bluuebunny/crossref_metadata_2025_split huggingface dataset:
‘Resistance is futile?’ – paradoxical inhibitory effects of KATP channel closure in glucagon‐secreting α‐cells
Authors: Zhang Quan , Dou Haiqiang , Rorsman Patrik 
Published: July 2020

AbstractBy secreting insulin and glucagon, the β‐ and α‐cells of the pancreatic islets play a central role in the regulation of systemic metabolism. Both cells are equipped with ATP‐regulated potassium (KATP) channels that are regulated by the intracellular ATP/ADP ratio. In β‐cells, KATP channels are active at low (non‐insulin‐releasing) glucose concentrations. An increase in glucose leads to KATP channel closure, membrane depolarization and electrical activity that culminates in elevation of [Ca2+]i and initiation of exocytosis of the insulin‐containing secretory granules. The α‐cells are also equipped with KATP channels but they are under strong tonic inhibition at low glucose, explaining why α‐cells are electrically active under hypoglycaemic conditions and generate large Na+‐ and Ca2+‐dependent action potentials. Closure of residual KATP channel activity leads to membrane depolarization and an increase in action potential firing but this stimulation of electrical activity is associated with inhibition rather than acceleration of glucagon secretion. This paradox arises because membrane depolarization reduces the amplitude of the action potentials by voltage‐dependent inactivation of the Na+ channels involved in action potential generation. Exocytosis in α‐cells is tightly linked to the opening of voltage‐gated P/Q‐type Ca2+ channels, the activation of which is steeply voltage‐dependent. Accordingly, the inhibitory effect of the reduced action potential amplitude exceeds the stimulatory effect resulting from the increased action potential frequency. These observations highlight a previously unrecognised role of the action potential amplitude as a key regulator of pancreatic islet hormone secretion.
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A Computational Investigation of the Impact of Multiple Injection Strategies on Combustion Efficiency in Diesel–Natural Gas Dual-Fuel Low-Temperature Combustion Engines
Authors: Bartolucci Lorenzo , Cordiner Stefano , Mulone Vincenzo , Krishnan Sundar R. , Srinivasan Kalyan K. 
Published: July 2020

AbstractDual-fuel diesel–methane low-temperature combustion (LTC) has been investigated by various research groups, showing high potential for emissions reduction (especially oxides of nitrogen oxide (NOx) and particulate matter (PM)) without adversely affecting fuel conversion efficiency in comparison with conventional diesel combustion. However, when operated at low load conditions, dual-fuel LTC typically exhibits poor combustion efficiencies. This behavior is mainly due to low bulk gas temperatures under lean conditions, resulting in unacceptably high carbon monoxide (CO) and unburned hydrocarbon (UHC) emissions. A feasible and rather innovative solution may be to split the pilot injection of liquid fuel into two injection pulses, with the second pilot injection supporting CO and UHC oxidation once combustion is initiated by the first one. In this study, diesel–methane dual-fuel LTC is investigated numerically in a single-cylinder heavy-duty engine operating at 5 bar brake mean effective pressure (BMEP) at 85% and 75% percentage of energy substitution (PES) by methane (taken as a natural gas (NG) surrogate). A multidimensional model is first validated in comparison with the experimental data obtained on the same single-cylinder engine for early single pilot diesel injection at 310 crank angle degrees (CAD) and 500 bar rail pressure. With the single pilot injection case as baseline, the effects of multiple pilot injections and different rail pressures on combustion and emissions are investigated, again showing good agreement with the experimental data. Apparent heat release rate and cylinder pressure histories as well as combustion efficiency trends are correctly captured by the numerical model. Results prove that higher rail pressures yield reductions of HC and CO by 90% and 75%, respectively, at the expense of NOx emissions, which increase by ∼30% from baseline still remaining at very low level (under 1 g/kWh). Furthermore, it is shown that postinjection during the expansion stroke does not support the stable development of the combustion front as the combustion process is confined close to the diesel spray core.
Optimizing Topology and Fiber Orientations With Minimum Length Scale Control in Laminated Composites
Authors: Luo Chuan , Guest James K. 
Published: July 2020

