bluuebunny/crossref_metadata_2025 huggingface dataset:
Substitutive models of press deflections for efficient numerical die cambering
Authors: Ottosson P , Pilthammar J , Wiklund D , Skåre T , Sigvant M
Published: June 2023

Cost and time for stamping die tryouts are significant within the car industry. A major contributing factor is that elastic deflections of stamping dies and presses are usually not considered during the virtual die design and forming simulation phase. Active surfaces of stamping dies are only cambered based on previous experiences of tool types and stamping presses. However, almost all stamping dies and presses are unique, and available experiences are not valid for new sheet materials. This leads to component deviations and often several loops of tool adjustments are needed. Previously partners within the SMART Advanced Manufacturing research project CAMBER have developed advanced deflection measuring devices to quantify the elastic deformations of stamping presses. Using these measurements, cambering methodologies can be utilized in sheet metal forming simulations. In this paper numerical substitutive stamping press models are described which are capable of compensating for measured stamping press dynamics. The result show that a numerical compensated tool can improve the contact by over 80% compared to the corresponding contact without compensation.
Impact of the process velocities on the quality of free-form bent parts
Authors: Scandola Lorenzo , Tschannerl Jeremias , Maier Daniel , Werner Matthias Konrad , Hartmann Christoph , Volk Wolfram
Published: June 2023

The geometrical accuracy of the bent components as well as their surface quality are crucial parameters to evaluate the feasibility of a bent geometry in free-form bending. In the process the deformation of the part is obtained by displacing and rotating a movable bending head with respect to the fixed holder with a given relative velocity with respect to the feed velocity. High process velocities have a beneficial effect on the realisation of bending radii and angles, but induce high local solicitations on the semi-finished part, which can result in surface defects like indentations and buckles. In this work the impact of the bending head velocity as well as of the feed velocity on the bend’s stability and the arising of indentations is investigated. Experimental tests with different head and feed velocity are conducted on mild, moderate and severe bends keeping the same kinematics. The resulting bending radii, angles and surface defects are evaluated. The results allow to identify the parameters having the highest influence on the quality of bent profiles and to propose a compromise between geometrical stability and surface quality.
Study of the Influence of part features on springback and its robustness
Authors: Niu Chao , Hu Zhili , Zhang Jian , Han Fei
Published: June 2023

The influence of part geometry on twist springback was studied by a A-pillar inner plate. The part structural parameters was divided into cross-section and longitudinal axis, and the response surface model was established to analyze the influences of various structural parameters on the twist springback. The results show that the straight line 1, straight line 3, angle 2 and angle 4 of the cross section have a significant effect on the twist springback. In addition, the twist springback increases continuously with increasing of total length and ratio of arc to straight line and the decreasing of radius in the longitudinal axis. After adding features through the angular edges along the longitudinal direction, the maximum springback at the part end drops from -10.92mm to -2.934mm. The springback robustness analysis of this part were also analyzed, the results show that the maximum springback is strongly related to material yield strength, and the robustness is improved greatly after adding part features.
Effect of strain mode and blank orientation on waviness for paint appearance of automotive outer panels
Authors: An Y G , Carless L , Chezan A R , Schouten F , Appelman M , Toose M , vanVeldhuizen B
Published: June 2023

Paint appearance is an important requirement for outer automobile panels. Since the last decade automotive manufacturers started reducing paint thickness to address environmental concerns. As a result, the surface roughening of steel substrate due to stamping becomes a critical factor for paint appearance. Although much research work has been conducted on surface roughening, limited research has been focused on waviness and stamping conditions in the pressing of highly formable sheet steels. In this work, the effect of strain mode and blank orientation on waviness evolution has been investigated. It was found that strain mode has a strong influence on waviness, in addition to strain magnitude. Also, the relative orientation of the applied major strain and the direction of the roughness profile relative to the rolling direction affects waviness. When surface waviness is compared at the same surface major strain, the waviness is highest in equibiaxial stretch, followed by plane strain tension in the rolling direction, and then plane strain tension in the transverse diction. When waviness is plotted against thickness strain, the waviness in plane strain tension stretched in the rolling direction is highest, independent of the roughness profile measurement direction. The waviness in equibiaxial stretching is almost the same as that in plane strain tension stretched in the transverse direction.
Formed developables - a new class of sheet metal parts
Authors: Bhuva J , Weiss M , Rolfe B , Jiao J , Paulino M
Published: June 2023

Sheet metal parts are broadly classified as stamped parts versus folded developables. While stamped parts are parts manufactured using conventional sheet metal forming techniques, folded developables are curved developable connections produced by the virtue of the classical theory of folded developables. However, folding is not suitable for parts where material integrity cannot be compromised at the fold lines. In such cases, forming techniques can be used to introduce a distributed curvature and avoid material self-intersection at the curved fold axis. This paper combines the two genres to introduce a third class of parts called the formed developables. A developable shaped, thin sheet metal of very high strength and reasonable inextensibility is formed by flange drawing over a die radius. The die tool establishes the required curved bend axis, and the die radius is small enough to introduce a distributed curvature. A developable connection is successfully formed where the two connected corrugations are mirror images of each other. While no tearing or wrinkling is observed, experimental strain measurements highlight significant surface strains in the transverse direction while marginal stretching strains are observed in the forming direction. A trend of equal and opposite transverse strains strongly suggests that the major deformation in this geometrical process, and in-turn the shape of the final part, is driven by the involved geometrical parameters.
Innovative experimental setup for the investigation of material models with regard to strain hardening behavior
Authors: Maier L , Eder M , Norz R , Volk W
Published: June 2023

