiceprint recognition, a transformer voiceprint recognition model based on Mel spectrum convolution neural network is proposed. Firstly, the transformer core looseness fault is simulated by setting different preloads, and the sound signals under different preloads are collected; Secondly, the sound signal is converted into a spectrogram that can be trained by convolutional neural network, and then the dimension is reduced by Mel filter bank to draw Mel spectrogram, which can generate spectrogram data sets under different preloads in batch; Finally, the data set is introduced into convolutional neural network for training, and the transformer voiceprint fault recognition model is obtained. The results show that the training accuracy of the proposed Mel spectrum convolution neural network transformer identification model is 99.91%, which can well identify the core loosening faults.
Cutting Process Model Design of Cutter Suction Dredger Based on Auto Regressive eXogenous and Radial Basis Function model
Authors: Zhang Huan , Yu Menghong , Yuan Wei
Published: December 2021

The dredging operation of the strander dredger is complex, and the mathematical model established according to its key equipment characteristics is not possible to describe such a system having time degeneration and non-linear. Therefore, based on the analysis of mud formation process of dredger, RBF-ARX model is used to model the cutting process, and mud concentration is taken as the output. This modeling method is a combination model based on the theory of Auto-Regressive eXogenous (ARX) model and Gauss radial basis function (Radial Basis Function) neural network (RBF). The comparison between the simulation results and the actual data shows that the model can accurately describe the dynamic characteristics of cutter suction dredger in the cutting process.
Tolerance analysis and optimization based on 3DCS
Authors: Gao Yuan
Published: December 2021

At present, with the increasing requirements of major enterprises on assembly accuracy, the problem of interference and excessive clearance between parts needs to be solved. In order to analyze and optimize the tolerances in the actual assembly of the parts, a three-dimensional vector ring model is proposed on the basis of the dimensional chain model, and the tolerance distribution is optimized by the “dichotomy method”. With the help of 3DCS, the virtual assembly of the automobile headlight is carried out, and the sensitivity analysis is carried out by establishing the measurement of the gap between the turn signal and headlight in the automobile headlight, and the simulation results are used to obtain a reasonable improvement in tolerance allocation that meets the design criteria and saves costs. The results are compared with the traditional method of optimizing the allocation of equal tolerances and are clearly superior, providing a method for optimizing the allocation of tolerances to parts in engineering practice.
Research on Density-Based K-means Clustering Algorithm
Authors: Liu Shuxin , Liu Xiangdong
Published: December 2021

Cluster analysis is an unsupervised learning process, and its most classic algorithm K-means has the advantages of simple principle and easy implementation. In view of the K-means algorithm’s shortcoming, where is arbitrary processing of clusters k value, initial cluster center and outlier points. This paper discusses the improvement of traditional K-means algorithm and puts forward an improved algorithm with density clustering algorithm. First, it describes the basic principles and process of the K-means algorithm and the DBSCAN algorithm. Then summarizes improvement methods with the three aspects and their advantages and disadvantages, at the same time proposes a new density-based K-means improved algorithm. Finally, it prospects the development direction and trend of the density-based K-means clustering algorithm.
Dairy productivity of Kazakh horse mares
Authors: Baimukanov D A , Semenov V G , Aubakirov Kh A , Zh Iskhan K , Kargayeva M T , Baimukanov A D
Published: December 2021

The work aimed to establish the influence of udder parameters of Kazakh mares on their formation of dairy productivity and the growth rate of foals during the milk period. The cup-shaped udder is characterized by a large base (the udder circumference at the base is 70.3 cm), the symmetrical arrangement of both udder lobes, with well-developed cylindrical nipples, the nipples are widely spaced between the two lobes. The round shaped udder is instead characterized by conical and short nipples and a smaller udder volume. For four months of lactation, 1051 liters of commercial milk were produced from mares with cup-shaped udder, while 823.6 liters- with round-shaped udder.The observation results showed that foals from mares with the cup-shaped and round - shapedudders on the first day of life were 39.8 and 39.6 kg of live weight, respectively, then after a month, it doubles, reaching 82.5 and 79.5 kg. The highest indicators of absolute gain - 42.7 kg, average daily gain - 1.42 kg, and relative gain -107.3% were observed in offspring with a cup-shaped udder. In foals delivered from mares with a round-shaped udder, the gain rates (39.9; 1.33 kg and 100.7%, respectively) were slightly lower.
Peculiarities of the logistic approach in the agro-industrial complex
Authors: Gordeeva L G , Filippova S P , Gordeev A A , Abrosimova M S , Litvinova O V , Talanova N V , Nesterova N V , Semenova A N
Published: December 2021

