bluuebunny/crossref_metadata_2025 huggingface dataset:
Development of a Solar Powered Electric Shuttle
Authors: Kehinde O. , Oyawale F. , Babaremu K.O , Efemwenkiekie U.K
Published: April 2021

Sunlight is readily available. We have heard of improvement in solar-powered vehicles and also Electric vehicles, but this project is aimed at combining the two sources, but the main focus was on the fabrication of the static body. The research work was based on the construction of the static body of the shuttle using mild steel as the primary material; the parts were a fabrication and welded together by the process of oxy-acetylene welding while other elements like seats etc. arc welding was used. Other procedures were the mechanical calculation such as weight consideration, steering correction angle and wheel alignment, the braking system, and general vehicle safety for the determination of the fabrication of the static body. The result obtained in the process is a static body of a shuttle that can be powered by either a combustion engine or an electric engine.
Light-weighting of single-sided motorcycle swing-arm through generative design
Authors: Balasubramanian Adarsh , Shaktivel G , Raghukiran N
Published: April 2021

This work explores the prospects of Generative Design to generate the single-sided swing-arm of a homologated motorcycle to perform the process of light-weighting by selecting two aluminum alloys, namely Al 6061 (primary) and Al 7075 (reference), as materials and 5-axis milling as the manufacturing method. This work also cites and summarizes a couple of previous studies to establish the findings that Al 7075 is a superior material for the manufacturing of the single-sided swing-arm when compared to steel and further proceeds to expatiate as to why Al 6061 should be considered as opposed to Al 7075 for increased gains from the process of light-weighting with substantiations from the analysis of the single-sided swing-arm under the simulated loads.
Effects of Bracing System on Multistoryed Steel Building
Authors: Meena Rahul Kumar , Awadhiya G P , Paswan Abhishek Prakash , Jayant Harshit Kumar
Published: April 2021

In recent years, in regions of the highly seismic prone area, steel construction has changed from moment resistant frames to concentrically braced frames. To withstand earthquake forces, bracing part of the structural pattern by providing extra stiffness plays a crucial role in structural action. Concentric bracing in building frames is one of the most common horizontal load resistance patterns. For this reason, seven distinct models were created by changing the bracing pattern in the steel frame and analyzed for wind and seismic forces A 20-story steel frame structure is explored in this presented work. From this research, it can be inferred that the bracing factor will have a very significant impact on structural behavior under seismic loading. The most desirable bracing framework is the Backward bracing pattern. Horizontal displacement at the top floor is decreased by approximately 50 percent for Backward braced in frame structure compared to without bracing pattern.
Cohesive Zone Modeling for Predicting Interfacial Delamination in over mold Components
Authors: Sai Krishnan M , Jeyanthi S , Mani Pradeep Kumar , Hareesh K T , Lenin Babu M. C
Published: April 2021

Delamination is one among the significant issues in over molding and electronic packaging. Notably, because of material compatibility and also the weak adhesion-strength of interfaces makes it complex. Typically, delamination takes place at the bimaterial interfaces. In order to predict interface delamination, the cohesive zone technique may be applied as an attainable tool. However, the proper alternative of the cohesive parameters still forms an obstacle for the general usage. The objectives of the work, analytical & numerical modeling of delamination of interfaces between molding compound and metal frames and its subsequent validation using numerical double cantilever beam test and four-point bend tests. In this work, the double cantilever beam and four-point bend tests are used to obtain the strain energy release rate of mode I and mode II values, these values are used as parameters for the cohesive zone method.
Design and Simulation of Henna-based Composite Substrate for UHF-RFID Application on Dielectric Properties
Authors: Zamil Nadzeefah , Ansari M N M , Jalil Y E , Nordin Noor Afeefah , Yahya Zainudin , Azlan A A
Published: April 2021

This paper presented the effect of dielectric properties of henna-based composite towards the performance of the tag antenna for UHF-RFID application. The dielectric properties focused in this work were dielectric constant and loss tangent. Henna-based composite was developed with different amount of henna loading as the substrate for RFID passive tag. The design of antenna was optimized using CST Microwave software to achieve resonance frequency at 915 MHz. The output parameters from this work were reflection coefficient (dB), bandwidth (MHz), gain (dB), directivity (dBi), antenna efficiency (%) and voltage standing wave ratio (VSWR). In conclusion, dielectric properties of the substrate affect all the output parameters significantly except for directivity value.
Study of heat transfer enhancement through the non-circular ducts using three dimensional numerical investigations and their comparisons
Authors: Mahato Shambhu Kumar , Rana Subhas Chandra , Barman Rabindra Nath
Published: April 2021

