bluuebunny/crossref_metadata_2025 huggingface dataset:
Tumor Immunity as Well as Its Treatment Methods
Authors: Bao Zhouyang
Published: June 2020

in the passing years, tumor immunotherapy has become a major research topic and up till now, some remarkable progress has been achieved. It has come up with a new oncotherapy method different from surgery, conventional chemoradiotherapy. Tumor immunotherapy aims to kill or inhibit tumor growth by activating the immune system of the human body itself or enhancing the functions of the immune system. This thesis reviews the research and development of oncolytic virus therapy, CAR-T therapy and phytochemical drug therapy.
Air distribution analysis of clean air conditioning in operating room of hospital
Authors: Zhimei Wen
Published: June 2020

Study on the clean air conditioning in operating room, the CFD numerical simulation method is used to analyze the indoor air distribution. In this paper, the air supply speed and the position of the air return outlet are analyzed. The results show that the air supply speed is the main factor affecting the air distribution in the operating room and the particle concentration distribution in the operating area. From the perspective of the indoor air distribution, the effect of continuous arrangement of air return outlet is the best. The results can be used for reference in the design of air distribution in the operating room of the hospital in the future.
Electromagnetic field simulation of large hollow reactor
Authors: Caiquanwen  , Yang Zheng
Published: June 2020

The electromagnetic interference problems of large-scale hollow reactor equipment are special and increasingly widespread. In order to thoroughly understand the electromagnetic interference of large hollow reactors on various equipment in a substation, a field test was performed near a SVC in a substation, and the electromagnetic field was explained from three aspects: the main ground network induced circulation, the secondary cable shield current, and the DC system ripple interference. Interference issues. Furthermore, a three-dimensional electromagnetic field simulation model was established for SVC and nearby areas, and the equivalence of the model was verified by comparing it with the spatial magnetic field and induced current on the site. Based on this analysis, the electromagnetic interference improvement and the effect of inductance value changes at different reactor heights were analyzed. The results show that, during normal operation of large hollow reactors, the electromagnetic interference between the nearby grounding system and the DC system has approached or exceeded its rated operating conditions. In the design, attention should be paid to the spatial location of the reactor and the ground network, the control room and the secondary screen cabinet.
Application of Authorization in Smart Grid based on the PasS Microservice architecture
Authors: Yi Ding , Donghui Tong , Xuegang Wang , Shuliang Zhang
Published: June 2020

This paper introduces a smart grid environment authorization service architecture based on XACML and SAML standards. Software prototypes are deployed with the platform as a service (PaaS) framework Appscale. Appscale is an open source AppEngine framework released by Google that can execute applications in the cloud to solve the problems caused by the distributed computing model. This paper mainly evaluates its scalability. Through the different configuration of all distributed databases, the test of the system running load is completed. The test results show that the number of nodes deployed by Appscale varies from very unstable behavior to waiting scalability.
Research on Multi-target Equipment Group Optimal Control Strategy for Smart Energy Gateway for Large Electric Customer
Authors: Junjun Shao , Weiguo Zhang , Xiaodong Cao , Liangliang Chen , Jie Song , hua Li
Published: June 2020

At present, the electric load in China is increasing rapidly. The peak-to-valley gap of the power grid is continuously increasing, which has brought a lot of economic and security issues. Traditional solutions usually start from the power supply side, with large cost and poor effect. With the deepening of electric technology research, electric power demand side management has attract more and more attention, and large electric customers have become the first choice of state grid companies due to their large power loads and high willingness to participate. In order to cooperate with large electric customers ‘participation in demand-side response, this paper builds an equipment group optimization model to meet the requirements of the load reduction instructions while taking users’ comfort and equipment participation into account. Finally, simulation verify the practicability of the proposed strategy.
Reliability Evaluation Method of Low-voltage Distribution Network Based on Linear Equation
Authors: Liao Qinglong , Wan Lingyun , Zhang Ying , Yang Qunying , Dai Hui , Xie Kaigui , Hu Bo , Li Dongyang
Published: June 2020

The research on the reliability of distribution network uses simulation method or analytical method widely. The existing analysis methods for distribution networks usually require network topology analysis for a single node. Based on the topological relationship of low-voltage distribution network, this paper proposes a new analytical model for low-voltage distribution network. Firstly, using the relationship between the upstream and downstream nodes of the line, an algebraic equation of the expected blackout time and the expected blackout frequency of the entire network could be construct. Secondly, the expected power outage time and the expected power outage frequency at each load point can be calculate. Finally, the average availability index and load loss expectations of the entire network are calculate from the expected power outage frequency and expected power outage time at each load point. The model proposed in this article can determine the reliability index of each load point using fewer algebraic equations, and the calculation is fast and accurate, which can provide a reference for the planning and operation of distribution.
Research on Energy Storage Capacity Allocation Technology of PV-Storage Microgrid for Balancing Source-Load Power
Authors: Yanping Shen , Yong Ju , Qian Ju
Published: June 2020

The low matching degree of photovoltaic output and load in the pv-storage microgrid will reduce the reliability of its power supply. Therefore, it is necessary to configure a certain capacity energy storage device to support source-load balance.This article first analyzes the impact of different load configurations and application scenarios on energy storage configuration, and then proposes an energy storage capacity configuration scheme with the minimum operating cost of the microgrid as the objective function and the constraints of the minimum power fluctuation in the network, and uses an improved particle swarm algorithm solve the solution. Finally, a numerical example is used to verify that the solution can stably support the source-load balance in the microgrid, reduce the power exchange at the common connection point of the microgrid, and improve the microgrid’s own power supply capacity.
Drone transports medical supplies to Puerto Rico based on shortest path
Authors: Liu Lijiang , You Zhiyu
Published: June 2020

