bluuebunny/crossref_metadata_2025 huggingface dataset:
Metabolomic profile associated with obstructive sleep apnoea severity in obese pregnant women with gestational diabetes mellitus: A pilot study
Authors: Reutrakul Sirimon , Chen Hui , Chirakalwasan Naricha , Charoensri Suranut , Wanitcharoenkul Ekasitt , Amnakkittikul Somvang , Saetung Sunee , Layden Brian T. , Chlipala George E.
Published: April 2021

Obstructive sleep apnoea (OSA) is prevalent in obese women with gestational diabetes mellitus (GDM). The present pilot study explored associations between OSA severity and metabolites in women with GDM. A total of 81 obese women with diet‐controlled GDM had OSA assessment (median gestational age [GA] 29 weeks). The metabolic profile was assayed from fasting serum samples via liquid chromatography–mass spectrometry (LC‐MS) using an untargeted approach. Metabolites were extracted and subjected to an Agilent 1,290 UPLC coupled to an Agilent 6,545 quadrupole time‐of‐flight (Q‐TOF) MS. Data were acquired using electrospray ionisation in positive and negative ion modes. The raw LC‐MS data were processed using the OpenMS toolkit to detect and quantify features, and these features were annotated using the Human Metabolite Database. The feature data were compared with OSA status, apnea–hypopnea index (AHI), body mass index (BMI) and GA using “limma” in R. Correlation analyses of the continuous covariates were performed using Kendall’s Tau test. Thepvalues were adjusted for multiple testing using the Benjamini–Hochberg false discovery rate correction. A total of 42 women (51.8%) had OSA, with a median AHI of 9.1 events/hr. There were no significant differences in metabolomics profiles between those with and without OSA. However, differential analyses modelling in GA and BMI found 12 features that significantly associated with the AHI. These features could be annotated to oestradiols, lysophospholipids, and fatty acids, with higher levels related to higher AHI. Metabolites including oestradiols and phospholipids may be involved in pathogenesis of OSA in pregnant women with GDM. A targeted approach may help elucidate our understanding of their role in OSA in this population.
Estimating bird flight height using 3‐D photogrammetry
Authors: Prinsloo N. D. , Postma M. , Ryan P. G. , Coetzee M. , de Bruyn P. J. N.
Published: April 2021

Harnessing wind or solar power have become popular “green” options for energy production. However, colliding with wind turbine blades or being burned by concentrated solar flux around power towers can present a substantial threat to birds. Assessing the severity of this risk to different bird species requires accurate estimates of their flight height. We developed a three‐dimensional (3‐D) stereophotogrammetric approach to determine bird flight heights. The accuracy of four varying stereophotogrammetric camera layouts was compared between each other and against laser‐based rangefinder measurements of static structures. Bird flight heights were measured and compared between species, and repetitive photographic captures over short time periods were tested for autocorrelation. Three out of four camera layouts performed equally well when measuring static structures at distances of up to 100 m (0.0 ± 0.3%; or 0.00 ± 0.03 m error), better than laser‐based rangefinders (0.3 ± 4.8%; or 0.12 ± 0.51 m error) on a small target. Photogrammetrically measured flight heights were precise to 0.07 ± 0.05 m up to ~275 m away and to within 1 m at 400 m, and measurable up to ~535 m away. Using this tested approach, repetitive, sequential flight heights of moving birds were significantly autocorrelated compared to random flight heights (P = 0.001). Species‐specific flight heights were distinct, practically demonstrating the approach’s potential application, however, scarcity of flight height data prompts further application of the approach to record distributions of flight height. This stereophotogrammetric method was accurate, cost‐effective, objective, and relatively simple to apply. It could measure flight heights, and potentially micro‐avoidance behaviour in 3‐D flight patterns, to ultimately identify species that are at potential risk of collision or burning with wind turbines and solar towers.
The impact of hepatitis B surface antigen on natural killer cells in patients with chronic hepatitis B virus infection
Authors: Du Yanqin , Anastasiou Olympia E. , Strunz Benedikt , Scheuten Janina , Bremer Birgit , Kraft Anke , Kleinsimglinhaus Karolina , Todt Daniel , Broering Ruth , Hardtke‐Wolenski Matthias , Wu Jun , Yang Dongliang , Dittmer Ulf , Lu Mengji , Cornberg Markus , Björkström Niklas K. , Khera Tanvi , Wedemeyer Heiner
Published: April 2021

Background & Aims

During chronic hepatitis B virus (HBV) infection, suppressed functionality of natural killer (NK) cells might contribute to HBV persistence but the underlying mechanisms remain elusive. A peculiar feature of HBV is the secretion of large amount of hepatitis B surface antigen (HBsAg). However, the effect of HBsAg quantities on NK cells is unclear. The aim was to determine the effects of HBsAg quantities on NK cell functionality in patients with chronic hepatitis B (CHB).

Methods

Eighty CHB patients were included and categorized into four groups based on their HBsAg levels. As a control, 30 healthy donors were enrolled. NK cell frequency, phenotype and function were assessed using flow cytometry and correlated with HBsAg levels and liver enzymes.

