bluuebunny/crossref_metadata_2025 huggingface dataset:
Effect of heating temperatures on AlSi coating microstructure and fracture during hot-tensile tests
Authors: Zaman S B , Hazrati J , de Rooij M B , van den Boogaard A H
Published: June 2021

In this article, the fracture behavior of different AlSi coating micro-structures is investigated. By changing the heating temperature, different AlSi coating micro-structures are obtained, due to varying diffusivity of iron. To study the fracture behavior of different coating micro-structures, uniaxial tensile tests are conducted at 700 °C. The hot tensile test involves heating the as-coated press hardening steel in a furnace to heating temperatures of 750, 920 and 1000 °C for 6 minutes of dwell time, after which the sample is cooled to the deformation stage at 700 °C. In this stage, the samples are uniaxially deformed for a fixed 20% macroscopic strain followed by cooling to room temperature. After the test, the coating micro-structure and fracture pattern are inspected under the microscope. For samples heated to 750 and 920 °C, coating fracture is observed; however, for samples heated to 1000 °C, no coating fracture is observed during the tensile deformation at 700 °C. The AlSi coating micro-structure, after heating at 1000 °C becomes sufficiently ductile to withstand 20% strain at 700 °C. The same micro-structure, however, fractures during uniaxial tensile deformation at 600 °C.
Implementation of Real Contact Areas into Sheet metal Forming Simulations using Digital Spotting Images
Authors: Essig P. , Liewald M. , Hol J.
Published: June 2021

Increasing demands on quality of outer car panels and shortened product development processes fundamentally challenge automotive manufacturers. Development times are significantly influenced by the manufacturing process of dies, which are introduced by the time-consuming manual grinding operations carried out during die try-out. Blue color paste is often used to visualize contact areas between die surfaces and blank to provide a spotting image. The spotting image can be used to evaluate and optimize the pressure distribution. A homogeneous pressure distribution positively influences the forming process in terms of flange draw-in and surface quality. This paper presents an approach for implementing real contact areas into forming simulations based on digital spotting images of active surfaces. Spotting images were produced for different drawing depths and subsequently extracted by image processing. The simulation model presented in this study includes different spotting levels in conjunction with theTriboFormfriction model to describe tribological conditions during forming more accurately.
A new machine learning based method for sampling virtual experiments and its effect on the parameter identification for anisotropic yield models
Authors: Wessel A , Morand L , Butz A , Helm D , Volk W
Published: June 2021

A new method for sampling virtual experiments on the initial yield surface is introduced for the plane stress state. The method is based on a machine learning technique called active learning, which can be used to adaptively sample a parameter space with respect to a certain criterion. For the evaluation of this new method, it is compared against a random sampling approach taken from literature and the effect of both methods on three different anisotropic yield models, namely Yld89, Yld2000-2d and Yld2004-18p (in-plane), is analysed. The results demonstrate that the active learning based sampling approach has advantages over the random sampling approach in terms of reliability and sample efficiency. Moreover, it is found that the effect of the sampling method on the resulting yield surface depends on the anisotropic yield model considered.
Virtual die spotting: Advanced setup for coupling of forming and structure simulation
Authors: Zgoll F , Götze T , Volk W
Published: June 2021

Shorter product life cycles and increasing product variety in the automotive industry are leading to increasing pressure on manufacturing of stamping dies for car body parts. A high amount of manual rework is needed to meet product quality, which is one of the main drivers for long production time and high cost. The long-term goal is to meet quality requirements directly after machining of the active tool surfaces to reduce the manual rework needed to a bare minimum. This can only be achieved by taking elastic deformations of tools and press into account during the virtual die making process.

To predict the deflection at the active surfaces during the forming process, a conventional forming simulation with rigid tools is coupled with a structure simulation using elastic tools and press. For the accurate representation of the deflection behaviour of the real press, substitute models of moving bolster and ram are used, which are based on press measurement data.

In this paper, different press deformation characteristics are presented, and the viability of the universal FE substitute model is evaluated. Further, advanced settings for the coupled FE simulation are discussed and the simulation results are validated with experimentally determined data.
Towards forming simulations by means of reduced integration-based solid-shell elements considering gradient-extended damage
Authors: Barfusz O. , van der Velden T. , Brepols T. , Reese S.
Published: June 2021