Puerto Rico suffered the worst hurricane which caused devastating damage in 2017. In order to deliver medical supplies in time and patrol the lines, NGOs try to improve the response capabilities of its by designing a portable disaster response system called DroneGo.DroneGo needs to find the optimal delivery path and the optimal equipment utilization rate for delivery according to the disaster relief conditions and schedule. In this paper, the integration of integer programming algorithm and Dijkstra algorithm is used to construct the shortest distribution path model for medical supplies transported by rescue drones in disaster areas. Using integer programming method, 7 kinds of drones and 3 kinds of medical packages are distributed, and then the DIjkstra algorithm is used to obtain the optimal distribution plan: San Juan Port is equipped with medical kits and three C-type drones, Arecibo Port allocates B-type drone patrol lines and medical kits for rescue, and Guayama Port only allocates drones for patrol lines. Using this distribution scheme greatly improves the efficiency of rescue, and distributes rescue materials reasonably and effectively, achieving the goals of optimal delivery path and optimal equipment utilization.
Method for Detecting Anomaly Data of WAMS System Based on GA-iForest
Authors: Yan Hongwen , Li Jiawei , Zuo Jian , Tang Jihong
Published: June 2020

Wide area measurement system problems such as anomalies, data missing, and real-time response deeply affect the operation and maintenance of the power grid. Considering the accuracy requirements of the system for anomaly detection, the detection accuracy and stability of traditional isolation forest are poor, so this paper proposes a new data anomaly detection method named GA-iForest. This method uses genetic algorithms to select isolated trees with high accuracy and obvious differences to optimize the structure of isolated forests. The new data anomaly detection method GA-iForest improves the accuracy and stability of detection, and mean while maintaining the high efficiency. The experiment uses standard simulation data sets and data from one province’s wide-area measurement system for experimental simulation. The result shows that the GA-iForest method has significantly improved accuracy and stability compared with the traditional isolation forest, LOF, and K-means methods.
The sitting-type furniture about the introduction of PSS theory for the old
Authors: Huang Nan , xu Jinfeng , Ren Peijie , Lai Haiyue , Fan Lanyue , Hu Jifei , Hong Zhigang
Published: June 2020

Under the general background of population aging, suitable products of the old have been developed, among which furniture of the old has also received people’s attention. Combining with the product service system (PSS), this paper studies the sitting-type furniture suitable for the elderly according to the psychological and physiological particularity of the elderly, and discusses the mode of PSS applied to the sitting-type furniture suitable for the aged, so as to promote the development of the sitting-type furniture suitable for the aged and better service for the old.
Sedimentary-diagenetic ore formation in the Jurassic system terrigenous deposits of the Tatarstan Republic
Authors: Korolev E A , Bakhtin A I , Eskin A A , Korolev A E , Barieva E R
Published: June 2020

Authigenic ore mineralization of the Jurassic terrigenous complexes rocks, widespread in the Tatarstan, is considered. It has been established that the ore minerals associations’ composition is determined by geochemical conditions of mineral formation environment. In rocks of oxide geochemical facies (sandstones, siltstones), iron, manganese and titanium oxides predominate. Pyrite framboids and copper-nickel intermetallide compounds predominate in rocks of neutral geochemical facies (green clays). The rocks of anoxic geochemical facies (black clay, oil shale) contain only pyrite framboids. The main factor determining the authigenic ore minerals associations composition is redox potential of environment.
Capacitive and migration parameters of the rocks of the upper part of the section in the east of the Russian platform
Authors: Musin R Kh , Zotina К E
Published: June 2020

This paper deals with values of the filtration coefficients of reservoir rocks that contain fresh undergroundwater, and changes in these values in space in the oil region of Tatarstan Republic. The article also considers the filtration coefficients and diffusion coefficients of Quaternary clay loams and the absorption capacity of low permeable formations in the Nizhnekamskaya petrochemical industrial zone; this zone is one of the largest in Europe. The main result of our research is that five key factors control the significant variability of rock permeability. These factors are the depth of the rocks, the geomorphological and structural location, facies formation conditions and location of the Neogene palaeovalleys. Low permeable rocks in the upper section of the Nizhnekamskaya industrial zone are widespread and have a high absorption capacity, which is almost similar to the capacity of montmorillonite; these factors determine the high protection of groundwater from surface pollution. The results obtained by the authors are necessary for rational hydrogeological and geoecological studies, as well as for the creation of computer geofiltration and geomigration models.
The chemical and mineral composition of volcanic ash in the Upper Carboniferous deposits of the Usolka section (South Ural, Russia)
Authors: Sungatullin R Kh , Sungatullina G M , Sadriev F F , Aysina R N
Published: June 2020

Volcanic ash from the Usolka section, which is proposed as an international standard for global correlation of the lower boundaries of the Kasimovian and Gzhelian Stages, is considered. The content of rock-forming components in ashes is given. It is shown that the ashes of the Gzhelian Stage differ from older deposits in higher contents of Al, Ca, Mn and lower contents of Si, Ti, Fe. An increase in the content of some microcomponents (Cu, Cr, Ba, S) to the lower boundary of the Kasimovian Stage was noted. For the first time, information has been obtained on the mineral composition of ashes, which allows them to be used for correlation.
Palm oil mill fly ash as a low-cost adsorbent for Rhodamine-B removal from industrial wastewater
Authors: Pinem J A , Utama P S , Irianty R S , Prawiranegara B A , Saputra Edy
Published: June 2020

