bluuebunny/crossref_metadata_2025 huggingface dataset:
Racial triangulation and shifting standards in mental health assessments
Authors: Gushue George V. , Lee Tina R. , Kim Jung Eun
Published: December 2021

This study investigated the presence of racial bias in mental health assessments among White trainees and clinicians using the shifting standards paradigm (Biernat, 2003) and the racial triangulation framework (Kim, 1999). A total of 181 White participants viewed one of three case vignettes, all of which were identical except for the race of a fictitious client named Karl. Participants completed a clinical impressions inventory (Gushue, 2004) and the internal causality subscale from the Causation Dimension Scale (Russell, 1982). Results indicated differences in examiner ratings based on Karl's race. Black Karl was rated as significantly less symptomatic, compared to White or East Asian Karl, consistent with the shifting standards paradigm (Biernat, 2003; Gushue, 2004). No difference was found in symptom severity ratings between White Karl and East Asian Karl. Symptoms were also more likely to be attributed to internal factors with Black Karl than with White or East Asian Karl.
Detection of sieric BAG3 in patients affected by cardiovascular diseases: State of art and perspectives
Authors: Maffioli Pamela , D'Angelo Angela , Tinelli Carmine , Falcone Colomba , Galasso Gennaro , Derosa Giuseppe
Published: December 2021

BAG3 is highly expressed in the heart and its functions are essential in maintaining cardiac muscle cells homeostasis. In the past, BAG3 was detected in serum from advanced heart failure patients and its higher levels were correlated to an increased death risk. Moreover, it has also been reported that BAG3 levels in serum are increased in patients with hypertension, a known cardiovascular risk marker. Evidence from different laboratories suggested the possibility to use BAG3‐based strategies to improve the clinical outcome of cardiovascular disease patients. This review aims to highlight the biological roles of intracellular or secreted BAG3 in myocardiocytes and propose additional new data on the levels of sieric BAG3 in patients with acute myocardial infarction (AMI), never assessed before. We evaluated BAG3 serum levels in relation to cardiovascular risk parameters in 64 AMI patients aged ≥18 years of either sex. We observed significant (p < .01) correlations of BAG3 positivity with dyslipidemic status and diabetic disease. We did not observe any significant correlations of BAG3 levels with smoking habit, hypertension or familiarity for AMI, although BAG3‐positive seemed to be more numerous than BAG3‐negative patients among hypertensives and among patients with familiarity for AMI. Furthermore, a significant (p < .001) correlation of BAG3 positivity with diuretics assumption was also noted. In conclusion, 32.8% of the patients were BAG3‐positive and were characterized by some particular features as comorbidity presence or concomitant therapies. The significance of these observations needs to be verified by more extensive studies and could help in the validation of the use of BAG3 as a biomarker in heart attack risk stratification.
Isolation and functional analysis ofOsAOS1 promoter for resistance toNilaparvata lugensStål infestation in rice
Authors: Li Hanpeng , Xu Xueliang , Han Kehong , Wang Zhengjie , Ma Weihua , Lin Yongjun , Hua Hongxia
Published: December 2021