The present contribution is concerned with the non-local damage analysis of geometrically non-linear shells. To this end, a low-order displacement-based solid-shell finite element formulation is combined with a gradient-extended damage-plasticity model. Due to a tailored combination of reduced integration with hourglass stabilization, the enhanced assumed strain (EAS) method and the assumed natural strain (ANS) method, the most dominant locking phenomena are eliminated. A polynomial approximation of the strain-like as well as the stress-like quantities within the weak forms enables the definition of a suitable and efficient hourglass stabilization. In this way, the internal element force vectors as well as the element stiffness contributions coming from the hourglass stabilization can be determined analytically. A numerical example of a circumferentially notched cylinder considering plasticity coupled with damage reveals the potential of the proposed methodology. Besides the ability to deliver mesh independent results within the softening regime, the framework is especially suitable for thin-walled structures, in which conventional low-order continuum elements suffer from well-known locking phenomena.
Development of a springback prediction for a hybrid laminate with sensor functionality
Authors: Graf A. , Kräusel V. , Rodio A. , Lanzotti A.
Published: June 2021

Developing the idea of lightweight construction even further, we have considered the integration of additional functionalities directly into the semi-finished product. Enormous weight savings can be achieved through integration into a large-scale production process. However, these new material composites in the form of hybrid laminates are accompanied by new challenges in terms of forming properties. In particular, there is a need to investigate how the plastic layer with sensor functionality in a hybrid laminate impacts its springback properties. To this end we designed tests using the design of experiments (DOE) technique and identified the significant factors using analyses of variance (ANOVA). Due to the material combination we had to include additional factors such as temperature and punch holding time. Our research showed an adequate distinction between springback and spring-forward behaviour. Utilising FEM, the results were simulated and compared. Our biggest challenge lay in the exact description of the interface between metal and plastic in the FEM.
A Numerical Study on Chain-Die Forming of the aluminium profiles with variable cross-section
Authors: Lu K , Liang Z , Liu Y , Zou T , Li D , Ding S
Published: June 2021

Roll forming is a widely used forming process of profile with constant cross-section because of its high quality, high efficiency, and low cost. However, variable cross-section profiles are becoming more common with the development of the vehicle industry while the demand can’t be met by the traditional roll forming technique. Chain-die forming is a newly introduced technique to deal with the problem. Chain-die forming extends the deformation zone by enlarging the rotation radii of the moulds. The study focused on the finite element simulations of chain-die forming aluminium profiles with variable cross-section and the comparation with high strength steels. The results showed the influence of materials such as anisotropy on wrinkling and scratch in chain-die forming and verify the finite element simulation in predicting the chain-die forming results.
Study on the influence of the strain rate sensitivity on the springback of the AA5086 alloy under warm forming conditions
Authors: Neto D M , Oliveira M C , Alves J L , Menezes L F
Published: June 2021

Warm forming processes have been successfully applied to overcome some important drawbacks of the aluminium alloys, such as poor formability and large springback. The virtual try-out of this type of processes requires the accurate prediction of springback. The process conditions considered in this work are the ones established for the benchmark 3 – Springback of an Al-Mg alloy in warm forming conditions, proposed under the Numisheet 2016 international conference. The material under analysis is the AA5086-H111 aluminium alloy. Its mechanical behaviour is described by a Hockett-Sherby hardening law and an orthotropic yield function. The numerical analysis of the warm forming process is performed considering different yield criteria, using a strain rate-dependent flow rule. Although the material presents a positive strain rate sensitivity at 240°C, the influence of the punch velocity on the punch force evolution is negligible due to the impact of the punch velocity on the temperature distribution in the cup. Since the hoop stress distribution on the ring (before splitting) is only slightly influenced by the punch velocity, the impact of the punch velocity on the springback is also negligible.
Effect of various shearing shape conditions for the scrap-used coining method on tensile residual stress on sheared edge
Authors: Honda Y , Yasutomi T , Yamagata M
Published: June 2021

Application of high strength steel for automobiles is required to achieve fulfilment of the CO2 emission regulation and improvement of collision safety. Nevertheless, high strength steel has the problem that hydrogen embrittlement and fatigue cracks are likely to occur especially on sheared edge. The previously proposed scrap-used coining method could reduce tensile residual stress on sheared edge using the scrap generated by shearing as the coining tool with a counter punch. However, the conditions this method could reduce tensile residual stress effectively were not clarified. In this report, the effects of the following shearing shape factors on residual stress on sheared edge were investigated, the size of shearing line curvature using punches with a diameter of 10 and 20 mm, positive and negative sign of curvature by testing both of the product and scrap part, and the flat and dome shape of counter punch head. Residual stress on sheared edge could be reduced in the 10 and 20 mm of punch diameter regardless of the product or scrap part. FEM analyses showed that the change of stress distribution in processing area during the scrap-used coining is caused by the shearing hole expansion and reduction and the sheared edge compression by contact of the product and scrap and these mechanisms are common to both of the parts. The dome shaped counter punch is able to reduce the coining load in addition to almost the same amount of residual stress as the flat shaped one. Thus, the tool cost decreases because the cushion pin required to get the reaction force for coining could be reduced.
A new Device for Determination of Forming-Limit-Curves under Hot-Forming Conditions
Authors: Triebus M , Gierse J , Marten T , Trôster T
Published: June 2021