In this study, the adsorption properties of Rhodamine-B (RB) on fly ash were investigated. Two different fly ashes conditions, including raw fly ash and activated fly ash, were selected for the adsorption experiment. The adsorption process is conducted by mixing fly ash 0.5; 1; 1,5 and 2g/L with the temperature of 30°C; 35°C; 45°C. The results showed that the HCl activation will enhance the MB adsorption capacity of fly ash, the higher the mass of adsorbent, and the higher mixing temperature, the better the performance of adsorbent is. Then, the great conditions for reducing RB with adsorbent mass 2g/L at temperature of 45°C, with a removal efficiency 90,54%
Torrefaction of Empty Fruit Bunches: Evaluation of Fuel Characteristics Using Response Surface Methodology
Authors: Helwani Z , Zulfansyah  , Fatra W , Fernando A Q , Idroes G M , Muslem  , Idroes R
Published: June 2020

Empty Fruit Bunches (EFB) can be used as an alternative energy source by torrefaction process. Torrefaction is a treatment process of biomass into solid fuel within temperature range of 200-300 °C in an inert condition. This research aims to study the effect of process variable interaction process and to study the characteristic of solid fuel resulted. Torrefaction of EFB was performed by using horizontal fixed bed reactor at three different temperatures, times and particle sizes, that are 225, 250 and 275 °C, for 15, 30 and 45 minutes, and particle size 2, 4 and 6 cm, respectively. Response surface methodology (RSM) was used for to optimization optimize of torrefaction conditions so that biofuel of with high energy density, maximum energy properties, and minimum weight loss could be manufactured. The analysis showed that increase in heating values was affected by treatment severity (cumulated effect of temperature, time and particle size). Our results clearly demonstrated an increased degradation of the material due to the combined effects of temperature and treatment time. While the reaction time had less impact on the energy density of torrefied biomass, the effect of reaction temperature was considerably stronger under the torrefaction conditions used in this study. The most significant factor affecting all responses was temperature of torrefaction, then followed by time and particle size. The optimized torrefaction conditions were verified empirically and the applicability of the model was confirmed. The torrefied biomass occurred more suitable than raw biomass in terms of calorific value, physical and chemical properties.
Dynamic engine charge simulation for unmanned aerial vehicles
Authors: Grishin Yu A , Bakulin V N
Published: June 2020

Rational use of wave processes of significant intensity in the intake pipes of piston engines allows providing dynamic charge, which leads to a noticeable increase in engine power, reduction of fuel consumption. This is especially true for engines used on unmanned aerial vehicles. For numerical calculation of the dynamic charge, a modification of the method of decay of an arbitrary discontinuity has been developed, based on the application of special gas-dynamic functions of the unsteady flow, which does not use a simplifying linearization and thus provides increased accuracy of the results required for wave processes of significant intensity. Corresponding calculations of the engine cylinder charge filling at dynamic charge have shown the possibility of the power increase by 24%, which corresponds well with the experimental data.
Effect of putrescine and type of light in callus of Gardenia Jasminoides L. content from some effective medical compounds
Authors: Kadhim Al-Maameri Ahmed A. , Almyali Ali Ahmed Hussein
Published: June 2020

The experiment was carried out in the laboratory of tissue culture of Plant Production Techniques Department, at Musaib Technical College to study the effect of different concentrations of putrescine and the type of light on the content of the Gardenia from some effective medical compounds. The experiment included two factor the first consisted of two sources of light, namely light (fluorescent), LED light (18 red: 2 blue) and the second factor, the addition of Putrescine with three concentrations (0.5, 1 and 1.5) mg.l-1. Some effective medical substances (Coumaric, Ferulic, Caffeorylquanic, Sinapic acid and Tannic) acids was measured in Callus Of Gardenia using high-performance liquid chromatography (HPLC).The results were analyzed using the statistical program Genstat and the mean was measured according to the least significant difference of LSD at the probability level of 5%. The results showed superior treatment of LED lighting in the concentration of all measured active compounds, The highest concentration of compounds (Ferulic, Caffeorylquanic and Sinapic) acids was given with a concentration of 0.5 mg.l-1. The highest concentration of compounds (Coumaric and Tannic) acids. The interaction (LED + Putrescine at 0.5) gave the highest concentration of compounds (Ferulic, Caffeorylquanic and Sinapic) in Callus of Gardenia.
Development of an Ecological-friendly Method for Ciprofloxacin Determination and Cloud Point Extraction in Pharmaceuticals using Fe(II) (FeSO4.7H2O)
Authors: Fahad Abbas S. , Thani Mohammed Z. , Abdullah Asmaa M. , Dhahir Saadiyah A
Published: June 2020