Insect pests have a great impact on the yield and quality of crops. Insecticide applications are an effective method of pest control, however, they also have adverse effects on the environment. Using insect‐inducible promoters to drive insect‐resistant genes in transgenic crops is a potential sustainable pest management strategy, but insect‐inducible promoters have been rarely reported. In this study, we found rice allene oxide synthase gene (AOS, LOC_Os03g12500) can be highly upregulated following brown planthopper (Nilaparvata lugensStål, BPH) infestation. Then, we amplified the promoter ofOsAOS1and theβ‐glucuronidasereporter gene was used to analyze the expression pattern of the promoter. Through a series of 5ʹ truncated assays, three positive regulatory regions in response to BPH infestation in the promoter were identified. The transgenic plants,P1R123‐min 35SandP1TR1‐min 35Spromoter‐driven snowdrop lectin (Galanthus nivalisagglutinin, GNA) gene, demonstrated the highest expression levels ofGNAand lowest BPH survival. Our work identified a BPH‐inducible promoter and three positive regions within it. Transgenic rice withGNAdriven byOsAOS1promoter and positive regions exhibited an expected lethal effect on BPH. This study proved the application potential of BPH‐inducible promoter and provided a novel path for the selection of insect‐resistant tools in the future.
Safety and response after peptide receptor radionuclide therapy with 177Lu‐DOTATATE for neuroendocrine tumors in phase 1/2 prospective Japanese trial
Authors: Kudo Atsushi , Tateishi Ukihide , Yoshimura Ryoichi , Tsuchiya Junichi , Yokoyama Kota , Takano Shoko , Kobayashi Noritoshi , Utsunomiya Daisuke , Hata Masaharu , Ichikawa Yasushi , Tanabe Minoru , Hosono Makoto , Kinuya Seigo
Published: December 2021

Background

The present prospective phase 1/2 study aimed to elucidate the efficacy and safety of 177Lu‐DOTATATE (four cycles of 7.4 GBq) in Japanese patients with unresectable, progressive neuroendocrine tumors (NETs).

Methods

From April 2018 to October 2020, 15 patients with advanced NETs (five midgut, eight pancreatic, and two lung NETs) were enrolled. Objective response rate (ORR), progression‐free survival (PFS), and adverse events (AEs) were evaluated. Pharmacokinetics and dosimetry were also evaluated in three midgut patients.

Results

The mean absorbed doses of 177Lu‐DOTATATE to the kidneys (20.7 Gy/29.6 GBq) and the bone marrow (0.631 Gy/29.6 GBq) were within the radiation tolerance doses. The ORR of the whole population was 53% (90% CI, 30%‐76%). ORRs of the midgut and non‐midgut NETs were 60% (90% CI, 19%‐92%) and 50% (90% CI, 22%‐78%), respectively. There was no difference in the maximum reduction rate of the sum of the target lesion diameters between patients with midgut and non‐midgut NET. The median PFS was not reached; the PFS rate at 52 weeks was 80% (90% CI, 56.1%‐91.7%). AEs of Grade 3 or higher were lymphopenia (47%) and leukopenia (7%).

Conclusion

177Lu‐DOTATATE demonstrated remarkable tumor shrinkage and tolerability in Japanese patients with advanced NETs.
Condomless receptive anal intercourse is associated with markers of mucosal inflammation in a cohort of men who have sex with men in Atlanta, Georgia
Authors: Kelley Colleen F. , Pollack Ilana , Yacoub Rami , Zhu Zhengyi , Van Doren Vanessa E. , Gumber Sanjeev , Amara Rama R. , Fedirko Veronika , Kraft Colleen S. , de Man Tom J. B. , Hu Yi‐Juan , Grimsley Ackerley Cassie , Sullivan Patrick S. , Bostick Roberd M.
Published: December 2021

Introduction

We previously showed that the rectal mucosal immune environment among men who have sex with men (MSM) engaging in condomless receptive anal intercourse (CRAI) is immunologically distinct from that of men who do not engage in anal intercourse (AI). Here, we further examined these differences with quantitative immunohistochemistry to better understand the geographic distribution of immune markers of interest.

Methods

We enrolled a cohort of MSM engaging in CRAI (n = 41) and men who do not engage in AI (n = 21) between October 2013 and April 2015. Participants were healthy, HIV‐negative men aged 18–45 from the metro Atlanta area. We performed rectal mucosal sampling via rigid sigmoidoscopy during two study visits separated by a median of nine weeks and timed with sexual activity for MSM engaging in CRAI. We used standardized, automated immunohistochemistry and quantitative image analysis to investigate the rectal mucosal distribution of neutrophils (MPO), IL‐17‐producing cells (IL‐17) and Tregs (FOXP3) in the lamina propria, and cellular proliferation (Ki67) and adherens junction protein (E‐cadherin) in the epithelium. We examined associations between biomarker expression and the rectal mucosal microbiota composition by 16s rRNA sequencing.