Forming-Limit-Curves (FLCs) are widely used to characterize the forming behaviour of materials. Nevertheless, the determination of FLCs for hot forming processes is a challenging and time-consuming procedure. At the Chair of Automotive Lightweight Design, a new device for the determination of FLCs under hot forming conditions was developed. In a sealed isothermal oven atmosphere, blank holder, die and punch are used for the FLC determination relying on the DIN EN ISO 12004-2. External hydraulic forces actuate the punch and blank holder. To ensure insulation from the thermal load set inside the hot oven atmosphere an innovative cooling system with extensive use of additively manufactured components with integrated cooling channels is used. For the feed of the different deep drawing tests geometries an airlock is installed, which allows keeping the temperatures constant during the testing procedure. Afterward the forming limits for the different geometries are evaluated with optical measurement systems. The developed test rig proved the ability to determine FLCs for isothermal temperatures up to 800° C.
Local formability assessment of AHSS steels with shear cut tensile tests
Authors: Larour P , Freudenthaler J , Pauli H , Kerschbaum M , Wagner L , Felbinger A , Sonnleitner F. , Angeli J
Published: June 2021

As an alternative to the ISO16630 hole expansion test, the punched tensile test is increasingly popular for edge crack characterization of AHSS advanced high strength steels. In this investigation the reduction of area as well as thickness reduction at fracture in the vicinity of left/right sample edge fracture sides has been determined by means of light optical microscopy according to the Hance local formability test methodology for 10% to 40% cutting clearance in (both sided) sheared cut vs. spark eroded or milled edge conditions. An edge crack index has been defined based on the tensile sample fracture shape. Local formability tensile properties based on area reduction or average thickness reduction are more sensitive to edge condition than Axx fracture elongation values. The determination of the reduction of area at fracture is however challenging due to projection issues. The % thickness reduction at minimum thickness as well as at left/right thickness in cut edge vicinity may offer some additional information about edge crack initiation and final fracture. The shear punch edge quality (punch and die tool wear, target vs. actual clearance) should be closely monitored for accurate reproducible testing results.
Comparison of different testing approaches to describe the fracture behaviour of AHSS sheets using experimental and numerical investigations
Authors: Behrens B-A , Rosenbusch D , Wester H , Dykiert M
Published: June 2021

The damage behaviour of Advanced High Strength Steel (AHSS) differs from conventional deep-drawing steels due to their microstructure. For example, shear fracture can occur unexpectedly without prior necking, leading to inaccuracies using Forming Limit Diagram (FLD). An improvement of failure prediction can be obtained by the use of stress state dependent damage models, which have to be parametrised by tests at different stress states for which a wide range of methods exists. Research is still needed regarding the choice of specimen, evaluation methodology and model accuracy. For that purpose, in this study two different experimental approaches are compared to analyse the fracture behaviour depending on the stress state of the complex phase steel CP800. Therefore, tensile specimens of various geometries are used on the one hand and butterfly tests in different orientations on the other. Subsequently, the modified Mohr-Coulomb (MMC) damage model is parametrised with the determined characteristic fracture values of the respective experimental methods. For additional comparison, also an FLD is determined. The different approaches are finally compared regarding their suitability for the parameterisation of stress state dependent damage models.
A new specimen for investigating shear fracture strain
Authors: Gál V , Lukács Zs
Published: June 2021

In the automotive industry, the edge formability of a sheet metal part is usually defined by the Forming Limit Diagram despite its shortcomings. The success of the FLD can be explained by its easy applicability for dedicated FEM codes and physical measurements. However, the diagram covers a large range of strain paths of sheet metal parts, it does not fully specify the edge formability in the negative minor strain field, which is important for drawing operation with a small radius. This explains the great attention paid in the recent decade to the development of the shear test. Manufacturing the latest shear specimens (such as Butterfly or Smiley) is a significant cost and time-consuming process. In this paper, the applicability of a new flat shear specimen geometry was investigated, using finite element methods and physical measurements. Since the cracking can initiate on the boundary section of the flat specimen, first the effect of three different manufacturing methods (Wire EDM, laser cutting and drilling) were investigated. Based on the results a new flat specimen was created and optimized by finite element methods. The shear fracture strain of the new specimen was measured by an optical measurement system and the results were compared with the fracture strain of the smiley specimen.
Validation of Part Holder Models of Car Body Upper Line Dies for Return Stroke Loads
Authors: Burkart M , Liewald M , Wied J , Kaminsky C
Published: June 2021