In this study, new spectrophotometric methods development for evaluation of ciprofloxacin are described. The first method including conversion of ciprofloxacin to colored complex with Fe (II) in the alkaline medium. The colored product has a yellow color with absorbance at λmax 450 nm. Between the concentration range (2-90 μg.mL−1), the Beers law is obeyed with correlation coefficient (R2) as 0.9996, limit of detection as 0.365 μg.mL−1, limit of quantification as 1.189 μg.mL−1. Secondly, cloud point extraction was used to determine of a trace amount of the colored product in the first method followed by measuring with a UV-Vis spectrophotometer. The linearity of calibration curve was above the range of (1-50μg.mL−1), the correlation coefficient (R2) was 0.9995. The Limit of detection (LOD) and Limit of quantification (LOQ) were found to be 0.129 and 0.387 μg.mL1 respectively. This method was successfully employed for ciprofloxacin detection in the several pharmaceutical samples by Rec. Was rang between (98-102.8).
Fuzzy Estimators for Parameters and Hazard Rate Function of Lindley Distribution: Simulation Study
Authors: Al-Noor N H , Subhi R S
Published: June 2020

The quantitative description of data is very essential for statistics. In standard statistics data are assumed to be numbers, vectors or classical functions. But in applications, real data are frequently not precise numbers or vectors, but often more or less imprecise. All kinds of data which cannot be presented as precise numbers or cannot be precisely classified are called non-precise or fuzzy. The present paper focused on obtaining the maximum likelihood and approximate Bayesian estimators of the parameters and hazard rate function for Lindley distribution when the data are available in fuzzy form. Since there are no exact forms, maximum likelihood estimators have been derived according to the algorithm of Newton- Raphson as an iterative technique and Bayes estimators have been derived based on informative gamma priors relative to squared error and precautionary loss functions according to a numerical approximate Lindley‘s technique. The obtained estimators have been compared through Monte-Carlo simulation study.
Reinforcement the Mechanical Properties of (NR50/SBRs50/OSP) Composites with Oyster Shell Powder and Carbon Black
Authors: Al-Nesrawya Sameer H. , Mohseenb Mohammed J. , Al-Bermany Ehssan
Published: June 2020

In this study, the rubber batches composites were prepared using Natural rubber (NR) and synthetic rubber (SBR) as model materials. The composites were reinforced using oyster shell powder (OSP) with particle size less than (225μm). Two groups of samples were prepared with (0, 5, 10, 15, 20, 25, 30, 40 and 60 pphr) with loading ratio of OSP and (CB-10pphr) of CB, whereas other composites were without CB. Density, viscosity and multi ultrasound velocity wave devices were applied to characterize the density according to the specification (ASTM-D1817-66) (Densitron), rheological properties with specification (ASTM-D2084-89) standard and mechanical properties, respectively. The result showed significant influence of the reinforcements (OSP) material and (CB) on some of these properties that exhibited an increasing with the increasing of loading ratio of (OSP) and (CB), such as density, relaxation amplitude and compressibility, but the other properties were decreasing like viscosity, relaxation time, velocity waves, bulk modulus and specific acoustic impedance.
Non-thermal plasma effects on structural and optical properties of Cd doped ZnO thin films
Authors: Mishjil Khudheir A , Abdulsada A H , Rashid H G , Mansour H L , Rasheed H S , Murbat H H , Habubi N F
Published: June 2020

Undoped ZnO and Cd doped ZnO thin films were deposited utilizing chemical spray pyrolysis. The effects of non-thermal plasma on the structural and optical properties were studied. XRD patterns indicate that all the deposited films were polycrystalline hexagonal structure, but the preferred orientation of un doped ZnO was (002), while for doped samples were orientated along (101). The effect of plasma exposure on crystal size, transmittance, absorption edge and optical energy gap were investigated. Results illustrate that the crystal size, transmittance and optical energy gap were decreased when doped samples exposure to plasma.
Determination of naturally occurring radionuclides in Disi aquifer water of Jordan
Authors: Al-Bedri M B H , Younis T A J , Abdulghani I J , Hameed W O
Published: June 2020

The Disi water samples were collected from different Disi aquifer wells in Jordan using a clean polyethylene container of 10-liter size. A hyper-pure germanium (HPGe) detector with high- resolution gamma-ray spectroscopy and a low background counting system was used for the identification of unknown gamma-rays emitting from radionuclides in the environmental samples. The ranges of specific activity concentrations of 226Ra and 228Ra in the Disi aquifer water were found to be from 0.302 ± 0.085 to 0.723 ± 0.207 and from 0.047 ± 0.010 to 0.525 ± 0.138 Bq L−1, with average values of 0.516 ± 0.090 and 0.287 ± 0.091 Bq L−1, respectively. The average combined radium (226Ra + 228Ra) activity and radium activity ratio (228Ra/226Ra) in Disi groundwater were found to be 0.803 ± 0.187 and 0.550 ± 0.178, respectively. A comparison was made between the present results and the international minimum recommended limits and previously published data from different countries.
Magneto-optical sensor based on the bandgap effect of a hollow-core photonic crystal fiber injected with Fe3O4
Authors: Aobaid R A , Hussain H S
Published: June 2020

A magnetic field sensor, using a hollow-core photonic crystal fiber (HC-PCF), based on the bandgap effect was designed and experimentally demonstrated. The water-based Fe3O4 was infiltrated into the core and the holes of the HC-PCF. The magnetic fluid was prepared with a concentration of 0.6mg/ml. A diode laser with a wavelength 532nm was used as a light source. Two types of HC-PCF were used: HC-1550-19 PCF and HC-800-02 PCF. The sensitivity was tested for a magnetic field that ranges from 0 mT to 24.5 mT. The results demonstrate that the sensitivity of the proposed sensors was 119.95 pm/mT and 151.27 pm/mT for HC-800-02 PCF and HC19-1550 PCF, respectively.
Color Image Enhancement Depending on Fuzzy Logic and Nonlinear Transform
Authors: Jawad M K , Daway H G , Mohamad H J
Published: June 2020

