bluuebunny/crossref_metadata_2025 huggingface dataset:
Design improvement of an airbox for a passenger vehicle
Authors: Tan J , Abu Bakar N Z
Published: December 2021

The purpose of an airbox is to provide the engine with a clean air flow for combustion. The high velocity of the fluid flow across the airbox will create a pressure drop resulting a decline in the vehicle’s performance. This project collaborates with an Original Equipment Manufacturer (OEM) to develop a numerical simulation model for a new airbox design and to compare its pressure drop with OEM production design. Reducing the pressure drop across the airbox can increase the efficiency of a vehicle, hence, reducing CO2 emissions. This research focuses on the passenger type vehicle as it is the highest source of carbon dioxide (CO2) being emitted for road transportation and these pollutant emissions have also caused many health problems on human. ANSYS Fluent program was used to carry out Computational Fluid Dynamics (CFD) simulation for both OEM and the new design. Then, the same simulation setup was used for the new design. The inlet size of the new design is larger when compared to the OEM design. After analysing both models, it was determined that the main reason behind the pressure loss was caused by the shape of the airbox and turbulent flow inside. The new airbox design shows reduction of 96% in the pressure drop within it and in return, enhancing the performance of the passenger vehicle. This conclude that numerical simulation model is able to provide a good indicator for the designer to choose the best design and proceed with fabrication and conduct actual test, thus saving a lot of prototyping and repeated testing cost.
Effect of the wing airfoil shape on the aerodynamics and performance of a jet-trainer aircraft – An optimization approach
Authors: Othman K A , Mahdi Al-Obaidi A S
Published: December 2021

Among the key factors in developing the performance of military aircraft are its aerodynamic characteristics and performance. This research presents the effect of shape of the wing airfoil on the aerodynamic characteristics and performance of the popular jet trainer aircraft L-39C. The aerodynamic data of different airfoil shapes were used to determine the aerodynamic characteristics and performance of the L-39C for different airfoil shapes in an effort to optimize the aircrafts aerodynamic and performance. NACA 64A012 airfoil is currently used on the L-39C, however, there may exist many airfoils that may have potential to improve the aerodynamic characteristics and hence the aircraft performance. For this purpose, a group of NACA airfoils are selected, namely, NACA 4412, NACA 2415, NACA 64212 and NACA 64215. Each of these airfoil influences the aerodynamic characteristics of the aircraft and hence its performance. For each airfoil, the aircraft performance in terms of thrust required, power required, and rate of climb at different altitudes and airspeeds are calculated and analysed. The airfoil data were calculated at cruising flight at zero angle of attack to reduce the variables that can affect the calculations. The results of the calculation and analysis showed that NACA 4412 has significant results in terms of aerodynamic characteristics although in terms of aerodynamic performance, the NACA 64A012 and NACA 4412 showed lower thrust required and power required. NACA 4412 has a (C

L
)max of 1.67, whereas NACA 64A012 has a (C

L
)max of 1.336, indicating that the airfoil stalled early at higher altitudes. NACA 4412 also showed better results in terms of aerodynamic characteristics compared to the other selected airfoils although NACA 64A012 shows some variance in the results. NACA 4412 and NACA 64A212 have shown to be promising in aerodynamic characteristics and performance where one has its own benefits over the other. Although in the end, NACA 4412 may be recommended for its aerodynamic characteristics and performance.
Effect of voltage and anodizing time on nano colloidal silver
Authors: Ravendran N , Chou P M
Published: December 2021

The objective of the present study was to investigate the effect of voltage and anodizing time on the average particle size of nano colloidal silver. The results of the zeta sizer analysis showed that the average particle size of the nano colloidal silver increased with increasing the voltage. On the other hand, anodizing time did not show a specific effect on the average particle size of the nano colloidal silver. The results also show that the samples prepared at 20 V with anodizing time of 2 hours exhibits an average particle size of less than 100 nm, which is potential to be used as disinfectant spray. Also, it shows that electrolysis is a suitable method to produce nano colloidal silver.
Recycling Polymer Blend made from Post-used Styrofoam and Polypropylene for Fuse Deposition Modelling
Authors: William L J W , Koay S C , Chan M Y , Pang M M , Ong T K , Tshai K Y
Published: December 2021

Fuse deposition modelling (FDM) has become a revolutionary manufacturing technology as it offers numerous advantages, including freedom of fabrication, mass customisation, fast prototyping, and cost-effectiveness. Thermoplastic material is commonly used as feedstock for FDM process. The current state of material development, the recycled plastic material also can be used as printing material for FDM machine. Expanded polystyrene (EPS) has been extensively used as packaging materials for many industries but rarely be recycled, as its relatively large volume with minimal weight is unconducive for transportation. This research aimed to utilize EPS waste and turn it into FDM feedstock. This research also aims to enhance the properties of recycled polystyrene (rPS) made from EPS waste by blending it with polypropylene (PP). Different ratios of rPS/PP blends were prepared and extruded into FDM filament using filament extruder. The formulated filaments were printed into specimen using FDM machine. This research found the filament made from rPS/PP blends can be printed into specimen with good printing quality if the nozzle temperature controlled at 240° C with 120 % extrusion rate. With this printing parameter, the specimen printed with rPS/PP blend filament exhibit the greatest adhesion between the deposited layers without any visible voids or gaps. Besides, the printed specimen with rPS/PP blends possess lower tensile strength, but higher tensile modulus as compared to the printed specimen with neat rPS. The addition of more PP decreased both tensile strength and modulus of rPS/PP blends. On the other hand, the rPS/PP blends have higher thermal stability as the PP content increased. Overall, the rPS/PP blends filament shows a great potential as a feedstock material for FDM fabrication.
Reference Current Generation for Active Power Filtering in Single-Phase Power System
Authors: Chew Siew Ting , Hoon Yap , Ahmad Hafisoh
Published: December 2021