Results

Compared to the healthy controls, a reshaping of NK cell pool towards more CD56bright NK cells was observed during CHB infection. Importantly, NK cells in patients with low HBsAg levels (<100 IU/mL) displayed an activated phenotype with increased expression of activation makers CD38, granzyme B and proliferation marker Ki‐67 while presenting with defective functional responses (MIP‐1β, CD107a) at the same time. Furthermore, NK cell activation was negatively correlated with patient HBsAg levels while NK function correlated with patient age.

Conclusions

The differential regulation of NK cell phenotype and function suggests that activation of NK cells in patients with low serum HBsAg levels may contribute to HBV clearance.
Associations between health‐related quality of life and health behaviors in Australian nursing students
Authors: Heidke Penny , Vandelanotte Corneel , Irwin Christopher , Williams Susan , Saluja Sonia , Khalesi Saman
Published: April 2021

Health‐related quality of life (HRQoL) is being increasingly studied as an indicator of wellbeing. This study evaluated the HRQoL of nursing students and relationships between lifestyle behaviors including smoking, diet, alcohol intake and physical activity. A cross‐sectional study was conducted in 2018 using the Short‐Form 12V2 to measure the HRQoL of 475 students from both regional and metropolitan universities in Queensland, Australia. z‐scores were aggregated into a Physical Composite Score (PCS) and a Mental Composite Score (MCS). Multivariate linear regression was used to explore the associations. Nursing students (94.5% female) had lower HRQoL scores relative to the general Australian population. Students enrolled at the regional university, with higher income; higher intakes of vitamin A, calcium, and iodine; and more physical activity had a higher Mental Composite Score, but those with health conditions and high intakes of meat, fat, carbohydrates, and sugar reported lower Physical Composite Score compared to their counterparts. Skipping breakfast, physical inactivity, and alcohol score were inversely associated with HRQoL. This study highlights the need for strategies to address the poor lifestyle and HRQoL in nursing students to support their physical and mental health.
Plant volatile organic compound (E)‐2‐hexenal facilitates Botrytis cinerea infection of fruits by inducing sulfate assimilation
Authors: Xu Yanqun , Tong Zhichao , Zhang Xiaochen , Zhang Xing , Luo Zisheng , Shao Wenyong , Li Li , Ma Quan , Zheng Xiaodong , Fang Weiguo
Published: April 2021

Investigation into plant–fungal pathogen interactions is one of the most interesting fields in plant sciences. However, the roles of plant volatile organic compounds in the arms race are still largely unknown.

Based on precise quantification of plant volatiles, we discovered that the plant volatile organic compound (E)‐2‐hexenal, at concentrations that were similar to or lower than those in tissues of strawberry and tomato fruits, upregulates sulfate assimilation in spores and hyphae of the phytopathogenic fungus Botrytis cinerea. This upregulation is independent of the types of sulfur sources in the plant and can be achieved in the presence of inorganic sulfate and organic sulfur sources.

Using the fungal deletion mutants, we further found that sulfate assimilation is involved in the infection of tomato and strawberry fruits by B. cinerea, and that the severity of the disease is proportional to the sulfate content in the fruits. Both before and during the infection, (E)‐2‐hexenal induced utilisation of plant sulfate by B. cinerea facilitates its pathogenesis through enhancing its tolerance to oxidative stress.

This work provides novel insights into the role of plant volatiles in plant–fungal pathogen interaction and highlights the importance of sulfur levels in the host in the prevention of grey mould disease.
Altered mismatch response precedes gray matter atrophy in subjective cognitive decline
Authors: Cheng Chia‐Hsiung , Chang Chiung‐Chih , Chao Yi‐Ping , Lu Hsinjie , Peng Shih‐Wei , Wang Pei‐Ning
Published: April 2021

The cross‐sectional identification of subjective cognitive decline (SCD) in cognitively normal adults is particularly important for the early effective prevention or intervention of the future development of mild cognitive impairments (MCI) or Alzheimer's disease (AD). A pre‐attentive neurophysiological signal that reflects the brain's ability to detect the changes of the environment is called mismatch negativity (MMN) or its magnetic counterpart (MMNm). It has been shown that patients with MCI or AD demonstrate reduced MMN/MMNm responses, while the exact profile of MMN/MMNm in SCD is substantially unknown. We applied magnetoencephalographic recordings to interrogate MMNm activities in healthy controls (HC,n = 29) and individuals with SCD (n = 26). Furthermore, we analyzed gray matter (GM) volumes in the MMNm‐related regions through voxel‐based morphometry and performed apolipoprotein E4 (APOE4) genotyping for all the participants. Our results showed that there were no significant differences in GM volume and proportions of APOE4 carriers between HC and SCD groups. However, individuals with SCD exhibited weakenedz‐corrected MMNm responses in the left inferior parietal lobule and right inferior frontal gyrus (IFG) as compared to HC. Based on the regions showing significant between‐group differences,z‐corrected MMNm amplitudes of the right IFG significantly correlated with the memory performance among the SCD participants. Our data suggest that neurophysiological changes of the brain, as indexed by MMNm, precede structural atrophy in the individuals with SCD compared to those without SCD.
Bayesian Modelling for Spatially Misaligned Health Areal Data: A Multiple Membership Approach
Authors: Gramatica Marco , Congdon Peter , Liverani Silvia
Published: April 2021