In modern press shops, the latest press technology is used to meet today’s efficiency requirements of sheet metal body part production. Thus, for example, servomechanical press ram drives enable optimized process control through configurable motion profiles of the ram, resulting in increased stroke rates and output of the press line. However, the acceleration of moving masses arising during post-forming operations of line dies can lead to critical loads for the upper die and press ram drive. Especially the part holder of line dies causes dynamic loads when being accelerated during the return stroke. In this regard, this paper deals with the validation of dynamic part holder models on the basis of experimental data obtained by a prototype tool. Finally, design specifications could be defined using the validated dynamic models, enabling the process windows of line dies to be extended in future for robust high-speed production processes in modern press shops.
Data-driven analysis of cold-formed pin structure characteristics in the context of versatile joining processes
Authors: Romisch D , Zirngibl C , Schleich B , Wartzack S , Merklein M
Published: June 2021

Due to increasingly strict emission targets and regulatory requirements, especially for companies in the transport industry, the demand for multi-material-systems is continuously rising in order to lower energy consumption. In this context, mechanical joining processes offer an environmentally friendly and flexible alternative to established joining methods, especially in the field of lightweight design. For example, cold-formed cylindrical pin structures show high potentials in joining multi-material-systems without auxiliary elements. The pin structures are joined either by pressing them directly into the joining partner or by caulking with a pre-punched part. However, to evaluate the strength of the joint and to ensure the joining reliability for versatile processes, such as changing joining partners or batch variations, engineering designers currently have only limited design principles available compared to thermal joining processes. Consequently, the design of an optimal pin joint requires cost- and time-intensive experimental investigations and adjustments to design or process parameters. As a solution, data-driven methods offer procedures for structuring data and identifying dependencies between varying process parameters and resulting pin structure characteristics. Motivated by this, the paper presents an approach for the data-driven analysis of cold-formed pin structures and offers a deeper understanding of how versatile processes affect the pin characteristics. Therefore, the application of an intelligent design of experiment in combination with several machine learning methods enable the setup of a best-fitting meta-model. Resulting, the determination of a mathematical model provides the opportunity to accurately estimate the pin height considering only relevant geometrical and process parameters with a prediction quality of 95 %.
Parametric Shape Optimization of Stretch Webs in a Progressive Die Process using a Neural Network Surrogate Model
Authors: Athreya S , Weinschenk A , Steinlehner F , Budnick D , Worswick M , Volk W. , Huhn S.
Published: June 2021

Progressive die stamping provides a solution for producing sheet metal parts in large quantities. These parts are connected to carriers by stretch webs. As the part undergoes bending and forming operations, the stretch webs are exposed to translational and rotational deformation. A suitable design of these entities is crucial to avoid failure caused by splits or excessive thinning. A common way to evaluate such designs is to use finite element (FEM) simulation. Since it is not efficient to run FEM based optimization studies for the design optimization and to enable further automation of the stretch web design, this paper is proposing the use of machine learning (ML) technologies. A surrogate model based on an artificial neural network is used as a predictor in the presented study. This neural network is used to optimize the geometric parameters of the stretch web to obtain a quality result. The model is trained using FEM results and the study shows that it was possible to obtain an accurate model with a prediction error of 5%. The trained surrogate model can be used for the optimization study. This approach is computationally inexpensive and can provide very good results.
Temperature-controlled tools for multi-stage sheet metal forming of high-strength aluminium alloys
Authors: Günzel J , Hauβ J , Groche P
Published: June 2021

The high-strength aluminium alloys EN AW-6082 and -7075 possess great light-weight construction potential due to their high specific strength. However, their range of applications is limited by the low cold formability and high springback in the ultra-high-strength T6 state. To extend formability, either preconditioned semi-finished products, requiring a subsequent heat treatment or temperature-supported process routes such as warm forming or hot forming die quenching (HFQ) are used. If the forming degrees achievable with these methods are not sufficient, multi-stage forming is required. The forming degrees are limited by strain hardening in case of a cold forming operation of preconditioned semi-finished products and by heat transfer between the component and the tool parts in case of temperature-supported process routes. In order to reduce or even eliminate the cooling of the component in the subsequent forming stages, a four-stage forming tool with temperature-controlled active parts was developed and its influences investigated in more detail. The paper will demonstrate how precise temperature control of the tool components contributes to an extension of the formability. In addition, reproducible and robust process conditions can be guaranteed throughout the entire process chain.
On thermal compensation of Hot-Form-Quench stamping die
Authors: Szegda D , Mohamed M , Ziane M
Published: June 2021

