bluuebunny/crossref_metadata_2025 huggingface dataset:
Experimental investigation on the potential of the Feedback Fx-LMS Active Noise Control technology for use in industrial generator sets
Authors: Ciampolini Marco , Bosi Lorenzo , Romani Luca , Toniutti Andrea , Giglioli Matteo , Maccari Paolo , Farruggia Daniele , Ferrara Giovanni
Published: October 2021

Active Noise Control (ANC) has been considered a promising technology for the abatement of acoustic noise from the mid-20th century. Feedback and Feedforward ANC algorithms, based on the destructive interference principle applied to acoustic waves, have been developed for different applications, depending on the spectrum of the noise source. Feedback ANC algorithms make use of a single control microphone to measure an error signal which is then employed by an adaptive filter to estimate the noise source and generate an opposite-phase control signal. The Fx-LMS (Filtered-X Least Mean Square) algorithm is mostly adopted to update the filter. Feedback ANC systems have proven to be effective for the abatement of low-frequency quasi-steady noises; however, different challenges must be overcome to realize an effective and durable system for high-temperature application. This paper aims at experimentally assessing the feasibility of a Feedback Fx-LMS ANC system with off-line Secondary Path estimation to be used in mid-size diesel gensets for the reduction of the exhaust noise. Several solutions are proposed, including the mechanical design, the development of the Fx-LMS algorithm in the LabVIEW FPGA programming language, and the key features required to prevent parts from thermal damage and fouling. The developed prototype was implemented on a 50-kW diesel genset and tested in a semi-anechoic chamber. The noise abatement inside the exhaust pipe and at different measurement points around the machine was evaluated and discussed, showing good potential for improving the acoustic comfort of genset users.
Modeling and Analysis of a Micro Gas Turbine Fuelled with Hydrogen and Natural Gas Blends
Authors: Barati Shahrokh , De Santoli Livio , Basso Gianluigi Lo
Published: October 2021

This study deals with implementing an analytical model to simulate the energy performance associated with a Micro Gas Turbine when H2NG (Hydrogen Enriched Natural Gas) blends are used as fuel. The experimental campaign validated the simulation results at the actual operating conditions of the Micro Gas Turbine. The experimental campaign for model validation has been carried out over the spring and summer periods. Additionally, the MGT performance has been detected when fuelled H2NG with hydrogen fraction ranges between 0% vol. to 10% vol., with a 2% vol. Step., according to the main findings, the fuel consumption is reduced significantly. Also, heat recovery and electrical reliability improve slightly even though environmental factors influence the system. A numerical model was developed with MATLAB-Simulink to model the operation of the MGT. Thus, the relative standard errors affecting the main output parameters have been determined.
A geometric study of different curves for the rotor profiles of a twin-screw compressor
Authors: Giuffrida Antonio
Published: October 2021

This paper presents the results of comparisons among some patented solutions for profiling the contours of the rotors in twin-screw compressors. Referring to a base case where all the generating curves are circumferences, patents suggesting to replace arcs of circumference with arcs of conic sections, i.e. parabola, ellipse and hyperbola, but even a straight line segment, are presented and guidelines for rotor profile construction are reported. After setting the size of the compressor, attention is paid to the inter-lobe area, as the sum of the area between two consecutive lobes in the male rotor and of the area of the groove in the female rotor. Actually, this area is strictly related to the volume displacement. Limited to the current case study, the profile including an elliptic segment seems to be the preferable solution for higher inter-lobe area, then for higher displacement, though a number of considerations should be necessary for a broader context.
Numerical study of the lean premixed PRECCINSTA burner with hydrogen enrichment
Authors: Filomeno Giovanni , Capurso Tommaso , Torresi Marco , Pascazio Giuseppe
Published: October 2021

Hydrogen combustion is one of the most promising solution to achieve a global decarbonization in power production and transports. Pure hydrogen combustion is far from becoming a standard but, during the energy transition, hydrogen co-firing can be a feasible and economically attractive shortterm measure. The use of hydrogen blending gives rise to several issues related to flashback, NOx emissions and thermo-acoustic instabilities. To improve the understanding of the effect of hydrogen enrichment, herein a numerical analysis of lean premixed hydrogen enriched flames is performed by means of 3D unsteady CFD simulations. The numerical model has been assessed against experimental results for both cold and reacting flows in terms of velocity profile (average) and flame shape (mean OH* radical fields). The burner under investigation is the swirl stabilized PRECCINSTA studied at the Deutsches Zentrum für Luft-und Raumfahrt (DLR). The DLR’s researchers have shown the effect of hydrogen addition on the flame topology and combustion instabilities at various operating conditions in terms of thermal power, equivalence ratio and H2 volume fraction. Simulations are in good accordance with experimental data both in terms of velocity and temperature profiles. The numerical model provides a qualitative estimation of the flame shape.
Prognostic techniques for aeroengine health assessment and Remaining Useful Life estimation
Authors: Caricato A. , Ficarella A. , Chiodo L. Spada
Published: October 2021

Predictive maintenance is the latest frontier in the management and maintenance of many industrial assets, including aeroengines. Made possible by last decades advances in monitoring equipment and machine learning algorithms, it permits individual-based maintenance schedules, on the basis of performance monitoring and estimates resulting from the application of diagnostic and prognostic techniques, whether on ground or real time. Predictive maintenance results in operational cost reduction and asset usage optimization, if compared with traditional maintenance strategies, which instead may suffer from unanticipated failure or unnecessary maintenance and therefore higher operational costs. In the study, Remaining Useful Life (RUL) estimates will be carried out for different turbofan engines, based on historical individual and fleet data made available by the Prognostics Center of Excellence at NASA.