Diabetes prevalence is on the rise in the United Kingdom, and for public health strategy, estimation of relative disease risk and subsequent mapping is important. We consider an application to London data on diabetes prevalence and mortality. In order to improve the estimation of relative risks, we analyse jointly prevalence and mortality data to ensure borrowing strength over the two outcomes. The available data involve two spatial frameworks, areas (Middle Layer Super Output Areas, MSOAs) and general practices (GPs) recruiting patients from several areas. This raises a spatial misalignment issue that we deal with by employing the multiple membership principle. Specifically, we translate areal spatial effects to explain GP practice prevalence according to proportions of GP populations resident in different areas. A sparse implementation in RStan of both the multivariate conditional autoregressive (MCAR) and generalised MCAR (GMCAR) with multiple membership allows the comparison of these bivariate priors as well as exploring the different implications for the mapping patterns for both outcomes. The necessary causal precedence of diabetes prevalence over mortality allows a specific conditionality assumption in the GMCAR, not always present in the context of disease mapping. Additionally, an area-locality comparison is considered to locate high versus low relative risk clusters.
Factorized estimation of high‐dimensional nonparametric covariance models
Authors: Zhang Jian , Li Jie
Published: April 2021

Estimation of covariate‐dependent conditional covariance matrix in a high‐dimensional space poses a challenge to contemporary statistical research. The existing kernel estimators may not be locally adaptive due to using a single bandwidth to explore the smoothness of all entries of the target matrix function. In this paper, we propose a novel framework to address this issue, where we factorize the target matrix into factors and estimate these factors in turn by the kernel approach. The resulting estimator is further regularized by thresholding and optimal shrinkage. Under certain mixing and sparsity conditions, we show that the proposed estimator is well‐conditioned and uniformly consistent with the underlying matrix function even when the sample is dependent. Simulation studies suggest that the proposed estimator significantly outperforms its competitors in terms of integrated root‐squared estimation error. We present an application to financial return data.
The ‘dirty work’ of risk in Northern Territory renal services
Authors: Puszka Stefanie
Published: April 2021

In remote Indigenous communities, people with end stage kidney disease have limited access to dialysis services and the vast majority of patients contend with urban displacement in order to access treatment. Through ethnographic encounters with Yolŋu renal patients and other actors in Northern Territory healthcare systems, this paper explores how the threats posed by end stage kidney disease are multiply conceptualised and imbued with different forms of moral and political value. Drawing on Mary Douglas’ cultural theory of risk, I consider how Yolŋu, health professionals and health policymakers construct topographies of safety and danger. I argue that medical risk is deployed in Northern Territory healthcare systems to perform the ‘dirty work’ of governing uncertainties and threats to renal patients’ health and of distributing treatment amongst patients and over space. The ‘dirty work’ of medical risk recasts questions of value and the distribution of resources into matters of safety and liability.
Association of Veterinary Hematology and Transfusion Medicine (AVHTM) Transfusion Reaction Small Animal Consensus Statement (TRACS). Part 1: Definitions and clinical signs
Authors: Davidow Elizabeth B. , Blois Shauna L. , Goy‐Thollot Isabelle , Harris Lauren , Humm Karen , Musulin Sarah , Nash Katherine J , Odunayo Adesola , Sharp Claire R. , Spada Eva , Thomason John , Walton Jenny , Wardrop K. Jane
Published: April 2021

Objective

To use a systematic, evidence‐based consensus process to develop definitions for transfusion reactions in dogs and cats.

Design

Evidence evaluation of the literature was carried out for identified transfusion reaction types in dogs and cats. Reaction definitions were generated based on synthesis of human and veterinary literature. Consensus on the definitions was achieved through Delphi‐style surveys. Draft recommendations were made available through industry specialty listservs and comments were incorporated.

Results

Definitions with imputability criteria were developed for 14 types of transfusion reactions.

Conclusions

The evidence review and consensus process resulted in definitions that can be used to facilitate future veterinary transfusion reaction research.
Thyroid storm in a dog secondary to thyroid carcinoma
Authors: Merkle Jennifer E. , Boudreaux Bonnie , Langohr Ingeborg , Hegler Ashley , Ryan Kirk , Fletcher Jon
Published: April 2021

Objective

To describe the clinical presentation, clinical course, and management of a dog with thyroid storm (TS) secondary to a functional thyroid carcinoma.

Case summary

A 12‐year‐old neutered female Golden Retriever was evaluated for severe weight loss, hyperthermia, and tachycardia. The dog had a ventral neck mass and markedly increased thyroxine concentration. Cervical ultrasound showed a suspected left thyroid mass with invasion into the jugular vein. Despite aggressive therapy, the patient progressed to a clinical TS. Postmortem examination was supportive of the clinical diagnosis.