Color image enhancement considered one of the challenging fields in image processing category. The nonlinear function based on a fuzzy logic algorithm is developed within this paper to enhance image color. The suggested algorithm used sigmoid mapping and the membership function which relied on histogram analysis to enhance image contrast. The results of the suggested algorithm compared with fuzzy logic (square method), fuzzy logic (cubic method), Histogram Equalization and Multi-Scale Retinex. Different criteria used to evaluate the performance of the presented algorithm like Mean-S, Mean-H, nature image quality evaluator, Lightness Order Error and entropy. The evaluated criteria show the suggested algorithm is better in color enhancement compared with the other methods.
Study the Structural, Optical, Thermal Reflectivity and Magnetic Properties For Thin Copper Substituted Zinc Ferrite Zn1-xCuxFe2O4 Prepared by Chemical Spray Pyrolysis
Authors: Hussain Saleem A , Abdulsada G J
Published: June 2020

Thin films of Copper- substituted Zinc ferrites as general Zn1-xCuxFe2O4 where (x = 0.0, 0.3, 0.5, 0.7, 0.9) It was prepared using the technique of spray pyrolysis technique on the glass substrate with a temperature equals (400±10oC). High purity of Copper nitrate, Zinc chloride and Iron oxalate were dissolved in 1 mole in de-ionized water. The prepared films are annealed at 520 oC. XRD pattern are used to study the structure of the prepared thin film ferrite. XRD results showed that the prepared thin films Zn1-xCuxFe2O4 are polycrystalline with spinel cubic structure. The results also showed the spinal ferrite structure was modified by the substitute ions. SEM results showed that the prepared films were of a uniform and homogenous nature. Results of thermal reflectivity showed that the reflectivity of the films increases with increasing of (x) and it is approximately greater than 60%. The magnetic properties of the prepared films were examined using Vibrating Sample Magnetometer(VSM). The magnetization measurements indicate that the Zn1-xCuxFe2O4 showed ferromagnetic demeanor at room temperature.
Stream functions for divergence-free vector fields
Authors: Kelliher James
Published: June 2020

In 1990, von Wahl and, independently, Borchers and Sohr showed that a divergence-free vector field

u
u

in a 3D bounded domain that is tangential to the boundary can be written as the curl of a vector field vanishing on the boundary of the domain. We extend this result to higher dimension and to Lipschitz boundaries in a form suitable for integration in flat space, showing that

u
u

can be written as the divergence of an antisymmetric matrix field. We also demonstrate how obtaining a kernel for such a matrix field is dual to obtaining a Biot-Savart kernel for the domain.
Prognostic durability of coronary computed tomography angiography
Authors: Chow Benjamin J W , Yam Yeung , Small Gary , Wells George A , Crean Andrew M , Ruddy Terrence D , Hossain Alomgir
Published: June 2020

Aims 

This large prospective cohort study sought to confirm the incremental prognostic value of coronary computed tomographic angiography (CCTA) measured over a prolonged follow-up duration. CCTA has diagnostic and prognostic value but data supporting its long-term prognostic value in a large prospectively recruited cohort with suspected coronary artery disease (CAD) has been limited.

Methods and results 

Consecutive patients (without history of myocardial infarction, revascularization, cardiac transplantation, and congenital heart disease) were prospectively enrolled. CCTA was evaluated for CAD severity, total plaque score (TPS), and left ventricular ejection fraction. Patients were followed for major adverse events (MAE) and major adverse cardiac events (MACE).

Over a total of 99 months, 8667 consecutive CCTA patients (mean age = 57.1 ± 11.1 years, 52.9% men) were prospectively enrolled and followed for a mean duration of 7.0 ± 2.6 years. At follow-up, there were a total of 723 MAE, 278 MACE, 547 all-cause deaths, 110 cardiac deaths, and 104 non-fatal myocardial infarction. Patients without coronary atherosclerosis at the time of CCTA had a very low annual event rate for both MAE and MACE (0.45%/year and 0.19%/year, respectively). Both MAE and MACE increased with increasing TPS and severity of CAD. In patients with non-obstructive CAD and who were statin-naive, TPS ≥5 had MACE rates >0.75%/year. Patients with high-risk CAD had an annual MAE and MACE rates of 3.52%/year and 2.58%/year, respectively. Adjusted hazard ratio of the severity of CAD based on multivariable analyses indicated that the prognostic values were incremental.

Conclusion 

CCTA has independent and incremental prognostic value that is durable over time. The absence of coronary atherosclerosis portends an excellent prognosis. Patients with increasing non-obstructive plaque burden have worse prognosis and a TPS threshold ≥5 may identify a population that may benefit from statin therapy.
P981Comparison of automark utilization and lesion metric target during paroxysmal atrial fibrillation ablation with a contact force-sensing ablation catheter: European and U.S. multicenter Experiences
Authors: Ramanna H , Lloret J L , Zahwe F , Porterfield C , Trines S , Djajadisastra I , Gibson D , Gururaj A , Alizadeh Dehnavi R , Raine D , James S , Razak E , Oommen S , Tao C , Olson N
Published: June 2020

Background

Accurate delivery of transmural lesion is associated with improved durability of pulmonary vein isolation and reduced reconduction. Lesion quality depends on multiple parameters such as radiofrequency power, tissue-catheter contact, duration of energy application, and catheter tip temperature. Consequently, energy delivery parameters vary based on individual operators’ preferences and procedural needs.