The design of Prognostics and Health Management (PHM) algorithms requires at first an analysis of available data to identify which of them is effectively related to equipment degradation and hence could be useful in determining future system evolution and predicting failure.

In particular, RUL prediction of test engines suffering from high pressure compressor fault with exponential degradation trend has been carried out with both regression and Artificial Neural Networks (ANNs). In turn, different regression models and neural network architectures have been compared, namely tree regression with different levels of tree depth, Gaussian Process Regression (GPR) with different kernel functions and Multilayer Perceptron (MLP) with one to three hidden layers and varying number of nodes. The objective is to demonstrate the capability of such machine learning algorithms to predict engine failure and thus their importance in supporting predictive maintenance planning, and to evaluate the quality of results in relation to the algorithm structure.

Results show comparable performance in terms of Mean Absolute Error (MAE) and Root Mean Square Error (RMSE) of predicted with respect to actual RUL, in particular predictions obtained through recourse to multilayer perceptron reveal to be the most accurate, with a RMSE of 17.38 and a MAE of 12.50.
Preliminary environmental and economic assessment of polyurethane foam produced by microwave-assisted liquefaction of riparian shrubs
Authors: Cardarelli Alessandro , Cotana Franco , Baffo Ilaria , Cavalaglio Gianluca , Barbanera Marco
Published: October 2021

The study aims to develop a full-scale plant to produce biobased PU foam from microwave liquefaction of riparian shrubs and to evaluate its environmental burden using a cradle-to-gate, scaled-up LCA approach. Life Cycle Inventory was built on experimental data for polyol synthesis by using Response Surface Methodology (RSM) to maximize the liquefaction yield. Bio-based PU foam was also compared with the petrochemical counterpart. Life Cycle Assessment was carried out using SimaPro 9.0 software and impacts were evaluated with EPD 2007 method. The results indicate that the methylene diphenyl diisocyanate production and the energy consumption for the liquefaction step are the major sources of impacts. Overall, the environmental superiority of biobased polyurethane cannot always be claimed with respect to their fossil counterpart. Finally, a simplified economic assessment showed that for the bio-based PU foam an interesting profitability could be obtained for a market price of 4.5 €/kg.
Visually low-impacting methods for the measurement of parameters related to IAQ risk indicators in exhibition halls
Authors: Cirrincione Laura , Ferrante Patrizia , La Gennusa Maria , Peri Giorgia , Rizzo Gianfranco , Scaccianoce Gianluca
Published: October 2021

Microclimate for cultural heritage plays a fundamental role in the degradation process of artefacts exhibited in museums. Generally, the Indoor Air Quality (IAQ) monitoring inside museums is based on conventional measurements of thermo-hygrometry parameters and longtime averaged measurements of atmospheric pollutants’ concentration. Unfortunately, all these approaches require electric supply and are usually characterized by a noticeable visual impact on the exhibition space, which clearly negatively affects the visitors’ experience. This paper intends to revisit and discuss a methodology (and its test application on field, to estimate the risk of damage of three artefacts displayed in an old museum of Palermo – Italy) perhaps prematurely underestimated that could usefully be re-proposed in particular contexts in which it is necessary to be careful to be as less invasive as possible, as in the case of museums housed in buildings of particular historical-cultural prestige. The discussed approach uses a non-destructive (or minimally invasive, at least) technique consisting in using two types of coupons, bi-metallic and marble ones, that allows an off-line monitoring of the indoor air aggressiveness inside museums, while avoiding consuming electricity and undesirable visual impacts on the site. Specifically, the estimated coupon damage is regarded as gauge to air aggressiveness, in order to provide an early warning of the risk of damage for the artefacts made of materials similar to those which the coupons are made of. Based on the considerations reported in the paper, the indirect evaluation of the air chemical aggressiveness through the assessment of the bi-metallic and marble coupons’ erosion seems to still candidates itself as a feasible method to be applied in complex exhibition scenes.
Possibilities of the power optimization in the Stirling cogeneration engine fuelled by the natural gas
Authors: Koščak Kolin Sonja , Naso Vincenzo , Binni Antonello , Bošnjak Antun
Published: October 2021