Effective sale of products is one of the main directions of increasing the financial stability of enterprises in the agro-industrial complex. The use of a logistic approach implies a change in the existing situation at the enterprises of the agro-industrial complex, the introduction of new technologies in order to reduce the costs of commodity movement, and the coordination of interaction between participants in the logistics system. It is necessary to take into account the specifics of the food market more fully, consider the logistics system in conditions when a large number of economically independent market entities enter the market. The paper examines theoretical approaches to studying the problem of using the logistic approach in the agro-industrial complex and reveals the basic nodes of the agro-logistics system. Peculiarities of using logistics in the agro-industrial complex are described, basic logistic flows and processes in the given branch are reviewed. Types of distribution of products in the agro-industrial complex are analyzed. Influence of use of logistic methods of management generally and of stocks in particular on production and financial activity of enterprises in the given sphere is estimated.
Numerical investigation on sealing performance of non-contact finger seal with herringbone groove surface topography
Authors: Chen Lingping , Zhang Yanchao , Cui Yahui , Zhi Bowen , Wang Jie , Wang Mingfeng
Published: December 2021

Since the last decade, the non-contact finger seal (NCFS) has attracted an increasing number of researchers due to its inherent flexibility and non-contact features, which can significantly improve the service life and reduce the leakage rate of the finger seals. In this paper, to enhance the NCFS sealing performance, lifting pads with twenty (20) different herringbone groove surface topographies are proposed based on the uniform design method. Numerical analysis is carried out based on the two-way fluid-structure interaction (FSI) method to better mimic the actual working conditions. The analysis of results using statistical tools reveals that the herringbone groove topographies placed on the bottom surface of low-pressure lifting pads can significantly improve the load-carrying capacity and sealing performance. In addition, the correlation analysis of the sealing performance and geometric parameters of the herringbone groove demonstrate that reducing the groove width or increasing the groove internal angle can improve the lifting and leakage capacities. Finally, the optimal herringbone groove and general structure (no groove) are comparatively analysed under variable working conditions, and the results show that the former has much better sealing performance.
Odoni’s conjecture on arboreal Galois representations is false
Authors: Dittmann Philip , Kadets Borys
Published: December 2021

Suppose

f
∈
K
[
x
]

f \in K[x]

is a polynomial. The absolute Galois group of

K
K

acts on the preimage tree

T

\mathrm {T}

of

0
0

under

f
f

. The resulting homomorphism

ϕ
f

:

Gal
K

→
Aut
⁡

T

\phi _f\colon \operatorname {Gal}_K \to \operatorname {Aut} \mathrm {T}

is called the arboreal Galois representation. Odoni conjectured that for all Hilbertian fields

K
K

there exists a polynomial

f
f

for which

ϕ
f

\phi _f

is surjective. We show that this conjecture is false.
Symmetric rigidity for circle endomorphisms having bounded geometry
Authors: Adamski John , Hu Yunchun , Jiang Yunping , Wang Zhe
Published: December 2021

Let

f
f

and

g
g

be two circle endomorphisms of degree

d
≥
2

d\geq 2

such that each has bounded geometry, preserves the Lebesgue measure, and fixes

1
1

. Let

h
h

fixing

1
1

be the topological conjugacy from

f
f

to

g
g

. That is,

h
∘
f
=
g
∘
h

h\circ f=g\circ h

. We prove that

h
h

is a symmetric circle homeomorphism if and only if

h
=
I
d

h=Id

.
Semicontinuity of automorphism groups in one complex variable
Authors: Krantz Steven
Published: December 2021

We prove a version of the Greene-Krantz theorem on semicontinuity of automorphism groups in the context of one complex variable with minimal boundary smoothness.
A geometric Jacquet-Langlands transfer for automorphic forms of higher weights
Authors: Yu Jize
Published: December 2021

In this paper, we give a geometric construction of the Jacquet-Langlands transfer for automorphic forms of higher weights. Our method is by studying the geometry of the mod

p
p

fibres of Hodge type Shimura varieties which satisfy a mild assumption and the cohomological correspondences between them.
A Potassium-Based Quality-of-Service Metric Reduces Phlebotomy Errors, Resulting in Improved Patient Safety and Decreased Cost
Authors: Lucas Fabienne , Mata Douglas A , Greenblatt Matthew B , Means Janet , Jarolim Petr
Published: December 2021

Objectives

Poor phlebotomy technique can introduce pseudohyperkalemia without hemolysis, requiring additional workup and placing a significant burden on patients, clinical teams, and laboratories. Such preanalytical biases can be detected through systematic evaluation of potassium concentrations on a per-phlebotomist basis. We report our long-term experience with a potassium-based quality-of-service phlebotomy metric and its effects on resource utilization.