Results

Relative to the colonic crypt base, IL‐17, FOXP3, and MPO expression increased towards the rectal lumen, while Ki67 decreased and E‐cadherin was more uniformly distributed. Throughout the rectal mucosa distribution examined, MSM engaging in CRAI had higher mean lamina propria MPO expression (p = 0.04) and epithelial Ki67 (p = 0.04) compared to controls. There were no significant differences in IL‐17, FOXP3 or E‐cadherin expression. We found no significant associations of the five biomarkers with the global rectal microbiota composition or the individual taxa examined.

Conclusions

Understanding the mucosal distribution of inflammatory mediators can enhance our knowledge of the earliest events in HIV transmission. Neutrophil enrichment and crypt epithelial cell proliferation likely represent sub‐clinical inflammation in response to CRAI in the rectal mucosa of MSM, which could increase the risk for HIV acquisition. However, the contributory role of the microbiota in mucosal inflammation among MSM remains unclear. HIV prevention may be enhanced by interventions that reduce inflammation or capitalize on the presence of specific inflammatory mechanisms during HIV exposure.
Understanding the role of uncertainty and anxiety in police decision‐making during the investigation of sudden unexpected deaths in children
Authors: Holmes Jonathan , Boulton Laura , Panter Heather
Published: December 2021

Existing policing policy offers a rational approach to decision‐making with minimal reference to human judgement within child death investigations. This study adopted a mixed methodology to capture decisional processes of 26 serving detective inspectors and detective sergeants whilst responding to an immersive scenario which simulated the first hours of a Sudden and Unexpected Death in Children (SUDC) investigation. Participants were presented with four decision points, during which they were asked to choose from decision options while reflecting upon personal and situational factors influencing that decision. Thematic analysis of responses found that investigators disclosed ‘anxiety’ and ‘uncertainty’ throughout their decision‐making during the scenario. In addition, there was no evidence of investigators utilising the models formally advocated within policing literature to make their decisions and assessments. As a result, it is suggested that further improvements are made regarding investigative decision‐making models within operational policing where ‘anxiety’ and ‘uncertainty’ is heightened.
Evolution and development of parrot pseudoteeth
Authors: Louryan Stéphane , Choa‐Duterre Myriam , Lejong Marie , Vanmuylder Nathalie
Published: December 2021

Parrot embryos carry peculiar appendages at their developing beak that have been described as pseudoteeth. To better characterize the pattern of development responsible for the emergence of these dental appendages, we examined parrot embryos combining conventional histology and microtomography approaches. Using immunohistochemistry, we observed the epithelial and mesenchymal expression of several proteins involved in tooth development in mammals. Parrot pseudoteeth arose by epithelial and mesenchymal evagination, and their early development was similar to the ontogeny of scales and feathers. There was no enamel tissue, and the evaginations were surrounded by the rhamphotheca. In adults, the rhamphotheca covers entirely the appendages, now represented by bone evaginations, which were more numerous in the lower than in the upper beak, being similar to the osseous teeth of the fossil Pelagornithidae. These embryonic pseudoteeth resembled reptile's first‐generation teeth and dental appendages of chicken talpid2mutants. Proteins involved in mammalian odontogenesis, such as SHH, BMP4, PITX2, and PAX9, were found to be generally expressed in beak epithelium and mesenchyme during parrot pseudoteeth development, with clusters of high‐level expression in the pseudoteeth rudiments. This suggests that a similar, highly conserved gene expression program gives rise to the appearance of odontode derivatives in numerous species, despite their divergent developmental paths. These results provide new insights into the development and evolution of odontode‐derived structures in vertebrates.
Full‐field experimental analysis of the influence of microstructural parameters on the mechanical properties of humeral head trabecular bone
Authors: Kusins Jonathan , Knowles Nikolas , Martensson Nicole , P. Columbus Melanie , Athwal George S. , M. Ferreira Louis
Published: December 2021