As the energy efficiency is at the heart of the integrated European Union energy policy, which aims to protect the environment through various research projects, the application of the Stirling engine for diffused electricity generation is one of the possible paths for low-carbon application. That is today particularly topical, just looking at the major interest paid at European level at the energy communities, also in terms of incentives and policies facilitating and supporting such initiatives. Although the tested engine V-160 runs on natural gas, its emissions can be neglected in comparison with the internal combustion engines, due to the much more favourable external combustion under the lower pressures and temperatures, as well as to the working medium, which is helium. Next step, becoming every day more and more relevant, will be using hydrogen as a clean (and green) fuel. A major advantage of the proposed engine for use in power generation is the constant speed under different loads. According to the thorough parametric analysis after 200 hours of operation of the engine at the University of Rome La Sapienza, new evidence of the possibilities of performance improvement was obtained. Compared to the Stirling engine with low temperature difference, it has a much lower Schmidt factor of about 21%, which means that a real thermodynamic efficiency of the cycle could be improved. The scope of the analysis was to determine the power that is changed due to the mass of helium and the power that is changed due to the temperature difference. Based on the experimental data, it is found that the temperature difference and the mass of the working medium have a reciprocal relationship. In such a working condition, the engine power is simultaneously increased due to the greater mass of helium, but at the same time decreased due to the decrease in the temperature difference, which is not valid for other types of Stirling engines. The resulting power can be optimized according to a new expression, presented in the paper.
Resonance Stirling Engine producing heat and power (CHP)
Authors: Schmid R. , Budliger J.P.
Published: October 2021

The free-piston Resonance Stirling engine forms a new “electricity producing heating system”. Its compact assembly operates reliably and at high efficiency, setting new standards for small heating systems. Complete units are currently submitted to a prolonged test program, preparing their production at an industrial scale.

The engines are heated from outside by a FLOX-burner (flameless flue gas recirculation burner), exposing the working gas to high temperatures. Even at low excess air rates the flue gases are virtually free of pollutants.

The free pistons of this resonance concept oscillate in a perfectly stable mode, entailing an important cyclic pressure swing to the working gas. The electric efficiency exceeds 25% and total efficiency (electricity + useful heat) lies above 90%. The heating power of the fuel is used with high benefit, promising a widespread application to this new technology.
A variant of the Fluidyne: the liquid piston ERICSSON engine
Authors: Chouder Ryma , Stouffs Pascal , Benabdesselam Azzedine
Published: October 2021

A special configuration of Stirling liquid piston engine, known as Fluidyne, was invented fifty years ago and many works have been devoted to it since then. A variant of the Fluidyne is presented, in which the two ends of the U-tube containing the liquid piston are closed by valves, so that the system obtained belongs to the family of Ericsson engines rather than to the family of Stirling engines. This type of low-tech system is considered to be suitable for the production of low-power mechanical energy (up to 1… kW), for example for pumping or to drive an electric generator from renewable primary energy conversion (solar, biomass, hot gaseous effluents, ). In the system considered, the working fluid of the Ericsson engine is air in open cycle. Different configurations are proposed for the extraction of mechanical energy. The preliminary design of a first demonstrator is presented. Results of a dynamic “intracycle” model of this liquid piston Ericsson engine are presented in the case of the coupling with a linear generator. The model allows to determine the frequency of operation of the engine, the instantaneous liquid piston position and the instantaneous working gas properties, so that the global performance of the engine can be predicted.
A Comprehensive Perspective of Waste Heat Recovery Potential from Solar Stirling Engines
Authors: Ramachandran Siddharth , Kumar Naveen , Mallina Venkata Timmaraju
Published: October 2021

Despite the higher efficiency advantage, the cost reduction of PV technology has been more successful compared to the dish Stirling engine (DSE) due to the large market volume and sturdy competition. Irrespective of the types of source, there exists a potential of waste heat recovery from Stirling engines operating at higher temperature regime. Accordingly, to make DSE commercially viable and efficient, innovative ways such as hybridization (combing a bottoming cycle), Co-generation, Tri-generation etc. need to be explored. In this paper, the techno-economic feasibility of hybridization of a typical solar DSE with a bottoming organic Rankine cycle (ORC) via. a heat recovery vapour generator (HRVG) is explored. The overall energetic and exergetic efficiency of the DSE has been improved by 5.79% and 5.64% while recovering the waste heat through a bottoming ORC. The design and effective incorporation of the HRVG with cooler side of the Stirling engine is identified to be crucial for the overall exergetic performance of solar Stirling-ORC. Further, the economic feasibility of a solar String-ORC combination is evaluated in terms of levelized cost of electricity (LCOE) and payback period. Both LCOE and payback period are found to be in comparable range with the PV technology.
Analysis of CO2 reduction with micro CHP facility: Renewable energies and Stirling engine
Authors: Auñon-Hidalgo Juan A. , Sidrach de Cardona Mariano , Auñón-Rodríguez Fernando , Cordón Marta
Published: October 2021