The study presents a new proposed reference current generation algorithm based on the synchronous reference frame (SRF) conventional algorithm in single-phase power system for an active power filtering. Shunt active power filter (SAPF) is often used as it can mitigate harmonic currents in the AC networks due to its superiority in dynamic-state conditions. The reference current generation algorithm is the most important control algorithms to control SAPF as it has the simplest implementation features. A proposed STF-based fundamental component identifier (STF-FCI) algorithm is implemented for the major improvements such as the removal of the unnecessary cosine function to reduce complexity of algorithm, employment of self-tuning filter (STF) to extract accurate fundamental component and to generate a sinusoidal reference current. The purpose of developing STF-FCI algorithm is to replace low pass filter (LPF) with a mean as it can generate a fast and accurate fundamental reference current to operate the SAPF in reducing the harmonics content of the power system and provide a fast response time in the dynamic-state conditions. This paper is presented under both steady-state which is capacitive (RC) load or inductive (RL) load as well as dynamic condition where capacitive load change to inductive load. The performance of steady-state condition will be evaluated in terms of THD values, ripple factor, power factor and phase difference. Under dynamic-state condition, the dynamic speed will be evaluated to capture the speed of the amplitude change in nonlinear load in a period of time. MATLAB-Simulink is used to design and evaluate the proposed STF-FCI algorithm with mean algorithm and LPF algorithm for comparison purpose. The simulation results had shown the major improvement when THD values, ripple factor, power factor and phase difference are reduced. The response time of the changing load is shorter by using mean algorithm compare to LPF algorithm. The simulation results obtained proved success when the proposed STF-FCI algorithm using mean algorithm are much better than LPF algorithm in steady-state and dynamic conditions under two voltage conditions i.e. ideal and distorted voltage.
The application of image processing for monitoring student’s attention level during online class
Authors: Ong J W , Chew W J , Phang S K
Published: December 2021

With the COVID-19 pandemic still causing the world to be quarantined in their house to prevent the spread of the virus, this means online classes are still the main method of conducting classes. This project aims to help lecturers monitor the students during class as they are having problems checking whether the students are paying attention or not. This project uses the student’s facial features to determine their attention level using two different coding algorithm Viola-Jones and Sobel edge. These two algorithms help to determine what kind of facial expression that the students are making. The Viola-Jones algorithm detects and captures the student’s facial features such as eyes and mouth while the Sobel edge algorithm detects the edges of the facial features to determine whether the eyes and mouth are open or closed. With the data collected it will run through the database to determine the student’s attention level and inform the lecturer.
Analysis of physics learning media needs based on mobile augmented reality (AR) on global warming for high school students
Authors: Nor M. , Halim Lilia
Published: December 2021

The rapid progress of the times requires an educational approach to be innovative and adaptive to changes in technology and information. Mobile Augmented Reality (MAR) is a system that incorporates technology in education. This method facilitates learning to be interesting, effective, and easily accessible to everyone. This survey research was an initial step in developing Augmented Reality based Modules for high school students on global warming. The importance of this research is that educational media using Augmented Reality is relatively new in the field of educational media. Analysis of learning problems and analysis of students are the two indicators used in the analysis of this need. Based on this research survey, it was found that augmented reality based educational media is viewed as important and necessary as learning materials in schools especially for students of high ability. The next phase is the development of MAR-based learning media that meets these requirements.
Identifying students’ difficulty in the basic of thermodynamics
Authors: Sutarja M C , Wulandari A Y R
Published: December 2021

Conceptual understanding is one of the main topics in physics educational research. It is important as the basic of other ability in education, such as argumentation, making scientific explanation and problem solving. This survey study aims to identify students’ difficulty to understand the basic of thermodynamics. There are 128 first year undergraduate students as the participants of the study. The data collection method is test. Result of the study shows that isobaric process of ideal gas and mechanical equilibrium state concepts are the most difficult concepts. Some difficulties are found in understanding the basic of thermodynamics: (1) because of the presence of higher cognitive load while solving conceptual problems, (2) when the question demands other ability, especially mathematical ability, to solve the conceptual problem, (3) because of students’ disability to integrate the knowledge. This study could be used to develop learning instruction or media in basic physics or introduction of thermodynamics course.
Development of Thermal Energy Conversion Devices into Electrical Energy as Physics Learning Teaching Aids
Authors: Umam D K , Saehana S , Kade A , Yunanli
Published: December 2021