Sheet metal formed parts are often produced in multistage processes. The multi-directional deformations that occur in this process pose a challenge for sufficiently accurate modeling of the material behavior. In this paper, we present an experimental methodology and its potential that serves as a basis for a comprehensive validation of material models with respect to multi-directional deformation. Therefore, we present the experimental results of pre-strained DP600 specimens, which we afterwards subjected by the MUC-Test. The MUC-Test has already been established as a methodology for validating material models under proportional loading. By using pre-strained specimens, this methodology can be extended to non-linearities in the load history. For the purpose of the paper, we pre-strain the sheet material in three conditions: uniaxial tension, plane strain and equibiaxial tension. Thus, we show that the MUC-Test is suitable for the representation of multi-directional strain histories and useful for comprehensive validation of material models.
Experimental characterization of forming behavior of 3rd GEN AHSS
Authors: Champolivier E , Brancherie D , Feissel P , Gaied S , Canourgues J-F
Published: June 2023

Third generation of Advanced High Strength Steels (3rd GEN AHSS) for cold stamping combine superior formability and ductility at higher strengths. Their combination with the Laser Welded Blanks (LWB) technology is one answer to improve safety and weight reduction of vehicules for automakers. In this study, a Nakazima test is used to evaluate the forming behavior of LWB based 3rd GEN AHSS and to estimate their Forming Limit. Tests equipped with a Digital Image Correlation (DIC) system are carried out for several materials combinations in order to understand the influence of the weld on LWB formability. The experimental results are used to determine the critical area during this forming test and a dedicated FLC for each material combination. The location of the onset of failure is investigated, from optical observations, DIC data as well as modeling. It appears that different failure locations are obtained depending on both AHSS combination and strain paths. In order to improve the accuracy of the determination of the onset of the failure, a method is proposed to evaluate the failure risk in base metal and in the vicinity of the weld. The improvement of failure prediction will be very helpful to analyze part formability and provide design recommendations.
Proposal of a New Tool for Pre-Straining Operations of Sheet Metals and an Initial Investigation of CR4 Mild Steel Formability
Authors: Barlo A , Sigvant M , Islam M S , Pérez Ll , Olofsson E , Al-Fadhli M , Pham Q T , Pilthammar J , Odenberger E-L
Published: June 2023

With the increased focus on reducing carbon emissions in the automotive industry, more advanced materials are introduced to reduce the vehicle weight, and more complex component geometries are designed to both satisfy customer demands and to optimize the vehicle aerodynamically. With the increase in component complexity, the strain paths produced during the forming operation of car body components often display a highly non-linear behavior which makes the task of failure prediction during the manufacturing feasibility studies more difficult. Therefore, CAE engineers need better capabilities to predict failure induced by strain path nonlinearity. This study proposes a new tool designed for creating bi-linear strain paths, by performing a pre-strain of a sheet large enough to cut out Nakajima specimens to perform the post-straining in any direction. From five pre-straining tests the tool present a stable pre-straining operation with a uniform strain field in a radius of 100 [mm] from the centre, corresponding to the region of interest of a Nakajima specimen. From the five pre-strained samples, different Nakajima specimens are cut transverse and longitudinal to the rolling direction and a failure prediction approach in an alternative, path independent evaluation space was used to predict the onset of necking with promising results.
Prediction strategy for the forming and stuffing of non-circular tube
Authors: Stennei M , Clausmeyer T , Grodotzki J , Rosenthal S , Stiglmair M , Tekkaya A. E.
Published: June 2023

The manufacturing of exhaust filter systems for cars typically comprises the forming of a tube and the later stuffing of the formed product with a ceramic monolith and an elastomer mat for filtration. It is shown, that for oval tubes the stuffing process leads to inhomogeneous deformation of the final product wherefore it must be considered when designing the tools for the forming step. The high number of iterations for the tool design can hence be reduced. Additionally, under certain conditions, the necessity of simulating the forming process is shown to no longer be given. The reason for this is that during the stuffing step, no plastic deformation is introduced in the tubes. Consequently, the forming history, including local strain and residual stress distributions, do not need to be explicitly considered. A simplified methodology is presented based on these findings, which can find the required cross-section geometry of the tube entering the stuffing process. The goal of the previous forming process therefore is to produce exactly that geometry, which can be done using conventional forming process planning approaches.
Wear characteristics of the tool in the cold stamping process of ultra high strength steel sheets by establishing a novel wear test method based on the progressive die
Authors: Bang J , Kim M , Bae G , Song J , Lee M G
Published: June 2023