Methods

Potassium monitoring and retraining of 26 full-time phlebotomists were piloted as a quality-of-service intervention. Changes in potassium concentrations and impact on resource utilization were assessed. An algorithm for data monitoring and phlebotomist feedback was developed, followed by institution-wide implementation.

Results

Systematic intervention and retraining normalized K+ concentrations and lowered the percentage of venipunctures with K+ above 5.2 mmol/L, leading to a marked increase in phlebotomist compliance. This change resulted in resources savings of 13% to 100% for individual phlebotomists, reducing the total extra laboratory time required for repeat phlebotomies to determine hyperkalemia, mostly in the high-volume phlebotomist group.

Conclusions

A quality-of-service algorithm that involved monitoring potassium concentrations on a per-phlebotomist basis with feedback and retraining contributed to a concrete, data-based quality improvement plan. The institution-wide implementation of this metric allowed for significant cost savings and a reduction in critical value alerts, directly affecting the quality of patient care.
Comparative phylogeography among eight Neotropical wild cat species: no single evolutionary pattern
Authors: Ruiz-García Manuel , Pinedo-Castro Myreya , Shostell Joseph Mark
Published: December 2021

The felid species of South America are thought to have arrived on the continent during the Great American Biotic Interchange (GABI) in the Pleistocene. However, molecular and palaeontological data do not agree on how this event affected speciation in felids. Here, we determine both the number of colonization events and the period when felines first migrated from North America to South America. In addition, we evaluate whether similar evolutionary events could have affected the eight Neotropical cat species in their levels of genetic diversity, spatial genetic structure and demographic changes. We analysed four concatenated mitochondrial genes of the jaguar, ocelot, margay, tigrina, pampas cat, Andean cat, puma and jaguarundi. The samples were representative of a wide distribution of these species in Central and South America. Our analysis suggests either three or four colonization events from North America to South America over the past 3 Myr, followed by subsequent speciation events and the attainment of high or very high genetic diversity levels for seven of the species. No unique evolutionary process was detected for any of the current Neotropical cat species.
Primary hyperoxaluria type 1: time for prime time?
Authors: Bacchetta Justine , Wood Kyle D
Published: December 2021

Oxalate crystals in the kidney were first described in 1925. Since then, many major milestones have been reached in the understanding of genetic primary hyperoxaluria(s). Primary hyperoxaluria type 1 (PH1) is an autosomal recessive disease due to a mutation in the AGXT gene, which encodes the hepatic peroxisomal enzyme alanine-glyoxylate aminotransferase (AGT), inducing excess oxalate production and further kidney stones, nephrocalcinosis and chronic kidney disease (CKD). Symptoms and age at diagnosis of PH1 vary dramatically, from the most severe infantile forms leading to end-stage kidney disease (ESKD) during the first months of life to the less severe adult forms with moderate CKD and recurrent kidney stones. In 2020, the Food and Drug Administration (FDA) and European Medicines Agency (EMA) approved a therapy based on RNA interference (RNAi) that profoundly reduces endogenous oxalate synthesis and dramatically changes the treatment algorithm for patients with PH1. The aim of this supplement of Clinical Kidney Journal includes contemporary reviews of the pathophysiology and genetics, (conventional) medical therapeutic management, urological therapeutic management and novel therapies (including not only RNAi, but also other therapeutic perspectives). The specific opinions of both adult and paediatric nephrologists will be compared and the ethical issues, as well as challenges faced by physicians and patients in developing countries, will also be discussed. Despite all the accomplishments, there are still looming questions that require further investigation and discovery.
Acidic environments trigger intracellular H+-sensing FAK proteins to re-balance sarcolemmal acid–base transporters and auto-regulate cardiomyocyte pH
Authors: Wilson Abigail D , Richards Mark A , Curtis M Kate , Gunadasa-Rohling Mala , Monterisi Stefania , Loonat Aminah A , Miller Jack J , Ball Vicky , Lewis Andrew , Tyler Damian J , Moshnikova Anna , Andreev Oleg A , Reshetnyak Yana K , Carr Carolyn , Swietach Pawel
Published: December 2021

Aims

In cardiomyocytes, acute disturbances to intracellular pH (pHi) are promptly corrected by a system of finely tuned sarcolemmal acid–base transporters. However, these fluxes become thermodynamically re-balanced in acidic environments, which inadvertently causes their set-point pHi to fall outside the physiological range. It is unclear whether an adaptive mechanism exists to correct this thermodynamic challenge, and return pHi to normal.