The present study numerically surveyed fluid characteristics such as friction factor and heat transfer through the different geometry of twisted ducts. A three-dimensional analysis is performed for the Reynolds number of 100-50000 for the air that acts as a working fluid and a uniform wall temperature boundary case is studied numerically throughout the simulation of ducts. Numerical results of this present study are validated against the experimental results. Heat transfer improvements are made over the hexagonally twisted channels, straight square duct and clockwise-counterclockwise (CW-CCW) twisted square channels. Twist ratios of 7 · 5, 11 · 5 and 16 · 5 are considered for the current simulations. Laminar flow to turbulent flow regimes over the ducts are briefly presented and discussed. Results show enhancement in heat transfer through the CW-CCW, hexagonal and straight square ducts(SSD) for the laminar as well as for turbulent regimes are figured out and perfectly described. It is seen that in laminar regime, twisted CW-CCW square duct performed well than twisted square and hexagonal duct. A comparison of friction coefficients are also established for both the channels. Less friction factor is observed for twisted CW-CCW duct compared to other duct.
Kinematics and compliance analysis of active suspension system and Development of control algorithm to maximize ride comfort
Authors: Karande Sandesh R , Chinnapandi Lenin Babu Mailan , Jeyaraj P , Subramanian Jeyanthi
Published: April 2021

It is important to understand the interrelationship between steering stability and NVH to adjust stiffness of the suspension to satisfy the aim of maximum ride comfort. This work aims to perform kinematic and compliance analysis on comprehensive quarter car model of McPherson suspension system to validate its reliability with respect to various road profiles and development of control algorithm to control its stiffness. Despite the wide usage of PID controllers, controllers based on Adaptive Neuro Fuzzy Inference System (ANFIS) are proved to give better results as they consider the non-linearity of active car suspension models. The modelling of the comprehensive non-linear quarter car active McPherson suspension system is done using MSC ADAMS and the control algorithm is implemented using MATLAB. The approach used is to perform parametric sensitivity analysis for prime parameters such as toe angle, camber angle and caster angle. The approach used to design a better robust control algorithm is achieved using µ-synthesis function of MATLAB.
Impact of web and counterweight shape factors on crank shaft design for better strength and optimised geometry
Authors: Mathan G , Daniel J , Vishnu P , Satyanarayana V
Published: April 2021

Automotive industry is continuously focusing on developing weight efficient engines for better fuel economy without altering engine performance. To achieve a trade-off between performance and fuel economy, the design always demands downsizing of engine components with optimum geometry. Crankshaft is such an important component in deciding engine performance and overall weight. Torsional and bending stiffness of crankshaft plays a vital role in its structural integrity, particularly the Critical Cross Section (CCS) which connects main journal and crankpin. In the present study, the objective is to upgrade the crankshaft for higher torsional and bending stiffness and reduce weight without changing its performance. Three geometric shape factors of the crankshaft are identified and optimized in FEA and analyzed in AVL Excite® (1-D) simulation for its structural performance. Study shows the identification of shape factors and effect of their variation on torsional and bending stiffness of crankshaft. In addition, sensitivity analysis for various shape factors and their optimization has been done. The identified shape factors help designers to identify any scope to optimize the geometry of crankshaft and understand its role in structural strength. Using this methodology, specific regions defined by shape factors can be optimized for better strength and weight.
Morocco’s housing challenge: Effect of current marketed building materials on the energy performance of residential buildings
Authors: Charai M , Sghiouri H , Mezrhab A , Karkri M , Moga L
Published: April 2021

The paper provides a research on the energy performance of current marketed building materials used for household construction in eastern Morocco. Firstly, the characterization of the thermophysical properties of commonly used building materials (cement, plaster, hollow bricks and insulation boards) was carried out using the Hot Disk method. A local building material database of eastern Morocco region was developed. It was found that the thermal conductivity of the most affordable insulation boards was of 0.03 W/mK, while the thermal conductivity of cement-based products ranged from 0.65 to 0.7 W/mK. The experimental results show that the Moroccan market of building materials cannot participate in promoting eco-construction and designing efficient lightweight building envelopes at local level. Therefore, a strong focus on the development of local low-cost insulation materials for building applications are needed. The numerical building performance analysis shows that available building practices are only efficient for passive heating. Further studied on passive cooling techniques are greatly required for designing low energy buildings in Morocco.
Advanced technology of municipal solid waste conversion for a circular economy
Authors: Lupu M L , Isopescu D N , Maxineasa S G , Baciu I-R , Antonescu I , Cucos I
Published: April 2021

One of the most important environmental problems of the big urban areas is represented by the large volume of waste resulted from different human activities. In the last decades, different technologies have been developed to resolve this significant issue, and the most representative is the conversion of municipal solid waste (MSW) in different types of by-products. The first part of this paper presents the current state of plasma conversion technology that can be used for processing waste, and also, its potential in the construction sector which could be taken advantage of the by-products (syngas and slag) resulted from the plasma gasification of municipal solid waste (MSW), to enhance energy-efficiency in this domain. In the second part of the paper, there are analyzed different technologies for managing and processing municipal solid waste (MSW), which can be used nowadays, and the parameters, related to the costs, the period of use, the energy consumption and the environmental impact. All these aspects are compared with those of plasma conversion technology. The plasma conversion system can be commercialized successfully, and its costs can be reduced by generating income in the form of by-products and added-value in producing performant products in a circular economy.
Assessment of seismic performance of RC frame structure with masonry infill panels partially uncoupled from the surrounding frame members
Authors: Mociran H A , Cobîrzan N
Published: April 2021