Abstract
Discrete material optimization (DMO) has proven to be an effective framework for optimizing the orientation of orthotropic laminate composite panels across a structural design domain. The typical design problem is one of maximizing stiffness by assigning a fiber orientation to each subdomain, where the orientation must be selected from a set of discrete magnitudes (e.g., 0 deg, ±45 deg, 90 deg). The DMO approach converts this discrete problem into a continuous formulation where a design variable is introduced for each candidate orientation. Local constraints and penalization are then used to ensure that each subdomain is assigned a single orientation in the final solution. The subdomain over which orientation is constant is most simply defined as a finite element, ultimately leading to complex orientation layouts that may be difficult to manufacture. Recent literature has introduced threshold projections commonly used in density-based topology optimization into the DMO approach in order to influence the manufacturability of solutions. This work takes this idea one step further and utilizes the Heaviside projection method within DMO to provide formal control over the minimum length scale of structural features, holes, and patches of uniform orientation. The proposed approach is demonstrated on benchmark maximum stiffness design problems, and numerical results are near discrete with strict length scale control, providing a direct avenue to controlling the complexity of orientation layouts. This ultimately suggests that projection-based methods can play an important role in controlling the manufacturability of optimized material orientations.
A Study on Basis Functions of the Parameterized Level Set Method for Topology Optimization of Continuums
Authors: Wei Peng , Yang Yang , Chen Shikui , Wang Michael Yu 
Published: July 2020

Abstract
In recent years, the parameterized level set method (PLSM), which rests on radial basis functions in most early work, has gained growing attention in structural optimization. However, little work has been carried out to investigate the effect of the basis functions in the parameterized level set method. This paper examines the basis functions of the parameterized level set method, including radial basis functions, B-spline functions, and shape functions in the finite element method (FEM) for topology optimization of continuums. The effects of different basis functions in the PLSM are examined by analyzing and comparing the required storage, convergence speed, computational efficiency, and optimization results, with the benchmark minimum compliance problems subject to a volume constraint. The linear basis functions show relatively satisfactory overall performance. Besides, several schemes to boost computational efficiency are proposed. The study on examples with unstructured 2D and 3D meshes can also be considered as a tentative investigation of prospective possible commercial applications of this method.
Research on the Influence of Clearance Variation on the Stiffness Fluctuation of Ball Bearing Under Different Operating Conditions
Authors: Fang Bin , Wan Shaoke , Zhang Jinhua , Hong Jun 
Published: July 2020

Abstract
The vibration induced by the varying compliance (VC) or the stiffness fluctuation of ball bearing plays a key role in the dynamic performance of the rotor system. The aim of this article is to study the stiffness fluctuation behaviors of ball bearing under different operating conditions. This article presents an improved mathematic model for ball bearing with wider applicability based on the new initial/reference position assumption and the ball-raceway contact/separation determination. The proposed model not only gets rid of the limitations of the raceway control hypothesis but also considers the space constraints of the cage on the balls. The advantages of the proposed model are presented through the typical working condition analysis, and the influences of the internal clearance on the stiffness and stiffness fluctuation of ball bearing under different operating conditions are given and discussed. The results show that bearing stiffness and stiffness fluctuation are determined by the external loads, rotating speeds, and internal clearances together, and properly increasing the axial load can effectively reduce the amplitudes and frequency components of the stiffness fluctuation. As an exploratory research work on the excitation source for the VC vibration of the bearing-rotor system, this article not only explains the complexity and diversity of the rotor VC vibration behavior from another side but also provides new ideas and important supplements for the rotor nonlinear analysis.
Design for Nonassembly: Current Status and Future Directions
Authors: Jung Sangjin , Laureijs Rianne E. , Combemale Christophe , Whitefoot Kate S. 
Published: July 2020