Methods and results

Following left ventricle cryo-damage, a diffuse pattern of low extracellular pH (pHe) was detected by acid-sensing pHLIP. Despite this, pHi measured in the beating heart (13C NMR) was normal. Myocytes had adapted to their acidic environment by reducing Cl−/HCO3− exchange (CBE)-dependent acid-loading and increasing Na+/H+ exchange (NHE1)-dependent acid-extrusion, as measured by fluorescence (cSNARF1). The outcome of this adaptation on pHi is revealed as a cytoplasmic alkalinization when cells are superfused at physiological pHe. Conversely, mice given oral bicarbonate (to improve systemic buffering) had reduced myocardial NHE1 expression, consistent with a needs-dependent expression of pHi-regulatory transporters. The response to sustained acidity could be replicated in vitro using neonatal ventricular myocytes incubated at low pHe for 48 h. The adaptive increase in NHE1 and decrease in CBE activities was linked to Slc9a1 (NHE1) up-regulation and Slc4a2 (AE2) down-regulation. This response was triggered by intracellular H+ ions because it persisted in the absence of CO2/HCO3− and became ablated when acidic incubation media had lower chloride, a solution manoeuvre that reduces the extent of pHi-decrease. Pharmacological inhibition of FAK-family non-receptor kinases, previously characterized as pH-sensors, ablated this pHi autoregulation. In support of a pHi-sensing role, FAK protein Pyk2 (auto)phosphorylation was reduced within minutes of exposure to acidity, ahead of adaptive changes to pHi control.

Conclusions

Cardiomyocytes fine-tune the expression of pHi-regulators so that pHi is at least 7.0. This autoregulatory feedback mechanism defines physiological pHi and protects it during pHe vulnerabilities.
The US Context of the Restatement of the Law (Fourth): The Foreign Relations Law of the United States
Authors: Stephan Paul
Published: December 2021

This article describes the creation and development of the Restatement of the Law (Fourth): The Foreign Relations Law of the United States from the perspective of its coordinating reporter. The article first describes how the American Law Institute goes about creating restatements of the law, emphasizing aspects of the process that a European audience might find unfamiliar. It looks at aspects of the US legal system, especially the significant role of the judiciary as authors of law, and explains how this role shapes a document that has US judges as one of its significant audiences. It then discusses how conflict over the content of foreign relations law and the role of international law in US domestic law affects the Restatement and how the reporters seek to navigate these troubled waters. Finally, it explores the areas where the new Restatement (Fourth) parts company with its famous predecessor, the Restatement (Third), supervised by the late professor Louis Henkin. The article argues that the changes represent two things: a transformation of the world of foreign relations in the 35 years since the earlier work and a corresponding move towards modesty on the part of the professors who made this Restatement.
76 Right mini-thoracotomy surgical Cox-maze (left atrial lesion) vs. catheter ablation using contact force-sensing technology in patients with persistent atrial fibrillation
Authors: D'Ambrosio Gabriele , Raffa Santi , Romano Silvio , Alothman Obaida , Borisov Georgi , Karam Issa , Thomas Kuntze , Geller J. Christoph
Published: December 2021

Aims

Pulmonary vein isolation (PVI) often is not sufficient in patients (pts) with persistent atrial fibrillation (AF). Substrate modification (SM) by catheter ablation (CA) of low-voltage zones (LVZ) has yielded favourable results, but those studies were performed before the introduction of contact force (CF) sensing technology. Surgical ablation (SA) studies support the hypothesis that empiric bi-atrial linear ablation (Cox Maze IV procedure) is able to improve success, but there is less data on outcome of patients undergoing left atrial (LA) linear lesions alone. In current guidelines, both CA and SA have Class IIa indication in pts with persistent AF. In this single-centre retrospective study, we analysed the long-term outcomes of CA and SA in pts with persistent AF.