This research aimed to produce a device for converting heat energy into electrical energy as a teaching aid for physics. This research process is development research, which refers to the Research and Development (R&D) model. The instrument used was a questionnaire with a five Likert scale, which addressed media experts, material experts, physics teachers in SMA Negeri 2 Sigi, and class XII MIA SMA Negeri 2 Sigi students. The product quality data obtained were analyzed using descriptive analysis. Based on the analysis of the media expert’s assessment, the quality of the product obtained a percentage value of 87.69% with the interpretation of “Very Good”. Based on the analysis of the assessment by material experts, the quality of the product obtained a percentage value of 84.44% with the interpretation “Very Good”. For the results of the physics teacher’s response, a percentage value of 86.00% was obtained with the interpretation “Strongly Agree”. For the results of the responses of class XII MIA students in the limited test, a percentage value of 83.56% was obtained with the interpretation “Strongly Agree”. The test results and questionnaire analysis showed that the heat energy conversion device developed into electrical energy was feasible to use.
What we can learn from 2018 liquefaction in Central Sulawesi: Stories from the survivors
Authors: Wahyono U , Astuti N M Wiwik
Published: December 2021

This paper provides the stories of the liquefaction survivors about their experiences during and after the disaster. It is a phenomenological study that used the semi-structured interview to obtain the data. The data were acquired from 30 participants. There are some important points that can be summarised from the stories of the survivors. During the disaster, local people inclined to underestimate the quake at the beginning of the shaking. It could indicate the level of their risk perception and awareness on disaster. In addition, a unique finding from this study was that the survivors had conducted the initial intervention priority as basic resources for survival such as shelter and information of the victims’ identity. Also, regarding the post-disaster data, the results indicated that the survivors experienced the symptoms of trauma due to the disaster. It indicates that the psychological aspect of the survivors was neglected during the recovery process. On that regard, long-term traumatic recovery activities should be put into accounted during the recovery processes for all the victims of a disaster regardless of their ages and genders. Another implication of this study is the opportunity to use these stories into learning activities, both in learning about science or disaster mitigation.
Design and Simulation of Electro-hydraulic Control Valve Based on AMESim
Authors: Li Bin , Li Guyang , Wu Wangyang , Zhang Xue , Guo Song , Wang Nei , Mao Xuyao
Published: December 2021

In this paper, the electro-hydraulic control valve commonly used in ships is taken as the research object, the working principle of the valve is introduced, the model of the valve is established by AMESim software, the model parameters are set and the simulation analysis is carried out. By changing the relevant parameters of the valve, the response speed of the valve can be improved. The simulation results show that the pressure area of load sensitive cavity and the diameter of damping hole have obvious influence on the response speed of valve.
Study on Optimization of Operating Parameters of Contact Mechanical Seal Based on Orthogonal Test
Authors: Dai LuLing
Published: December 2021

The working condition parameters of common contact mechanical seals are experimentally studied by orthogonal experimental design. The effects of working condition parameters on mechanical seal performance are compared by variance and range analysis, and the optimal sealing working condition is put forward. The results show that the spring specific pressure has a great influence on the leakage of mechanical seal, and the leakage decreases rapidly with the increase of spring specific pressure; With the increase of spring specific pressure, the friction power consumption increases. According to the test results, considering the requirements of mechanical seal performance and service life, the optimal spring specific pressure is 0.028 MPa under the condition of medium pressure ps
=0.60 MPa and motor speed n =2960 r/min. At this time, the leakage is 6.120 ml/h and the friction power consumption is 0.648 kW.
Simulation analysis and experiment of sampling process of wheel brush sampler based on discrete element method
Authors: Wei Qiming , Liu Ran , Zhang Hua , Wu Xingyuan , Luo Haitao
Published: December 2021

In order to study the brush sweep sampling process through simulation analysis, the structure of the asteroid sampler is simplified on the basis of retaining the wheel brush. Soybean particles are selected as the verification sampling particles, and the physical and contact parameters of calibrated soybean particles are applied to the discrete element simulation software EDEM and the relationship between the sampling wheel brush speed and torque is analysed. At the same time, a set of wheel brush asteroid sampler ground torque test system is built to verify the accuracy of the discrete element simulation results. The results show that the driving torque of the sampling wheel brush is mutational in the process of sampling, and the faster the rotation speed of the sampling wheel brush, the more the mass of the collected particles, and the greater the driving torque required for the sampling wheel brush. This research provides a method basis for the structure selection and parameter optimization design of the asteroid sampler.
Cluster analysis of time series K-Means line loss based on DWT distance
Authors: Song Liming , Chen Zhimin , Meng XinXin , Kang Shuai
Published: December 2021

This paper constructs an indicator system composed of inherent attributes and time characteristics of the line based on the line loss, and proposes a K-Means line loss cluster analysis model based on this indicator system. The line is classified according to the clustering results. The result is 314.51 on the CH index (Calinski Harabasz Index), 0.19 on the Silhouette Cofficient (Silhouette Cofficient), and a running time of 0.508s. Compared with the traditional algorithm, it is greatly improved. The field of line loss analysis has guiding significance.
Data Security Protection Mechanism of Video and Image Feature Modeling Based on Domestic Crypto Algorithm
Authors: Tu Yueqiang
Published: December 2021