Purpose

To characterize and compare the utilization of automated lesion marking feature and lesion delivery parameters used during paroxysmal atrial fibrillation ablation performed with a magnetic sensor enabled contact force-sensing catheter across European and U.S. centers.

Methods

Procedural data were prospectively collected in clinical cases performed with a new magnetic sensor enabled, contact force ablation catheter within the first 6 months of use at participating centers in Europe and the U.S. Use of bidirectional CF catheters, steerable sheaths, automated lesion marking software and associated lesion delivery parameters during paroxysmal atrial fibrillation ablation were evaluated.

Results

A total of 149 cases across 37 centers in 11 European countries, and 112 cases across 31 U.S. centers were analyzed. A bidirectional contact force catheter (56.4% and 90.2%), a steerable sheath (65.8% and 69.6%), and the automated lesion marking module (77.9% and 90.2%) were used in most European and U.S. cases, respectively. The most commonly reported energy delivery parameters were: lesion index (LSI), Force-Time Integral (FTI), and time from European cases; LSI, average force, and FTI for U.S. cases (Table). Target LSI values were recorded for 126 cases in Europe and 34 in the U.S, ranging from 3 to 6. In anterior/roof segments, most common LSI target values for anterior/roof and posterior/inferior segments were 6 (42.9%) and 5 (51.2%) in Europe, and 5.5 (44.1%) and 5 (54.5%) in the U.S. PVI was confirmed with an average of 20.3 minutes waiting period (69.1%) for European cases and exit block (57.1%) in U.S. cases. First pass PVI were 67.1% and 74.4% for European and U.S. cases, respectively.

Conclusion

Energy delivery parameters and PVI confirmation method varied considerably by geography during paroxysmal atrial fibrillation ablation using the magnetic sensor enabled, contact force ablation catheter. Further study on efficacy implication on these differences in practice should be examined.

Energy delivery parameters used Paroxysmal AF N LSI FTI Time Imp Drop Avg Force Other N/A Europe 149 44.0 % 13.4 % 7.0 % 6.0 % 2.4 % 1.0 % 26.2 % U.S. 112 31.2% 17.9 % 6.2 % 8.0 % 23.2 % 11.7 % 1.8 % Energy delivery parameters used in paroxysmal AF ablation in Europe and U.S.
673Bipolar radiofrequency ablation supported by non-ionic catheter irrigation
Authors: Futyma P R , Kulakowski P
Published: June 2020

Introduction

Bipolar radiofrequency catheter ablation (Bi-RFCA) or irrigation of ablation catheter (AC) using non-ionic coolant, such as dextrose-5 in water (D5W), are novel ways to improve lesion formation in case of arrhythmia refractoriness. Combination of these two methods has not yet been described.

Puprose

To determine feasibility and effectiveness of Bi-RFCA additionally supported by non-ionic catheter irrigation for treatment of refractory premature ventricular complexes (PVC) or ventricular tachycardia (VT).

Methods

Consecutive patients after failed extensive Bi-RFCA or D5W-irrigated ablation for symptomatic PVCs or non-sustained VT (nsVT) underwent Bi-RFCA supported with D5W coolant.

Results

We ultimately enrolled 2 patients (2 males, age 64 ± 12 years) after failed extensive ablations for the left ventricular summit PVCs and nsVT to undergo Bi-RFCA supported with D5W irrigation of both AC and intracardiac return electrode (IRE). Previous pharmacological antiarrhythmic treatment consisting of at least one drug and catheter ablation failed in both patients. Bi-RFCA was delivered between earliest activation sites located in the left/right aortic commissure and the left pulmonic cusp (Figure). Efforts were made to achieve safe distance from coronary arteries, AC, and IRE.  Bipolar RFCA (35 ± 7W power, 8 ± 4 applications, 199 ± 166s RF time)  led to acute elimination of PVCs in both patients. Baseline impedance oscillated around 250Ω and initial 50-70Ω impedance drop was observed during first 20s of bipolar applications, followed by impedance rise up to 350-450Ω. No steam pop occurred and  there were no complications during procedures. All antiarrhythmic drugs were discontinued. Follow-up lasted 8 ± 2 months, there was no nsVT recurrence and 90,4% PVC burden reduction was achieved: from 30000 to 3100 PVC/day in patient #1 and from 39000 to 3500 PVC/day in patient #2. Both patients remained symptom-free.

Conclusion

Bi-RFCA can be additionally supported using non-ionic D5W coolant. Such approach is feasible and can be safe and effective. More data on impedance imbalance during D5W-supported bipolar RF applications is warranted.

Abstract Figure. Fluoroscopic view and 12-lead ECG
P1393Prolonged atrial electrical conduction as a predictor of atrial fibrillation after atrioventricular nodal reentrant tachycardia ablation
Authors: Marinheiro R , Parreira L , Amador P , Mesquita D , Farinha J , Fonseca M , Esteves A , Ferreira J , Lopes C , Duarte C , Venancio J , Santos B , Caria R
Published: June 2020

BACKGROUND

Patients (pts) with atrioventricular nodal reentrant tachycardia (AVNRT) have a higher incidence of atrial fibrillation (AF) during follow-up. Conventional risk factors can play a role in AF development, however atrial electrical conduction properties may be implicated in AF pathogenesis.