AbstractNonassembled products, which are produced from a raw material and post-processed to a final form without any assembly steps, form a large and potentially growing share of the manufacturing sector. However, the design for manufacturing literature has largely focused on assembled products and does not necessarily apply to nonassembled products. In this paper, we review the literature on design for nonassembly (DFNA) and the broader literature on design for manufacturing that has design guidelines and metrics applicable to nonassembled products, including both monolithic single-part products and nonassembly mechanisms. Our review focuses on guidelines that apply across multiple manufacturing processes. We identify guidelines and metrics that seek to reduce costs as well as provide differentiated products across a product family. We cluster the guidelines using latent semantic analysis and find that existing DFNA guidelines fall into four main categories pertaining to (1) manufacturing process, (2) material, (3) tolerance, and (4) geometry. We also identify existing product family metrics that can be modified for nonassembled products to measure some aspects of these categories. Finally, we discuss possible future research directions to more accurately characterize the relationships between design variables and manufacturing costs, including investigating factors related to the complexity of operations at particular process steps and across process steps.
Mode-Pursuing Sampling Method Using Discriminative Coordinate Perturbation for High-Dimensional Expensive Black-Box Optimization
Authors: Wu Yufei , Long Teng , Shi Renhe , Gary Wang G. 
Published: July 2020

Abstract
This article presents a novel mode-pursuing sampling method using discriminative coordinate perturbation (MPS-DCP) to further improve the convergence performance of solving high-dimensional, expensive, and black-box (HEB) problems. In MPS-DCP, a discriminative coordinate perturbation strategy is integrated into the original mode-pursuing sampling (MPS) framework for sequential sampling. During optimization, the importance of variables is defined by approximated global sensitivities, while the perturbation probabilities of variables are dynamically adjusted according to the number of optimization stalling iterations. Expensive points considering both optimality and space-filling property are selected from cheap points generated by perturbing the current best point, which balances between global exploration and local exploitation. The convergence property of MPS-DCP is theoretically analyzed. The performance of MPS-DCP is tested on several numerical benchmarks and compared with state-of-the-art metamodel-based design optimization methods for HEB problems. The results indicate that MPS-DCP generally outperforms the competitive methods regarding convergence and robustness performances. Finally, the proposed MPS-DCP is applied to a stepped cantilever beam design optimization problem and an all-electric satellite multidisciplinary design optimization (MDO) problem. The results demonstrate that MPS-DCP can find better feasible optima with the same or less computational cost than the competitive methods, which demonstrates its effectiveness and practicality in solving real-world engineering problems.
A Quantile-Based SORA Method Using Maximum Entropy Method With Fractional Moments
Authors: He Wanxin , Yang Hua , Zhao Gang , Zeng Yan , Li Gang 
Published: July 2020

Abstract
Reliability-based design optimization (RBDO) is receiving more attention from researchers because it can help to minimize cost reasonably in practical engineering. A large number of methods have been proposed to solve RBDO problems, most of which are based on the theory of the first-order reliability method (FORM). Therefore, the deficiencies of the FORM limit applications of general RBDO methods such as the dependency on the minimum performance target point (MPTP). In this study, we apply the fractional moment-based maximum entropy method to the RBDO problems for the first time and propose a novel RBDO method using the quantile-based sequential optimization and reliability assessment method. Because the proposed method is MPTP free, the shortcomings of FORM-based RBDO methods can be overcome. To demonstrate the performance of the proposed method, we test five numerical examples and one engineering example by the proposed method and three popular RBDO methods. The results show that the proposed method can balance the accuracy and the efficiency compared with other methods.
A Survey of Modeling and Optimization Methods for Multi-Scale Heterogeneous Lattice Structures
Authors: Liu Yuan , Zheng Guolei , Letov Nikita , Zhao Yaoyao Fiona 
Published: July 2020