New or unique information provided

To the authors’ knowledge, this is the first report of TS in a dog.
Analysis of Hazards for Autonomous Driving
Authors: Schwalb Edward
Published: April 2021

Hazard analysis is the core of numerous approaches to safety engineering, including the functional safety standard ISO-26262 (FuSa) and Safety of the Intended Function (SOTIF) ISO/PAS 21448. We focus on addressing the immense challenge associated with the scope of training and testing for rare hazard for autonomous drivers, leading to the need to train and test on the equivalent of >108 naturalistic miles. We show how risk can be estimated and bounded using the probabilistic hazard analysis. We illustrate the definition of hazards using well-established tests for hazard identification. We introduce a dynamic hazard approach, whereby autonomous drivers continuously monitor for potential and developing hazard, and estimate their time to materialization (TTM). We describe systematic TTM modeling of the various hazard types, including environment-specific perception limitations. Finally, we show how to enable accelerated development and testing by training a neural network sampler to generate scenarios in which the frequency of rare hazards is increased by orders of magnitude.
Stochastic Finite Element Thermal Analysis of a Ball Grid Array Package
Authors: Upreti Rahul , Chintamani Siddarth , Patil Sandeep , Akbariyeh Ashkan , Dennis Brian H.
Published: April 2021

This paper presents a straight-forward finite element approach for the quantification of electronic package thermal performance under uncertainty. The method makes use of high accuracy sensitivity calculations and a gradient-based minimization method. The approach was applied to the thermal analysis of a ball grid array (BGA) package under uncertainty to illustrate its capabilities. The effect of uncertainty in the heat source, heat transfer coefficient, ambient temperature, and thermal conductivities of the component materials on the probability of exceeding a specified average junction temperature at the die-heat-spreader interface was studied. In addition, the performance and accuracy of two different methods for computing the required sensitivities were compared. Results showed that the average junction temperature probability was more sensitive to some system parameters over others, providing crucial information for selecting the manufacturing tolerance of BGA package components. For parameters identified as especially sensitive, selecting components with tighter tolerances will reduce uncertainty and increase the overall reliability. And for less sensitive parameters, selecting larger tolerance could help reduce manufacturing costs.
Underfill Flow in Flip-Chip Encapsulation Process: A Review
Authors: Ng Fei Chong , Abas Mohamad Aizat
Published: April 2021

The scope of review of this paper focused on the precuring underfilling flow stage of encapsulation process. A total of 80 related works has been reviewed and being classified into process type, method employed, and objective attained. Statistically showed that the conventional capillary is the most studied underfill process, while the numerical simulation was mainly adopted. Generally, the analyses on the flow dynamic and distribution of underfill fluids in the bump array aimed for the filling time determination as well as the predictions of void occurrence. Parametric design optimization was subsequently conducted to resolve the productivity issue of long filling time and reliability issue of void occurrence. The bump pitch was found to the most investigated parameter, consistent to the miniaturization demand. To enrich the design versatility and flow visualization aspects, experimental test vehicle was innovated using imitated chip and replacement fluid, or even being scaled-up. Nonetheless, the analytical filling time models became more accurate and sophiscasted over the years, despite still being scarce in number. With the technological advancement on analysis tools and further development of analytic skills, it was believed that the future researches on underfill flow will become more comprehensive, thereby leading to the production of better packages in terms of manufacturing feasibility, performances, and reliability. Finally, few potential future works were recommended, for instance, microscopic analysis on the bump–fluid interaction, consideration of filler particles, and incorporation of artificial intelligence.
Nonlinear Dynamics of the Parametric Pendulum With a View on Wave Energy Harvesting Applications
Authors: Dotti Franco E. , Virla Juan N.
Published: April 2021

In this article, nonlinear dynamics tools are employed to quantify the ability of pendulum harvesters to recover energy from the sea waves. The versatility of pendulum harvesters is highlighted, as it is shown that devices can be scaled to produce usable energy from 6 W to 10 kW. Several aspects of the pendulum's dynamics having a key influence on power generation are discussed using bifurcation diagrams, parameter spaces, and basins of attraction. Parameter ranges that minimize the need for a control action are identified, and an explanation is provided on why tilting the pendulum's plane of rotation improves power generation. A practical mathematical model of the parametric pendulum is formulated for such a purpose. This model incorporates the possibility of accounting arbitrary number of concentric masses while allowing a simple and direct correlation between dimensionless approaches and the myriad possible physical configurations of the system.
Lagrangian Transport and Chaotic Advection in Three-Dimensional Laminar Flows
Authors: Speetjens Michel , Metcalfe Guy , Rudman Murray
Published: April 2021

