bluuebunny/crossref_metadata_2025_split huggingface dataset:
Blood group P1 prediction using multiplex PCR genotyping of A4GALT among Thai blood donors
Authors: Thinley Jigme , Nathalang Oytip , Chidtrakoon Sarisa , Intharanut Kamphon 
Published: December 2020

SummaryObjectivesThis study aimed to investigate single‐nucleotide variants (SNVs) associated with P1 expression among Thai blood donors and develop a genotyping method using multiplex polymerase chain reaction (PCR) to predict P1 blood group status.BackgroundThe α1,4‐galactosyltransferase (A4GALT), also called Gb3/CD77 synthase or P1/Pk synthase enzyme, is encoded by the A4GALT gene and catalyses the transfer of galactose from uridine diphosphate‐galactose to lactosylceramide, creating the Pk antigen (Gb3). The same enzyme synthesises the P1 antigen by adding terminal galactose to paragloboside. The A4GALT transcripts are elevated in P1, and different SNVs in transcription factor‐binding regions of A4GALT correlate with P1 and P2 phenotypes.Material and MethodsA total of 218 blood samples from Thai blood donors at the Thammasat University Hospital were tested for the P1 antigen using the conventional tube technique. Genomic DNA was extracted, and non‐coding regions of A4GALT were sequenced and analysed. A multiplex PCR assay was developed and validated to identify P1‐associated SNVs and was subsequently tested on 1022 Thai DNA samples of unknown P1 antigen status.ResultsIn the tested cohort (n = 218), P1 and P2 phenotypes were found in 24.77% and 75.23% of donors, respectively. Moreover, three SNVs—rs8138197 (C/T), rs2143918 (T/G) and rs5751348 (G/T)—correlated 100% with both phenotypes. Finally, findings agreed with serological phenotyping and DNA sequencing results, confirming their validity for predicting P1 antigen positivity.ConclusionsThis study confirmed that three SNVs also correlated with P1/P2 phenotypes among Thais, as expected. A multiplex PCR found that SNVs rs2143918 (T) and rs5751348 (G) predicted blood group P1 and is an accurate, reproducible, cost‐effective and less time‐consuming alternative to traditional methods.
Defining natural factors that stimulate and inhibit cellulose:xyloglucan hetero‐transglucosylation
Authors: Herburger Klaus , Franková Lenka , Pičmanová Martina , Xin Anzhou , Meulewaeter Frank , Hudson Andrew , Fry Stephen C. 
Published: December 2020

SUMMARYCertain transglucanases can covalently graft cellulose and mixed‐linkage β‐glucan (MLG) as donor substrates onto xyloglucan as acceptor substrate and thus exhibit cellulose:xyloglucan endotransglucosylase (CXE) and MLG:xyloglucan endotransglucosylase (MXE) activities in vivo and in vitro. However, missing information on factors that stimulate or inhibit these hetero‐transglucosylation reactions limits our insight into their biological functions. To explore factors that influence hetero‐transglucosylation, we studied Equisetum fluviatile hetero‐trans‐β‐glucanase (EfHTG), which exhibits both CXE and MXE activity, exceeding its xyloglucan:xyloglucan homo‐transglucosylation (XET) activity. Enzyme assays employed radiolabelled and fluorescently labelled oligomeric acceptor substrates, and were conducted in vitro and in cell walls (in situ). With whole denatured Equisetum cell walls as donor substrate, exogenous EfHTG (extracted from Equisetum or produced in Pichia) exhibited all three activities (CXE, MXE, XET) in competition with each other. Acting on pure cellulose as donor substrate, the CXE action of Pichia‐produced EfHTG was up to approximately 300% increased by addition of methanol‐boiled Equisetum extracts; there was no similar effect when the same enzyme acted on soluble donors (MLG or xyloglucan). The methanol‐stable factor is proposed to be expansin‐like, a suggestion supported by observations of pH dependence. Screening numerous low‐molecular‐weight compounds for hetero‐transglucanase inhibition showed that cellobiose was highly effective, inhibiting the abundant endogenous CXE and MXE (but not XET) action in Equisetum internodes. Furthermore, cellobiose retarded Equisetum stem elongation, potentially owing to its effect on hetero‐transglucosylation reactions. This work provides insight and tools to further study the role of cellulose hetero‐transglucosylation in planta by identifying factors that govern this reaction.
A Novel Design for a Compliant Mechanism Based Variable Stiffness Grasper Through Structure Modulation
Authors: Chandrasekaran Karthik , Somayaji Adarsh , Thondiyath Asokan 
Published: December 2020