Methods and results

In the CA group (Figure 1), pts underwent PVI and additional SM in the presence of LVZ (roof line and supero-septal line) using TactiCath™ or SmartTouch™ ablation catheters aiming at contact values ≥10 g < 20 g and FTI >400 g/s. Ablation was performed in a temperature-controlled fashion with energy of 30 W except at the posterior wall (20–25 W). In the SA group (Figure 2), pts underwent ablation procedure (creation of a pure LA endocardial lesion set consistent with the Cox Maze IV) performed by a right mini-thoracotomy approach using the Atricure™ cryoablation probe, a left atrial appendage (LAA) epicardial exclusion using the Atriclip™ system, and mitral valve repair in the presence of severe mitral valve regurgitation. No right atrial lesions were created. 196 pts were included. 120 pts underwent CA [median age: 65 (58–72) years, median LA volume index (LAVI): 66 (56–75) ml/m2], in pts with LVZs PVI + SM was performed [bidirectional block of lines in 100%]. 76 pts underwent SA [median age: 64 (58–74) years, median LAVI 90 (78–103) ml/m2], in 42 pts a mitral valve repair was performed. At 24 months (figure), 89% and 68% of pts were free of AF in the SA and CA group, respectively, mainly without antiarrhythmic drugs (92% SA group and 89% CA group).

Conclusions

In patients with persistent AF, SA performed by a right mini-thoracotomy approach with linear lesions limited to LA leads to excellent 2-year freedom from AF despite significantly larger LAVI compared with the CA group. LAA epicardial exclusion likely contributed to surgical efficacy by eliminating the LAA as trigger/driver.
655 The valuable interaction among cardiac surgeon and electrophysiologist for transvenous rotational mechanical lead extraction
Authors: Migliore Federico , Tarzia Vincenzo , Bernardo Dall’Aglio Pietro , Falzone Pasquale Valerio , Iliceto Sabino , Gerosa Gino
Published: December 2021

Aims

Recent studies have shown that evolution RL bidirectional rotational mechanical sheath (Cook Medical, USA) is an effective and safe technique for transvenous lead extraction (TLE). We reported our experience with the bidirectional rotational mechanical tools using a multidisciplinary approach highlighting the value of a joint cardiac surgeon and electrophysiologist collaboration.

Methods and results

The study population comprised 84 patients (77% male; mean age 65 ± 18 years) undergoing TLE. After multidisciplinary evaluation, a combined procedure was considered. The main indication for TLE was infection in 54 cases (64%).Overall, 152 leads were extracted with a mean implant duration of 94 ± 63 months (range: 6–421). Complete procedural success rate, clinical success rate, and lead removal with clinical success rate were 91.6% (77/84), 97.6% (82/84), and 98.6% (150/152), respectively. Eighteen combined procedures were performed in 12 patients (14%), such as ‘hybrid approach’ (n = 2) or TLE concomitant to: (i) transcatheter aspiration procedure for large vegetation (n = 8); (ii) left ventricular assistance device implantation as bridge to cardiac transplantation (n = 1); (iii) permanent pacing with epicardial leads (n = 6); and (iv) tricuspid valve replacement (n = 1).One major complication (1.2%) and 11 (13%) minor complications were encountered. No injury to the superior vena cava occurred and no procedure-related deaths were reported. During a mean time follow-up of 21 ± 18 months, 17 patients (20%) died. They were more often diabetics (P = 0.02), and they underwent TLE more often for infection (P = 0.004).

Conclusions

Our results support the finding that excellent outcomes can be achieved in performing TLE of chronically implanted leads by using the evolution RL bidirectional rotational mechanical sheath and a multidisciplinary team approach involving both electrophysiologist and cardiac surgeon as first line operators.
707 Transvenous radiofrequency ablation of epicardial posterior-septal accessory pathways in children with WPW syndrome: can technology and imaging innovations improve the outcome?
Authors: Pazzano Vincenzo , Tamborrino Pietro Paolo , Di Mambro Corrado , Silvetti Massimo Stefano , Drago Fabrizio
Published: December 2021

Aims

The aim of the study was to analyse our recent single-centre experience about epicardial posterior-septal accessory pathways transcatheter ablation in children and young patients using radiofrequency through the coronary sinus, in order to understand which mapping and ablation strategy is associated with higher success rate and safety.

Methods and results

We reviewed all the cases of ablation of overt accessory pathways (in Wolff–Parkinson–White syndrome) with epicardial posterior-septal localization performed in children or young patients at our institution in the last 5 years. Twenty-two paediatric patients (mean age: 13 ± 3 years) with epicardial posterior-septal accessory pathways (15 in coronary sinus and 7 in the Middle Cardiac Vein) underwent radiofrequency transcatheter ablation with CARTO 3TM. Acute success rate was 77%. No patient was lost to follow-up (mean time 14.4 ± 9 months). The recurrence rate was 18%. Two patients underwent a successful redo-procedure; the overall long-term success rate was 68%. NAVISTAR® catheter presented the highest acute success rate in the coronary sinus. NAVISTAR SMARTTOUCH® was the only catheter that did not present recurrences after the acute success and it was successfully used in two patients previously unsuccessfully treated with a NAVISTAR THERMOCOOL®. Integration with angio-CT of coronary sinus branches obtained with CARTOMERGE was associated with higher success rate in patients with a previous failed ablation attempt.