The Cogeneration laboratory is a research facility in the University of Málaga (UMA) that allows for the behavioural study of a renewable energy installation combining solar resources and micro-CHP. Energy generation in the system is provided by a 3 kWp photovoltaic array, two solar thermal connectors and a Whispergen EU1 Stirling micro-CHP unit. Energy storage in the facility is provided by water tank and lithium-ion battery. This laboratory is managed through a programmable Mitsubishi PLC that permits the simulation of different thermal and electrical load profiles, as well as the mode of operation. The electrical energy management is controlled by the solar inverter. Environmental data, are measured using a top of the line weather station.The system’s real time status is logged through the programmable PLC. All this data is transferred and analysed in a purpose-built MATLAB-based software, where power and energy balances are conducted, efficiencies are calculated, and a CO2 emissions evaluation is studied.The CO2 emissions analysis is carried to evaluate the carbon dioxide emissions generated by the facility when the electrical and thermal demand are provided by the joint solar and micro-CHP system. These emissions come from the burning of natural gas in the micro-CHP Stirling engine, and the usage of electricity from the grid. With the current mode of operation, a reduction of up to 70% in CO2 emissions has been achieved, with an energy generation that exceeds the demand.
Analysis of Thermodynamic Modelling for Gamma Type Double Piston Cylinder Engine
Authors: Abdul Rab Asary , Francesco Catapano , Bianca Maria Vaglieco
Published: October 2021

The exhaust of an automotive engine is one of the main causes of air pollution. These days, many researchers are investigating the waste heat recovery of automotive engines. A two-cylinder gamma-type Stirling engine is chosen for this purpose. The exhaust of a diesel engine is chosen as a heat input source for this purpose. This work explains the isothermal, ideal adiabatic, and non-ideal simple analysis of the Stirling engine. A set of differential equations are solved using Runge-Kutta 4th order method using MATLAB software. These equations describe the pressure, pressure variation, mass, mass flow, and energy flow in the Stirling engine which estimate the power and efficiency. Using non-ideal simple analysis, pressure drop analysis, piston finite speed, heat transfer losses of Stirling engine are calculated. The power estimated by isothermal, adiabatic, simple, and experimental analysis is 133.82 W, 143.75 W, 93.2 W, 111.43 W, and thermal efficiency is 30.70 %, 30.90%, 21.20%, 24.70% respectively. The results of these models are in close agreement with the experimental results.
Analysis of the operating parameters in a Stirling cryocooler
Authors: Maldonado Aguilar Diego José , Auñón Hidalgo Juan Antonio , Eskubi Mauri , Martínez Pablo
Published: October 2021

In this work, the results obtained in different tests performed on a Stirling cryocooler are shows, as well as a comparative analysis of these results with different load pressures. The prototype is a single-acting Stirling engine with a piston and displacer, which is used to liquefy air with helium as the working fluid; this is an integral Stirling (β-type). A three-phase asynchronous electric motor drives the Stirling engine and cooling, in the hot focus, is performed with a pressurized water circuit. In the cold focus are reached very low temperatures, around 75 K (-198 °C). The study has been developed at different load pressures of the working fluid and it shows a comparative analysis about the most important work parameters evolution. The parameters studied are the following: cooling water inlet and outlet temperatures, cold and hot focus temperatures, voltage and intensity consumed by the electric motor that drives the Stirling engine and quantity of liquid air obtained. The results show that it is very likely to use this configuration in industrial processes when they need cold and heat simultaneously.
Experiment Study of Ignition Characteristics in An Axial-flow-injector Burner for Stirling Engine
Authors: Kun Liu , Tian Lu , Jian Lan , Xiaoyu Huang , Guofeng Yin
Published: October 2021

To investigate the ignition characteristics of an axial-flow injection burner for a Stirling engine, a combustion chamber was designed. Diesel was used as fuel and oxygen as oxidant. The experiments of ignition characteristics were carried out with an electric plug igniter. The ignition characteristics under different combustion chamber pressure, pre-oxygen supply time, oxygen supply flow and ignition position were studied. The experimental results show that, with the increase of the pressure, the ignition time of the burner increases gradually, and the ignition success rate decreases gradually. The oxygen flow rate is related to ignition time in a certain range, while the pre-oxygen supply time has little effect. With the ignition position moving downward, the ignition time decreases gradually.
Unit boundary length quantum disk: a study of two different perspectives and their equivalence
Authors: Cerclé Baptiste
Published: October 2021

The theory of the two-dimensional Liouville Quantum Gravity, first introduced by Polyakov in his 1981 work has become a key notion in the study of random surfaces. In a series of articles, David, Huang, Kupiainen, Rhodes and Vargas, on the one hand, and Duplantier, Miller and Sheffield on the other hand, investigated this topic in the realm of probability theory, and both provided definitions for fundamentals objects of the theory: the unit area quantum sphere and the unit boundary length quantum disk. In a recent article, Aru, Huang and Sun showed that the definitions given in the case of the sphere coincide. We study here the two different perspectives provided for the unit boundary length quantum disk and show that they define the same probabilistic objects by considering two similar limiting procedures giving rise to them.
Zurück zum Sport nach einer Handverletzung
Authors: Seyhan Harun , Blömker Frank , Paries Cornelia , Zander Andrea
Published: October 2021

Liebe Leserinnen, liebe Leser!