Abstract
Robots utilize graspers for interacting with an environment. Conventional robotic graspers have difficulty conforming to objects of varied shape and exerting varying grasping forces. Variable stiffness soft robotic graspers provide these features but face issues such as slow response time, the requirement of external power packs for operation and low variation of stiffness. A variable stiffness compliant robotic grasper that is simple in design and operation would improve end effectors used in assistive robotics and prostheses for handling a wide array of objects. In this paper, we present the design of a novel variable stiffness compliant robotic grasper that can change its stiffness through structural transformations. Current designs utilizing structural transformations do not provide shape conformance while grasping objects. We propose a design for a soft robotic grasper using the concept of stability of truss structures. This design is capable of partially conforming to the surface of an object being grasped and can rapidly vary its stiffness utilizing compliant rotating elements embedded in the grasper jaws. The grasper behavior is modeled using finite element analysis (FEA) and validated experimentally. Our results demonstrate that structural transformation of flexible elements is a potential solution for achieving variable stiffness in a grasper.
Velocity-Domain Motion Quality Measures for Surgical Performance Evaluation and Feedback
Authors: Murali Barathwaj , Belvroy Viony M. , Pandey Shivam , Bismuth Jean , Byrne Michael D. , O'Malley Marcia K. 
Published: December 2020

Abstract
Endovascular navigation proficiency requires a significant amount of manual dexterity from surgeons. Objective performance measures derived from endovascular tool tip kinematics have been shown to correlate with expertise; however, such metrics have not yet been used during training as a basis for real-time performance feedback. This paper evaluates a set of velocity-based performance measures derived from guidewire motion to determine their suitability for online performance evaluation and feedback. We evaluated the endovascular navigation skill of 75 participants using three metrics (spectral arc length, average velocity, and idle time) as they steered tools to anatomical targets using a virtual reality simulator. First, we examined the effect of navigation task and experience level on performance and found that novice performance was significantly different from intermediate and expert performance. Then we computed correlations between measures calculated online and spectral arc length, our “gold standard” metric, calculated offline (at the end of the trial, using data from the entire trial). Our results suggest that average velocity and idle time calculated online are strongly and consistently correlated with spectral arc length computed offline, which was not the case when comparing spectral arc length computed online and offline. Average velocity and idle time, both time-domain based performance measures, are therefore more suitable measures than spectral arc length, a frequency-domain based metric, to use as the basis of online performance feedback. Future work is needed to determine how to best provide real-time performance feedback to endovascular surgery trainees based on these metrics.
Reliable Calculation of Thermoacoustic Instability Risk Using an Imperfect Surrogate Model
Authors: Guo Shuai , Silva Camilo F. , Polifke Wolfgang 
Published: December 2020

Abstract
One of the fundamental tasks in performing robust thermoacoustic design of gas turbine combustors is calculating the modal instability risk, i.e., the probability that a thermoacoustic mode is unstable, given various sources of uncertainty (e.g., operation or boundary conditions). To alleviate the high computational cost associated with conventional Monte Carlo simulation, surrogate modeling techniques are usually employed. Unfortunately, in practice, it is not uncommon that only a small number of training samples can be afforded for surrogate model training. As a result, epistemic uncertainty may be introduced by such an “inaccurate” model, provoking a variation of modal instability risk calculation. In the current study, using Gaussian process (GP) as the surrogate model, we address the following two questions: First, how to quantify the variation of modal instability risk induced by the epistemic surrogate model uncertainty? Second, how to reduce the variation of risk calculation given a limited computational budget for the surrogate model training? For the first question, we leverage on the Bayesian characteristic of the GP model and perform correlated sampling of the GP predictions at different inputs to quantify the uncertainty of risk calculation. We show how this uncertainty shrinks when more training samples are available. For the second question, we adopt an active learning strategy to intelligently allocate training samples such that the trained GP model is highly accurate particularly in the vicinity of the zero growth rate contour. As a result, a more accurate and robust modal instability risk calculation is obtained without increasing the computational cost of surrogate model training.
Effect of Cold-Rolling on Hydrogen Diffusion and Trapping in X70 Pipeline Steel
Authors: Thomas Alen , Szpunar Jerzy A. 
Published: December 2020

Abstract
In this investigation, we prepared samples with five different grain misorientations by cold-rolling an X70 pipeline steel plate. The hydrogen permeation and hydrogen visualization experiments were used to compute the diffusion parameters and to reveal the diffusion path in steel samples. The dual-polarized permeation experiment allowed us to show that permeability and effective diffusion coefficient were decreased with an increase in misorientation. Hence, the total and irreversible trapping sites were also raised with the extent of deformation in the steel. On the other hand, the visualization study permitted us to show that hydrogen diffusion intensity changes within the microstructure. The diffusion intensity increases in the order of non-deformed grains, grain boundaries, and deformed grains with deformed grains as the easiest path for hydrogen diffusion.
Influences of Iteration Details on Flow Continuities of Numerical Solutions to Isothermal Elastohydrodynamic Lubrication With Micro-Cavitations
Authors: Liu Shuangbiao , Qiu Liangwei , Wang Zhijian , Chen Xiaoyang 
Published: December 2020