The present study numerically analyses the influence of physical and mechanical properties of the materials used for masonry infill panels upon the seismic response of low rise reinforced concrete frame structure. A four-storey residential building (benchmark), located in Timisoara, a moderate seismic area, has been designed according to the current Romanian design codes. Then, infill panels considered uncoupled from the frame members along their lateral and upper edges, have been added to the structure. Infill panels have been investigated in four variants, by using 2 types of masonry units (hollowed ceramic blocks and AAC), alternatively built with mortars specific for regular bed joints (G) and thin bed joints (T), for which a comparative modal response spectrum analysis has been carried out. The seismic behaviour of buildings in all these cases has been analysed in terms of peak inter-storey drifts under two limit states and of the out-of-plane strength of infill panels. The results show that the peak inter-storey drifts reductions compared to the benchmark structure are up to 59% at SLS, and 61% at ULS. Regarding the out-of-plane behaviour of the infill panels it was noted that safety verification is fulfilled only for one of the abovementioned cases. As a final remark, the results obtained in this study highlight the importance of physical and mechanical properties of the masonry infill panels in the assessments of seismic response of frame structure buildings.
Pushover analysis of R.C. framed structures with infill panels made of masonry having various properties
Authors: Mociran H A , Cobîrzan N
Published: April 2021

The seismic performances of R.C. frame structures were determined in terms of inter-storey drifts at two limit states, internal forces and moments (axial forces and bending moments), and the in-plane behaviour of infills. A nonlinear static analysis (pushover) was carried out in order to assess the seismic performance of buildings, to identify the expected plastic mechanisms and to plot the capacity curves. In pushover analysis, the vertical distribution of the monotonically increasing horizontal loads, was performed according to the first mode pattern. The nonlinear behaviour of structural members for pushover analysis was modelled by using the lumped plasticity, from where it derives that the potential plastic hinges were situated at the beams ends (which yield due to the bending moment), at the top and bottom of the columns at any storey (which yield based on the interaction of axial force and bending moment) and in the struts (which yield due to the axial force).
Study on determination of an object material using the microwave doppler sensor
Authors: Oda K , Nakamura K , Ikebata K , Kobayashi Y
Published: April 2021

In this study, to consider a method for detecting the sediment portion of avalanches containing sediment using microwave Doppler sensors, we confirmed whether the signal processing obtained by the sensors can differentiate the objects. Since microwaves in this frequency band are not easily affected by rain and snowfall, these are being developed for use in dashboard camera and other applications. However, it is necessary to understand the attenuation of the microwave for the snow in order to apply this technology to detect the sediment in the avalanche. It is also necessary to know the rate of reflection of microwaves from the snow and sand. Therefore, it is necessary to verify whether the reflection of the microwave from the sediment is correctly measured or not. In this report, we discuss the results of the verification to see if the distance between the sensor and the object, which is known in advance, can be detected correctly.
Mixed Matrix Membrane Incorporating of MgAl-CO3 Layered-Double-Hydroxide for Enhanced Carbon Dioxide Separation
Authors: Fajrina N. , Yusof N. , Ismail A.F. , Jaafar J. , Aziz F. , Salleh W.N.W. , Ismail N.M.
Published: April 2021

In this study, mixed matrix membranes were fabricated by incorporating MgAl-CO3 layered double hydroxides (LDH) into polysulfone (PSF) coated with low-cost commercial PEBAX polymer for enhancing CO2/CH4 separation. LDH was synthesized via a simple co-precipitation method and flat sheet membranes were fabricated by dry/wet inversion phase. The gas separation performance on pure PSF and LDH/PSF membranes were investigated. The physical property, chemical structure and membrane morphology were characterized by XRD, FTIR, and SEM. The sample membranes were tested with CO2 and CH4 gas for permeance performance and selectivity of CO2/CH4 was calculated. By incorporation of LDH, the CO2 permeance increased about 54.6%. LDH mixed matrix membranes displayed the 18.2 GPU of CO2 permeance and CO2/CH4 selectivity of 18.0. The LDH based membrane produces innovation in membrane technology by improving its morphology and permeance performance with great potential for large-scale CO2 capture and separation.
Fabrication and characterization of composite hollow fibre membrane derived from hydroxyapatite cow bone and kaolin
Authors: Najieha Kamarudin Suraya , Riduan Jamalludin Mohd , Nor Suhaida Rasman Siti , Khadijah Hubadillah Siti , Arif Budiman Pauzan Mohd , Hafiz Dzarfan Othman Mohd
Published: April 2021

Due to its superior behaviour, membrane separation has been applied widely towards water and wastewater treatment. Compare to polymeric counterparts, ceramic membrane has become innovation technology nowadays as it can be used both separation and adsorption application. The conventional ceramic membrane made from alumina, however, in view of its high-cost output. As a result, exploring to a cheap ceramic material derived from clay and waste is gaining attention. In this study, hydroxyapatite derived from cow bone waste and kaolin were used as the main materials for the fabrication of ceramic hollow fibre membrane via phase inversion and sintering technique. The membrane composition was varied through kaolin:hydroxyapatite ration into three composition (40:0, 0:40, 20:20). Result showed the ceramic membrane fabricated from 20 wt% kaolin and 20 wt% hydroxyapatite induces excellent performance at water flux of 10168.5 L/m².h and mechanical strength at 13.33 MPa.
Ionic Liquid Blend Thin Film Composite Membrane for Carbon Dioxide Separation
Authors: Nur Alwani Shafie Siti , Viriya Vinosha , Abdul Hadi Md Nordin Nik , Roil Bilad Muhammad , Dzul Hakim Wirzal Mohd
Published: April 2021