Abstract
This paper aims to provide a comprehensive review of the state-of-the-art modeling and optimization methods for multi-scale heterogeneous lattice structures (MSHLS) to further facilitate the more design freedom. In this survey, a design process including optimization and modeling for MSHLS is proposed. Material composition and multi-scale geometric modeling methods for representation of material and geometry information are separately discussed. Moreover, the optimization methods including multi-scale and multi-material optimization design methods, as well as the simulation methods suitable for MSHLS are, respectively, reviewed. Finally, the relationship, advantages, and disadvantages of MSHLS modeling and optimization methods are summarized with discussion and comparison, which provides a guidance to further take advantage of MSHLS to improve the performance and multifunctional purpose of production for software developers and researchers concerning the design approaches and strategies currently available.
The Effect of Gapping on Compressor Performance
Authors: Przytarski Pawel J. , Wheeler Andrew P. S. 
Published: July 2020

Abstract
In this paper, we study the effect of rotor-stator axial gap on midspan compressor loss using high-fidelity scale-resolving simulations. For this purpose, we mimic the multi-stage environment using a new numerical method that recycles wake unsteadiness from a single blade passage back into the inlet of the computational domain. As a result, a type of repeating-passage simulation is obtained such as observed by an embedded blade-row. We find that freestream turbulence levels rise significantly as the size of the rotor-stator axial gap is reduced. This is because of the effect of axial gap on turbulence production, which becomes amplified at smaller axial gaps and drives increases in dissipation and loss. This effect is found to raise loss by between 5.5% and 9.5% over the range of conditions tested here. This effect significantly outweighs the beneficial effects of wake recovery on loss.
Chapter 6: Preservice Teachers’ Perceptions of Twitter for Health and Physical Education Teacher Education: A Self-Determination Theoretical Approach
Authors: Hyndman Brendon P. , Harvey Stephen 
Published: July 2020

Purpose: Limited research has been conducted relating to the use of social media during health and physical education teacher education. The aim of this study was to investigate preservice teachers’ perceptions of the value of using Twitter for health and physical education teacher education. Methods: Preservice teachers completed a qualitatively designed survey. Thematic analyses were conducted via Computer Assisted Qualitative Data Analysis Software, aligned to self-determination theory. Results: Twitter was perceived to be valuable for the following motivational components: (a) autonomy (choice over professional development, latest ideas, and learning flexibility), (b) relatedness (enhancing communication, tailored collaborations, and receiving practical support), and (c) competence (transferring ideas to classes, increasing technological competence, and keeping ahead of other teachers). Yet there were concerns due to Twitter’s public exposure to undesired Twitter users (relatedness) and how to navigate the platform (competence). Discussion/Conclusions: The study provides guidance to health and physical education teacher education providers on how digital learning via Twitter can meet preservice teachers’ learning needs.
Neoproterozoic Amdo and Jiayuqiao microblocks in the Tibetan Plateau: Implications for Rodinia reconstruction
Authors: Liu Yiming , Wang Yuhua , Li Sanzhong , Santosh M. , Guo Runhua , Yu Shengyao 
Published: July 2020

Abstract
The Tibetan Plateau is composed of several microblocks, the tectonic affinity and paleogeographic correlations of which remain enigmatic. We investigated the Amdo and Jiayuqiao microblocks in central Tibet Plateau with a view to understand their tectonic setting and paleogeographic position within the Neoproterozoic supercontinent Rodinia. We present zircon U-Pb and Lu-Hf isotope, and whole-rock geochemical data on Neoproterozoic granitic gneisses from these microblocks. Zircon grains from the Jiayuqiao granitic gneiss yielded an age of 857 ± 9 Ma with variable εHf(t) values (–8.9 to 4.0). The Amdo granitic gneisses yielded ages of 893 ± 5 Ma, 807 ± 5 Ma, and 767 ± 11 Ma, with εHf(t) values in the range of –4.9 to 3.5. Geochemically, the granitoids belong to high-K calc-alkaline series, with the protolith derived from partial melting of ancient crustal components. The ascending parental magma of the Amdo granitoids experienced significant mantle contamination as compared to the less contaminated magmas that generated the Jiayuqiao intrusions. In contrast to the Lhasa, Himalaya, South China, and Tarim blocks, we suggest that the Amdo and Jiayuqiao microblocks probably formed a unified block during the Neoproterozoic and were located adjacent to the southwestern part of South China craton. The Neoproterozoic magmatism was probably associated with the subduction of the peripheral ocean under the South China craton and the delamination of lithospheric mantle beneath the Jiangnan orogen.
Neonatal cardiac surgery in low resource settings: implications of birth weight
Authors: Gunasekara Chamith Mendis , Moynihan Katie , Sudhakar Abish , Sunil Gopalraj Sumangala , Kotayil Brijesh P , Bayya Praveen Reddy , Kumar Raman Krishna 
Published: July 2020