AIMS

to evaluate atrial conduction times and assess its effect on AF development during follow-up.

METHODS

We studied AVNRT pts who performed EPS and catheter ablation of the slow pathway between 2013 and 2016 in a single center. Pts with AF or valvular disease were excluded. We evaluated duration of symptoms due to AVNRT, conventional risk factors for AF (age, gender, obesity, hypertension, diabetes and structural heart disease (SHD)), left atrium (LA) enlargement and electrophysiologic study (EPS) time intervals related with atrial electrical conduction properties. We measured the time interval between: (1) the beginning of the P wave on the ECG to the A deflection in His-bundle electrogram (P-AHis); (2) the beginning of the P wave to the mid-distal coronary sinus (CS) atrial electrogram (P-CS) and (3) the beginning of the P wave to the H deflection in His-bundle electrogram (P-HHis).

RESULTS

Fifty-two pts were evaluated during a median follow-up of 63 months (IQR 51-69): 22% male, median age 55 years (IQR 42-67). AF occurred in 9 patients (17%) (39 cases per 1000 person-years). Patients with AF were older (67 vs 53 years, p= 0.005) and had more frequently LA enlargement (33% vs 7%, p= 0.024) but they did not differ in hypertension, obesity, diabetes, SHD and duration of symptoms. EPS measured intervals P-AHis and P-HHis interval were not different between the groups (26.0 vs 22.8 ms, p = 0.89 and 151 vs 106 ms, p= 0.56, respectively) but P-CS were prolonged in patients with AF (70 vs 55 ms, p = 0.02) (figure 1). Univariate logistic analysis for AF is presented in table 1. There was no interaction between P-CS and LA enlargement (p = 0.87). In multiavariate analysis, only P-CS was independently associated with AF (table).

CONCLUSIONS

In this group of patients with AVNRT, P-CS, but not other atrial conduction intervals, was independently associated with AF development. The possible role of LA electrical conduction impairment in AVNRT pts for AF development needs further studies.

Univariate and multivariate analysis Univariate analysis Multivariate analysis OR 95% CI p-value OR 95% CI p-value Age (years) 1.10 1.02-1.19 0.016 1.10 1.00-1.21 0.051 LA enlargement 7.00 1.10-44.71 0.040 3.42 0.41-28.03 0.255 P-CS 1.07 1.021.14 0.013 1.06 1.01-1.12 0.044 OR Odds ratio. CI: confidence interval

Abstract Figure. Box-plot for the studied intervals
P1097Heart rate acceleration is a poor surrogate of complete parasympathetic denervation of sinus node during cardioneuroablation
Authors: Wichterle D , Jansova H , Stiavnicky P , Peichl P , Cihak R , Kautzner J
Published: June 2020

Background

Ablation of superior paraseptal ganglionic plexi is invariantly associated with the acceleration of sinus rhythm. This is considered a favourable sign during cardioneuroablation for the treatment of recurrent neurally-mediated cardioinhibitory syncope or symptomatic sinus bradycardia.

Purpose

In this retrospective study, we investigated whether the magnitude of sinus rhythm acceleration corresponds with directly assessed sinus nodal parasympathetic denervation.

Methods

The study included 48 patients (age: 39 ± 13 years, 58% males) who underwent cardioneuroablation in general anaesthesia. The procedural endpoint was non-responsiveness (i.e. loss of original cardioinhibitory response) of the sinus node to extracardiac high-frequency stimulation of the vagal nerve. The magnitude of sinus rhythm acceleration was compared between patients who reached or did not reach this endpoint.

Results

All patients had positive atropine test (baseline heart rate: 65 ± 14 bpm; post-atropine: 109 ± 22 bpm). Complete sinus nodal denervation as assessed by vagal nerve stimulation was achieved in 44/48 (92%) patients. Intraprocedurally, heart rate accelerated from 54 ± 11 to 85 ± 14 bpm (difference: 31 ± 10; median 29; interquartile range: 24–40; total range: 13–61 bpm). This change did not correlate with age and was not related to pre-procedural post-atropine sinus rhythm acceleration. There was no difference in heart rate acceleration between the patient with and without sinus nodal denervation (Figure).

Conclusions

Sinus rhythm acceleration is not reliable endpoint for cardioneuroablation. Guidance by extracardiac vagal nerve stimulation may help to tailor the procedures to increase the clinical success rate and, at the same time, to avoid patient overtreatment.

Abstract Figure.
236Automatic classification of 20 different types of atrial tachycardia using 12-lead ECG signals
Authors: Luongo G , Schuler S , Rivolta M W , Doessel O , Sassi R , Loewe A
Published: June 2020

Funding Acknowledgements

Supported by the European Union"s Horizon 2020 research and innovation programme under the Marie Sklodowska-Curie grant agreement No.766082 (MY-ATRIA)

Background

 Atrial Flutter (AFl) as a common reentrant atrial tachycardia is driven by self-sustainable mechanisms that cause excitation to propagate along pathways different from sinus rhythm. Intracardiac electrophysiological mapping and catheter ablation is often performed without prior knowledge of the mechanism perpetuating AFl in a given patient, likely prolonging the procedure time of these invasive interventions. We investigated the feasibility of automatically identifying 20 different AFl types based on the non-invasive 12-lead electrocardiogram (ECG) using machine learning. 