Today, most premium and EV vehicle body in white structures rely heavily on lightweight materials and lightweighting technologies to offset vehicle mass. Increased utilisation of lightweight metals is also being observed in mainstream vehicles. Press hardened steels have gained significant use, however high and ultra-high strength aluminium alloys are starting to follow as their usability is enhanced and exploited. Both material groups require hot forming technologies to be used in manufacture of vehicles components. Thermal expansion of aluminium alloys is approximately twice those of steel, and hence leads to significant material contraction during in-die quenching. This is especially pronounced for large area or long components. Therefore, stamping dies employed in the Hot-Form-Quench (HFQ) process used to manufacture lightweight components from aluminium alloys are required to be compensated for thermal expansion/contraction. This paper presents simulation methodology developed in PAM-STAMP and used to verify the level of die compensation required and the effect of the compensation on the part dimensional conformance after HFQ forming.
A new cracking resistance index based on fracture mechanics for high strength sheet metal ranking
Authors: Frómeta D. , Parareda S. , Lara A. , Grifé L. , Tarhouni I. , Casellas D.
Published: June 2021

Driven by current safety and weight reduction policies in the automotive sector, the development of new high strength sheet metal products has experienced unprecedented growth in the last years. With the emergence of these high strength materials, new challenges related to their limited ductility and higher cracking susceptibility have also raised. Accordingly, the development of new fracture criteria accounting for the material’s cracking resistance has become unavoidable. In this work, a new cracking resistance index (CRI) based on fracture mechanics is proposed to classify the crack propagation resistance (i.e. the fracture toughness) of high strength metal sheets. The index is based on the fracture energy obtained from tensile tests with sharp-notched specimens. The procedure is very fast and simple, comparable to a conventional tensile test, and it may be used as routine testing for quality control and material selection. The CRI is investigated for several advanced high strength steel (AHSS) sheets of 0.8-1.6 mm thickness with tensile strengths between 800 and 1800 MPa. The results show that the proposed index is suitable to rank high strength steel sheets according to their crack propagation resistance and it can be correlated to the material’s crashworthiness and edge cracking resistance.
Simulation based approach for light weighting of Connecting rod by tube hydro forming process
Authors: Pandey A K , Walunj B S , Date P P
Published: June 2021

Several attempts have been made to reduce the weight of vehicles in order to increase overall fuel efficiency. Most attempts are focused on the light-weighting of BIW parts. However, very few attempts have been reported on the light-weighting of engine and transmission components. The present study aims at another method of light-weighting and manufacture of the light-weight connecting rod. To reduce the weight of connecting rod a new innovative manufacturing route using tube hydroforming has been proposed. A seamless tube is used as the raw material, which is deformed to its final shape by tube hydroforming. An innovative set of design features were needed for manufacturability using a tube as a raw material. Critical parameters of the solid connecting rod, such as diameters of holes at the big end as well as the small end, and the centre to centre distance, have been maintained equal to the reference solid forged connecting rod. Forming limit diagram has been used to predict the forming safety of the material during the forming process.
Study on new hot stamping tool with low cost and high cooling efficiency
Authors: Peng S , Zhou J , Qian S , Zhang M , Liu J , Meng Y
Published: June 2021

A new manufacturing method of hot stamping tool with CCC is proposed in this study. A pair of optimal hot stamping tool should have long service life, low manufacturing cost and good cooling performance simultaneously. The CuCrZr alloy and Fe-based alloy is selected as interlayer layer (IL) and surface layer (SL) respectively. The maximum stress of new tool was less than the yield strength of the corresponding welding materials, which demonstrated that new tool manufactured by surfacing technology could satisfy the strength requirement and deserve further research.
Effect of grain boundary engineering on corrosion behavior of nickel-based alloy 825 in sulfur environment
Authors: Fan Zhou , Zhang Yidong , Hu Xiaogang , Yang Dawei , Wang Yang , Liu Jianyi
Published: June 2021

Grain boundary engineering (GBE) by appropriate deformation and heat treatment processes was applied to nickel-based alloy 825 due to its excellent corrosion resistance. The microstructure of nickel-based alloy was analyzed by electron backscatter diffraction (EBSD) and the effect of GBE on the corrosion resistance in high sulfur-containing environments was studied by electrochemical method. The results show that the ratio of low Σvalue coincidence site lattice (CSL) grain boundary is obviously improved from 47.1% to 65.5%. The special angle grain boundaries Σ3, Σ9, Σ27 and so on are randomly distributed on the network of the large angle grain boundaries, which destroy the connectivity of the original grain boundary network, and effectively block the corrosion cracking of the material along them. The corrosion resistance of nickel-based alloy 825 in high sulfur environments is enhanced verified by polarization curve and scanning electrochemical microscope, providing references for corrosion protection during the exploitation of high sulfur gas reservoirs.
The nurse-coordinated cardiac care bridge transitional care programme: a randomised clinical trial
Authors: Jepma Patricia , Verweij Lotte , Buurman Bianca M , Terbraak Michel S , Daliri Sara , Latour Corine H M , ter Riet Gerben , Karapinar - Çarkit Fatma , Dekker Jill , Klunder Jose L , Liem Su-San , Moons Arno H M , Peters Ron J G , Scholte op Reimer Wilma J M
Published: June 2021

Background

after hospitalisation for cardiac disease, older patients are at high risk of readmission and death.