Video and image monitoring is increasingly appearing in our home, travel and other aspects. Through video and image analysis and comparison of video and image monitoring data, it can provide strong analysis support capabilities for social security prevention and control, traffic command, safety production and so on. Video and image feature modeling is a necessary prerequisite for video and image analysis and comparison. Video and image feature modeling forms video and image feature data. Video and image feature data reflects the most essential information of various elements such as people, vehicles and objects. However, video and image data is easy to be damaged, changed and leaked in the process of collection, aggregation, analysis, modeling and storage, Facing data security risks. This paper proposes a set of video and image feature modeling data security protection mechanism based on domestic algorithm to realize the whole process encryption protection of data acquisition, transmission and storage.
A Graph Neural Network gas concentration prediction model based on Spatio-Temporal data
Authors: Zhang Zhaozhao , Ye Yuhao , Dong Lihong
Published: December 2021

For the problem of low prediction accuracy caused by traditional neural network gas concentration prediction models which did not consider temporal and spatial characteristics of gas data, this paper proposed a Spatial-Temporal graph neural network gas prediction model based on Spatial-Temporal data. Its essence was the integration of graph convolutional network and WaveNet network. In spatial dimension, graph convolutional network was used to aggregate the information of neighbor nodes, and adaptively adjusts the spatial association strength of each node according to the attention mechanism to captured the spatial characteristics of gas data. In temporal dimension, WaveNet network model was introduced, Dilated Causal Convolution was used to extract the temporal characteristics of gas data on temporal dimensions. According to the distance between gas sensors in the mine, the gas data spatial structure was constructed by Thresholded Gaussian kernel function. Experiment with the measured gas temporal and spatial data, using Mean Absolute Error (MAE) as an indicator of predictive accuracy. The experimental results show that the prediction model mentioned in this paper is significantly improved compared with the prediction accuracy of other predictive models.
Advanced NIR ratiometric probes for intravital biomedical imaging
Authors: Huang Haoying , Qiu Ruijuan , Yang Hongchao , Ren Feng , Wu Feng , Zhang Yejun , Zhang Hong , Li Chunyan
Published: December 2021

Near-infrared (NIR) fluorescence imaging technology (NIR-I region, 650–950 nm and NIR-II region, 1000–1700 nm), with deeper tissue penetration and less disturbance from auto-fluorescence than that in visible region (400–650 nm), is playing a more and more extensive role in the field of biomedical imaging. With the development of precise medicine, intelligent NIR fluorescent probes have been meticulously designed to provide more sensitive, specific and accurate feedback on detection. Especially, recently developed ratiometric fluorescent probes have been devoted to quantify physiological and pathological parameters with a combination of responsive fluorescence changes and self-calibration. Herein, we systemically introduced the construction strategies of NIR ratiometric fluorescent probes and their applications in biological imaging in vivo, such as molecular detection, pH and temperature measurement, drug delivery monitoring and treatment evaluation. We further summarized possible optimization on the design of ratiometric probes for quantitative analysis with NIR fluorescence, and prospected the broader optical applications of ratiometric probes in life science and clinical translation.
Landscape resource management for sustainable crop intensification
Authors: Anantha K H , Garg Kaushal K , Singh Ramesh , Akuraju Venkataradha , Dev Inder , Petrie Cameron A , Whitbread Anthony M , Dixit Sreenath
Published: December 2021

Crop intensification is required to meet the food demands of an increasing population. This paper presents data from three paired scaling-up initiatives to compare the benefits of landscape-based interventions over individual plot-level interventions using evidence generated in the Indian semi-arid tropics. A range of soil and water conservation interventions were implemented in a decentralized manner following the landscape-based approach. The plot-level approach focused only on balanced fertilizer application and improved crop cultivars while the landscape-based interventions primarily addressed moisture availability, which was the key to reducing risks of crop failure besides aiding productivity gain and enhanced land and water-use efficiency. These interventions have additionally harvested 50–150 mm of surface runoff and facilitated groundwater recharge in 550–800 mm rainfall zones. Individual plot-level interventions also improved the crop yield significantly over the control plots. However, crop intensification was not achieved due to limited moisture availability. Landscape-based interventions produced 100%–300% higher crop production per year, greater income generation (>100%), and improved water productivity. Landscape-based interventions were also found to be beneficial in terms of reducing soil loss by 75%–90% and improving base flow availability additionally by 20–75 d in a year compared to untreated watersheds. With increased moisture availability, fallow lands in respective watersheds have been utilized for cultivation, thereby enhancing crop intensification. The findings of the study provide critical insights into the design of approaches suitable for scaling-up projects in order to both create impact and target the United Nations Sustainable Development Goals.
The cyber-consciousness of environmental assessment: how environmental assessments evaluate the impacts of smart, connected, and digital technology
Authors: Mulrow John , Gali Manasi , Grubert Emily
Published: December 2021