To utilize the superior properties of ionic liquid (IL), this work developed thin film composite (TFC) membrane incorporated with [EMIM][Tf2N] prepared via interfacial polymerization (IP). The effect of IL on membrane properties and CO2/CH4 separation performance were studied. The IL loading was varied from 1-5wt%. The fabricated membranes were characterized and the gas separation performance of the membranes was evaluated in term of CO2 permeability and CO2/CH4 selectivity. Analysis from Fourier-transform Infrared Spectroscopy (FTIR) shows the presence of [EMIM][TF2N] functional groups proving the successful attachment of the IL in the membrane. Furthermore, it is noted that with increasing IL loading up to 3vol%, the surface morphology became rougher and the membrane became more rigid based on the Differential Scanning Calorimeter (DSC) thermogram and Atomic Force Microscopy(AFM) analysis, accordingly. Based on the gas permeation test at 1 bar feed pressure, membrane with 5wt% of IL showed CO2 permeability of 3424.44 GPU and CO2/CH4 selectivity of 32.15. Compared to pure TFC membrane, TFC/IL membranes showed as much as 103 times and 32 times improvement for CO2 permeability and CO2/CH4 selectivity, accordingly. The improved gas separation performance shows promising results of incorporating IL in TFC membrane for CO2 separation.
Large strain and low hysteresis in (1-x)Bi0.5(Na0.75K0.25)0.5TiO3-xSrTiO3 lead-free piezoceramics
Authors: Liu Zixuan , Ruan Tingting , Li Qiong , Liu Yunfei , Lyu Yinong , Mao Minmin
Published: April 2021

(1-x)Bi0.5(Na0.75K0.25)0.5TiO3-xSrTiO3 (BNKT-xST) incipient piezoelectric ceramics with x = 0.05-0.35 were fabricated using solid-state reaction technique. The microstructure and electrical properties are discussed as functions of ST content. The X-ray diffraction patterns confirm that all the compositions form a solid solution without any secondary phase. As the ST content increases, the grain growth is inhibited, and the ferroelectric phase transforms into the relaxor phase, which can be confirmed by the P-E and I-E loops. For the compositions of x = 0.05, 0.30 and 0.35, a large strain of 0.28%, 0.24% and 0.18% with a low hysteresis of 16.2%, 10.0% and 4.7% can be obtained. We propose that the large strain and low hysteresis behavior are beneficial from the disruption of long-range ferroelectric phase and the increase in relaxor phase, which should provide a feasible paradigm to promote the applications of precise micro-actuators.
Experimental investigations of Al2O3- and ZrO2-based coatings deposited by detonation spraying
Authors: Rakhadilov Bauyrzhan , Kantay Nurgamit , Sagdoldina Zhuldyz , Erbolatuly Dosym , Bektasova Gulsym , Paszkowski Maciej
Published: April 2021

This paper presents the results of experimental investigations of the physical and mechanical properties, structure and surface morphology of Al2O3- and ZrO2-based coatings deposited by detonation spraying. The coatings were sprayed onto titanium-alloyed steel 12Ch18N10T (GOST 4986-79). The thickness of the coatings ranged from 250 to 1100 μm. After the deposition of the coatings the mechanical properties of the steel’s surface layer significantly improved. Its microhardness increased threefold, reaching the maximum value of over 11 GPa. Also the tribological properties of the material detonation sprayed onto the steel were tested. A significant decrease in the kinetic friction coefficient was observed. For the steel with the ZrO2 coating the friction coefficient decreased by nearly half, reaching the value of 0.330. An increase in abrasive wear resistance was noted. Moreover, the results of electron microscopy, energy-dispersive X-ray spectroscopy and X-ray diffraction examinations evaluating the structural properties and surface morphology of the coatings are presented.
Experimental validation of bulk-graphene as a thermoelectric generator
Authors: Uzair Khan Muhammad , Naveed Amir , Ehtisham Gillani Syed , Awan Dawar , Arif Muhammad , Afridi Shaista , Hamyun Muhammad , Asif Muhammad , Tabassum Saadia , Sadiq Muhammad , Lais Muhammad , Aslam Muhammad , Ullah Jan Saeed , Ahad Zeeshan
Published: April 2021