Objective

the cardiac care bridge (CCB) transitional care programme evaluated the impact of combining case management, disease management and home-based cardiac rehabilitation (CR) on hospital readmission and mortality.

Design

single-blind, randomised clinical trial.

Setting

the trial was conducted in six hospitals in the Netherlands between June 2017 and March 2020. Community-based nurses and physical therapists continued care post-discharge.

Subjects

cardiac patients ≥ 70 years were eligible if they were at high risk of functional loss or if they had had an unplanned hospital admission in the previous 6 months.

Methods

the intervention group received a comprehensive geriatric assessment-based integrated care plan, a face-to-face handover with the community nurse before discharge and follow-up home visits. The community nurse collaborated with a pharmacist and participants received home-based CR from a physical therapist. The primary composite outcome was first all-cause unplanned readmission or mortality at 6 months.

Results

in total, 306 participants were included. Mean age was 82.4 (standard deviation 6.3), 58% had heart failure and 92% were acutely hospitalised. 67% of the intervention key-elements were delivered. The composite outcome incidence was 54.2% (83/153) in the intervention group and 47.7% (73/153) in the control group (risk differences 6.5% [95% confidence intervals, CI −4.7 to 18%], risk ratios 1.14 [95% CI 0.91–1.42], P = 0.253). The study was discontinued prematurely due to implementation activities in usual care.

Conclusion

in high-risk older cardiac patients, the CCB programme did not reduce hospital readmission or mortality within 6 months.

Trial registration

Netherlands Trial Register 6,316, https://www.trialregister.nl/trial/6169
Leaf size estimation based on leaf length, width and shape
Authors: Schrader Julian , Shi Peijian , Royer Dana L , Peppe Daniel J , Gallagher Rachael V , Li Yirong , Wang Rong , Wright Ian J
Published: June 2021

Background and Aims

Leaf size has considerable ecological relevance, making it desirable to obtain leaf size estimations for as many species worldwide as possible. Current global databases, such as TRY, contain leaf size data for ~30 000 species, which is only ~8% of known species worldwide. Yet, taxonomic descriptions exist for the large majority of the remainder. Here we propose a simple method to exploit information on leaf length, width and shape from species descriptions to robustly estimate leaf areas, thus closing this considerable knowledge gap for this important plant functional trait.

Methods

Using a global dataset of all major leaf shapes measured on 3125 leaves from 780 taxa, we quantified scaling functions that estimate leaf size as a product of leaf length, width and a leaf shape-specific correction factor. We validated our method by comparing leaf size estimates with those obtained from image recognition software and compared our approach with the widely used correction factor of 2/3.

Key Results

Correction factors ranged from 0.39 for highly dissected, lobed leaves to 0.79 for oblate leaves. Leaf size estimation using leaf shape-specific correction factors was more accurate and precise than estimates obtained from the correction factor of 2/3.

Conclusion

Our method presents a tractable solution to accurately estimate leaf size when only information on leaf length, width and shape is available or when labour and time constraints prevent usage of image recognition software. We see promise in applying our method to data from species descriptions (including from fossils), databases, field work and on herbarium vouchers, especially when non-destructive in situ measurements are needed.
Effect of different heating conditions on odor of yellowtail Seriola quinqueradiata muscles
Authors: Hamakawa Yumi , Mukojima Kaori , Uchiyama Maki , Okada Shoko , Mabuchi Ryota , Furuta Ayumi , Tanimoto Shota
Published: June 2021

The effects of different heating conditions set to prevent food poisoning on the volatile components, lipid oxidation, and odor of yellowtail, Seriola quinqueradiata, were investigated. The heating conditions did not affect the lipid oxidation, fatty acid composition, and volatile compounds of each part of the flesh. High-temperature/short-time (90 °C for 6 min) heating led to significantly higher trimethylamine (TMA) contents in all muscle parts and higher odor intensity of TMA in dark muscle (DM) compared to those of lower temperature heating. Sensory evaluation showed that the odor intensities of all muscle parts heated at high-temperature/short-time were stronger than those at low-temperature/long-time (63 °C for 30 min). All DM samples had less odor palatability than the other flesh parts. Therefore, DM may have contributed to the unfavorable odor of steamed yellowtail meat and high-temperature/short-time heating may have enhanced the odor of all flesh parts compared with those subjected to low-temperature/long-time.
MutaFrame—an interpretative visualization framework for deleteriousness prediction of missense variants in the human exome
Authors: Ancien François , Pucci Fabrizio , Vranken Wim , Rooman Marianne
Published: June 2021

Motivation

High-throughput experiments are generating ever increasing amounts of various -omics data, so shedding new light on the link between human disorders, their genetic causes and the related impact on protein behavior and structure. While numerous bioinformatics tools now exist that predict which variants in the human exome cause diseases, few tools predict the reasons why they might do so. Yet, understanding the impact of variants at the molecular level is a prerequisite for the rational development of targeted drugs or personalized therapies.