Demands for lightweighting and crashworthiness of the vehicle body have increased. For this purpose, advanced high strength steel to the automobile body was regarded as a solution with respect to manufacturing cost and impact energy absorption. However, increasing the strength of the automotive steel sheet lead to a diversity of problems caused by the tool wear due to higher forming load than that of commonly used steel sheets. Hence, systematic wear experiment and evaluation methods are required to quantitatively and qualitatively evaluate the tool wear amount in the sheet metal forming process. In this study, a methodology is proposed to quantitatively evaluate the wear of sheet metal forming tool based on the experimental results. In order to carry out a systematic wear test and save the time and cost, the progressive die set was designed to be suitable for wear test. The designed testing machine can simultaneously test four types of punches made under various tooling conditions such as materials, shapes, and coatings. Through the measurement of the wear depth, roughness, and surface imaging of the punch and product roughness, which represent the wear characteristics, quantitative evaluation methods for tool wear in the sheet metal forming process are established. By referring to the wear test results, it is confirmed that it is appropriate to analyze the reasonable tool wear characteristics by using the proposed methodology for quantifying the tool wear in the sheet metal forming process.
Optimization of wear-, fracture- and corrosion performance of Vanadis 6 steel through cryogenic treatment and tempering
Authors: Jurči P , Yarasu V , Dlouhý I , Bartkowska A
Published: June 2023

Vanadis 6 cold work tool steel was vacuum austenitized, room temperature quenched, differently cryogenically treated (-75, -140 and -196 °C for different durations) and double tempered, at temperatures of either 170 or 530 °C. Galling resistance was assessed by pin-on-disc testing of differently treated specimens against CuSn bronze, at wide ranges of sliding velocities and loads. The obtained results show that cryogenic treatments combined with low temperature tempering improves anti-galling performance of the steel. The best tribological properties were obtained when high-temperature tempering was combined with cryogenic treatment at -196 °C, due to the maximum extent of microstructural alteration generated by this kind of treatment. The improvement in wear performance is accompanied with slight but undisputable increase in corrosion resistance of the steel, at almost no affected toughness as compared with the state after conventional heat treatment. In conclusion, the obtained results imply an opportunity to simultaneously improve wear performance, corrosion resistance and toughness of the examined steel, by choosing a proper combination of cryogenic treatment and tempering.
Friction and lubrication modelling in sheet metal forming: Influence of local tool roughness on product quality
Authors: Domhof A T M , Waanders D. , Hol J , Sigvant M
Published: June 2023

To improve the accuracy of forming simulations, advanced friction models are increasingly used in the industry. These models account for the physical properties of the sheet, tool and lubrication and describe the tribological conditions during the forming operation. One of the main influencing factors on the tribology system, and therefore the friction coefficient, is the surface roughness of the tools. Until now, it is often assumed all tools have the same uniform surface roughness. In reality however, the tool might have different surface conditions dependent on the type and location of the tool. That is, the blank holder might be differently polished than the punch, and sharp radii might have a different tool roughness compared to flat areas. This paper investigates a significant number of tool measurements from different tool sets from Volvo Cars, and quantifies the effect of local surface conditions on product quality.
Unusually large magnetic moment and tricritical behavior of the CMR compound NaCr2O4 revealed with high resolution neutron diffraction and
μ+
SR
Authors: Nocerino Elisabetta , Forslund Ola Kenji , Sakurai Hiroya , Hoshikawa Akinori , Matsubara Nami , Andreica Daniel , Zubayer Anton , Mazza Federico , Saito Takashi , Sugiyama Jun , Umegaki Izumi , Sassa Yasmine , Månsson Martin
Published: June 2023

The mixed valence Cr3+/Cr4+ compound NaCr2O4, hosts a plethora of unconventional electronic properties. In the present study, muon spin rotation/relaxation (

μ
+

SR) and high-resolution time-of-flight neutron powder diffraction measurements were carried out on high-quality samples to clarify the complex magnetic ground state of this unique material. We identified a commensurate canted antiferromagnetic order (C-AFM) with a canting angle of the Cr spin axial vector equal to

θ

c

=
(
8.8
±
0.5

)

∘

, and an estimated Cr moment

μ

C
r

C

∼
(
4.30
±
0.01
)

μ

B

. Such an unusually large value of

μ

C
r

C

is compatible with the existence of high-spin Cr sites created by the presence of an unconventional negative charge transfer state in NaCr2O4. In addition to the C-AFM structure, a novel magnetic supercell was also revealed. Such supercell display an incommensurate (IC)-AFM propagation vector (0 0

1
2

−

δ

), having a Cr moment

μ

C
r

I
C

=
(
2.20
±
0.03
)

μ

B

. It is suggested that the C-AFM and IC-AFM modulations have two different electronic origins, being due to itinerant and localized contributions to the magnetic moment respectively. Finally, the direct measurement of the magnetic order parameter for the C-AFM structure provided a value of the critical exponent