Die Finger sind besonders bei Ballsportarten vielen Mikro- und Makrotraumen
ausgesetzt. In Deutschland treten jedes Jahr ca. 1,5 Millionen
Sportunfälle auf, 53% davon ereignen sich im Vereinssport,
47% beim Freizeitsport. Dabei wird immer die Frage gestellt, wann die
gewohnte Sportart nach einer Verletzung oder Operation an der Hand wieder
ausgeübt werden kann. Der Druck auf Sportler*innen ist immens
hoch, nach einer Verletzung über eine kurze Auszeit und schnelle
Rekonvaleszenz wieder Topleistungen bringen zu können.
Enterocutaneous Fistula and Pneumoretroperitoneum due to Ruptured Psoas Abscess
Authors: Patel Tapan , Patel Shivani
Published: October 2021

Psoas abscess is a rare condition that can present with vague clinical features. Its insidious onset can lead to a delay in diagnosis, resulting in high rates of complications and mortality. Here we describe a unique case of a patient presenting with enterocutaneous fistula and pneumoretroperitoneum due to ruptured psoas abscess.
Recent advances in the design of biosensors based on novel nanomaterials: An insight
Authors: Chauhan Nidhi , Saxena Kirti , Tikadar Mayukh , Jain Utkarsh
Published: October 2021

Biosensors have acquired much importance in drug discovery, medical diagnostics, food safety, defense, security, and monitoring of environmental conditions. Furthermore, there has been great progress in the potential applications of advanced nanomaterials in biosensors. Every year there are several advances in sensing techniques that can be attributed to nanomaterials, biorecognition elements, or their related fabrication techniques. The further development of nanotechnology-based sensors provides a wide variety of opportunities to modern research. Advanced nanomaterials can provide remarkable optical, electrical, mechanical, and catalytic properties. For example, transition metals and organic polymers have been used in the fabrication of powerful, sensitive, and precise biosensors. The distinctive properties of advanced nanomaterials have been widely incorporated into biosensors. However, fabrication techniques also play important roles in the development of these devices. Therefore, we present a review of some of the advanced nanomaterials that have been widely used over the last few years and discuss their fabrication techniques. The focus of this review is to provide a directional perspective of recently fabricated advanced nanomaterial-based biosensors in the diagnosis of various diseases.
People mistake the internet’s knowledge for their own
Authors: Ward Adrian F.
Published: October 2021

Significance

In the current digital age, people are constantly connected to online information. The present research provides evidence that on-demand access to external information, enabled by the internet and search engines like Google, blurs the boundaries between internal and external knowledge, causing people to believe they could—or did—remember what they actually just found. Using Google to answer general knowledge questions artificially inflates peoples’ confidence in their own ability to remember and process information and leads to erroneously optimistic predictions regarding how much they will know without the internet. When information is at our fingertips, we may mistakenly believe that it originated from inside our heads.
Are There Magnetars in High-mass X-Ray Binaries?*
Authors: Xu Kun , Li Xiang-Dong , Cui Zhe , Li Qiao-Chu , Shao Yong , Liang Xilong , Liu Jifeng
Published: October 2021

Magnetars form a special population of neutron stars with strong magnetic fields and long spin periods. About 30 magnetars and magnetar candidates known currently are probably isolated, but the possibility that magnetars are in binaries has not been excluded. In this work, we perform spin evolution of neutron stars with different magnetic fields in wind-fed high-mass X-ray binaries and compare the spin period distribution with observations, aiming to find magnetars in binaries. Our simulation shows that some of the neutron stars, which have long spin periods or are in widely-separated systems, need strong magnetic fields to explain their spin evolution. This implies that there are probably magnetars in high-mass X-ray binaries. Moreover, this can further provide a theoretical basis for some unclear astronomical phenomena, such as the possible origin of periodic fast radio bursts from magnetars in binary systems.
Switching dynamics in

-symmetric structures with saturable cubic nonlinear response
Authors: Chaudhary Priyanka , Mishra Akhilesh Kumar
Published: October 2021

In recent years, the field of

-symmetry has witnessed a surge of research interest due to its ability to exploit even the losses of the system.