Results

We present the updated MutaFrame webserver, which aims to meet this need. It offers two deleteriousness prediction softwares, DEOGEN2 and SNPMuSiC, and is designed for bioinformaticians and medical researchers who want to gain insights into the origins of monogenic diseases. It contains information at two levels for each human protein: its amino acid sequence and its three-dimensional structure; we used the experimental structures whenever available, and modeled structures otherwise. MutaFrame also includes higher-level information, such as protein essentiality and protein–protein interactions. It has a user-friendly interface for the interpretation of results and a convenient visualization system for protein structures, in which the variant positions introduced by the user and other structural information are shown. In this way, MutaFrame aids our understanding of the pathogenic processes caused by single-site mutations and their molecular and contextual interpretation.

Availability and implementation

Mutaframe webserver at http://mutaframe.com/.

Supplementary information

Supplementary data are available at Bioinformatics online.
Clinician perspectives and sense of efficacy about the implementation of recovery-oriented practice in mental health
Authors: Chisholm Janice , Petrakis Melissa
Published: June 2021

Recovery-oriented practice (ROP) is being steadily adopted worldwide. The current research examined the perspectives of clinicians about ROP pre-implementation at a clinical mental health service. The method was a survey consisting of fourteen questions regarding implementation of ROP and clinicians reported self-efficacy about work within a ROP framework. The research design was mixed methods couched within a narrative approach. It was exploratory and social constructivist in nature. This article explores quantitative data. Participants were 203 mental health clinicians from multidisciplinary backgrounds—including social work, nursing, occupational therapy, psychiatry, psychology, other medical and other allied health. There were 142 females, 46 males; 15 did not specify their sex. Results showed that clinicians perceived their practice was recovery-oriented 83.6 per cent of the time. Overall, 81 per cent chose the most recovery-oriented statement prior to formal training in ROP. This study concludes that clinicians are committed to the implementation of ROP. They do not believe ROP is easy to implement; however, they do believe it can be successfully implemented in the clinical treatment setting. With the support of stakeholders, these findings may be used to aid the ongoing implementation of ROP into the study service, and add to social work literature.
Spinal cord compression is associated with brain plasticity in degenerative cervical myelopathy
Authors: Cronin Alicia E , Detombe Sarah A , Duggal Camille A , Duggal Neil , Bartha Robert
Published: June 2021

The impact of spinal cord compression severity on brain plasticity and prognostic determinates is not yet fully understood. We investigated the association between the severity of spinal cord compression in patients with degenerative cervical myelopathy, a progressive disease of the spine, and functional plasticity in the motor cortex and subcortical areas using functional magnetic resonance imaging. A 3.0 T MRI scanner was used to acquire functional images of the brain in 23 degenerative cervical myelopathy patients. Patients were instructed to perform a structured finger-tapping task to activate the motor cortex to assess the extent of cortical activation. T2-weighted images of the brain and spine were also acquired to quantify the severity of spinal cord compression. The observed blood oxygen level-dependent signal increase in the contralateral primary motor cortex was associated with spinal cord compression severity when patients tapped with their left hand (r = 0.49, P = 0.02) and right hand (r = 0.56, P = 0.005). The volume of activation in the contralateral primary motor cortex also increased with spinal cord compression severity when patients tapped with their left hand (r = 0.55, P = 0.006) and right hand (r = 0.45, P = 0.03). The subcortical areas (cerebellum, putamen, caudate and thalamus) also demonstrated a significant relationship with compression severity. It was concluded that degenerative cervical myelopathy patients with severe spinal cord compression recruit larger regions of the motor cortex to perform finger-tapping tasks, which suggests that this adaptation is a compensatory response to neurological injury and tissue damage in the spinal cord.
Cerebellar Continuous Theta Burst Stimulation Facilitates Auditory–Vocal Integration in Spinocerebellar Ataxia
Authors: Lin Qing , Chang Yichen , Liu Peng , Jones Jeffery A , Chen Xi , Peng Danhua , Chen Mingyuan , Wu Chao , Liu Hanjun
Published: June 2021