β
=
0.245
≈

1
4

, suggesting a non conventional critical behavior for the magnetic phase transition in NaCr2O4.
Prospects required for future light-source facilities: a case of UVSOR synchrotron facility
Authors: Kera S , Matsui F , Tanaka K , Taira Y , Araki T , Ohigashi T , Iwayama H , Fujimoto M , Matsuda H , Salehi E , Katoh M
Published: June 2023

The synchrotron radiation facility is a large-scale public infrastructure that provides advanced light sources and is used for various academic research and application development. For 40 years, UVSOR Synchrotron Facility has been leading the field as a facility that has developed and utilized cutting-edge light source technology in the low-photon-energy regime. The next UVSOR aims to establish a center for quantum photon science research through the development of unexplored characterization technologies by advanced use of light sources and a measurement and analysis support environment. The science of molecular dynamics with spatio-temporal hierarchies for evaluating and controlling the functions of complex systems will be pioneered. The assets of UVSOR and the fundamental measurement and analysis technology of the Institute for Molecular Science will be inherited effectively and progressively. We plan to contribute to strengthening the foundation of many fundamental disciplines to create next-generation industrial applications.
Investigation on the environmental impact of R32, R152a and R41 refrigerant blends
Authors: Karthik M S Kiran , John Samuel K , Bhargav K Pawan , Varma K S Dileep , Subramanian Anirudh , Santhosh Kanna N , Bibin B S , Gundabattini Edison
Published: June 2023

The improper usage of refrigerants has a drastic impact on the environment, which is contributing to global warming and ozone layer depletion. The refrigerants which are being used currently have a very high GWP (Global Warming Potential) value that signifies an adverse impact on global warming. Refrigerant properties can be enhanced and modified by making refrigerant blends. This research uses GWP as a measure of refrigerant impact on global warming and provides alternative refrigerant blends for R32, R41, and R152a refrigerants. The results show 89.1% and 88.64% reduction in the GWP value of the R32 refrigerant blend and R152a refrigerant blend respectively. The R41 refrigerant blend has shown a reduction of 78.26%, with higher performance characteristics.
Brain-inspired nanophotonic spike computing: challenges and prospects
Authors: Romeira Bruno , Adão Ricardo , Nieder Jana B , Al-Taai Qusay , Zhang Weikang , Hadfield Robert H , Wasige Edward , Hejda Matěj , Hurtado Antonio , Malysheva Ekaterina , Dolores Calzadilla Victor , Lourenço João , Castro Alves D , Figueiredo José M L , Ortega-Piwonka Ignacio , Javaloyes Julien , Edwards Stuart , Davies J Iwan , Horst Folkert , Offrein Bert J
Published: June 2023

Nanophotonic spiking neural networks (SNNs) based on neuron-like excitable subwavelength (submicrometre) devices are of key importance for realizing brain-inspired, power-efficient artificial intelligence (AI) systems with high degree of parallelism and energy efficiency. Despite significant advances in neuromorphic photonics, compact and efficient nanophotonic elements for spiking signal emission and detection, as required for spike-based computation, remain largely unexplored. In this invited perspective, we outline the main challenges, early achievements, and opportunities toward a key-enabling photonic neuro-architecture using III–V/Si integrated spiking nodes based on nanoscale resonant tunnelling diodes (nanoRTDs) with folded negative differential resistance. We utilize nanoRTDs as nonlinear artificial neurons capable of spiking at high-speeds. We discuss the prospects for monolithic integration of nanoRTDs with nanoscale light-emitting diodes and nanolaser diodes, and nanophotodetectors to realize neuron emitter and receiver spiking nodes, respectively. Such layout would have a small footprint, fast operation, and low power consumption, all key requirements for efficient nano-optoelectronic spiking operation. We discuss how silicon photonics interconnects, integrated photorefractive interconnects, and 3D waveguide polymeric interconnections can be used for interconnecting the emitter-receiver spiking photonic neural nodes. Finally, using numerical simulations of artificial neuron models, we present spike-based spatio-temporal learning methods for applications in relevant AI-based functional tasks, such as image pattern recognition, edge detection, and SNNs for inference and learning. Future developments in neuromorphic spiking photonic nanocircuits, as outlined here, will significantly boost the processing and transmission capabilities of next-generation nanophotonic spike-based neuromorphic architectures for energy-efficient AI applications. This perspective paper is a result of the European Union funded research project ChipAI in the frame of the Horizon 2020 Future and Emerging Technologies Open programme.
Ambient air temperature and temperature variability affecting blood pressure—a repeated-measures study in Augsburg, Germany
Authors: Woeckel Margarethe , Schneider Alexandra , Cyrys Josef , Wolf Kathrin , Meisinger Christa , Heier Margit , Peters Annette , Breitner Susanne
Published: June 2023