Digitally enabled technologies are increasingly cyber-physical systems (CPSs). They are networked in nature and made up of geographically dispersed components that manage and control data received from humans, equipment, and the environment. Researchers evaluating such technologies are thus challenged to include CPS subsystems and dynamics that might not be obvious components of a product system. Although analysts might assume CPS have negligible or purely beneficial impact on environmental outcomes, such assumptions require justification. As the physical environmental impacts of digital processes (e.g. cryptocurrency mining) gain attention, the need for explicit attention to CPS in environmental assessment becomes more salient. This review investigates how the peer-reviewed environmental assessment literature treats environmental implications of CPS, with a focus on journal articles published in English between 2010 and 2020. We identify nine CPS subsystems and dynamics addressed in this literature: energy system, digital equipment, non-digital equipment, automation and management, network infrastructure, direct costs, social and health effects, feedbacks, and cybersecurity. Based on these categories, we develop a ‘cyber-consciousness score’ reflecting the extent to which the 115 studies that met our evaluation criteria address CPS, then summarize analytical methods and modeling techniques drawn from reviewed literature to facilitate routine inclusion of CPS in environmental assessment. We find that, given challenges in establishing system boundaries, limited standardization of how to evaluate CPS dynamics, and failure to recognize the role of CPS in a product system under evaluation, the extant environmental assessment literature in peer-reviewed journals largely ignores CPS subsystems and dynamics when evaluating digital or digitally-enabled technologies.
On the degrees of irreducible factors of a polynomial
Authors: Jakhar Anuj , Kotyada Srinivas
Published: December 2021

Assume that

f
(
x
)
=

a
n

x
n

+

a

n
−
1

x

n
−
1

+
⋯
+

a
0

,

a
0

≠
0

f(x) = a_nx^n + a_{n-1}x^{n-1} + \cdots + a_0, a_0\neq 0

is a polynomial with rational coefficients and let

p
p

be a prime number whose highest power

r
i

r_i

dividing

a
i

a_i

(where

r
i

=
∞

r_i = \infty

if

a
i

=
0

a_i = 0

) satisfies

r
n

=
0

r_n = 0

,

r
i

≥
1

r_i \geq 1

for

0
≤
i
≤
n
−
1

0\leq i\leq n-1

. In this article, we explicitly construct a number

d
d

depending only on

r
i

r_i

’s and show that each irreducible factor of

f
(
x
)

f(x)

has degree at least

d
d

over

Q

\mathbf {Q}

. This result extends the famous Eisenstein-Dumas irreducibility criterion. In fact, we prove our result in a more general setup for polynomials with coefficients in an arbitrary valued field.
A change of variable for Dahlberg-Kenig-Pipher operators
Authors: Feneuil Joseph
Published: December 2021

In the present article, we give a method to deal with Dahlberg-Kenig-Pipher (DPK) operators in boundary value problems on the upper half plane.

We give a nice subclass of the weak DKP operators that generates the full class of weak DKP operators under the action of bi-Lipschitz changes of variable on

R

+
n

\mathbb {R}^n_+

that fix the boundary

R

n
−
1

\mathbb {R}^{n-1}

. Therefore, if one wants to prove a property on DKP operators which is stable by bi-Lipschitz transformations, one can directly assume that the operator belongs to the subclass. Our method gives an alternative proof to some past results and self-improves others beyond the existing literature.
The simplicial volume of contractible 3-manifolds
Authors: Bargagnati Giuseppe , Frigerio Roberto
Published: December 2021

We show that the simplicial volume of a contractible

3
3

-manifold not homeomorphic to

R

3

\mathbb {R}^3

is infinite. As a consequence, the Euclidean space may be characterized as the unique contractible

3
3

-manifold with vanishing minimal volume, or as the unique contractible

3
3

-manifold supporting a complete finite-volume Riemannian metric with Ricci curvature uniformly bounded from below. In contrast, we show that in every dimension

n
≥
4

n\geq 4

there exists a contractible

n
n

-manifold with vanishing simplicial volume not homeomorphic to

R

n

\mathbb {R}^n

. We also compute the spectrum of the simplicial volume of irreducible open

3
3

-manifolds.
The Short Story: A Very Short Introduction
Authors: Kahn Andrew
Published: December 2021

The Short Story: A Very Short Introduction charts the rise of the short story from its original appearance in magazines and newspapers. For much of the 19th century, tales were written for the press, and the form’s history is marked by engagement with popular fiction. The short story then earned a reputation for its skilful use of plot design and character study distinct from the novel. This VSI considers the continuity and variation in key structures and techniques such as the beginning, the creation of voice, the ironic turn or plot twist, and how writers manage endings. Throughout, it draws on examples from an international and flourishing corpus of work.
Native BK virus nephropathy in lung transplant: a case report and literature review
Authors: Albasha Waseem , Vahdani Golnaz , Ashoka Ankita , Bracamonte Erika , Yau Amy A
Published: December 2021

Classically described in renal allografts, BK virus nephropathy is increasingly recognized in native kidneys of other non-renal solid organ transplants. We discuss a 68-year-old woman with a history of bilateral lung transplant referred for worsening renal function, confirmed to have BK virus nephropathy by biopsy with a serum BK virus polymerase chain reaction of over 59 million copies/mL. She was managed with a reduction in immunosuppression and intravenous cidofovir with no improvement in her clinical parameters. The seven prior reported cases of polyoma virus nephropathy in lung transplant recipients are reviewed, and the challenges of screening and management are discussed.
Nesting innovations allow population growth in an invasive population of rose-ringed parakeets
Authors: Hernández-Brito Dailos , Tella José L , Blanco Guillermo , Carrete Martina
Published: December 2021