Clinical studies have shown the efficacy of transcranial magnetic stimulation in treating movement disorders in patients with spinocerebellar ataxia (SCA). However, whether similar effects occur for their speech motor disorders remains largely unknown. The present event-related potential study investigated whether and how abnormalities in auditory–vocal integration associated with SCA can be modulated by neuronavigated continuous theta burst stimulation (c-TBS) over the right cerebellum. After receiving active or sham cerebellar c-TBS, 19 patients with SCA were instructed to produce sustained vowels while hearing their voice unexpectedly pitch-shifted by ±200 cents. Behaviorally, active cerebellar c-TBS led to smaller magnitudes of vocal compensations for pitch perturbations than sham stimulation. Parallel modulatory effects were also observed at the cortical level, as reflected by increased P1 and P2 responses but decreased N1 responses elicited by active cerebellar c-TBS. Moreover, smaller magnitudes of vocal compensations were predicted by larger amplitudes of cortical P1 and P2 responses. These findings provide the first neurobehavioral evidence that c-TBS over the right cerebellum produces modulatory effects on abnormal auditory–motor integration for vocal pitch regulation in patients with SCA, offering a starting point for the treatment of speech motor disorders associated with SCA with cerebellar c-TBS.
The Effects of Malaria in Pregnancy on Neurocognitive Development in Children at 1 and 6 Years of Age in Benin: A Prospective Mother–Child Cohort
Authors: Garrison Amanda , Boivin Michael J , Fiévet Nadine , Zoumenou Roméo , Alao Jules M , Massougbodji Achille , Cot Michel , Bodeau-Livinec Florence
Published: June 2021

Background

Malaria in pregnancy (MiP) contributes significantly to infant mortality rates in sub-Saharan Africa and has consequences on survivors, such as preterm birth and low birth weight. However, its impact on long-term neurocognitive development in children remains unknown.

Methods

Our prospective cohort included pregnant women and their live-born singletons from the Malaria in Pregnancy Preventive Alternative Drugs clinical trial. MiP was assessed using microscopy and real-time quantitative polymerase chain reaction (qPCR). Neurocognitive development in children was assessed using the Mullen Scales of Early Learning and the Kaufman Assessment Battery for Children, 2nd edition (KABC-II), at 1 and 6 years of age, respectively.

Results

Of 493 pregnant women, 196 (40%) were infected with malaria at least once: 121 (31%) with placental malaria diagnosed by qPCR. Multiple linear regression B-coefficients showed that impaired gross motor scores were associated with MiP at least once (−2.55; confidence interval [95% CI]: −5.15, 0.05), placental malaria by qPCR (−4.95; 95% CI: −7.65, −2.24), and high parasite density at delivery (−1.92; 95% CI: −3.86, 0.02) after adjustment. Malaria and high parasite density at the second antenatal care visit were associated with lower KABC-II Non-Verbal Index scores at 6 years (−2.57 [95% CI: −4.86, −0.28] and −1.91 [−3.51, −0.32]), respectively.

Conclusions

This prospective cohort study provides evidence that MiP, particularly late term, could have important negative consequences on child development at 1 and 6 years of age. Mechanisms behind this association must be further investigated and diagnostic methods in low-income countries should be strengthened to provide adequate treatment.

Clinical Trials Registration

NCT00811421.
On the Effect of the Key-Expansion Algorithm in Simon-like Ciphers
Authors: Lu Jinyu , Liu Yunwen , Ashur Tomer , Li Chao
Published: June 2021

In this work, we investigate how the choice of the key-expansion algorithm and its interaction with the round function affect the resistance of Simon-like ciphers against rotational-XOR cryptanalysis. We observe that, among the key-expansion algorithms we consider, Simon is most resistant, while Simeck is much less so. Implications on lightweight ciphers design are discussed and open questions are proposed.
Epicardial origin of cardiac arrhythmias: clinical evidences and pathophysiology
Authors: Chaumont Corentin , Suffee Nadine , Gandjbakhch Estelle , Balse Elise , Anselme Frédéric , Hatem Stéphane N
Published: June 2021

Recent developments in imaging, mapping, and ablation techniques have shown that the epicardial region of the heart is a key player in the occurrence of ventricular arrhythmic events in several cardiac diseases, such as Brugada syndrome, arrhythmogenic cardiomyopathy, or dilated cardiomyopathy. At the atrial level as well, the epicardial region has emerged as an important determinant of the substrate of atrial fibrillation, pointing to common underlying pathophysiological mechanisms. Alteration in the gradient of repolarization between myocardial layers favouring the occurrence of re-entry circuits has largely been described. The fibro-fatty infiltration of the subepicardium is another shared substrate between ventricular and atrial arrhythmias. Recent data have emphasized the role of the epicardial reactivation in the formation of this arrhythmogenic substrate. There are new evidences supporting this structural remodelling process to be regulated by the recruitment of epicardial progenitor cells that can differentiate into adipocytes or fibroblasts under various stimuli. In addition, immune-inflammatory processes can also contribute to fibrosis of the subepicardial layer. A better understanding of such ‘electrical fragility’ of the epicardial area will open perspectives for novel biomarkers and therapeutic strategies. In this review article, a pathophysiological scheme of epicardial-driven arrhythmias will be proposed.