Transport and mixing of scalar quantities in fluid flows is ubiquitous in industry and Nature. While the more familiar turbulent flows promote efficient transport and mixing by their inherent spatio-temporal disorder, laminar flows lack such a natural mixing mechanism and efficient transport is far more challenging. However, laminar flow is essential to many problems, and insight into its transport characteristics of great importance. Laminar transport, arguably, is best described by the Lagrangian fluid motion (“advection”) and the geometry, topology, and coherence of fluid trajectories. Efficient laminar transport being equivalent to “chaotic advection” is a key finding of this approach. The Lagrangian framework enables systematic analysis and design of laminar flows. However, the gap between scientific insights into Lagrangian transport and technological applications is formidable primarily for two reasons. First, many studies concern two-dimensional (2D) flows, yet the real world is three-dimensional (3D). Second, Lagrangian transport is typically investigated for idealized flows, yet practical relevance requires studies on realistic 3D flows. The present review aims to stimulate further development and utilization of know-how on 3D Lagrangian transport and its dissemination to practice. To this end, 3D practical flows are categorized into canonical problems. First, to expose the diversity of Lagrangian transport and create awareness of its broad relevance. Second, to enable knowledge transfer both within and between scientific disciplines. Third, to reconcile practical flows with fundamentals on Lagrangian transport and chaotic advection. This may be a first incentive to structurally integrate the “Lagrangian mindset” into the analysis and design of 3D practical flows.
Direct Re-Usability of Lead-Plated Tin Bronze as Negative Plate for Lightweight Lead-Acid Battery
Authors: Yang Tong , Qian Shengqiang , Luo Yuting , Wang Xinhu , Wang Zhenwei
Published: April 2021

Lead-plated tin-bronze mesh was adopted as the negative grid to assembly 2V-DZM-20Ah lead-acid battery. Compared with the conventional negative plate, the weight of each tin-bronze plate was reduced by about 17 g, the weight of the single cell was reduced by 13.67%, and the mass specific capacity of the single cell was increased by about 7 Wh · kg−1. The sulfation of the negative side was suppressed due to the high electronic conductivity of bronze-based negative plate. The failure expansion of the positive side was also restricted due to the strong negative structure. The dissembled negative grid of lead-plated tin bronze after 450 cycles of 100% discharge of degree was still intact and dense. After the dissembled negative grid was reassembled into a 2-V single cell, the battery exhibited similar performance to that with a new one. Generally speaking, the direct re-usability of tin-bronze-based grid sharply simplifies the grid recovery and opens a greatly attracting direction for developing lightweight, high-energy technique of lead-acid batteries.
Frictional Characteristics of Carbide Ceramics in Water
Authors: Zhang Wei , Chen Xiaoyu , Yamashita Seiji , Kubota Mitsuhiro , Kita Hideki
Published: April 2021

Frictional characteristics of carbide ceramics (SiC, B4C–SiC, and B4C) sliding against SiC balls in water were measured over a wide range of test conditions. Carbide ceramics can obtain hydrodynamic lubrication with low friction coefficients at 20 and 40 N; however, carbide ceramics cannot obtain hydrodynamic lubrication with low friction coefficients at 5 N. Carbide ceramics exhibit lower friction coefficients at 20 and 40 N than those at 5 N in each lubrication regime. Carbide ceramics can exhibit a wider application range with low friction at high loads (20 and 40 N). The low friction of carbide ceramics is achieved by the combination of hydrodynamic lubrication and tribochemical reactions. The products of tribochemical reactions of carbide ceramics improve the viscosity of water at or near the worn surfaces of carbide ceramics, promoting the hydrodynamic lubrication for carbide ceramics. B4C ceramic shows lower friction coefficients than those of SiC and B4C–SiC ceramics in boundary lubrication and mixed lubrication at 20 and 40 N.
Role of Well-Dispersed Carbon Nanotubes and Limited Matrix Degradation on Tribological Properties of Flame-Sprayed PEEK Nanocomposite Coatings
Authors: Li Yupeng , Man Zhiqiang , Lin Xinyu , Wei Lai , Wang Haonan , Lei Mingkai
Published: April 2021

High-performance carbon nanotubes reinforced polyether ether ketone (CNTs/PEEK) nanocomposites display an excellent combination of mechanical, thermal, and tribological properties. It is a challenge to deposit high-performance CNTs/PEEK nanocomposite coatings via the coating techniques based on solution or melting processes due to low solubility and high melting point of PEEK for tribological applications. In this work, the CNTs/PEEK nanocomposite coatings with CNTs contents of 0.1, 0.5, 1.0, and 2.0 wt% were prepared by flame spraying of mixed PEEK and CNTs powders using mechanical blending (MB) and ultrasound dispersion (UD) methods. The flame-sprayed CNTs/PEEK nanocomposite coatings using UD powders preserved good CNTs dispersion, low porosity, and surface roughness, adhesive coating–substrate interfaces. The thermal degradation of PEEK ascribed to overheating of in-flight particles and flame-rescanning coatings was limited by good CNTs dispersion in flame-sprayed CNTs/PEEK nanocomposite coatings with an increase of CNT contents. The good dispersion of CNTs aided in initiating crystallization and confined crystalline growth resulting in high crystallinity degree and small crystallite size of PEEK matrix in the flame-sprayed CNTs/PEEK nanocomposite coatings. The uniform nanocomposite coatings with well-dispersed CNTs and few PEEK degradation in optimum content of 1.0 wt% preserved enhanced microhardness and superiorly tribological properties. The well-dispersed CNTs bonding with PEEK matrix enhanced the mechanical strength to restrict the generation of fatigue cracks from defects of voids, which promoted self-lubrication and wear resistance of flame-sprayed CNTs/PEEK nanocomposite coatings.
Are Two Heads Better Than One for Computer-Aided Design?
Authors: Phadnis Vrushank , Arshad Hamza , Wallace David , Olechowski Alison
Published: April 2021