Quest for alternate energy sources is the core of most of the research activities these days. No matter how small or large amount of energy can be produced by utilizing the non-conventional techniques and sources, every bit of innovation can reshape the future of energy. In this work, experimental analysis of the thermoelectric (TE) properties of bulk-graphene in the temperature range of (303 to 363) K is presented. Graphene powder was pressed to form a pellet which was used to fabricate the TE device. The effects of temperature on the Seebeck coefficient, electrical and thermal conductivities, and the dimensionless figure of merit (FOM) were measured. The increasing value of the Seebeck coefficient (thermopower) with temperature is indicant of the metallic behavior. Additionally, the observed thermopower (TEP) is positive, which shows that the majority charge carriers are holes and peaked to a value of 56 μV K−1 at 363 K. The thermopower of the pellet is four times larger than the previously reported values for single layer graphene (SLG) and few layer graphene (FLG). In addition to this, low values of the thermal conductivity were observed for the pellet which is one of the requirements of a good TE material. Besides this, an upward trend is observed with increasing temperature for FOM, which attains a peak value of 0.0016 at 363 K, which is almost ten times that of the previously reported values.
Bandgap optimization of sol–gel-derived TiO2 and its effect on the photodegradation of formic acid
Authors: Zouheir Morad , Assila Ouissal , Tanji Karim , El Gaidoumi Abdelali , Araña Javier , Doña Rodríguez José Miguel , Smått Jan-Henrik , Huynh Tan-Phat , Kherbeche Abdelhak
Published: April 2021

This work reports a key factor, the H2SO4 concentration, in controlling the physicochemical properties of titanium dioxide (TiO2) photocatalysts during the sol–gel synthesis. The photocatalysts synthesized using different concentrations of H2SO4 possess specific anatase/rutile ratios and crystallite sizes as well as surface areas, resulting in different photocatalytic performance in the degradation of formic acid in solution. The best photocatalytic performance is observed for the TiO2 photocatalyst containing a relatively high percentage of the rutile phase (∼84%), which is obtained from the sol–gel synthesis without H2SO4.
Large deviations in the perceptron model and consequences for active learning
Authors: Cui H , Saglietti L , Zdeborová L
Published: April 2021

Active learning (AL) is a branch of machine learning that deals with problems where unlabeled data is abundant yet obtaining labels is expensive. The learning algorithm has the possibility of querying a limited number of samples to obtain the corresponding labels, subsequently used for supervised learning. In this work, we consider the task of choosing the subset of samples to be labeled from a fixed finite pool of samples. We assume the pool of samples to be a random matrix and the ground truth labels to be generated by a single-layer teacher random neural network. We employ replica methods to analyze the large deviations for the accuracy achieved after supervised learning on a subset of the original pool. These large deviations then provide optimal achievable performance boundaries for any AL algorithm. We show that the optimal learning performance can be efficiently approached by simple message-passing AL algorithms. We also provide a comparison with the performance of some other popular active learning strategies.
A Qualitative Study on the Experiences of Women With Breast Implant Illness
Authors: Tang Samantha , Anderson Natalie E , Faasse Kate , Adams William P , Newby Jill M
Published: April 2021

Background

Breast implant illness (BII) is a term used to describe physical and psychological symptoms experienced by some women following breast implant surgery. Few studies have examined the experiences of women with BII—a poorly understood condition with no clear cause or treatment.

Objectives

The aim of this study was to explore women’s experiences of BII, including symptoms, healthcare encounters, social media, and explant surgery.

Methods

Employing an exploratory qualitative methodology, researchers undertook semistructured interviews with 29 women who self-identified as having BII. Interviews were audio-recorded and transcribed verbatim. Data were analyzed by inductive thematic analysis.

Results

Thematic analysis of the interviews identified 6 themes: (1) symptoms without explanation; (2) invalidation and invisibility; (3) making the BII connection; (4) implant toxicity; (5) explant surgery: solution to suffering?; and (6) concealed information. BII was described as distressing and debilitating across multiple domains including relationships, work, identity, and physical and mental health, and symptoms were attributed to implant toxicity and immune system rejection of foreign objects. When their experience was not validated by healthcare professionals, many looked to social media for information, support, and understanding, and saw explant as their only chance of recovery.

Conclusions

BII is disabling mentally and physically. Women with BII require support, understanding, and validation, and proactive treatment to prevent disability. With unclear pathophysiology, future research should examine how biopsychosocial approaches can be used to guide treatment, and how to best support women with BII, focusing on early detection and evidence-based education and intervention.

Level of Evidence: 4
GSpace: an exact coalescence simulator of recombining genomes under isolation by distance
Authors: Virgoulay Thimothée , Rousset François , Leblois Raphaël
Published: April 2021

Motivation

Simulation-based inference can bypass the limitations of statistical methods based on analytical approximations, but software allowing simulation of structured population genetic data without the classical n-coalescent approximations (such as those following from assuming large population size) are scarce or slow.

Results

We present GSpace, a simulator for genomic data, based on a generation-by-generation coalescence algorithm taking into account small population size, recombination and isolation by distance.

Availability and implementation

Freely available at site web INRAe (http://www1.montpellier.inra.fr/CBGP/software/gspace/download.html).
CentromereArchitect: inference and analysis of the architecture of centromeres
Authors: Dvorkina Tatiana , Kunyavskaya Olga , Bzikadze Andrey V , Alexandrov Ivan , Pevzner Pavel A
Published: April 2021

Motivation

Recent advances in long-read sequencing technologies led to rapid progress in centromere assembly in the last year and, for the first time, opened a possibility to address the long-standing questions about the architecture and evolution of human centromeres. However, since these advances have not been yet accompanied by the development of the centromere-specific bioinformatics algorithms, even the fundamental questions (e.g. centromere annotation by deriving the complete set of human monomers and high-order repeats), let alone more complex questions (e.g. explaining how monomers and high-order repeats evolved) about human centromeres remain open. Moreover, even though there was a four-decade-long series of studies aimed at cataloging all human monomers and high-order repeats, the rigorous algorithmic definitions of these concepts are still lacking. Thus, the development of a centromere annotation tool is a prerequisite for follow-up personalized biomedical studies of centromeres across the human population and evolutionary studies of centromeres across various species.