Certain traits of recipient environments, such as the availability of limiting resources, strongly determine the establishment success and spread of non-native species. These limitations may be overcome through behavioral plasticity, allowing them to exploit alternative resources. Here, we show how a secondary cavity nester bird, the rose-ringed parakeet Psittacula krameri, innovates its nesting behavior as a response to the shortage of tree cavities for nesting in its invasive range in Tenerife (Canary Islands). We observed that some breeding pairs excavated their own nest cavities in palms, thus becoming primary cavity nester, whereas others occupied nests built with wood sticks by another invasive species, the monk parakeet Myiopsitta monachus. The use of these novel nesting strategies increased the number of breeding pairs by up to 52% over 6 years, contributing to a 128.8% increase of the whole population. Innovative nests were located at greater heights above ground and were more aggregated around conspecifics but did not result in greater breeding success than natural cavities. Occupation of monk parakeet colonies by rose-ringed parakeets also benefited the former species through a protective-nesting association against nest predators. Our results show how an invasive species innovate nesting behaviors and increase nest-site availability in the recipient environment, thus facilitating its population growth and invasion process. Potential behavioral innovations in other invasive rose-ringed parakeet populations may be overlooked, and should be considered for effective management plans.
444 Epidemiology of subclinical atrial fibrillation in patients with cardiac implantable electronic devices: a systematic review and meta-regression
Authors: Borgi Marco , Proietti Marco , Romiti Giulio Francesco , Vitolo Marco , Di Rocco Arianna , Farcomeni Alessio , Miyazawa Kazuo , Healey Jeff S , Lane Deirdre , Boriani Giuseppe , Basili Stefania , Lip Gregory Y. H
Published: December 2021

Aims

In recent years, attention to subclinical atrial fibrillation (SCAF), defined as the presence of atrial high-rate episodes (AHREs), in patients with cardiac implantable electronic devices (CIEDs), has gained much interest as a determinant of clinical AF and stroke risk. To perform a systematic review and meta-regression of the available scientific evidence regarding the epidemiology of SCAF in patients receiving CIEDs.

Methods and results

PubMed and EMBASE were searched for all studies documenting the incidence of AHREs in patients (n = 100 or more) with CIEDs without any previous history of AF from inception to 20 August 2021, screened by two independent blind reviewers. This study was registered in PROSPERO: CRD42019106994. Among the 2614 results initially retrieved, 54 studies were included, with a total of 72 784 patients. Meta-analysis of included studies showed a pooled prevalence of SCAF of 28.1%, with an incidence rate (IR) of 16 new SCAF cases per 100 patient-years (I2 = 100%). Multivariate meta-regression analysis showed that age and follow-up time were the only significant determinants of IR, explaining a large part of the heterogeneity (R2 = 61.5%, P < 0.001), with higher IR at earlier follow-up and in older patients, decreasing over follow-up time and increasing according to mean age. Older age, higher CHA2DS2-VASc score, history of AF, hypertension, CHF, and stroke/TIA were all associated with SCAF occurrence.

Conclusions

In this systematic review and meta-regression analysis, IR of SCAF increased with age and decreased over longer follow-up times. SCAF was associated with older age, higher thromboembolic risk, and several cardiovascular comorbidities.
217 Why it is important to recognize Brugada syndrome in athletes: a case report
Authors: Colangelo Lidia , Colangelo Maria , Stefanini Luca
Published: December 2021

Aims

The Brugada syndrome (Brs) is an inherited disorder associated with risk of ventricular fibrillation and sudden cardiac death in a structurally normal heart. The purpose of this case presentation was to spread awareness about this condition, highlight the importance of timely diagnosis and effective treatment of this channelopathy especially in asymptomatic young athletes at high risk of sudden cardiac death.

Methods and results

In this report, we discuss the case of a 47-year-old male. He was a tennis player who performed a visit to the sports doctor to have issued a certificate for competitive fitness. He had no familiar history of sudden death or syncope. The patient’s electrocardiogram (ECG) revealed J-point elevation and ST-segment elevation in the right precordial leads V1 and V2 positioned in the second, third, or fourth intercostal space, showing classic type II ‘saddleback’ morphology in V2 and BrS was suspected. Hence, the patient underwent Holter ECG monitoring with evidence of spontaneous type 1 Brugada pattern (‘coved’ morphology), as well as frequent ventricular ectopic beats with left branch block morphology. Indeed, a diagnosis of BrS was made. Antiarrhythmic prophylaxis therapy with hydroquinidine was initiated and the patient was suspended from competitive activity with a 3-month follow-up.