Conclusions

Epicardial posterior-septal accessory pathways can be successfully treated with transvenous radiofrequency ablation in more than half of the cases in children/young patients. Acute success rate does not seem to depend on catheters used but contact-force catheter seems to be useful in cases with recurrences. Image integration with cardiac-CT reconstruction of coronary sinus branches anatomy can be useful to better guide ablation in case of previously failed attempts.
258 Cancer incidence during follow-up in patients with new onset atrial fibrillation treated with DOACs and its impact on bleeding risk
Authors: Angeli Francesco , Bartoli Lorenzo , Fabrizio Michele , Armillotta Matteo , Sansonetti Angelo , Stefanizzi Andrea , Amicone Sara , Chiti Chiara , Magnani Ilenia , Bergamaschi Luca , Foà Alberto , Paolisso Pasquale , Galiè Nazzareno , Pizzi Carmine
Published: December 2021

Aims

Cancer is increasingly recognized as strictly related to atrial fibrillation (AF). In patients with AF, the relationship between cancer and cardioembolic or bleeding risk during oral anticoagulant therapy is unknown. To assess the bleeding and ischaemic burden of a baseline or newly diagnosed cancer in patients treated with direct oral anticoagulants (DOACs) for non-valvular AF (NVAF).

Methods and results

All consecutive patients treated with DOACs were enrolled among those with new-onset AF and indication for oral anticoagulant between January 2017 and March 2019. During follow-up, bleeding events, newly diagnosed primitive or metastatic malignancy and major cardiovascular events (MACEs) were evaluated. At baseline, CHA2DS2-VASc, HAS-BLED, ATRIA, and ORBIT scores were used to assess the haemorrhagic and ischaemic risk. Major bleedings (MBs) were defined according to the ISTH definition. Anaemia was defined as haemoglobin levels below 11 g/dl in women and 12 mg/dl in men. 1258 patients constituted the study population and followed for a mean time of 21.6 ± 9.5 months. Overall, 66 patients (5.2%) were affected by malignant neoplasia at baseline, whereas 59 (4.7%) were diagnosed with a malignancy during follow-up. Among baseline characteristics, anaemia was associated with cancer at enrolment (43.9% vs. 22.5%, P < 0.001) but not at follow-up (29.3% vs. 23.4%, P = 0.341). MACEs were not associated with cancer at baseline (5.3% vs. 5.2%, P = 1.0) and at follow-up (5% vs. 4.9%, P = 1.0). No association was observed between major ischaemic events and cancer at enrolment or follow-up (5.3% vs. 4.4%, P = 0.83 and 4.4% vs. 5%, P = 0.82). Despite no statistically significant differences in haemorrhagic risk at baseline, the overall bleeding events and MB were associated with newly diagnosed cancer (9.2% vs. 3.9%, P = 0.001 and 13.8% vs. 4.5%, P = 0.001, respectively) but not at baseline (5.2% vs. 5.5%, P = 0.82 and 9.2% vs. 5.2%, P = 0.162). At multivariate analysis adjusted for age, hypertension and renal function, anaemia, and a newly diagnosed cancer during follow-up remained independent predictor of MB [respectively, HR: 1.27, 95% CI: 1.52–1.06, P = 0.009 and HR: 3.53, 95% CI: 7.71–1.62, P = 0.001].

Conclusions

Bleeding risk assessment is an ongoing challenge in patients with NVAF on DOACs. During follow-up, newly diagnosed primitive or metastatic cancer is a strong predictor of bleeding regardless of baseline haemorrhagic risk assessment. In contrast, such association is not observed with malignancy at baseline. A proper diagnosis and treatment could therefore decrease cancer-related bleeding risk. On the contrary, our study shows that cancer is not an ischaemic risk modifier, either diagnosed at baseline or follow-up.
537 Oversensing due to micro-air bubbles leading to inappropriate shocks in patient with subcutaneous implantable cardioverter defibrillator
Authors: Seganfreddo Francesca , Golino Michele , Ceriani Francesca , Matteo Federica , Morello Matteo , Licciardello Claudio , Marazzato Jacopo , Vilotta Manola , Caravati Fabrizio , De Ponti Roberto
Published: December 2021

Aims

Subcutaneous air has been reported as uncommon cause of early device malfunction after implantation of subcutaneous implantable cardioverter defibrillator (S-ICD).