Results

We describe the CentromereArchitect, the first tool for the centromere annotation in a newly sequenced genome, apply it to the recently generated complete assembly of a human genome by the Telomere-to-Telomere consortium, generate the complete set of human monomers and high-order repeats for ‘live’ centromeres, and reveal a vast set of hybrid monomers that may represent the focal points of centromere evolution.

Availability and implementation

CentromereArchitect is publicly available on https://github.com/ablab/stringdecomposer/tree/ismb2021

Supplementary information

Supplementary data are available at Bioinformatics online.
Expected 10-anonymity of HyperLogLog sketches for federated queries of clinical data repositories
Authors: Tao Ziye , Weber Griffin M , Yu Yun William
Published: April 2021

Motivation

The rapid growth in of electronic medical records provide immense potential to researchers, but are often silo-ed at separate hospitals. As a result, federated networks have arisen, which allow simultaneously querying medical databases at a group of connected institutions. The most basic such query is the aggregate count—e.g. How many patients have diabetes? However, depending on the protocol used to estimate that total, there is always a tradeoff in the accuracy of the estimate against the risk of leaking confidential data. Prior work has shown that it is possible to empirically control that tradeoff by using the HyperLogLog (HLL) probabilistic sketch.

Results

In this article, we prove complementary theoretical bounds on the k-anonymity privacy risk of using HLL sketches, as well as exhibit code to efficiently compute those bounds.

Availability and implementation

https://github.com/tzyRachel/K-anonymity-Expectation.
SAILER: scalable and accurate invariant representation learning for single-cell ATAC-seq processing and integration
Authors: Cao Yingxin , Fu Laiyi , Wu Jie , Peng Qinke , Nie Qing , Zhang Jing , Xie Xiaohui
Published: April 2021

Motivation

Single-cell sequencing assay for transposase-accessible chromatin (scATAC-seq) provides new opportunities to dissect epigenomic heterogeneity and elucidate transcriptional regulatory mechanisms. However, computational modeling of scATAC-seq data is challenging due to its high dimension, extreme sparsity, complex dependencies and high sensitivity to confounding factors from various sources.

Results

Here, we propose a new deep generative model framework, named SAILER, for analyzing scATAC-seq data. SAILER aims to learn a low-dimensional nonlinear latent representation of each cell that defines its intrinsic chromatin state, invariant to extrinsic confounding factors like read depth and batch effects. SAILER adopts the conventional encoder-decoder framework to learn the latent representation but imposes additional constraints to ensure the independence of the learned representations from the confounding factors. Experimental results on both simulated and real scATAC-seq datasets demonstrate that SAILER learns better and biologically more meaningful representations of cells than other methods. Its noise-free cell embeddings bring in significant benefits in downstream analyses: clustering and imputation based on SAILER result in 6.9% and 18.5% improvements over existing methods, respectively. Moreover, because no matrix factorization is involved, SAILER can easily scale to process millions of cells. We implemented SAILER into a software package, freely available to all for large-scale scATAC-seq data analysis.

Availability and implementation

The software is publicly available at https://github.com/uci-cbcl/SAILER.

Supplementary information

Supplementary data are available at Bioinformatics online.
The sex life aquatic: sexually dimorphic scale mechanoreceptors and tactile courtship in a sea snake Emydocephalus annulatus (Elapidae: Hydrophiinae)
Authors: Crowe-Riddell Jenna M , Jolly Chris J , Goiran Claire , Sanders Kate L
Published: April 2021

Evolutionary transitions from terrestrial to aquatic habitats involve major selective shifts in animal signalling systems. Entirely marine snakes face two challenges during underwater social interactions: (1) finding mates when pheromones are diffused by water currents; and, once a mate is located, (2) maintaining contact and co-ordinating mating when tactile cues are diminished by buoyancy force. We explore the potential tactile roles of scale protuberances in the mating of turtle-headed sea snakes [Emydocephalus annulatus (Hydrophiinae)] by investigating sexual dimorphism in museum specimens (N = 59). In addition to the previously noted rostral spine on the snout, we found that mature males have enlarged structures located on the chin (genial knobs) and near the cloaca (anal knobs). Ultrastructural data indicates that the rostral spine is comprised of thickened epidermal and dermal layers, similar to rugosities on the body, and likely provide stimulation to the female during prodding by the male. In contrast, the genial and anal knobs have dermally derived central cells indicative of enlarged scale mechanoreceptors (i.e. sensilla). We suggest that these mechanoreceptors are critical to mating success: genial knobs may help amorous males orient to the direction of female motion; whereas, and anal knobs likely give somatosensory feedback for cloacal alignment
O9: DETECTION OF RELEVANT GENE MUTATIONS IN GLIOMA USING PLASMA CELL FREE DNA
Authors: Ita M , Nolan Y , Toulouse A , Wang JH , Lim CH , O'sullivan MGJ , Kaar GF , Redmond HP
Published: April 2021

