bluuebunny/crossref_metadata_2025_split huggingface dataset:
Non-contact capacitive sensing for ECG recording in small animals
Authors: Wang Ting-Wei , Lin Shien-Fong 
Published: April 2020

Abstract
Rat electrocardiography (ECG) is frequently used in biomedical research as a model for exploring heart function in a wide variety of experimental conditions. Subcutaneous ECG is a common approach to record rat heart rhythm using implanted needle electrodes to sense the rat ECG signals with the animal under deep anesthesia. However, such an invasive measurement could cause inconvenience due to cumbersome animal preparation, and the anesthetics are likely to interfere with the autonomic regulation of cardiac rhythm. Most studies used the galvanic contact between animal limb and electrode sensing surface to record cardiac signals from small animals. However, the non-contact approach of capacitive ECG sensing for small laboratory animals has not been extensively investigated. This study aims to develop a non-contact ECG system to promote the ECG measurement of laboratory animals for biomedical research. The method utilizes the capacitive coupling technique to detect cardiac signals in awake rats (R-wave amplitude of only 0.2 mV) through a non-conductive layer. The proposed system generates non-contact ECG signals with distinguishable R-peaks at a limb-electrode capacitance above 8.5 pF and maximum through-thickness of the non-conductive layer of 0.4 mm for heart rate assessment. In conclusion, this study provides non-contact ECG monitoring based on capacitive electrodes to improve the throughput of ECG measurement procedures for biomedical research and establish a lower bound of coupling capacitance for non-contact application to heart rate. The new method is ideally suited for the rapid evaluation of autonomic regulation of heart rhythm in awake laboratory small animals.
A novel procedure for determining the optimal MLC configuration parameters in treatment planning systems based on measurements with a Farmer chamber
Authors: Saez Jordi , Hernandez Victor , Goossens Jo , De Kerf Geert , Verellen Dirk 
Published: April 2020

Abstract
Modelling of the multi-leaf collimator (MLC) in treatment planning systems (TPS) is crucial for the dose calculation accuracy of intensity-modulated radiation therapy plans. However, no standardised methodology for their configuration exists to date. In this study we present a method that separates the effect of each dosimetric characteristic of the MLC, offering comprehensive equations for the determination of the configuration parameters used in the TPS model. The main advantage of the method is that it only requires prior knowledge of the nominal leaf width and is based on doses measured with a Farmer chamber, which is a very well established and robust methodology. Another significant advantage is the required time, since measuring the tests takes only about 30 minutes per energy. Firstly, we provide a theoretical general formalism in terms of the primary fluence constructed from the transmission map obtained from an MLC model for synchronous and asynchronous sweeping beams. Secondly, we apply the formalism to the RayStation TPS as a proof of concept and we derive analytical expressions that allow the determination of the configuration parameters (leaf tip width, tongue-and-groove width, x-position offset and MLC transmission) and describe how they intertwine. Finally, we apply the method to Varian’s Millennium120 and HD120 MLCs in a TrueBeam linear accelerator for different energies and determine the optimal configuration parameters. The proposed procedure is much faster and streamlined than the typical trial-and-error methods and increases the accuracy of dose calculation in clinical plans. Additionally, the procedure can be useful for standardising the MLC configuration process and it exposes the limitations of the implemented MLC model, providing guidance for further improvement of these models in TPSs.
The Use of Variable Frequency Drives of Centrifugal Pumps atthe Pumping Station
Authors: Zyubin I , Pankratov S , Petrov A , Babikova D 
Published: April 2020

Abstract
The article presents the experience of operating real pumping stations in urban water supply. The basic principles of practical modeling of the operation of a group of pumps for a common load are considered. The main errors in the modernization of pumping equipment of water supply units are analyzed.
Study of Cavitation Characteristics of a Cryogenic Pump by Computational Fluid Dynamic Methods
Authors: Babikova D , Petrov A 
Published: April 2020

Abstract
This article is devoted to the study of cavitation characteristics of a centrifugal cryogenic pump. Hydrodynamic simulation of the fluid flow in the wet part of the pump was carried out in order to determine the output parameters of the pump. A critical increase in the temperature of liquid helium, corresponding to the beginning of cavitation in the pump, was determined. A cavitation performance of the pump was built under given operating conditions and a critical NPSH was determined.
Methodology for the comprehensive optimization of a centrifugal pump with a magnetic coupling
Authors: Zaytseva A , Protopopov A 
Published: April 2020

Abstract
The article considers the design of a leakproof pump with a magnetic coupling operating on a chemical fluid. In this work the optimization of the pump assembly was carried out, including hydrostatic bearings and a magnetic coupling, using the STARCCM + simulation package. The throttle diameters optimal for this design are calculated. The author minimized the overflows in the auxiliary cooling paths of the coupling and the axial force on the pump rotor.
Predicted resource of the most loaded bearing of a horizontal centrifugal pump
Authors: Shablovskiy A , Menagarishvili N , Makhlaeva A , Emshina E 
Published: April 2020