Methods

 Electrophysiological fast marching computer simulations of 20 different atrial tachycardia scenarios (micro-/macro-reentry, scar-related/anatomical/functional, figure-of-eight, focal, different locations) were performed and propagated to the standard 12-lead ECG based on the Courtemanche atrial action potential model. The virtual study population comprised combinations of 8 different anatomical bi-atrial models with 2 orientational variants each and 8 different torso models yielding a total of 2512 ECGs. From each ECG, we extracted 114 features from different domains (e.g., time, frequency, entropy, wavelet, non-linear recurrence analysis). The dataset was randomly split into 1256 training samples, 628 validation samples and 628 test samples while maintaining a balanced AFl type distribution. A radial basis neural network (RBNN) was trained as a classifier after selection of the most informative features. 

Results

The RBNN yielded a test set accuracy of 90% regarding the identification of the AFl mechanism using 10 features (from different domains). The most discriminative single feature was the cycle length that alone led to a test set accuracy of 74%, while the remaining feature set without cycle length (9 features) reduced the test set accuracy to 33%. The machine learning approach generalized well regarding unseen torso geometries (90% accuracy if training was performed on only 7 torso models) but rather poor regarding atrial anatomies (23% if the atrial anatomical model was not seen during training) indicating that more than the currently used 8 atrial models should be included during training to cover the relevant anatomical variability. 

Conclusions

Our results show that a machine learning classifier can potentially identify a high number of different AFl types using the 12-lead ECG. This non-invasive method can aid in planning and tailoring AFl treatment for patients. Application to clinical data is necessary as a next step to pave the way for clinical translation.

Abstract Figure.
P1395The role of hyponatremia in the development of atrial fibrillation after cardiac surgery
Authors: Pavlikova A , Shevelyok A , Vatutin N
Published: June 2020

Background. Atrial fibrillation (AF) is one of the most common complication after cardiac surgeries. Age, valvular heart disease, heart failure, chronic obstructive pulmonary disease and a history of AF are well known risk factors for postoperative AF. On the other hand, hyponatremia is also a frequent disorder in patients undergoing cardiac surgery but its relationship with AF has not been studied.

Purpose. We evaluated the impact of hyponatremia on the incidence of postoperative AF in patients undergoing cardiac surgery with cardiopulmonary bypass.

Methods. The retrospective study included case history of 222 patients (174 men and 48 women, median age 64.5 [range 58.0; 69.0] years) who underwent cardiac surgery with cardiopulmonary bypass between January 2015 and December 2018.  In all patients intraoperative sodium level was analyzed. Hyponatremia was defined as serum sodium level < 135 mmol/l. Primary outcome was the episode of AF in postoperative period.

Results. The incidence of postoperative AF was 18.9% (95% confidence interval (CI) 14.1-24.3 P = 0.05). Patients with AF more often had obesity, diabetes mellitus and a history of myocardial infarction and were more likely to perform combined surgery compared to non-AF patients (all Ps < 0.05). The prevalence of hyponatremia was significantly higher among AF group compared with non-AF (95.2% versus 77.8%, P = 0.017). Hyponatremia was the independent risk factors of postoperative AF in Cox regression models adjusted for covariates (odds ratio 5.31; 95% CI 1.42-18.7; P = 0.017).

Conclusion.  In this analysis serum sodium level was closely associated with the risk of AF. These findings suggest that hyponatremia may cause the development of postoperative AF in patients undergoing cardiac surgery with cardiopulmonary bypass.
P1418Heart failure and atrial fibrillation: clinical, prognostic and echocardiographic outcome
Authors: La Greca C , Cirasa A , Pecora D , Sorgato A , Simoncelli U , Campana M , Cuccia C
Published: June 2020

Background

Catheter ablation (CA) for atrial fibrillation (AF) in heart failure (HF) patients is 

associated with a lower rate of cardiac events compared to medical therapy.

Purpose

This study deals with the clinical, echocardiographic and prognostic outcomes in these patients.

Methods

From a single center 47 patients with AF, HF and left ventricular ejection fraction (LVEF) 

 <50%, underwent CA. The primary endpoints were NYHA functional class, LVEF and MAGGIC 

(Meta-Analysis Global Group in Chronic Heart Failure) Risk score before the procedure and after 12 

months. 

Results

The median age of patients was 59 years; 49% had paroxysmal AF. At 12-month a 

significant improvement of NYHA class (median before II [interquartile range (IQR) II-III] vs 

median after I [IQR I-II]) and of LVEF (median before 44% [IQR 37-47] vs median after 55% 

[IQR49-57]) was observed (p-value 0.000). The MAGGIC 1-year and 3-year probability of death was 

estimated before (mean score 13 [IQR 11-17]) and at 12-month (mean score 11 [IQR 8-13]) showing 

a significant decrease in the probability of death (p-value 0.000). At 12-month patients with reduced 

LVEF before the ablation had more HF hospitalizations than HF mid-range patients (p-value 0.035). 

Coronary artery disease (CAD) (HR 5, p-value 0.035) and MAGGIC score (HR 1.2, p-value 0.030) 

were predictors of HF hospitalization.

Conclusion

CA for AF in HF patients was associated with a significant improvement of NYHA 

functional class and LVEF and a higher life expectation. CAD history, LVEF <40% and MAGGIC 

score before ablation were predictors of HF hospitalization at 12-month follow-up.