-symmetry and its implications have been explored widely in the realm of photonics. In this work, we present a numerical investigation on the role of

-symmetry in switching characteristics of a fibre Bragg grating (FBG) with cubic saturable nonlinear response. We have explored such FBGs in both

-symmetric and broken

-symmetric regimes. In addition, we have also studied the effect of

-symmetry in switching characteristics of soliton pulse in directional coupler with saturable cubic nonlinear response and noticed that only unbroken regime provides switching in directional coupler.
Incommensurability-induced sub-ballistic narrow-band-states in twisted bilayer graphene
Authors: Gonçalves Miguel , Olyaei Hadi Z , Amorim Bruno , Mondaini Rubem , Ribeiro Pedro , Castro Eduardo V
Published: October 2021

We study the localization properties of electrons in incommensurate twisted bilayer graphene for small angles, encompassing the narrow-band regime, by numerically exact means. Sub-ballistic states are found within the narrow-band region around the magic angle. Such states are delocalized in momentum-space and follow non-Poissonian level statistics, in contrast with their ballistic counterparts found for close commensurate angles. Transport results corroborate this picture: for large enough systems, the conductance of samples with fixed width decreases with the system size in the longitudinal direction for incommensurate angles within the sub-ballistic regime. Our results show that incommensurability/quasiperiodicity effects are of crucial importance in the narrow-band regime. The incommensurate nature of a general twist angle must therefore be taken into account for an accurate description of magic-angle twisted bilayer graphene.
Systematic assessment of the biocompatibility of materials for inkjet-printed ozone sensors for medical therapy
Authors: Petani Lisa , Wehrheim Valerie , Koker Liane , Reischl Markus , Ungerer Martin , Gengenbach Ulrich , Pylatiuk Christian
Published: October 2021

The biocompatibility of medical sensors is of great importance. In order to prevent harm of the patient during measurement, this aspect must be considered throughout the entire design process. Biocompatibility can be achieved by various methods. For example, the sensor can be encapsulated, only biocompatible materials can be used for the sensor, or anti-inflammatory agents can be applied to the surface of the sensor. In this paper the focus is on sensors fully fabricated from biocompatible materials. Two exemplary inkjet-printed amperometric and impedimetric sensors are systematically assessed regarding their biocompatibility. Both sensors can be used for the measurement of dissolved ozone during oxygen-ozone injection therapy. For the sensors each material is evaluated with respect to the international standard ISO 10993. Overall, many amperometric and impedimetric sensors are fabricated from a small set of materials. The assessment reveals that for this specific application an amperometric sensor consisting of gold and silver nanoparticle inks, inkjet-printed on a polydimethylsiloxane membrane, and passivated with SU-8 ink offers the highest biocompatibility and reaches a good compliance with other important requirements. In addition, biological characterization tests are required for the specific medical application to validate the biocompatibility. From this study, it can be concluded that the findings on biocompatibility can also be transferred to other sensors that are made of the same set of materials but are for other applications. This applies to oxygen, glucose, pH, hydrogen peroxide, sweat lactate, and acetone sensors.
How Do We Jump-Start Self-measured Blood Pressure Monitoring in the United States? Addressing Barriers Beyond the Published Literature
Authors: Wall Hilary K , Wright Janet S , Jackson Sandra L , Daussat Lura , Ramkissoon Nar , Schieb Linda J , Stolp Haley , Tong Xin , Loustalot Fleetwood
Published: October 2021

Hypertension is highly prevalent in the United States, and many persons with hypertension do not have controlled blood pressure. Self-measured blood pressure monitoring (SMBP), when combined with clinical support, is an evidence-based strategy for lowering blood pressure and improving control in persons with hypertension. For years, there has been support for widespread implementation of SMBP by national organizations and the federal government, and SMBP was highlighted as a primary intervention in the 2020 Surgeon General’s Call to Action to Control Hypertension, yet optimal SMBP use remains low. There are well-known patient and clinician barriers to optimal SMBP documented in the literature. We explore additional high-level barriers that have been encountered, as broad policy and systems-level changes have been attempted, and offer potential solutions. Collective efforts could modernize data transfer and processing, improve broadband access, expand device coverage and increase affordability, integrate SMBP into routine care and reimbursement practices, and strengthen patient engagement, trust, and access.
Conserving threatened species during rapid environmental change: using biological responses to inform management strategies of giant clams
Authors: Watson Sue-Ann , Neo Mei Lin
Published: October 2021

Giant clams are threatened by overexploitation for human consumption, their valuable shells and the aquarium trade. Consequently, these iconic coral reef megafauna are extinct in some former areas of their range and are included in the International Union for Conservation of Nature (IUCN) Red List of Threatened Species and Convention on International Trade in Endangered Species of Wild Fauna and Flora. Now, giant clams are also threatened by rapid environmental change from both a suite of local and regional scale stressors and global change, including climate change, global warming, marine heatwaves and ocean acidification. The interplay between local- to regional-scale and global-scale drivers is likely to cause an array of lethal and sub-lethal effects on giant clams, potentially limiting their depth distribution on coral reefs and decreasing suitable habitat area within natural ranges of species. Global change stressors, pervasive both in unprotected and protected areas, threaten to diminish conservation efforts to date. International efforts urgently need to reduce carbon dioxide emissions to avoid lethal and sub-lethal effects of global change on giant clams. Meanwhile, knowledge of giant clam physiological and ecological responses to local–regional and global stressors could play a critical role in conservation strategies of these threatened species through rapid environmental change. Further work on how biological responses translate into habitat requirements as global change progresses, selective breeding for resilience, the capacity for rapid adaptive responses of the giant clam holobiont and valuing tourism potential, including recognizing giant clams as a flagship species for coral reefs, may help improve the prospects of these charismatic megafauna over the coming decades.
Willingness to participate in cardiac telerehabilitation: results from semi-structured interviews
Authors: Falter Maarten , Scherrenberg Martijn , Kindermans Hanne , Kizilkilic Sevda , Kaihara Toshiki , Dendale Paul
Published: October 2021