Abstract
The paper gives a derivation of the formula for calculating the predicted resource of the most loaded bearing of a horizontal centrifugal pump. A model of a horizontal centrifugal pump, as well as the action of axial forces and radial reactions, are considered.
The presence of the “locking effect” when the fluid flows through the cylindrical throttle channels
Authors: Kuznetsov V , Yarots V 
Published: April 2020

Abstract
A study was made for the continuous flow of the working fluid through a cylindrical throttle channel (so-called “locking effect”). The flow of the fluid into the atmosphere and the change in absolute pressure at the inlet to the throttle channel ranging between 0.221 MPa and 0.24 MPa are studied. It was found that the pressure in the compressed section inside the throttle channel remains almost constant and equal to 4 kPa. A comparison is made of the experimental values of the flow rate determined for the same absolute pressure difference Δp in the separated and unseparated flow regimes. Knowing that the value of the flow coefficient μ in the zone of the existence of the “locking effect” can be determined from known data for the process of fluid outflow from holes with a sharp edge in a thin wall. Also, similar phenomena occur when fluid flows through small holes and slots in the guide, control and regulatory equipment of various hydraulic systems.
Calculation of the hydro-pneumatic suspension damper
Authors: Britsin S , Ryabinin M , Sarach E 
Published: April 2020

Annotation
The paper considers general approaches to the design and calculation of the characteristics of hydropneumatic dampers that can be used in the suspensions of mobile cars. It is paid particular attention to the determination of the main hydraulic characteristics of the flow part of the damper, including a direct-acting belt valve, based on numerical simulation.
Investigation of the flow part of a high-speed vane pump of a hydraulic unit using numerical hydrodynamic modeling
Authors: Derevianko M , Ryabinin M 
Published: April 2020

Annotation
On this paper was studied the flow part of a high-speed vane pump of a hydraulic unit for pumping fuel of a passenger transport aircraft. To solve the task was used a numerical method for hydrodynamic modeling. It is described the used mathematical model. The obtained pressure and torque graphs on the shaft are given, depending on the feed of the centrifugal pump. The obtained data can be used for further design of the hydraulic unit.
Complex optimization of vaned stators of high-speed centrifugal pumps for thermal stabilization systems
Authors: Kochetov A , Petrov A , Kuleshova M 
Published: April 2020

Abstract
The scope of the pumps for thermal stabilization systems, the main elements of such pumps, their configurations and basic requirements for pumps of this type are considered. In order to increase efficiency, an optimization of the pump vaned stator is carried out. Such simulation results as efficiency and pressure values for each variant are obtained. The data received is analyzed and appropriate conclusion on the efficiency of optimization approach is made.
Tough and conductive polymer hydrogel based on double network for photo-curing 3D printing
Authors: Ding Xueyuan , Jia Runping , Gan Zuzhong , Du Yong , Wang Dayang , Xu Xiaowei 
Published: April 2020

Abstract
Conductive hydrogels (CHs) have attracted significant attention in wearable equipment and soft sensors due to their high flexibility and conductivity. However, CHs with high-strength and free-structure still need to be further explored. Herein, 3D printing high-strength conductive polymer hydrogels (CPHs) based on a double network was prepared. Firstly, PHEA-PSS hydrogels were prepared by copolymerizing 2-Hydroxyethyl acrylate (HEA) with 4-Vinylbenzenesulfonic acid (SSS) using a photo-curing 3D printer. Then 3, 4-Ethylenedioxythiophene (EDOT) was in situ polymerized in the network of PHEA-PSS to obtain the PHEA-PSS/PEDOT hydrogels. It can not only satisfy the printing of complex spatial structures, but also has high mechanical and electrical properties. When the content of EDOT is 12 wt%, the tensile strength of the PHEA-PSS/PEDOT hydrogels is close to 8 MPa, the electrical conductivity reach to 1.2 S cm−1 and the elasticity remain unchanged. Due to the presence of hydrogen and coordination bonds, CPHs have certain self-heal ability. In addition, the resistance of the hydrogel is sensitive to the changes of external pressure. The results show that CPHs can be used as a 3D printing material for flexible sensors.
Electron localisation descriptors in ONETEP: a tool for interpreting localisation and bonding in large-scale DFT calculations
Authors: Clements R J , Womack J C , Skylaris C-K 
Published: April 2020