Background

Comprehensive molecular profiling of gliomas provide information essential for accurate biological classification beyond traditional histopathology. Genomic profiling utilizing tumour tissue samples inevitably involves obtaining tissues through potentially hazardous surgical procedures or stereotactic biopsies carrying risks of morbidity and mortality. Tissues from biopsies may also be insufficient or fail to capture a comprehensive picture of the tumours genetic profile due to tumour heterogeneity. In these contexts, complementary minimally invasive strategies are needed for molecular profiling of gliomas. Cell free DNA (cfDNA) has emerged as an easily accessible biomarker containing fragments of circulating tumour DNA (ctDNA) released into plasma through apoptosis. We explored its potential utility in genomic profiling of brain tumours.

Method

Plasma cfDNA from patients with radiographically suspected brain malignancies were extracted and quantified before planned surgical interventions. Cell free DNA was extracted using a QIAamp Circulating Nucleic Acid Kit (Qiagen), and was quantified (ng cfDNA/mL) using a DS-11 FX Spectrophotometer (DeNovix). Pathway focused profiling of somatic mutation status was performed using QBiomarker Somatic Mutation PCR Arrays for human brain cancers (Qiagen) through real time PCR (Roche).

Result

Somatic mutations in human brain cancer were evaluated in the following genes; BRAF, CTNNB1/beta-catenin, EGFR, IDH1, IDH2, KRAS, NF2, NRAS, PIK3CA, and PTEN. A total of 14 (70%) patients had greater than 1 somatic mutation detected in their plasma cfDNA.

Conclusion

We postulate that glioma derived circulating tumour DNA occur in plasma, and genomic analysis using cell free DNA may complement current methods of glioma genomic characterisation.

Take-home message

Glioma derived circulating tumour DNA occur in plasma.
O20: PREOPERATIVE INTRAVENOUS IRON THERAPY AND SURVIVAL AFTER COLORECTAL CANCER SURGERY: LONG TERM RESULTS FROM THE INTRAVENOUS IRON IN COLORECTAL CANCER-ASSOCIATED ANAEMIA (IVICA) TRIAL
Authors: Dickson EA , Keeler BD , Ng O , Kumar A , Brookes MJ , Acheson AG
Published: April 2021

Background

Intravenous iron is now the standard treatment to correct preoperative anaemia. However, iron may promote tumour growth and progression which could influence cancer recurrence and survival. We explore the long term postoperative outcomes of patients receiving oral (OI) or intravenous iron (IVI) as part of a randomised controlled trial.

Method

The multicentre IVICA trial randomised anaemic colorectal cancer patients in a 1:1 fashion to receive either OI or IVI prior to their elective operation. Follow up analysis of all patients was performed and Kaplan-Meier survival estimates and Cox proportional hazard models were used to compare groups. A pooled analysis comparing patients who did/did not achieve preoperative resolution of anaemia was also undertaken.

Result, Data were available for 106 of the 116 IVICA patients (OI n=55, IVI n=51). Median follow up was 61 months (IQR 38-68, [range 1-80]). Overall survival estimates at 3 and 5 years were 82%(95% CI 76-90) and 72%(58-83) respectively for OI and 75%(61-86) and 59%(45-72) for IVI, P=0.106. No significant difference in 5-year overall survival (HR 1.73, 95% CI 0.90-3.34 P=0.102) or disease-free survival (HR 1.50, 95% CI 0.83-2.73 P=0.182) was observed between groups. Those non-anaemic at operation demonstrated improved 5 year overall survival (HR 3.26 [1.01-10.58], P=0.05). Non-significant trends in improved disease-free survival (HR 2.29 [0.91-5.81], p=0.08) were observed for the non-anaemic group

Conclusion

Preoperative correction of anaemia confers a postoperative survival advantage following elective colorectal cancer surgery. Due to its superior efficacy intravenous iron is recommended as the treatment of choice for this anaemia.

Take-home message

Preoperative correction of anaemia, achieved most effectively with intravenous iron, may offer improved long term postoperative survival after colorectal cancer surgery.
O47: IKK-ALPHA AS A POTENTIAL NOVEL TARGET FOR TREATMENT OF COLORECTAL CANCER
Authors: Patel M , Quinn JA , Pennel KAF , Flanagan D , Horgan PG , McMillan DC , MacKay S , Sansom O , Edwards J
Published: April 2021

Introduction

There is substantial evidence linking NF-κB and cancer-related processes. The aim of this study was to investigate the role of IKKα, the main catalytic component of non-canonical NF-κB pathway in colorectal cancer (CRC).

Method

Immunohistochemistry and immunofluorescence was used to examine expression of IKKα in 1030 patients undergoing resection for stage I-III CRC. To assess IKKα inhibition, organoids were prepared from wild type (WT) mouse colon, mouse models of CRC (Apc and Apc.KRAS.pT53.TGFbR2 (AKPT)) and patient derived human organoids. These were treated with an IKKα inhibitor, SU1433 and organoid size and cell viability assessed.