Abstract
Studying elastohydrodynamic lubrication (EHL) of line contacts involving micro-cavitations, this paper examines various numerical solutions with a focus on their explicit flow continuities from inlet to exit. For the first time, influences of relaxation details, error controls, differential schemes, and mesh densities on flow continuity in EHL are revealed systemically. Furthermore, hybrid relaxation factors are introduced, the line relaxation is enabled with earlier boundary-condition enforcement, and a typical iteration process is updated with a three-in-one iteration control. Such a process is further integrated with two different starvation/cavitation treatments: one explicitly adjusts reformation locations, and the other uses a fractional film content parameter to adjust the Couette term originated by Bayada et al. The mass conservation results for problems with multiple micro-cavitations occurring inside the lubrication region are compared, and flow curves clearly demonstrate satisfactory continuities. These insights are beneficial for EHL simulations.
The Cost on System Performance of Requirements on Differentiable Variables
Authors: Hazelrigg George A. , Stolfi Philip 
Published: December 2020

Abstract
System design is commonly thought of as a process of maximizing a design objective subject to constraints, among which are the system requirements. Given system-level requirements, a convenient management approach is to disaggregate the system into subsystems and to “flowdown” the system-level requirements to the subsystem or lower levels. We note, however, that requirements truly are constraints, and they typically impose a penalty on system performance. Furthermore, disaggregation of the system-level requirements into the flowdown requirements creates added sets of constraints, all of which have the potential to impose further penalties on overall system performance. This is a highly undesirable effect of an otherwise beneficial system design management process. This article derives conditions that may be imposed on the flowdown requirements to assure that they do not penalize overall system performance beyond the system-level requirement.
A Symmetric Multichamber Hydraulic Cylinder With Variable Piston Area: An Approach to Compact and Efficient Electrohydrostatic Actuation
Authors: Bartlett Harrison L. 
Published: December 2020

Abstract
This paper presents an approach for designing symmetric (effective cylinder area during extension is the same as that during retraction) multichamber cylinders with discretely variable piston area. The design methodology is presented in a generalizable manner and is demonstrated on an example five-chamber cylinder design. A method for finding symmetric multichamber cylinder configurations from a given cylinder topology is presented, and subsequently, a method for discretely varying the effective piston area is developed, subject to a cylinder symmetry constraint. Furthermore, an algorithm is presented to optimally switch the effective cylinder area of an electrohydrostatic actuation system either to minimize the magnitude of motor torque or to minimize resistive power losses in the system. Additionally, a method for optimizing standard (constant area) hydraulic cylinders to minimize motor torque magnitude or resistive power losses is presented. These methods are then demonstrated on an example electrohydrostatic actuation system via simulation. Results indicate that this multichamber cylinder approach with discretely variable piston area may allow for the design of compact and efficient actuators relative to standard methods.
Design of Bionic Foldable Wing Mimicking the Hind Wings of theC. BuquetiBamboo Weevil
Authors: Li Xin , Guo Ce , Ma Yaopeng , Zheng Yu 
Published: December 2020

AbstractThe bamboo weevil, Cyrtotrachelus buqueti, has excellent flight ability and strong environmental adaptability. When it flies, its fore wings and hind wings are unfolded, whereas when it crawls, its fore wings are closed, and its flexible hind wings are regularly folded under the fore wings. In this paper, the hind wing folding/unfolding pattern of C. buqueti is analyzed and a new bionic foldable wing with rigid–flexible coupling consisting of a link mechanism and a wing membrane is constructed. The movement of the link at the wing base mimics the contraction of a muscle in the thorax that triggers scissor-like motion and the deployment of the veins. Elastic hinges are used to mimic the rotational motion of the wing base and the vein joints. The static/dynamic characteristics of bionic foldable wings are further analyzed, and the LS-DYNA software is used to investigate rigid–flexible coupling dynamics. The elastic deformation of the wing membrane, kinematic characteristics of the linkage mechanism, and modes of the whole system are calculated. Static analysis of the structure reveals that the foldable wing has excellent stiffness characteristics and load-bearing capacity. The bionic foldable wing is constructed using three-dimensional (3D) printing technology, and its folding and unfolding performance is tested. Evaluation of its performance shows that the bionic wing has a large fold ratio and can achieve stable folding and unfolding motions. A slightly tighter assembly between the pin and the hinge hole ensures that the wing does not fold back during flapping.
Large Eddy Simulation of Film Cooling Over a Flat Plate in Supersonic Flow
Authors: Sharma Hitesh , Singh Dushyant , Singh Ashutosh Kumar 
Published: December 2020