Methods and results

A 43-year-old man was admitted to our hospital due to syncopal episodes. During a brain computed tomography (CT), he was resuscitated from cardiac arrest due to ventricular fibrillation. Further investigations excluded ischaemic heart disease and cardiac magnetic resonance showed signs of prior myocarditis. After successful screening, an S-ICD was inserted for secondary prevention using the standard technique. The chest X-ray excluded acute post-procedural complications. Three days after implantation, he experienced two inappropriate shocks while conscious. Device interrogation revealed frequent high-amplitude signals followed by two shocks (Figure 1A and B) that could be interpreted as oversensing. During provocative maneuvers on the generator case, minimal and intermittent noise only on the secondary sensing vector was observed. Lateral and antero-posterior chest X-ray excluded subcutaneous air. However, the general agreement based on previous reports was that oversensing as observed in Figures 1A and B was typical for noise due to micro-air bubbles in the connection between the lead and the generator case. As a consequence, the sensing vector was successfully changed and no other inappropriate shocks were observed during follow-up.

Conclusions

Entrapped micro-air bubbles in the connection between the leads and the generator case can cause inappropriate shocks in the early period after S-ICD implantation. Timely recognition of this complication is important to prevent inappropriate shocks. It can occur shortly after the procedure even if the intra-procedural parameters were normal and chest X-ray excluded acute complications. As demonstrated in our case, the device can be reprogrammed using another sensing vector to solve these oversensing problems.
549 The role of conventional and speckle tracking echocardiography in the evaluation of leadless endocardial pacing with Micra-AV
Authors: Soldato Nicolò , Bozza Nicola , Basile Paolo , Pontone Gianluca , Siena Paola , Memeo Riccardo , Santobuono Vincenzo Ezio , Carella Maria Cristina , Favale Stefano , Guaricci Andrea Igoren
Published: December 2021

Aims

Micra-AV pacing system is a leadless pacemaker (LP) implanted in the right ventricle which can provide atrio-ventricular (AV) synchronous pacing. Echocardiographic data assessing left ventricle contractility 24–48 h after Micra AV implantation are lacking. To evaluate via conventional echocardiography and speckle-tracking echocardiography (STE), which was the best pacing modality (VVI vs. VDD) able to ensure the most efficient hemodynamic performance assessed by left ventricle ejection fraction (LF-EF) and global longitudinal strain (GLS).

Methods and results

We studied nine patients with high degree AV-block, enrolled in our Institution in a range of time of 5 months. All patients had first degree AV block (PQ interval between 160 and 340 ms). They were considered suitable candidates for MICRA-AV implantation according to current guidelines. Both LF-EF and GLS were performed 24–48 h after device implantation by two experienced echocardiographic physicians. The mean age of the population was 79 ± 8 years (8 were male, 89%). Risk factors more represented were hypertension and dyslipidaemia. The maximum PQ interval was 256 ± 51 ms. VDD pacing modality allows better LV-EF values than those obtained with a VVI stimulation (with a difference that was statistically significant difference, P-value = 0.008). Similarly, we obtained better GLS values during VDD pacing as respect to VVI (P-value = 0.008).

Conclusions

Left ventricle ejection fraction and LV-GLS improve early after leadless MICRA-AV implantation during VDD as compared to VVI pacing modality.
726 Outcomes of ischaemic stroke in patients with atrial fibrillation
Authors: Strisciuglio Teresa , Pergolae Valerio , Ammirati Giuseppe , Addeo Lucio , Todde Gaetano , Esposito Giovanni , Rapacciuolo Antonio
Published: December 2021

Aims

Atrial fibrillation (AF) increases the risk of ischaemic strokes (IS) and is associated with a more severe neurological impairment. We sought to investigate whether AF also impacts the neurological recovery and whether patients with AF have a different response to the treatment.