Conclusions

The BrS is a hereditary disease characterized by a typical ECG pattern potentially predisposing active individuals with no patent structural heart disease to ventricular arrhythmias (VA) and sudden cardiac death (SCD). Nowadays, it is difficult to discern the true burden of BrS due to the unknown real prevalence of asymptomatic patients and the dynamic variability of the ECG pattern in individuals. The purpose of this case presentation was to spread awareness about this condition, highlight the importance of timely diagnosis, and effective treatment of this channelopathy especially in asymptomatic young athletes at high risk of SCD. Indeed, exercise may potentially worsen the ECG abnormalities in BrS patients, resulting in higher peak J-point amplitudes during the vasovagal reaction of the recovery period, possibly leading to an increased risk of cardiac events. Moreover, the enhanced vagal tone in athletes could be both a BrS risk factor and an exercise effect. For this reason, athletic pre-participation screening is essential for minimizing the risk for SCD in athletes participating in either competitive or leisure sporting activities.
409 Not all ST elevation are myocardial infarction: a lesson learned from ‘spiked helmet sign’
Authors: Del Monaco Guido , Bombace Sara , Taormina Antonio
Published: December 2021

Aims

ST segment elevation is an electrocardiogram (ECG) finding first of all suggestive of acute coronary syndrome (ACS). However, there are other causes of ST segment elevation that seem to not have any relationship with coronary artery disease (CAD). One of these is the so-called ‘Spiked Helmet Sign’ (SHS), an ECG pattern characterized by upslope of ST segment before R wave onset that is reported to be found in critical illness and is associated with negative outcomes.

Methods and results

A 14-years-old boy came comatose (Glasgow Coma Scale = 4) to the Emergency Room after being run over by a car. He was immediately intubated and mechanically ventilated. Baseline ECG was reported to be normal, showing an incomplete right bundle branch block and a slightly prolonged QTc interval. CT-scan showed subarachnoid haemorrhage and multiple skull fractures requiring decompressive craniectomy. During hospitalization the patient developed marked hypotension complicated by rise of inflammation indexes and 12 lead ECG revealed new-onset of diffuse ST-segment elevation with spike-and-dome appearance mainly in lateral precordial leads, while lead II and V2 didn’t show any ST-segment alteration. Transthoracic echocardiogram was reported to be normal. Due to critical conditions and low likelihood of CAD, angiography wasn’t performed. The clinical course was worsened by occurrence of hyperkalaemia, acute kidney injury, and multiple episodes of ventricular tachycardia evolving in pulselessness electrical activity which required advanced life support. The patient subsequently died due to multi-organ failure, without the possibility of escalation therapy due to his status. SHS is an emerging ECG sign that is reported to be associated with critical conditions (mechanical ventilation, sepsis, bowel perforation) and in the majority of cases it is not related to CAD. It usually occurs in inferior leads (especially in case of abdominal disease) and in precordial leads (pneumothorax, aortic dissection, mechanical ventilation). Our patient had features consistent with previous cases reported in literature and, even if he experienced several episodes of cardiac arrest and blood exams revealed elevated values of cardiac troponin, the typical ECG pattern and the normal echocardiogram suggest SHS instead of ACS, avoiding unnecessary percutaneous coronary intervention. As reported in literature, even if in our case the appearance of this sign was associated with poor prognosis.

Conclusions

SHS mainly occurs in critically ill patients and is associated with death and poor outcomes. The potential pathophysiological mechanisms are still unclear. It is important to promptly recognize this pattern and differentiate between other causes of ST-segment elevation to select the appropriate therapy according to the setting. This is the first case-report among Italian hospitals of SHS.
714 Effects of direct irradiation on cardiac implantable electronic devices
Authors: Mitacchione Gianfranco , Arabia Gianmarco , Bontempi Luca , Cerini Manuel , Salghetti Francesca , Milidoni Antonino , Ahmed Ashraf , Bognoni Ludovica , Aboelhassan Mohamed , Curnis Antonio
Published: December 2021

Aims

Cardiac implantable electronic devices (CIEDs) may sustain damages during a course of radiation therapy, especially when the beam is directed onto the pulse generator, with device electrical reset and/or sudden battery drain. 2010 HRS/ASA expert consensus, and all CIEDs manufacturers, recommend to avoid devices direct irradiation with an accumulated dose that exceed five grays (Gy). In our prospective study, we tested the effects of direct irradiation on CIEDs with different radiation doses, also higher than 5 Gy.

Methods and results

Thirty-seven CIEDs of Medtronic, Abbott, Biotronik, and Boston Scientific were collected during system upgrading or lead extraction procedures. All devices were considered if they had at least 80% of residual battery capacity. All CIEDs were programmed with same default electrical parameters. Depending by CIED type, pacing mode was configured in VVI, VVIR, VDDR, or DDDR, and biventricular stimulation was activated, if present. ICDs electrical therapies were set-up with a pre-determined configuration. All devices were singularly placed in a 30 cm × 30 cm plastic bowl containing 2 l of deionized water that was placed over 5 cm Rockwool to simulate the backscatter and irradiated by a linear accelerator (Elekta Synergy®). CIEDs were divided into two groups depending on irradiation dose delivered: 5 Gy and 10 Gy. No significant differences in battery drainage were observed after irradiation respect to baseline in 5 Gy as well 10 Gy group [7.9 ± 3.1 vs. 7.5 ± 2.1 (years) battery longevity, P = 0.693; 7.7 ± 3.1 vs. 7.4 ± 2.1 (years) battery longevity, P = 0.677, respectively) (Figure). Moreover, all CIEDS saved the baseline program setting, without device reset events (Table).