Understanding the mechanical properties of trabecular bone within the metaphysis of the proximal humerus is becoming increasingly important for the design of humeral head joint replacement components that prioritize bone preservation. The aim of this study was to perform full‐field mechanical testing methods on isolated trabecular bone cores from the humeral head to experimentally measure the local magnitude of strain before macroscopic failure and to characterize the ultimate strength of each core. Isolated cubic trabecular bone cores were extracted from the center of humeral head osteotomies retrieved from (1) patients with end‐stage osteoarthritis (OA) undergoing total shoulder arthroplasty (TSA) and (2) normal nonpathologic cadaveric humeral heads. A custom computed tomography (CT)‐compatible loading device was used to perform compressive mechanical testing. For 10 of the OA specimens, stepwise loading was performed directly within a microCT scanner and digital volume correlation (DVC) was used to measure full‐field strains throughout the trabecular structure. A higher variability in ultimate strength was measured for the trabecular cores retrieved from OA humeral heads (range: 2.8–7.6 MPa) compared to the normal cadaveric humeral heads (range: 2.2–5.4 MPa), but no statistically significant difference between the groups was found (p = 0.06). Ultimate strength was strongly correlated with bone volume fraction (OA r2 = 0.72; normal r2 = 0.76) and bone mineral content (OA r2 = 0.79; normal r2 = 0.77). At the trabecular level, 95th percentile of third principal strains, measured at a subvolume size of 152 µm, exceeded 19,000 µε for each of the 10 specimens (range: −19,551 to −36,535 µε) before macroscopic failure of the cores occured. No strong linear correlations (r2 ≥ 0.50) were found between the median or 95th percentile of DVC third principal strain and the corresponding morphometric parameters of each individual bone core. The results of this study indicate that bone volume fraction and bone mineral content heavily influence the apparent ultimate strength of trabecular bone cores collected from OA patients undergoing TSA. Clinical significance: The strong correlations observed within this study further emphasize the importance of considering bone mineral content or bone volume fraction measurements in assessing the localized risk of trabecular bone fracture for orthopedic applications.
Annual protein yield and extractable protein potentials in three legumes and two grasses
Authors: Thers Henrik , Eriksen Jørgen
Published: December 2021

BACKGROUND

New protein sources with low environmental and climatic impact are needed. Perennial crops show advantages as compared to annual crops and the upcoming biorefinery technology can extract proteins from the perennial biomass for protein concentrate production. The search for best‐suited biomass crops needs to include harvest during the full growing season to support economic viability of biorefinery plants. Here we examined two grasses under increasing N fertilizer regime (175, 350 and 525 kg N ha−1) and three legumes, subject to a four‐cut strategy. The well‐defined Cornell Net Carbohydrate and Protein System (CNCPS) was used to estimate potential extractable protein. A key, previously presented in the literature, was applied in order to translate the CNCPS results into potential extracted protein concentrate.

RESULTS

Crude protein (CP) yield per hectare was highest in red clover in 2015 (2907 kg CP ha−1) and the fertilized (525 kg N ha−1) tall fescue in 2016 (2435 kg CP ha−1). When translating the numbers into potential extraction of protein concentrate, the red clover had the highest protein concentrate yield per hectare in 2015 (835 kg CP ha−1) and lucerne in 2016 (803 kg CP ha−1).