Abstract
In the present work, large eddy simulation (LES) was performed to access the film cooling performance in the supersonic flow over a flat plate with a perpendicular slot injection configuration. The study was carried out for three mainstream Mach No.; Mα = 1.2, 2.67, and 3.3 and three coolant stream Mach No.: 0.05, 0.1, and 0.15. In supersonic flow, temperature rise inside the boundary layer is a major issue considering it causes high rates of heat transfer to the coolant film. To select a suitable LES sub-grid scale (SGS) model, LES results obtained from the present study using the LES SGS models such as Smagorinky-Lilly, wall adapted local eddy viscosity (WALE), and wall-modeled LES (WMLES) models were compared with DNS results of Keller and Kloker. The parametric study showed that the higher mainstream Mach No. caused increased wall temperature and reduced effectiveness. The film cooling effectiveness appeared to reduce almost by 10% when the mainstream Mach No. is increased from 1.2 to 2.67; however, no apparent difference was observed in effectiveness between the mainstream Mach No. 2.67 and 3.3. It was found that doubling and tripling the coolant stream Mach No. from 0.05 to 0.1 and 0.15, the length of potential core region also doubled and tripled, respectively, from 4 X/S to 8 X/S and 13 X/S and hence significant improvement in the film cooling effectiveness was observed.
Prediction of NOx Emissions for a Range of Engine Hardware Configurations Using Artificial Neural Networks
Authors: Papaioannou Nick , Fang XiaoHang , Leach Felix , Davy Martin H. 
Published: December 2020

Abstract
The predictive ability of artificial neural networks where a large number of experimental data are available, has been studied extensively. Studies have shown that ANN models are capable of accurately predicting NOx emissions from engines under various operating conditions and different fuel types when trained well. One of the major advantages of an ANN model is its ability to relearn when new experimental data is available, thus continuously improving its accuracy. The present work explored the potential of an ANN model to predict NOx emissions for various engine configurations outside its training envelop. This work also looked into quantifying the amount of new data required to improve the accuracy of the model when exposed to unknown conditions. The chosen ANN model was constructed using data from a high-speed direct injection diesel engine and is capable of accurate NOx emissions over a wide range of operating conditions. The optimized network utilized 14 input parameters and is using 6 neurons in a single hidden layer feed-forward neural network. Experimental data from the various engine configurations tested, were then used to predict NOx from the existing ANN model. The results indicate that when the new data are within the baseline training envelop, the ANN model is capable of accurate NOx prediction even when there are substantial changes in engine configuration such as piston material. Similar results were also observed when the injector nozzle is changed. However, the model’s performance drops significantly when new data, outside the baseline training envelop, were employed indicating that additional training is required. As such, various methods for retraining the ANN model were explored with the selected method showing the best compromise between new-data accuracy and old-data accuracy retention. The retrained ANN model developed was found to be an effective tool in predicting NOx emissions for different engine configurations and operating conditions.
Computational Fluid Dynamics Investigation on Multiple Injector Concepts at Different Swirl Ratios in a Heavy Duty Engine
Authors: Nyrenstedt Gustav , Ben Houidi Moez , Babayev Rafig , Im Hong , Johansson Bengt 
Published: December 2020

Abstract
Numerical studies investigated how multiple injectors can reduce the high heat losses associated with swirl, as a further attempt to enhance thermal efficiencies of high-pressure combustion engines. Computational fluid dynamics simulations employed the Reynolds-averaged Navier-Stokes approach for one, two- and three injector configurations. High and medium load conditions were simulated at different swirl ratios. In general, an increased swirl ratio reduced engine efficiency. However, for all swirl ratios, three injectors provided higher efficiency. Two injectors decreased the heat losses for all swirl ratios, and injection against the swirl with multiple injectors provided high efficiencies. In combination with a waste heat recovery system, the two-injector case delivered an efficiency increase of 2.2%-points for the medium load case. Three injectors delivered high efficiencies at all swirl ratios as an effect of a high flow rate and low heat losses. The multiple injector configurations evaluated in this study proved non-beneficial for the high load case. Spray-to-spray interactions lowered the combustion — and indicated efficiencies. However, the three injector case showed potential for delivering high indicated efficiency, from an increased flow rate, at high loads.