ObjectiveWe sought to evaluate the association between low birth weight (LBW) and outcomes following neonatal cardiac surgery in a low-income and middle-income country setting where LBW prevalence is high and its impact on surgical outcomes is undefined.DesignSingle-centre retrospective cohort study.SettingReferral paediatric hospital in Southern IndiaPatientsAll neonatal cardiac surgical cases between January 2011 and December 2018. LBW was defined as <2.5 kg.Main outcome measuresPatient demographics, corrective versus palliative surgery and postoperative outcomes were collected from the institutional database which undergoes regular audit as part of International Quality Improvement Collaborative for Congenital Heart Disease. In-hospital mortality was the primary outcome measure.ResultsOf 569 neonatal cardiac operations, 123 (21.6%) had LBW (mean: 2.2±0.3 kg); 18.7% <2 kg and 21.1% were preterm (<37 weeks). Surgery type (corrective vs palliative) or non-cardiac anomalies were not associated with birth weight. Birth weight did not correlate with ICU length of stay (LOS) and mechanical ventilation but was lower in those with postoperative sepsis. Overall in-hospital mortality was 7.0%; LBW neonates had higher mortality (OR 2.16, 95% CI 1.09 to 4.29, p=0.025). Multivariable analyses revealed birth weight (OR per 100 g decrease in weight: 1.12; 95% CI 1.03 to 1.22), age at surgery (OR per day increase in age of 0.93; 95% CI 0.87 to 0.99) and palliative intervention (OR 4.46 (95% CI 1.91 to 10.44) as independent predictors of in-hospital mortality.ConclusionLBW adversely impacts in-hospital mortality outcomes following neonatal cardiac surgery in a resource-limited setting without increase in ICU or hospital LOS.
Overlap between child protection services and the youth justice system: protocol for a retrospective population-based cohort study using linked administrative data in Manitoba, Canada
Authors: Nickel Nathan C , Turnbull Lorna , Wall-Wieler Elizabeth , Au Wendy , Ekuma Okechukwu , MacWilliam Leonard , Enns Jennifer Emily , Lee Janelle Boram , McCulloch Scott , Burchill Charles , Brownell Marni 
Published: July 2020

IntroductionChildren who have a history of involvement in child protection services (CPS) are over-represented in the youth and adult criminal justice systems. There are significant health and socioeconomic implications for individuals involved in either or both CPS and the justice system. Understanding the ‘overlap’ between these two systems would provide insight into the health and social needs of this population. This protocol describes a research programme on the relationship between the child welfare and the youth justice systems, looking specifically at the population involved in both CPS and the youth justice system. We will examine the characteristics associated with involvement in these systems, justice system trajectories of individuals with a history of CPS involvement and early adult outcomes of children involved in both systems.Methods and analysisAdministrative data sets will be linked at the individual level for three cohorts born 1991, 1994 and 1998 in Manitoba, Canada. Involvement in CPS will be categorised as ‘placed in out-of-home care’, ‘received in-home services, but was not placed in care’ or ‘no involvement’. Involvement in the youth justice system will be examined through contacts with police between ages 12 and 17 that either led to charges or did not proceed. Individual, maternal and neighbourhood characteristics will be examined to identify individuals at greatest risk of involvement in one or both systems.Ethics and disseminationThe study was approved by the University of Manitoba Health Research Ethics Board and permission to access data sets has been granted by all data providers. We also received approval for the study from the First Nations Health and Social Secretariat of Manitoba’s Health Information Research Governance Committee and the Manitoba Metis Federation. Strategies to disseminate study results will include engagement of stakeholders and policymakers through meetings and workshops, scientific publications and presentations, and social media.