Abstract
Electron localisation descriptors, such as the electron localisation function (ELF) and localised orbital locator (LOL) provide a visual tool for interpreting the results of electronic structure calculations. The descriptors produce a quantum valence shell electron pair repulsion (VSEPR) representation, indicating the localisation of electron pairs into bonding pairs and lone pairs in single molecules, coordination compounds and crystalline solids. We have implemented the ELF and LOL within ONETEP, a DFT code designed to perform calculations on systems containing thousands of atoms with plane-wave accuracy. This is possible using a linear-scaling formulation of DFT in which the Kohn–Sham orbitals are expressed in terms of a set of strictly localised non-orthogonal generalised Wannier functions (NGWFs), themselves expanded in a psinc basis set. In this paper, we describe our implementation and explore the chemical insights offered by electron localisation descriptors in ONETEP in a range of bonding and nonbonded situations.
Sedation Modulates Frontotemporal Predictive Coding Circuits and the Double Surprise Acceleration Effect
Authors: Witon Adrien , Shirazibehehsti Amirali , Cooke Jennifer , Aviles Alberto , Adapa Ram , Menon David K , Chennu Srivas , Bekinschtein Tristan , Lopez Jose David , Litvak Vladimir , Li Ling , Friston Karl , Bowman Howard 
Published: April 2020

Abstract
Two important theories in cognitive neuroscience are predictive coding (PC) and the global workspace (GW) theory. A key research task is to understand how these two theories relate to one another, and particularly, how the brain transitions from a predictive early state to the eventual engagement of a brain-scale state (the GW). To address this question, we present a source-localization of EEG responses evoked by the local-global task—an experimental paradigm that engages a predictive hierarchy, which encompasses the GW. The results of our source reconstruction suggest three phases of processing. The first phase involves the sensory (here auditory) regions of the superior temporal lobe and predicts sensory regularities over a short timeframe (as per the local effect). The third phase is brain-scale, involving inferior frontal, as well as inferior and superior parietal regions, consistent with a global neuronal workspace (GNW; as per the global effect). Crucially, our analysis suggests that there is an intermediate (second) phase, involving modulatory interactions between inferior frontal and superior temporal regions. Furthermore, sedation with propofol reduces modulatory interactions in the second phase. This selective effect is consistent with a PC explanation of sedation, with propofol acting on descending predictions of the precision of prediction errors; thereby constraining access to the GNW.
An Epidemic Recovery Framework to Jump-start Analysis, Planning, and Action on a Neglected Aspect of Global Health Security
Authors: Schoch-Spana Monica 
Published: April 2020

AbstractEpidemic readiness and response command the disproportionate attention of health security decision makers, planners, and practitioners, overshadowing recovery. How patients and their families, health organizations, community sectors, and entire societies recuperate from major outbreaks requires more systematic study and better translation into policy and guidance. To help remedy this neglected aspect of health emergency management, we offer a working definition for epidemic recovery and a preliminary model of postepidemic recovery. Guiding this framework’s development are insights gleaned from the more mature study of postdisaster reconstruction and rehabilitation as well as recognition that postoutbreak recovery—which involves infectious disease, a biological hazard—presents challenges and opportunities distinct from events involving geological or meteorological hazards. Future work includes developing a consensus around characteristics of successful epidemic recovery, applying these metrics to support preincident planning for postepidemic recovery, and using such a scheme to track and inform actual recovery from an epidemic.
Contact Tracing for COVID-19: An Opportunity to Reduce Health Disparities and End the Human Immunodeficiency Virus/AIDS Epidemic in the United States
Authors: Nosyk Bohdan , Armstrong Wendy S , del Rio Carlos 
Published: April 2020

Abstract
Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) testing and contact tracing have been proposed as critical components of a safe and effective coronavirus disease 2019 (COVID-19) public health strategy. We argue that COVID-19 contact tracing may provide a unique opportunity to also conduct widespread HIV testing, among other health-promotion activities.
Left atrial appendage thrombus on full-dose dabigatran treatment: a case report
Authors: Candelaresi Paolo , Iannuzzi Angela , Servillo Giovanna , Gottilla Rossella 
Published: April 2020

Abstract

Background
Dabigatran is a direct competitive thrombin inhibitor approved for stroke prevention in non-valvular atrial fibrillation. At full-dose, dabigatran showed similar rates of bleedings and higher efficacy compared to warfarin.

Case summary
We report a case of acute ischaemic stroke in a patient treated with dabigatran 150 mg b.i.d. for atrial fibrillation. After an off-label treatment with idarucizumab, a humanized monoclonal antibody approved for dabigatran reversal, we performed a successful intravenous thrombolysis (IVT). Transoesophageal echocardiography showed a left atrial appendage (LAA) thrombus, despite full-dose dabigatran and an adequate therapy adherence.