Conclusions

Our data confirm that CIEDs direct irradiation of 5 Gy is safe, of note, direct irradiation up to 10 Gy seems to be similarly safe concerning the risk of CIEDs electrical reset and/or unexpected battery drain.
116 Continuous vs. discontinuous arrhythmia monitoring in patients with myocarditis: insights from a single-centre experience
Authors: Peretto Giovanni , Marzi Alessandra , Paglino Gabriele , Mazzone Patrizio , Sala Simone , Bella Paolo Della
Published: December 2021

Aims

Although potentially life-threatening, arrhythmias in myocarditis are under-reported. To assess diagnostic yield and clinical impact of continuous arrhythmia monitoring (CAM) in patients with arrhythmic myocarditis.

Methods and results

We enrolled consecutive adult patients (n = 104; 71% males, age 47 ± 11 years, mean LVEF 50 ± 13%) with biopsy-proven active myocarditis and de novo ventricular arrhythmias (VA). All patients underwent prospective monitoring by both sequential 24-h Holter ECGs (4/y in the first year; 2/y in years 2–5; 1/y later) and CAM, including either ICD (n = 62; 60%) or loop recorder (n = 42; 40%). By 3.7 ± 1.6 year follow-up, 45 patients (43%) had VT, 67 (64%) NSVT, and 102 (98%) premature ventricular complexes (PVCs). As compared to Holter ECG (average 9.5 exams per patient), CAM identified more patients with VA (VT: 45 vs. 4; NSVT: 64 vs. 45; both P < 0.001), more VA episodes (VT: 100 vs. 4%; NSVT: 91 vs. 12%), and earlier NSVT timing (median 6 vs. 24 months, P < 0.001). Conversely, Holter ECG allowed VA morphology characterization and daily PVC quantification. The time to first treatment modification was 12 ± 9 months by CAM vs. 33 ± 16 months by Holter ECG (P < 0.001), and drug withdrawal was always CAM-dependent. Guided by CAM findings, 8 patients (8%) started anticoagulants for newly diagnosed atrial arrhythmias. Differently from ICDs, loop recorders did not interfere with the interpretation of cardiac magnetic resonance.

Conclusions

In patients with arrhythmic myocarditis, CAM allowed accurate arrhythmia detection and showed a considerable clinical impact. As a complementary exam, VA characterization and PVC burden were better assessed by repeated Holter ECGs.
284 Worsening renal function as an outcome predictor in patients with new onset atrial fibrillation on direct oral anticoagulant
Authors: Bartoli Lorenzo , Angeli Francesco , Armillotta Matteo , Sansonetti Angelo , Fabrizio Michele , Magnani Ilenia , Stefanizzi Andrea , Foà Alberto , Paolisso Pasquale , Rinaldi Andrea , Galiè Nazzareno , Pizzi Carmine
Published: December 2021

Aims

In patients with atrial fibrillation (AF), baseline kidney function is used to guide oral anticoagulant (OA) selection and dosing, and chronic kidney disease (CKD) is a significant outcome predictor. However, the incidence of worsening renal function (WRF) and its prognostic role during treatment with direct oral anticoagulants (DOACS) has been poorly explored. To assess the prognostic role of WRF in terms of bleedings and major adverse cardiovascular events (MACEs) in a cohort of patients with newly diagnosed non-valvular AF (NVAF) treated with DOACs.

Methods and results

Between January 2017 and March 2019, we enrolled all the patients with newly diagnosed NVAF and OA indication, treated with DOACs. Renal function was assessed using the mean value of the estimated glomerular filtration rates (eGFR) calculated using Cockcroft–Gault (CG), modification of diet in renal disease (MDRD), and Chronic Kidney Disease Epidemiology Collaboration (CKD-EPI) formulas. CHA2DS2-VASc and HAS-BLED scores were used at baseline to estimate the ischaemic and haemorrhagic risk, respectively. At follow-up, WRF was identified as a decrease in eGFR of at least 20% while bleedings were classified according to the international society of thrombosis and haemostasis (ISTH) criteria. Finally, we defined AF progression as the transition from paroxysmal to persistent or permanent AF or from persistent to permanent AF. 1009 patients with newly diagnosed NVAF started on DOAC were enrolled. They were followed-up for 21.6 ± 9.5 months. Overall, WRF was observed in 181 cases (18%). Patients with WRF had higher rates of progression of AF (18.5% vs. 11.8%, P = 0.02), MACEs (20.4% vs. 12.9%, P = 0.09) and major bleedings (MBs) (9.4% vs. 4.7%, P = 0.013). WRF did not correlate with all bleedings, stroke, or acute coronary syndrome (ACS). However, those who presented WRF using CKD-EPI formula had higher ACS incidence (6.1% vs. 2.5%, P = 0.015), and generally better-predicted MACEs. At multivariate analysis adjusted for age, hypertension, baseline HAS-BLED score and WRF, the latter emerged as an independent predictor of MB (OR: 1.9, 95% CI: 1.059–3.51).

Conclusions

In patients with newly diagnosed NVAF treated with DOACs, WRF is associated with AF progression and MACEs, and emerged as an independent predictor of major bleedings. WRF evaluated with CKD-EPI formula better predicted MACEs.