Ambient air temperature and temperature variability are supposed to influence blood pressure (BP); however, findings are inconsistent. We examined the effects of short-term changes in ambient temperature and temperature variability on systolic BP (SBP), diastolic BP (DBP), mean arterial pressure (MAP), and pulse pressure (PP) in a repeated-measures study. Repeated BP measurements were available for 3184 participants from the German population-based Cooperative Health Research in the Region of Augsburg (KORA) S4 survey (1999–2001) and two follow-up examinations (2006–08 and 2013–14). Daily meteorological data were obtained from fixed measurement stations including air temperature and diurnal temperature range (DTR). We used confounder-adjusted additive mixed models to examine immediate (same-day, lag 0), delayed (lag 1 to lag 4), and cumulative (up to lag 0–13) exposure effects. Decreases in air temperature were associated with increases in SBP, DBP, and MAP, while we observed no effects for PP at all. For example, a 1 °C decrease in the 14-day moving average (lag 0–13) mean air temperature was associated with a 0.54% [95% confidence interval [95%CI]: 0.41%;0.68%] increase in SBP. Furthermore, decreasing DTR was linked to increasing SBP, DBP, and MAP measures. In the sensitivity analyses, results were found to be robust. Examination of exposure–response functions according to season revealed, that associations for summer and winter can be considered linear, while we detected non-linear functions in spring and autumn. Furthermore, exposure–response functions also differed in the three different surveys. As BP levels influence the risk of cardiovascular mortality, our results show the importance of considering temperature and its variation as potential risk factors. As ongoing climate change affects temperature variability, it is important to understand how the body adapts to changing ambient temperatures.
Emerging diagnostic and therapeutic technologies based on ultrasound-triggered biomaterials
Authors: Huang Danqing , Wang Jinglin , Wen Baojie , Zhao Yuanjin
Published: June 2023

Ultrasound (US) is a kind of acoustic wave with frequency higher than 20 kHz. Learning from the echo detection ability of bats and dolphins, scientists applied US for clinical imaging by sending out US waves and detecting echoes with shifted intensities and frequencies from human tissue. US has long played a critical role in noninvasive, real-time, low-cost and portable diagnostic imaging. With the in-depth study of US in multidisciplinary fields, US and US-responsive materials have shown practical value in not only disease diagnosis, but also disease treatment. In this review, we introduce the recently proposed and representative US-responsive materials for biomedical applications, including diagnostic and therapeutic applications. We focused on US-mediated physicochemical therapies, such as sonodynamic therapy, high-intensity focused US ablation, sonothermal therapy, thrombolysis, etc, and US-controlled delivery of chemotherapeutics, gases, genes, proteins and bacteria. We conclude with the current challenges facing the clinical translation of smart US-responsive materials and prospects for the future development of US medicine.
Specifying Interpersonal Responsibilities in Private Law: Property Perspectives
Authors: Walsh Rachael
Published: June 2023

Recognizing Wrongs reflects an ongoing challenge within private law theory: once an ideal of interpersonal responsibility and accountability is recognised at private law’s centre, how are these dimensions of private law to be developed in a manner that does not unduly undermine systemic predictability and clarity? This article responds to this challenge from the perspective of property law and theory. It suggests that inspiration as to the kinds of core unifying values that could clarify private law’s obligational dimensions can be found in varied sources, including in Thomistic property thinking, with opportunities for identifying and developing interpersonal responsibilities already existing in property doctrine, for example in the law of servitudes. As we face urgent sustainability challenges, with their strong inter-generational dimensions, the article argues that scholars should think afresh about the need to clarify the moral basis of interpersonal responsibilities in respect of property, with the Thomistic focus on human sustenance providing one candidate for reasoning about ownership obligations.
Improved structure-related prediction for insufficient homologous proteins using MSA enhancement and pre-trained language model
Authors: Meng Qiaozhen , Guo Fei , Tang Jijun
Published: June 2023

In recent years, protein structure problems have become a hotspot for understanding protein folding and function mechanisms. It has been observed that most of the protein structure works rely on and benefit from co-evolutionary information obtained by multiple sequence alignment (MSA). As an example, AlphaFold2 (AF2) is a typical MSA-based protein structure tool which is famous for its high accuracy. As a consequence, these MSA-based methods are limited by the quality of the MSAs. Especially for orphan proteins that have no homologous sequence, AlphaFold2 performs unsatisfactorily as MSA depth decreases, which may pose a barrier to its widespread application in protein mutation and design problems in which there are no rich homologous sequences and rapid prediction is needed. In this paper, we constructed two standard datasets for orphan and de novo proteins which have insufficient/none homology information, called Orphan62 and Design204, respectively, to fairly evaluate the performance of the various methods in this case. Then, depending on whether or not utilizing scarce MSA information, we summarized two approaches, MSA-enhanced and MSA-free methods, to effectively solve the issue without sufficient MSAs. MSA-enhanced model aims to improve poor MSA quality from the data source by knowledge distillation and generation models. MSA-free model directly learns the relationship between residues on enormous protein sequences from pre-trained models, bypassing the step of extracting the residue pair representation from MSA. Next, we evaluated the performance of four MSA-free methods (trRosettaX-Single, TRFold, ESMFold and ProtT5) and MSA-enhanced (Bagging MSA) method compared with a traditional MSA-based method AlphaFold2, in two protein structure-related prediction tasks, respectively. Comparison analyses show that trRosettaX-Single and ESMFold which belong to MSA-free method can achieve fast prediction ($\sim\! 40$s) and comparable performance compared with AF2 in tertiary structure prediction, especially for short peptides, $\alpha $-helical segments and targets with few homologous sequences. Bagging MSA utilizing MSA enhancement improves the accuracy of our trained base model which is an MSA-based method when poor homology information exists in secondary structure prediction. Our study provides biologists an insight of how to select rapid and appropriate prediction tools for enzyme engineering and peptide drug development.