CONCLUSION

The results revealed that the entire season needs attention for optimization and not only the first cut, since both CP yields and quality peaks in different cuts across the five species and 2 years. Further knowledge of CP yield responses to field management and species mixtures are needed in order to advise farmers on the optimal crop for biorefining. © 2021 Society of Chemical Industry.
Influence of reinforcing particles on microstructure and mechanical properties of friction stir processed aluminium alloy AA7075‐T651
Authors: Bhavya S. I. , Suvarna R. L. , Perumalla J. R.
Published: December 2021

This paper emphasis the improvement of mechanical properties of AA7075‐T651 using friction stir processing through localized surface modification by adding nano boron carbide particles. The reinforcement techniques such as the groove and blind hole methods were used by changing reinforcements of nano boron carbide and a matrix of AA7075‐T651 surface composites volume percentages (2 %, 4 %, and 6 %) along with tool rotational speed and processing speeds. Optical microscopy, scanning electron microscope and x‐ray diffraction analysis were used to examine the particle dispersion for the surface composites and to correlate with the enhanced mechanical properties. Results revealed that high input parameters have given grain coarsening and precipitate agglomeration and low input parameters provide poor nugget metal consolidation and no vertical material flow. The L9 orthogonal Array designed and optimized the process parameters for enhancing the surface properties of processed samples. Mechanical properties like ultimate tensile strength, yield strength, hardness, percentage of elongation and impact strength were evaluated for the groove friction stir processing method and blind‐hole friction stir processing methods. From the results, it has been observed that the blind‐hole technique resulted in higher hardness and the homogenous dispersion of nano boron carbide particles in the stir zone than the groove method. Consequently, for blind‐hole friction stir processing, grey relational analysis (GRA) and particle swarm optimization (PSO) approaches were proposed to optimise process parameters. From the compared optimization results between grey relational analysis and particle swarm optimization, particle swarm optimization approach was shown the best optimization results. Successively, the optimum condition in the respective experimentation is accomplished. Based on these observation and results, final validation tests were carried by changing the volume percentages of reinforcement keeping tool rotation speed and tool processing speed as constant. It is apparent that dynamic recrystallization in aluminium alloy at the processed zone due to presence of heterogeneous nucleation sites with nano boron carbide particles.
Self‐lubricating CrAlVN coatings for turning of Ti6Al4V: oxidation and wear behavior
Authors: Bobzin K. , Brögelmann T. , Stachowski N. , Hintze W. , Möller C. , Ploog P.
Published: December 2021

The titanium alloy Ti6Al4V enables significant performance increases in various branches of industry. Nevertheless, it is difficult to machine, because of its material properties. Due to the low thermal conductivity of titanium, the heat generated while turning Ti6Al4V mainly flows into the tool leading to high temperature loads. In addition, the comparatively low Young's modulus and high yield strength contributes to high mechanical stresses during machining. Temperature active, self‐lubricating physical vapor deposition hard coatings appear to be suitable for reducing friction and tool wear during turning of Ti6Al4V compared to the most commonly used uncoated carbide tools. The ability of the coating to form lubricating oxide phases at high temperatures is crucial for this purpose. This paper investigates the oxidation and diffusion behavior of vanadium doped chromium aluminium nitride (CrAlN) coatings after heat treatment at ϑ = 600 °C, ϑ = 700 °C und ϑ = 800 °C in atmosphere as well as the resulting coating properties. The wear behavior of certain coating variants while turning of Ti6Al4V is analyzed.
Microstructure evolution and texture formation of 16 % chromium ferritic stainless steel following simulated batch annealing treatments in mass production
Authors: Wang Z. , Peng G. , He T. , Li M.
Published: December 2021

Batch annealing technique is mainly used in industry for improving productivity as a few steel coils were stacked and heated in a bell‐type furnace. The microstructure evolution, texture formation and mechanical properties of 16 % chromium ferritic stainless steel under different simulated batch annealing and subsequent cold‐rolled annealing conditions were investigated in this work. Results showed that batch annealing process applied in mass production could not produce fully recrystallized and homogenously equiaxed grains even at very high temperatures up to 900 °C for 30 hours. With increased batch annealing temperature, a large number of chromium carbides precipitated in ferrite, while some unstable Fe‐carbide precipitates were gradually dissolved. Relatively lower cold‐rolled annealing temperature (830 °C) led to finer grains and superior mechanical properties of 16 % chromium ferritic stainless steel. Increased batch annealing temperature improved the intensity of {111}//normal direction γ‐fiber textures at the expense of other orientations including {hkl}<110> α‐fiber, {334}<4
3>, thus improving the formability of ferritic stainless steel.
Therapeutic advances in non‐small cell lung cancer: Focus on clinical development of targeted therapy and immunotherapy
Authors: Cheng Yuan , Zhang Tao , Xu Qing
Published: December 2021