Aims

Cardiac rehabilitation (CR) is indicated in patients with cardiovascular disease but participation rates remain low. Telerehabilitation (TR) is often proposed as a solution. While many trials have investigated TR, few have studied participation rates in conventional CR non-participants. The aim of this study was to identify the percentage of patients that would be willing to participate in a TR programme to identify the main perceived barriers and facilitators for participating in TR.

Methods and results

Two groups of patients were recruited: CR non-participants and CR participants. Semi-structured interviews were conducted. Thirty non-participants and 30 participants were interviewed. Of CR non-participants, 33% would participate in TR and 10% would participate in a blended CR programme (combination of centre-based CR and TR). Of CR participants, 60% would participate in TR and 70% would be interested in a blended CR programme. Of those that would participate in TR, 44% would prefer centre-based CR, 33% would prefer a blended CR programme, and 11% would prefer a full TR programme. In both groups, the main facilitating aspect about TR was not needing transport and the main barrier was digital literacy.

Conclusion

For CR non-participants, TR will only partly solve the problem of low participation rates and blended programmes might not offer a solution. Cardiac rehabilitation participants are more prepared to participate in TR and blended CR. Digital literacy was in both groups mentioned as an important barrier, emphasizing the challenges for healthcare and local governments to keep educating all types of patients in digital literacy.
Oral anticoagulation therapy with rivaroxaban in elderly patients with atrial fibrillation. Results from EMIR study
Authors: Esteve Pastor M , Marin F , Anguita M , Sanmartin M , Rafols C , Roldan V , Perez C , Barrios V , Lekuona Goya I , Perez Cabeza A , Cosin Sales J ,   EMIR study investigators
Published: October 2021

Background

Atrial fibrillation (AF) in elderly patients increases both bleeding and thromboembolic risks. Elderly patients benefit as much from anticoagulation therapy with positive net clinical benefit. However, there have been few studies that focused on the efficacy and safety of direct oral anticoagulants in elderly patients.

The aim of this subanalysis from EMIR study was to assess the effectiveness of rivaroxaban in patients older than 75 years old.

Methods

EMIR Study (acronym from 'Estudio observacional para la identificaciόn de los factores de riesgo asociados a eventos cardiovasculares Mayores en pacientes con fIbrilaciόn auricular no valvular tratados con un anticoagulante oral directo (Rivaroxaban)') was an observational, multicenter, post-authorization and prospective study that involved AF patients under oral anticoagulation with rivaroxaban at least 6 months before enrolment. We analyzed baseline clinical characteristics and adverse events after 2.5 years of follow up.

Results

We analyzed 1,433 patients with median age of 74.7 (67.7–81.6). Of them 691 (48.2%) were ≥75 years. Elderly patients had higher prevalence of cardiovascular risk factors such previous stroke (16.8% vs 8.5%; p<0.001), heart failure (25.0% vs 20.6%; p<0.001), higher CHA2DS2-VASc (4.4±1.3 vs 2.7±1.2; p<0.001) and HAS-BLED (1.9±1.0 vs 1.2±1.0; p<0.001) scores. After 2.5 (2.2–2.6) years of follow-up, we observed low rate of adverse events in patients under rivaroxaban therapy. We observed higher rate of adverse events in elderly population for thromboembolic events (1.13%/year vs 0.36%/year; p=0.017) and major bleeding events (1.80%/year vs 0.36%/year; p<0.001) but those adverse rates were lower than expected according to previous studies (i.e. ROCKET-AF trial, rivaroxaban group had 4.86%/year of major bleeding or in XANTUS study was 3.2%/year of major bleeding in patients >75 years). We did not observe differences between groups from MACE (1.13%/year vs 1.01%/year; p=0.875) or cardiovascular death (0.86%/year vs 0.42%/year; p=0.170).

Conclusion

In real-world elderly population, rivaroxaban showed higher rates of thromboembolic and major bleeding events in elderly patients but with annual rates lower than expected according to previous studies like ROCKET-AF or XANTUS. Similar annual rates in elderly were observed for MACE and cardiovascular mortality than in younger patients, being rivaroxaban a good therapeutic alternative even for the elderly.