Contact

guofei@csu.edu.cn, jj.tang@siat.ac.cn
Cell shape characterization, alignment, and comparison using FlowShape
Authors: van Bavel Casper , Thiels Wim , Jelier Rob
Published: June 2023

Motivation

The shape of a cell is tightly controlled, and reflects important processes including actomyosin activity, adhesion properties, cell differentiation, and polarization. Hence, it is informative to link cell shape to genetic and other perturbations. However, most currently used cell shape descriptors capture only simple geometric features such as volume and sphericity. We propose FlowShape, a new framework to study cell shapes in a complete and generic way.

Results

In our framework a cell shape is represented by measuring the curvature of the shape and mapping it onto a sphere in a conformal manner. This single function on the sphere is next approximated by a series expansion: the spherical harmonics decomposition. The decomposition facilitates many analyses, including shape alignment and statistical cell shape comparison. The new tool is applied to perform a complete, generic analysis of cell shapes, using the early Caenorhabditis elegans embryo as a model case. We distinguish and characterize the cells at the seven-cell stage. Next, a filter is designed to identify protrusions on the cell shape to highlight lamellipodia in cells. Further, the framework is used to identify any shape changes following a gene knockdown of the Wnt pathway. Cells are first optimally aligned using the fast Fourier transform, followed by calculating an average shape. Shape differences between conditions are next quantified and compared to an empirical distribution. Finally, we put forward a highly performant implementation of the core algorithm, as well as routines to characterize, align and compare cell shapes, through the open-source software package FlowShape.

Availability and implementation

The data and code needed to recreate the results are freely available at https://doi.org/10.5281/zenodo.7778752. The most recent version of the software is maintained at https://bitbucket.org/pgmsembryogenesis/flowshape/.
MolClustPy: a Python package to characterize multivalent biomolecular clusters
Authors: Chattaraj Aniruddha , Nalagandla Indivar , Loew Leslie M , Blinov Michael L
Published: June 2023

Low-affinity interactions among multivalent biomolecules may lead to the formation of molecular complexes that undergo phase transitions to become supply-limited large clusters. In stochastic simulations, such clusters display a wide range of sizes and compositions. We have developed a Python package, MolClustPy, which performs multiple stochastic simulation runs using NFsim (Network-Free stochastic simulator); MolClustPy characterizes and visualizes the distribution of cluster sizes, molecular composition, and bonds across molecular clusters. The statistical analysis offered by MolClustPy is readily applicable to other stochastic simulation software, such as SpringSaLaD and ReaDDy.

Availability and implementation

The software is implemented in Python. A detailed Jupyter notebook is provided to enable convenient running. Code, user guide, and examples are freely available at https://molclustpy.github.io/
Migration of Eastern North American monarch butterflies via the South-east and the Atlantic: evidence from stable isotopes, thin layer chromatography, DNA and phenotype
Authors: Dockx Cristina , Hobson Keith A , Kronforst Marcus , Kardynal Kevin J , Pozo Carmen , Schuster Jack , Green Delbert A , Dix Margaret , Nallu Sumitha , Lynch Steve
Published: June 2023

Monarch butterflies, Danaus plexippus (L.), from eastern North America are well known for their incredible autumn migration to Mexico; however, not all monarchs follow this route. There is evidence of monarchs overwintering and reproducing in Florida, arriving to insular and continental Caribbean, and roosting by the thousands in the Yucatán, Mexico. This work aims to present evidence that these monarchs are part of two current migratory routes, that we consider as the south-eastern and the Atlantic routes, routes that were probably more prominent in the past. Monarchs were collected for 12 months in south Florida, for 4 years in Cuba in November and once in March, in the Yucatán and Guatemala at different times, and once in northern Venezuela. We used two independent techniques, stable hydrogen isotope (δ2H) analyses of the wings and/or thin layer chromatography (TLC), to trace the monarch’s natal grounds. We analysed the DNA of monarchs collected in St. Marks in the Florida Panhandle, Cuba and Guatemala, and compared those data against previously-analysed DNA data from monarchs in the Americas to characterize their genetic structure and to assess the possible movement and presence of North American monarchs and/or their alleles outside the USA. Our results support the existence of south-eastern and Atlantic migratory routes. TLC, isotope and DNA analyses showed the arrival of likely North American monarchs in Cuba, Yucatán, Guatemala, Venezuela and other areas of the Americas. North American monarchs found in these areas have different natal grounds, phenotypic traits and DNA signature than Mexican migrants. Monarchs from the south-eastern route mostly originated in the south-east USA and fed on local Asclepias spp., such as Asclepias viridis, Asclepias humistrata, Asclepias perennis and Asclepias asperula. Butterflies from this migratory route move east, enter the Florida Peninsula, pass to Cuba, fly to the Yucatán and then to Guatemala where they appear to overwinter in the high mountains of Guatemala where Abies guatemalensis occurs. Monarchs that are part of the Atlantic route move east of the Appalachians, enter the Florida Peninsula, and from there pass to the insular and continental Caribbean. The main host plants for the Atlantic monarchs are A. perennis and A. humistrata; in contrast, Mexican monarchs mainly feed on Asclepias syriaca. Some monarchs from these two proposed migratory routes, south-eastern and Atlantic, will stay in the places where they travelled and others will return via Florida and Mexico. We propose a scenario for how the different migratory routes evolved.
Effect of Holder pasteurization and UV-C irradiation on bacteriophage titres in human milk
Authors: Stinson Lisa F , Geddes Donna T , Furfaro Lucy L
Published: June 2023