Discussion
There are few cases of LAA thrombus during dabigatran treatment reported in literature till date. We analyse the possible pathogenetic mechanisms involved in dabigatran failure, including drug interactions and unexpected genetic variations interfering with dabigatran serum levels suggesting periodical assessment of direct Oral Anticoagulant levels. Furthermore, we confirm initial reports of safety and efficacy of intravenous thrombolysis after idarucizumab, in case of dabigatran failure.
‘Minimalist approach’ for transcatheter mitral valve replacement using intracardiac echocardiography and conscious sedation: a case series
Authors: Cubeddu Robert J , Sarkar Abdullah , Navas Viviana , Navia Jose L 
Published: April 2020

Abstract

Background
Transcatheter aortic valve implantation operators have adapted to a less invasive technique by foregoing the use of general anaesthesia and transoesophageal echocardiography. This is known as a ‘minimalist approach’. This approach has yet to be explored in transcatheter mitral valve replacement (TMVR). Two patients with high perioperative risk underwent TMVR using only monitored conscious sedation (CS) and intracardiac echocardiography (ICE).

Case summary
The patients were symptomatic and required treatment of severe mitral regurgitation and severe mitral stenosis in a mitral valve ring and prosthetic mitral valve, respectively. With the use of an antegrade transseptal approach, the procedure was conducted under CS using ICE only. After placement of the prosthetic mitral valve, the valve was assessed by advancing the ICE catheter through the interatrial septal defect and no significant paravalvular leak occurred. In one case, ad hoc treatment of right to left shunting was successfully pursued. Valve function was excellent immediately and at 24 h after implantation and resulted in significant haemodynamic improvement.

Conclusion
With more TMVR cases being conducted, the ‘minimalist approach’ with CS and ICE may be considered in selected cases.
Mitral valve bio-prosthesis and annuloplasty thrombosis during extracorporeal membrane oxygenation: case series
Authors: Challa Abhinay , Latona Jilani , Fraser John , Spanevello Michelle , Scalia Gregory , Burstow Darryl , Platts David 
Published: April 2020

Abstract

Background
Veno-arterial extracorporeal membrane oxygenation (VA-ECMO) is a well-recognized form of haemodynamic support for patients with refractory cardiogenic shock, who are unable to be weaned off cardiopulmonary bypass. Thrombosis or bleeding from cannula sites or surgical wounds are the leading cause of morbidity and mortality in these patients, and presents a delicate balance of anticoagulation during management of patients undergoing circulatory support.

Case summary
In this case series, we discuss three cases of patients undergoing mitral valve replacements or repair with thrombosis of their new bio-prosthesis in the immediate post-operative setting. All three patients were supported with VA-ECMO post-operatively, and thrombosis occurred despite anticoagulation.

Discussion
During extracorporeal membrane oxygenation, the reduced flow throughout the heart increases the risk of intra-cardiac thrombosis. This is of particular importance in the context of mitral valve replacements and repairs, where the bio-prosthesis is an additional risk factor for thrombosis. Our cases demonstrate the morbidity and mortality of such complications, with the likely aetiology being low transvalvular flow in a newly inserted valve combined with the pro-thrombotic state created by the VA-ECMO circuit.
Delineating anatomy and function with multimodality imaging: a case report of giant right coronary artery aneurysms
Authors: Kassab Kameel , Iskander Mina , Malhotra Saurabh , Pyslar Nataliya 
Published: April 2020

Abstract

Background
Giant coronary artery aneurysms (CAAs) are rare and have been reported in patients with connective tissue diseases, arteritides, and atherosclerosis. Given the rarity of the condition, multimodality imaging is essential for comprehensive evaluation of coronary aneurysms and determination of their haemodynamic significance.

Case summary
A 58-year-old Filipino female was evaluated for dyspnoea on exertion of one month. Chest computed tomography (CT) showed right coronary artery (RCA) aneurysms. Invasive coronary angiogram (ICA) confirmed two giant aneurysms of the RCA. Distal RCA could not be opacified due to contrast stagnation in the proximal aneurysms. Coronary CT angiography (CCTA) depicted an additional giant distal RCA aneurysm not visualized on ICA with intraluminal thrombosis. Contrast-enhanced cardiac magnetic resonance imaging (CMR) revealed delayed time to peak perfusion in the mid to apical inferior walls, on first-pass imaging, without myocardial scarring. Late gadolinium images revealed aneurysmal wall inflammation.

Discussion
This case highlights the anatomical findings of giant CAA and the application of multimodality imaging for their accurate characterization. While ICA confirmed the presence of the aneurysms, CCTA enabled the assessment of their full extent and depict intraluminal thrombosis. Contrast-enhanced CMR delineated aneurysm wall characteristics, with first-pass images demonstrating reduced inferior wall perfusion at rest, which was likely the cause of patient’s exertional symptoms. Management of giant coronary aneurysms involves surgical resection with bypass grafting.