With the availability of cloud-based software, ubiquitous internet, and advanced digital modeling capabilities, a new potential has emerged to design physical products with methods previously embraced by the software engineering community. One such example is pair programming, where two coders work together synchronously to develop one piece of code. Pair programming has been shown to lead to higher-quality code and user satisfaction. Cutting-edge collaborative computer-aided design (CAD) technology affords the possibility to apply synchronous collaborative access in mechanical design. We test the generalizability of findings from the pair programming literature to the same dyadic configuration of work in CAD, which we call pair CAD. We performed human subject experiments with 60 participants to test three working styles: individuals working by themselves, pairs sharing control of one model instance and input, and pairs able to edit the same model simultaneously from two inputs. We compare the working styles on speed and quality and propose mechanisms for our observations via interpretation of patterns of communication, satisfaction, and user cursor activity. We find that on a per-person basis, individuals were faster than pairs due to coordination and overhead inefficiencies. We find that pair work, when done with a single shared input, but not in a parallel mode, leads to higher-quality models. We conclude that it is not software capabilities alone that influence designer output; choices regarding work process have a major effect on design outcomes, and we can tailor our process to suit project requirements.
Double-Helix Linear Actuators
Authors: Sabelhaus Andrew P. , Zampaglione Kyle , Tang Ellande , Chen Lee-Huang , Agogino Adrian K. , Agogino Alice M.
Published: April 2021

Many robotic systems require linear actuation with high forces, large displacements, and compact profiles. This article presents a series of mechanisms, termed double-helix linear actuators (DHLAs), designed for this purpose. By rotating the fixed end of a double-helix linear actuator, its helix angle changes, displacing at the free end. This article proposes two concepts for DHLA designs, differing in their supporting structure, and derives kinematic and geometric models for both. Prototypes of each concept are presented, and for the more promising “continuous-rails” design, hardware tests are conducted that validate the actuator’s kinematic model and characterize its force transmission properties. The final prototypes can exert both tension and compression forces, can displace up to 75% of their total length, and show consistent trends for torque versus force load. These designs have the potential to overcome the force and displacement limitations of other linear actuators while simultaneously reducing size and weight.
Generation and Enforcement of Process-Driven Manufacturability Constraints: A Survey of Methods and Perspectives for Product Design
Authors: Patterson Albert E. , Lee Yong Hoon , Allison James T.
Published: April 2021

Design-for-manufacturing (DFM) concepts have traditionally focused on design simplification; this is highly effective for relatively simple, mass-produced products, but tends to be too restrictive for more complex designs. Effort in recent decades has focused on creating methods for generating and imposing specific, process-derived technical manufacturability constraints for some common problems. This paper presents an overview of the problem and its design implications, a discussion of the nature of the manufacturability constraints, and a survey of the existing approaches and methods for generating/enforcing the minimally restrictive manufacturability constraints within several design domains. Five major design perspectives or viewpoints were included in the survey, including the system design (top-down), product/component design (bottom-up), the manufacturing process-dominant case (product/component design under a specific process), the part-redesign perspective, and sustainability perspective. Manufacturability constraints within four design levels or scales were explored as well, ranging from macro-scale to sub-micro-scale design. Very little previous work was found in many areas, revealing several gaps in the literature. What is clearly needed is a more general, design-method-independent approach to collecting and enforcing manufacturability constraints.
Reliability-Informed Life Cycle Warranty Cost and Life Cycle Analysis of Newly Manufactured and Remanufactured Units
Authors: Li Meng , Nemani Venkat P. , Liu Jinqiang , Lee Michael A. , Ahmed Navaid , Kremer Gül E. , Hu Chao
Published: April 2021

Standard life cycle techniques such as life cycle warranty cost (LCWC) analysis and life cycle analysis (LCA) are used to respectively quantify the relative economical and environmental advantages of remanufactured goods while simultaneously identifying avenues for improvement. In this paper, we contribute to the literature on life cycle studies by incorporating reliability into LCWC analysis and LCA with the goal of improving long-term/multiple life cycle decision making. We develop a branched power-law model to incorporate the physical degradation mechanisms leading to reduced reuse rates of system parts over multiple life cycles. We then follow a standard LCA protocol to quantify the difference between a new unit and its remanufactured version in terms of environmental impact items such as abiotic depletion potential, global warming potential, and energy consumption. We then devise four practical warranty policies that vary in the choice of replacement and/or provision for extended warranty. All possible replacement scenarios for multiple life cycles are explored for each policy and a mathematically rigorous framework is provided, where the reliability information is used to calculate probabilistic LCWC and life cycle impact items. This reliability-informed LCWC analysis and LCA framework enables design engineers to compare design options and warranty policies by quantifying both economical and environmental impacts to aid in decision making. Although the framework is presented in a general form applicable to any engineered system, we demonstrate the utility of this framework by using a case study of an infinitely variable transmission used in agricultural equipment.
Evolutionary Gaussian Processes
Authors: Planas Robert , Oune Nick , Bostanabad Ramin
Published: April 2021