Human milk is the optimal nutrition source for infants and contains a complex mix of bioactive compounds and microorganisms. When unavailable, pasteurized donor milk may be provided, particularly to preterm infants. Holder pasteurization (HP) is typically implemented in human milk banks to prevent pathogen transmission. Given the impact of heat on milk bioactives, ultraviolet-C irradiation (UV-C) is an alternative being explored and has demonstrated effective bactericidal activity. In addition to bacteria, milk contains viruses, including primarily bacteriophages (phages) and which likely influence the developing bacterial microbiome of infants. However, the effect of pasteurization on human milk phages is unknown. This study assessed the effect of HP and UV-C on titres of exogenous bacteriophages inoculated into human milk. Ten donor human milk samples were tested in parallel with water controls. Milk samples or water controls were inoculated to a final concentration of 1 × 104 PFU/mL (±1 log) each of a thermotolerant Escherichia coli phage (T4) and a thermosensitive Staphylococcus aureus phage (BYJ20) and subjected to HP and UV-C treatments. UV-C inactivated both phages within milk and water controls, however, HP was ineffective against the thermotolerant T4 phages. Initial data suggest that UV-C treatment may eliminate phage with potential to affect preterm infant gut colonization. Further studies should extend this to other phages.
The Epidemiology and Societal Impact of Aging-Related Functional Limitations: A Looming Public Health Crisis
Authors: Newman Anne B
Published: June 2023

Functional impairment and disability become increasingly common with aging. As more people are reaching old age, the number of people needing care will rise, creating a crisis of need for care. Population studies and clinical trials have demonstrated the importance of the detection of early loss of strength and walking speed in predicting disability and in designing interventions to prevent functional decline. There is a large societal burden linked to age-related disorders. Physical activity is to date the only intervention that has prevented disability in a long-term clinical trial, but is difficult to sustain. Novel interventions are needed to maintain function in late life.
Maladaptive Immune Activation in Age-Related Decline of Muscle Function
Authors: Montano Monty , Correa-de-Araujo Rosaly
Published: June 2023

Age-related changes in immune competency and inflammation play a role in the decline of physical function. In this review of the conference on Function-Promoting Therapies held in March 2022, we discuss the biology of aging and geroscience with an emphasis on decline in physical function and the role of age-related changes in immune competence and inflammation. More recent studies in skeletal muscle and aging highlighting a crosstalk between skeletal muscle, neuromuscular feedback, and immune cell subsets are also discussed. The value of strategies targeting specific pathways that affect skeletal muscle and more systems-wide approaches that provide benefits in muscle homeostasis with aging are underscored. Goals in clinical trial design and the need for incorporating differences in life history when interpreting results from these intervention strategies are important. Where applicable, references are made to papers presented at the conference. We conclude by underscoring the need to incorporate age-related immune competency and inflammation when interpreting results from interventions that target specific pathways predicted to promote skeletal muscle function and tissue homeostasis.
Living Alone, Environmental Hazards, and Falls Among U.S. Older Adults
Authors: Lee Haena , Lim Justin H
Published: June 2023

Background and Objectives

Physical conditions of living environments can affect the incidence of falls; however, prior work has focused typically on 1 domain at a time—either neighborhood or home, capturing limited environmental boundaries of older adults. We examined how neighborhood together with the home environment affect the incidence of falls over time and whether living arrangement modifies the influence of the environmental risks on falls.

Research Design and Methods

Using the 2012–2020 waves of the Health and Retirement Study (HRS; N = 1,893), we fitted logistic regression to estimate the incidence of falls over an 8-year study period. We used the neighborhood and housing data that are collected systematically by trained observers in the HRS to assess environmental hazards. Sidewalk quality, neighborhood disorder, and the presence of green space were measured to capture outdoor environmental hazards. Indoor environmental hazards included the presence of housing decay and poorly maintained stairways. All models were stratified by living arrangement.