Methods and results

Data of patients admitted to the Stroke Unit of our institution from January to December 2020 were retrieved from the local database. The stroke severity was calculated by mean of the National Institute of Health Stroke Scale (NIHSS) at hospital admission (NIHSSad), at 24 h (NIHSS24) and at discharge (NIHSSdis). The functional capacity was assessed by the modified Rankin score (mRS). As for the neurological recovery, this was assessed by the delta NIHSS at 24 h (Δ24 = NIHSS24−NIHSSad) and at discharge (Δdis = NIHSSdis−NIHSSad). Out of 545 patients with IS 64 had known history of AF or were admitted with AF. Patients with AF had higher NIHSSad (13.9 ± 7 vs. 8.5 ± 7; P < 0.001) and NIHSS24 (9.6 ± 8 vs. 6.4 ± 7; P = 0.007) than patients without, however the neurological improvement was greater (Δdis −7.4 ± 9 vs. −3.4 ± 6; P = 0.002), indeed the NIHSSdis was similar (4.2 ± 5 vs. 4.2 ± 6; P = 0.98). Patients with AF also had a more impaired mRS before the ischaemic event and at discharge (2.4 ± 1.9 vs. 1.6 ± 1.7, P = 0.02; 1.2 ± 1.2 vs. 0.4 ± 0.9, P < 0.001). Among AF patients with CHADVASC ≥ 3, 34% of them were taking antiplatelet therapy, 31% anticoagulants, and 35% didn’t take any therapy. Of interest, no differences in the NIHSSad nor in the NIHSSdis were found between them and neither in the Δdis. As for the treatment of AF patients, no differences in the neurological recovery were observed between those treated with intravenous thrombolysis and those not treated at all (Δdis 2.8 ± 5 vs. 2.8 ± 8, P = 1), whereas the Δdis was significantly higher in patients treated with mechanical thrombectomy (−11.7 ± 7, P = 0.007).

Conclusions

Patients with AF experience more severe stroke, however the neurological recovery is greater than in patients without the arrhythmia. The treatment with antiplatelets or anticoagulants before the event does not reduce the severity of the stroke and does not influence the improvement of the NIHSS at discharge. The mechanical thrombectomy is more effective in reducing the neurological impairment.
487 Instrumental evaluation of mild cognitive decline in hypertensive patients: the role of transcranial doppler
Authors: Junior Ferruzzi Germano , Visco Valeria , Loria Francesco , Donnarumma Sofia , Galasso Gennaro , Iaccarino Guido , Vecchione Carmine , Ciccarelli Michele
Published: December 2021

Aims

Hypertension is a known risk factor for stroke and vascular dementia. Recent studies have also shown that arterial hypertension represents a clear risk factor for mild cognitive decline and its evolution into Alzheimer’s disease. Really, mild cognitive decline significantly compromises the patient’s quality of life, reducing compliance with therapy and increasing mortality and hospitalization. Diagnosis of dementia is challenging and requires both ruling out potentially treatable underlying causes and ruling in a diagnosis of dementia subtype. Currently, this diagnosis is based on the execution of second-level investigations (e.g. neuroimaging), that are expensive and not always available. For this reason, we analysed a population of hypertensive patients without atrial fibrillation and/or cerebrovascular and/or neurodegenerative diseases, with the aim of verifying the existence of an association between cognitive impairment and flows on the middle cerebral artery (MCA).

Methods

We considered 33 hypertensive patients (age 64.90 co1.40 years; 72% male). Specifically, we considered anthropometric, clinical, laboratory, and echocardiographic parameters. Also, we administered: an accurate, sensitive, and specific screening test (QMCI) for the assessment of intermediate cognitive decline (MCI), which explores spatial and temporal orientation, registration, delayed recall, clock design, logical memory and verbal fluency in a concise time (5 min—score 0–100); a compliance questionnaire (Morisky medication adherence scale); a questionnaire on nutritional status (MNA). Finally, we recorded transcranial Doppler flows on the MCA.

Results

There is no QMCItot score compatible with dementia (<20) among the patients analysed. A statistically significant inverse association emerged between total QMCI score and Morisky score (P < 0.0001); in addition, the analysis of the different sections of the QMCI questionnaire showed: an inverse relationship between the Morisky score and the clock test (P 0.013), delayed recall (P 0.024) and logical memory (P 0.028). By comparing the Doppler velocities sampled on the MCA with QMCI scores, a statistically significant inverse relationship was found between mean flow velocity and orientation at QMCI (P 0.023), between PSV and orientation (P 0.017) and between EDV and orientation (P 0.049) (Figure).

Conclusions

In conclusion, our study demonstrates for the first time the existence of a significant association between the QMCI and the sampling of the MCA at the ultrasound Doppler. Studies on a larger population will be needed to confirm this association and to test the translational relevance, in particular to tailor therapeutic approach in patients with abnormal MCA Doppler.