Result

High cytoplasmic expression of IKKα was associated with increasing T stage (p=0.012), poor tumour differentiation (p=0.010), tumour necrosis (p=0.013) and low proliferation status (p=0.013). High punctate IKKα expression was associated with reduced CSS (HR1.20 95%CI 1.02-1.42, p<0.001). Immunofluorescence showed IKKα was co-located with a Golgi-related structure. SU1433 did not significantly impact on WT (C57/B16) organoid viability up to a concentration of 1uM, however organoid size and cell viability was significantly reduced in a dose-dependent manner in organoids from both Apc and AKPT mouse models. A similar reduction was observed in patient derived human organoids.

Conclusion

Punctate IKKα expression was associated with poor cancer specific survival in CRC patients. The relationship between IKKα and the Golgi requires further investigation. Inhibition with SU1433, impacted on CRC mouse and patient derived human organoid size and cell viability. These results suggest that IKKα following further investigation could be employed as a novel therapeutic target in CRC.

Take-home message

IKKα is up-regulated in patients undergoing surgery for CRC, this is associated with poor survival outcome and inhibition of IKKα and has presented itself as a novel therapeutic target. The relationship between IKKα and the Golgi has raised interesting questions regarding the molecular behaviour of IKKα and this warrants further investigation.
O51: ARTIFICIAL INTELLIGENCE UTILIZING RECURRENT NEURAL NETWORKS TO CONTINUOUSLY MONITOR COMPOSITES OF SURGICAL EXPERTISE
Authors: Yilmaz R , Winkler-Schwartz A , Mirchi N , Reich A , Del Maestro R
Published: April 2021

Introduction

Many surgical adverse events occur secondary to technical errors related to poor bimanual skills, fatigue and lack of the required expertise. We developed AI algorithms to continuously assess surgical bimanual technical performance during virtual reality simulated surgical tasks. To our knowledge, this is the first attempt in surgery to train AI algorithms to continuously monitor and evaluate bimanual skills comprehensively.

Method

Fifty individuals from four expertise levels (14 experts/neurosurgeons, 14 senior residents, 10 junior residents, 12 medical students) performed two virtual reality simulated surgical tasks with haptic feedback: a subpial tumor resection 5 times and a complex, realistically simulated brain tumor operation once. Each task required complete tumor removal while minimizing bleeding and damage to surrounding tissues using a simulated ultrasonic aspirator and a bipolar. A recurrent neural network continually tracked individual bimanual performance utilizing 16 performance metrics generated every 0.2 seconds.

Result

The recurrent neural network algorithm was successfully trained using neurosurgeons and medical students' data, learning the composites of expertise comparing high and lower skill levels. The trained algorithm outlined and monitored technical skills every 0.2 second continuously organizing performance of each surgical task into three levels: ‘excellent’, ‘average’ and ‘poor’. The percentage time spent on each level was calculated and significant differences found between all four groups for ‘excellent’ and ‘poor’ levels.

Conclusion

AI-powered surgical simulators provide an advanced assessment and training tool. AI's ability to continuous assess bimanual technical skills during surgery may further define the composites necessary to train surgical expertise.

Abbrev

AI: artificial intelligence

Take-home message

By advanced artificial intelligence algorithms surgeon's bi-manual technical skills can be assessed continuously, time periods of poor performance which increase the possibility of errors in performance can be identified.
O54: GENDER REPRESENTATION IN EDITORIAL BOARDS OF INTERNATIONAL GENERAL SURGERY JOURNALS
Authors: Gallivan ER , Arshad SR , Skinner H , Burke JR , Young AL
Published: April 2021

Introduction

Despite women constituting over half of new UK doctors, and a similar proportion worldwide, gender disparity remains an issue throughout academic medicine. Surgery has shown particularly slow progress towards gender parity. This study aims to quantify gender representation within editorial boards of the top 25 general surgical journals.

Method

All surgical journals were collated using the SCImago Journal Rank (SJR) and Journal Impact Factor (JIF). Non general surgery journals were excluded. Journals were contacted requesting gender editorial team demographics. Editorial board data was collected via journal websites on 20th November 2019.

Result

The top 25 surgical journals were determined through SJR and JIF ranking methods. Editorial board data was publicly available for 31 of these 32 different surgical journals. This data was then examined. Women accounted for 18.4% (576/3135) of total editorial board positions. Women constituted 12.5% (5/40) of Editors-in-Chief positions, 31.6% (31/98) of Deputy Editors and 17.2% (416/2415) of general editorial board positions.

Conclusion

For the first time, gender disparity has been demonstrated within editorial boards of the most prominent general surgery journals. The implications of such significant gender disparity are wide reaching. Action should be taken to champion fair female representation, eliminate risk of bias and provide more visible female role models in academic surgery.

Take-home message

For the first time, this study demonstrates gender disparity in Editorial boards of major general surgery journals. Action should be taken to champion fair female representation, eliminate risk of bias and provide more visible female role models in academic surgery.