Emulation plays an important role in engineering design. However, most emulators such as Gaussian processes (GPs) are exclusively developed for interpolation/regression and their performance significantly deteriorates in extrapolation. To address this shortcoming, we introduce evolutionary Gaussian processes (EGPs) that aim to increase the extrapolation capabilities of GPs. An EGP differs from a GP in that its training involves automatic discovery of some free-form symbolic bases that explain the data reasonably well. In our approach, this automatic discovery is achieved via evolutionary programming (EP) which is integrated with GP modeling via maximum likelihood estimation, bootstrap sampling, and singular value decomposition. As we demonstrate via examples that include a host of analytical functions as well as an engineering problem on materials modeling, EGP can improve the performance of ordinary GPs in terms of not only extrapolation, but also interpolation/regression and numerical stability.
Designing an Optimal Modular-Based Product Family Under Intellectual Property and Sustainability Considerations
Authors: Kim Jinju , Saidani Michael , Kim Harrison M.
Published: April 2021

With the rapid development of new technology and the growing global competition in industry, it is essential for companies to protect their sensitive product designs and technologies. To ensure that their systems are not exploited by potential patent infringers, original equipment manufacturers often apply physical attributes and/or reduce commonality within a product family to prevent easy reusing and recovering. Yet, these design strategies are key barriers to the sustainable recovery and recycling of products. To address these trade-offs, this paper proposes a stepwise methodology to identify the sustainable optimal product family architecture design while protecting intellectual property on sensitive parts or modules. The developed approach notably allows the selection of suitable and sustainable candidates to share among products, taking into account the cost-benefit of commonality within the product family. To demonstrate and test the proposed methodology, a case study is performed with a printer-product family. Environmental savings resulting from the new modular-based architecture obtained for this product family are quantified and discussed.
The Influence of Process Management: Uncovering the Impact of Real-Time Managerial Interventions via a Topic Modeling Approach
Authors: Gyory Joshua T. , Kotovsky Kenneth , Cagan Jonathan
Published: April 2021

Computationally studying team discourse can provide valuable, real-time insights into the state of design teams and design cognition during problem-solving. The particular experimental design, adopted from previous work by the authors, places one of the design team conditions under the guidance of a human process manager. In that work, teams under this process management outperformed the unmanaged teams in terms of their design performance. This opens the opportunity to not only model design discourse during problem-solving, but more critically, to explore process manager interventions and their impact on design cognition. Utilizing this experimental framework, a topic model is trained on the discourse of human designers of both managed and unmanaged teams collaboratively solving a conceptual engineering design task. Results show that the two team conditions significantly differ in a number of the extracted topics and, in particular, those topics that most pertain to the manager interventions. A dynamic look during the design process reveals that the largest differences between the managed and unmanaged teams occur during the latter half of problem-solving. Furthermore, a before and after analysis of the topic-motivated interventions reveals that the process manager interventions significantly shift the topic mixture of the team members’ discourse immediately after intervening. Taken together, these results from this work not only corroborate the effect of the process manager interventions on design team discourse and cognition but provide promise for the computational detection and facilitation of design interventions based on real-time, discourse data.
Multi-Objective Optimization for High-Dimensional Expensively Constrained Black-Box Problems
Authors: Cheng George H. , Gary Wang G. , Hwang Yeong-Maw
Published: April 2021

Multi-objective optimization (MOO) problems with computationally expensive constraints are commonly seen in real-world engineering design. However, metamodel-based design optimization (MBDO) approaches for MOO are often not suitable for high-dimensional problems and often do not support expensive constraints. In this work, the situational adaptive Kreisselmeier and Steinhauser (SAKS) method was combined with a new multi-objective trust region optimizer (MTRO) strategy to form the SAKS-MTRO method for MOO problems with expensive black-box constraint functions. The SAKS method is an approach that hybridizes the modeling and aggregation of expensive constraints and adds an adaptive strategy to control the level of hybridization. The MTRO strategy uses a combination of objective decomposition and K-means clustering to handle MOO problems. SAKS-MTRO was benchmarked against four popular multi-objective optimizers and demonstrated superior performance on average. SAKS-MTRO was also applied to optimize the design of a semiconductor substrate and the design of an industrial recessed impeller.
Acoustic Field-Assisted Two-Photon Polymerization Process
Authors: Lichade Ketki M. , Pan Yayue
Published: April 2021