Funding Acknowledgement

Type of funding sources: Private grant(s) and/or Sponsorship. Main funding source(s): Bayer Hispania S.L.
Evolocumab, a PCSK9 inhibitor, co-incubated with doxorubicin and trastuzumab reduces death of cardiomyocytes through reduction of MyD88-NLRP3-NF-kB-mTORC1
Authors: Quagliariello V , Bonelli A , Paccone A , Buccolo S , Iovine M , Conforti G , Botti G , Maurea N
Published: October 2021

Introduction

Inhibition of proprotein convertase subtilisin/kexin type 9 (PCSK9) is a novel treatment for hypercholesterolaemia; recent studies evidenced that PCSK9i reduces cardiovascular diseases and risk of atherosclerosis. Evolocumab, a PCSK9i, reduced the risk of cardiovascular events in patients with atherosclerotic cardiovascular diseases when added to maximally tolerated statin therapy (± ezetimibe), and recent data from the ODYSSEY OUTCOMES trial indicate that alirocumab added to maximally tolerated statin therapy (± other lipid-lowering drugs) reduces the risk of cardiovascular events in patients with a recent acute coronary syndrome.

Purpose

Considering the expression of PCSK9 in heart tissues and cardiomyocytes, we aimed to study for the first time the putative cellular effects of evolocumab in human cardiomyocytes incubated with doxorubicin, trastuzumab, their sequential treatments

Methods

Human fetal cardiomyocytes (HFC cell line) were exposed to subclinical concentration of doxorubicin, trastuzumab, sequential treatment of both (all 100 nM), alone or in combination with evolocumab (50 nM) for 48h. After the incubation period, we performed the following tests: determination of cell viability, through analysis of mitochondrial dehydrogenase activity, study of lipid peroxidation (quantifying cellular Malondialdehyde and 4-hydroxynonenal), intracellular Ca2+ homeostasis. Moreover, pro-inflammatory studied were also performed (activation of NLRP3 inflammasome; expression of TLR4/MyD88; mTORC1 Fox01/3a; transcriptional activation of p65/NF-κB and secretion of cytokines involved in cardiotoxicity (Interleukins 1β, 8, 6).

Results

Evolocumab co-incubated with doxorubicin alone or in sequence with trastuzumab exerts cardioprotective effects, enhancing cell viability of 35–43% compared to untreated cells (p<0,05 for all); Evolocumab reduced significantly the cardiotoxicity through MyD88/NF-KB/cytokines axis and mTORC1 Fox01/3α mediated mechanisms.

Conclusion

PCSK9 inhibitor evolocumab exerts direct cellular effects in cardiomyocytes during doxorubicin and trastuzumab exposure with anti-inflammatory effects. These results indicated that evolocumab should be studied in cancer-bearing mice treated with anthracyclines and HER2-blocking agents in order to reduces cardiovascular events.

Funding Acknowledgement

Type of funding sources: Public grant(s) – National budget only. Main funding source(s): Ministero della Salute, Ricerca Corrente Project
Automated processing of thermal imaging to detect COVID-19 and microvascular dysfunction
Authors: Brzezinski R Y , Rabin N , Lewis N , Peled R , Tsur A , Kerpel A , Marom E M , Shenhar-Tsarfaty S , Naftali-Shani N , Rahav G , Grossman E M , Zimmer Y , Ovadia-Blechman Z , Leor J , Hoffer O
Published: October 2021

Background

Coronavirus disease 2019 (COVID-19) is associated with microvascular dysfunction. Non-invasive thermal imaging can hypothetically detect changes in perfusion, inflammation and vascular injury. We sought to develop a new point-of-care, non-contact thermal imaging tool to detect COVID-19 by microvascular dysfunction, based on image processing algorithms and machine learning analysis.

Materials and methods

We captured thermal images of the back of 101 individuals, with (n=62) and without (n=39) COVID-19, using a portable thermal camera that connects directly to smartphones. We developed new image processing algorithms that automatically extract multiple texture and shape features of the thermal images (Figure 1A). We then evaluated the ability of our thermal features to detect COVID-19 and systemic changes of heat distribution associated with microvascular disease. We also assessed correlations between thermal imaging to conventional biomarkers and chest X-ray (CXR).

Results

Our novel image processing algorithms achieved up to 92% sensitivity in detecting COVID-19 with an area under the curve of 0.85 (95% CI: 0.78, 0.93; p<0.01). Systemic alterations in blood flow associated with vascular disease were observed across the entire back. Thermal imaging scores were inversely correlated with clinical variables associated with COVID-19 disease progression, including blood oxygen saturation, C- reactive protein, and D-dimer. The thermal imaging findings were not correlated with the results of CXR.

Conclusions

We show, for the first time, that a hand-held thermal imaging device can be used to detect COVID-19. Non-invasive thermal imaging could be used to screen for COVID-19 in out-of-hospital settings, especially in low-income regions with limited imaging resources. Moreover, thermal imaging might detect micro-angiopathies and endothelial dysfunction in patients with COVID-19 and could possibly improve risk stratification of infected individuals (Figure 1B).

Funding Acknowledgement

Type of funding sources: Public Institution(s). Main funding source(s): 1. The Israel Innovation Authority2. The Nicholas and Elizabeth Slezak Super Center for Cardiac Research and Biomedical Engineering at Tel Aviv University Figure 1. A. Representative steps of our thermal image processing algorithms. B. A schematic illustration of the research design and potential impact.