Results

Neighborhood and housing environment were independently associated with the odds of falls net of demographic characteristics and preexisting health conditions, and effects were significant for people living alone only. The presence of green space and poorly maintained stairways were associated with greater odds of falling, net of covariates during 8 years of follow-up (odds ratios = 2.10 and 2.65, p < .05, respectively). None of the environmental risk factors were significant for those living with others.

Discussion and Implications

Falls in old age may be determined in part by a combination of outdoor and indoor risk factors. More research is needed to understand pathways that lead to greater vulnerability among older adults living alone to environmental hazards.
The Threefold Path to Equity: Approaches for Health and Aging Researchers
Authors: Iveniuk James , Wilder Jocelyn , Monk Ellis
Published: June 2023

The authors present a model for pursuing equity in research on health and aging, in terms of: (a) community-driven research governance, with reference to examples inside and outside of the United States, (b) a focus on policy change, where policy is defined broadly in terms of all legislative and regulatory change, and (c) equity-focused research practices, at the level of measurement, analysis, and study design. The model is visualized as a “threefold path” that researchers may walk, to achieve changes within our field, and changes in how we interface with other fields, and communities.
Endoscopic aortic valve surgery in isolated and concomitant procedures
Authors: Zoni Daniele , Cresce Giovanni Domenico , Hinna-Danesi Tommaso , Benvegnù Luciana , Poddi Salvatore , Gallo Michele , Sella Massimo , Salvador Loris
Published: June 2023

OBJECTIVES

To evaluate early outcomes of endoscopic aortic valve replacement (AVR) and risks of concomitant procedures done through the same working port.

METHODS

At our institution, we performed a data analysis of 342 consecutive patients (from July 2013 to May 2021) who underwent endoscopic AVR with or without associated major procedure. Preoperative, intraoperative, postoperative data were evaluated. Subsequently, we perform a comparative analysis between the isolated and concomitant surgery group. The surgical access was a 3- to 4-cm working port in the second right intercostal space and 3 additional 5-mm mini-ports for the introduction of the thoracoscope, the transthoracic clamp and the vent line. Cardiopulmonary by-pass was achieved through peripheral cannulation.

RESULTS

105 patients (30.7%) underwent combined procedure: 2 coronary artery bypass (1.9%), 21 ascending aorta replacement (19.6%), 41 mitral surgery (38.3%), 16 mitral and tricuspid surgery (15%) and 25 other procedure (27%). Death occurred in 1 patient (0.4%) in the isolated group versus 2 patients (1.9%) in the combined group (P = 0.175). Seven strokes were observed, 4 in isolated procedures (1.7%) and 3 in the concomitant ones (2.85%) (P = 0.481). Surgical revision for bleeding was performed always through the same access in 13 patients (5.4%) versus 11 patients (10.4%) (P = 0.096). Pacemaker implantation was necessary in 5 patients (2.1%) versus 8 patients (7.6%) (P = 0.014). Median intubation time was 5 (2) h vs 6 (8) (P < 0.080).

CONCLUSIONS

Through a single working port made for endoscopic AVR, a concomitant procedure may be done without affecting in-hospital mortality and postoperative stroke rate.
Epidemiology of Burn Injuries Among Adult Females in Southern Iran; A Retrospective Study from 2007 to 2022
Authors: Akbar Mohammadi Ali , Goodarzian MReza , Parvar Seyedeh Yasamin , Rafiei Elham , Keshavarz Mohammad , Zardosht Mitra
Published: June 2023

Burn—by flame, flush, scald, electrical, and chemical types—accounts for 5%–12% of trauma injuries worldwide. In Iranian studies, females were the main victims of domestic burns with higher mortality and frequencies. This retrospective study evaluates the epidemiology and etiology of burn injuries in females aged 25–64 years between October 2007 and May 2022 in southern Iran.

Demographics and burn etiology information were collected by questionnaires at admission. Univariate and multivariate regression analysis was used to determine the relationship between variables and burn mortality. Pearson’s Chi-Square and One-way ANOVA tests were utilized to compare different burn etiologies.

Of 3212 females with burn injuries, 1499 (46.6%) were included with a mean age of 38.5 ± 10.8 years. Flame (59.7%) and flush (28.9%) were significantly the most common injuries mechanism. Burn was most common in rural areas (53.9%) and indoor settings (62.1%) (P-value < .001). 77.9% of the population were under-diploma (P-value < .001), and 3.5% were divorced with higher burn-suicide attempts. The mean Total Body Surface Area (TBSA%) was 41.1 ± 28.3%, and the mean Length of Stay (LOS) was 14.5 ± 13.2 days with a 39.1% mortality rate. With univariate and multivariate analysis, TBSA%, indoor places, flame, flush, and urban living were risk factors for burn mortality.

Briefly, flame in indoor settings is the most common type of burn injury affecting adult females with lower educational levels living in rural areas. Such epidemiological studies of burns in adult females may be helpful for health policymakers to develop burn prevention programs.