This study successfully integrates acoustic patterning with the Two-Photon Polymerization (TPP) process for printing nanoparticle–polymer composite microstructures with spatially varied nanoparticle compositions. Currently, the TPP process is gaining increasing attention within the engineering community for the direct manufacturing of complex three-dimensional (3D) microstructures. Yet the full potential of TPP manufactured microstructures is limited by the materials used. This study aims to create and demonstrate a novel acoustic field-assisted TPP (A-TPP) process, which can instantaneously pattern and assemble nanoparticles in a liquid droplet, and fabricate anisotropic nanoparticle–polymer composites with spatially controlled particle–polymer material compositions. It was found that the biggest challenge in integrating acoustic particle patterning with the TPP process is that nanoparticles move upon laser irradiation due to the photothermal effect, and hence, the acoustic assembly is distorted during the photopolymerization process. To cure acoustic assembly of nanoparticles in the resin through TPP with the desired nanoparticle patterns, the laser power needs to be carefully tuned so that it is adequate for curing while low enough to prevent the photothermal effect. To address this challenge, this study investigated the threshold laser power for polymerization of TPP resin (Pthr) and photothermal instability of the nanoparticle (Pthp). Patterned nanoparticle–polymer composite microstructures were fabricated using the novel A-TPP process. Experimental results validated the feasibility of the developed acoustic field-assisted TPP process on printing anisotropic composites with spatially controlled material compositions.
A tale of two curves and their influence on rocket and supersonic jet noise research
Authors: Gee Kent L.
Published: April 2021

This letter describes how a landmark 1960s supersonic jet noise experiment influenced subsequent noise models. A discrepancy in other researchers' application of Potter and Jones's axial decomposition of the sound power generated from a laboratory-scale jet can be traced to an erroneous plot in the original report. Whereas most jet noise research indicates the dominant sound power is generated upstream of the supersonic core tip, propagation of this error in the ubiquitous NASA SP-8072 report has caused rocket noise modelers for five decades to disproportionately allocate sound power generation to the subsonic flow.
Vocal fold kinematics and relative fundamental frequency as a function of obstruent type and speaker age
Authors: Park Yeonggwang , Wang Feng , Díaz-Cádiz Manuel , Vojtech Jennifer M. , Groll Matti D. , Stepp Cara E.
Published: April 2021

The acoustic measure, relative fundamental frequency (RFF), has been proposed as an objective metric for assessing vocal hyperfunction; however, its underlying physiological mechanisms have not yet been fully characterized. This study aimed to characterize the relationship between RFF and vocal fold kinematics. Simultaneous acoustic and high-speed videoendoscopic (HSV) recordings were collected as younger and older speakers repeated the utterances /ifi/ and /iti/. RFF values at voicing offsets and onsets surrounding the obstruents were estimated from acoustic recordings, whereas glottal angles, durations of voicing offset and onset, and a kinematic estimate of laryngeal stiffness (KS) were obtained from HSV images. No differences were found between younger and older speakers for any measure. RFF did not differ between the two obstruents at voicing offset; however, fricatives necessitated larger glottal angles and longer durations to devoice. RFF values were lower and glottal angles were greater for stops relative to fricatives at voicing onset. KS values were greater in stops relative to fricatives. The less adducted vocal folds with greater KS and lower RFF at voicing onset for stops relative to fricatives in this study were in accordance with prior speculations that decreased vocal fold contact area and increased laryngeal stiffness may decrease RFF.
‘Huge hole’ in testing data blurs racial, ethnic disparities
Authors: Servick Kelly
Published: April 2021

Researchers seek better data on pandemic's uneven burden.
The pandemic virus is slowly mutating. But does it matter?
Authors: Kupferschmidt Kai
Published: April 2021

Linking genomic changes to viral behavior proves difficult.
Technology Feature | The road to reducing traffic accidents in China
Authors: O'Meara Sarah
Published: April 2021

Biomarkers for neurological diseases used to be few and far between, but better technology is making it easier for researchers to track brain health by measuring molecules. This means less invasive testing, earlier diagnosis, faster drug development, and—hopefully—more effective treatments.
Pandemic scientists fight burnout
Authors: Wadman Meredith
Published: April 2021

Running on empty at bedside, bench, and beyond.
A plateful of medicine
Authors: Kaiser Jocelyn
Published: April 2021

Special diets might boost the power of drugs to vanquish tumors.
Tumor-initiating cells establish an IL-33–TGF-β niche signaling loop to promote cancer progression
Authors: Taniguchi Sachiko , Elhance Ajit , Van Duzer Avery , Kumar Sushil , Leitenberger Justin J. , Oshimori Naoki
Published: April 2021

Deconstructing a perilous loop

Cancer cells that give rise to solid tumors reside in a specialized microenvironment containing growth factors that support tumor growth and progression. The mechanisms by which tumor cells within this so-called “niche” attract and sustain these growth factors are poorly understood. Studying a mouse model of squamous cell carcinoma, Taniguchi
et al.
identified a signaling loop initiated by certain tumor cells within the niche that become more invasive on exposure to transforming growth factor β (TGF-β). They show that the tumor cells release the cytokine interleukin-33, which induces the differentiation of nearby myeloid cells into macrophages. These macrophages in turn release TGF-β, which feeds back to the tumor cells, promoting their malignant progression.

Science
this issue p.
eaay1813
The rotten apples of Brazil's agribusiness
Authors: Rajão Raoni , Soares-Filho Britaldo , Nunes Felipe , Börner Jan , Machado Lilian , Assis Débora , Oliveira Amanda , Pinto Luis , Ribeiro Vivian , Rausch Lisa , Gibbs Holly , Figueira Danilo
Published: April 2021

Brazil's inability to tackle illegal deforestation puts the future of its agribusiness at risk