Lung cancer still contributes to nearly one‐quarter cancer‐related deaths in the past decades, despite the rapid development of targeted therapy and immunotherapy in non‐small cell lung cancer (NSCLC). The development and availability of comprehensive genomic profiling make the classification of NSCLC more precise and personalized. Most treatment decisions of advanced‐stage NSCLC have been made based on the genetic features and PD‐L1 expression of patients. For the past 2 years, more than 10 therapeutic strategies have been approved as first‐line treatment for certain subgroups of NSCLC. However, some major challenges remain, including drug resistance and low rate of overall survival. Therefore, we discuss and review the therapeutic strategies of NSCLC, and focus on the development of targeted therapy and immunotherapy in advanced‐stage NSCLC. Based on the latest guidelines, we provide an updated summary on the standard treatment for NSCLC. At last, we discussed several potential therapies for NSCLC. The development of new drugs and combination therapies both provide promising therapeutic effects on NSCLC.
On the convergence of two types of estimators of quadratic variation
Authors: Yu Xisheng
Published: December 2021

Recently, two types of innovative estimators of the quadratic variation (QV), namely, RVB and RVQ estimators, are established in Yu (2020, doi.org/10.1002/mma.6863) for an asset's log‐price process permitting time‐varying spot volatility. Both estimators utilize either higher order or cross‐terms of log‐return and they hence have been demonstrated having better convergence property than existing ones (e.g., the widely known realized volatility). However, the proof of the convergence property of RVB/RVQ is rather cumbersome and algebraically complicated. Besides, imposing the spot volatility to be deterministic function of time in the log‐price process seems to have deviated from reality. This article devotes attention to (1) relaxing the volatility restriction on the semimartingale process of asset's price and (2) substantially shortening the original proofs by alternatively employing two useful lemmas (called high‐order Itô isometry and adjoint Itô identity) developed in this study.
Statistical modeling for the monostatic radar cross‐section characteristics of stealth aircraft using the Swerling‐chi/inverse generalized gamma composite distribution model
Authors: Wang Jianbo , Ye Jianyu , Hua Guang
Published: December 2021

In this article, a new Swerling‐chi/inverse generalized gamma composite distribution model is proposed for modeling the monostatic radar cross‐section (RCS) statistical characteristics of stealth aircraft. Under some conditions, the proposed distribution model can be reduced to the Fisher‐Snedecor distribution model and the Swerling‐chi distribution model. A typical stealth aircraft without radar absorption materials (RAM) is selected as an application for simulation using the adaptive cross approximation (ACA) technique. Based on the nonlinear least‐squares criterion, monostatic RCS statistical characteristics of the front sector of this aircraft are fitted using the proposed composite model. For the comparison purpose, monostatic RCS statistical characteristics of this aircraft are also fitted with the conventional RCS distribution models. Goodness‐of‐fit tests of the proposed distribution model and the conventional distribution models are analyzed in terms of the error‐of‐fit results and the test results. Simulation results validate the efficiency and robustness of the proposed distribution model.
Systematical NMR analysis of swainsonine, a mycotoxin from endophytic fungus Alternaria oxytropis
Authors: Tan Xiangmei , Wang Yanduo , Liu Zhenliang , Liu Liliang , Yu Meng , Ding Gang
Published: December 2021

Swainsonine (SW, 1), a unique indolizine with poly‐hydroxyl groups, was re‐isolated from the plant endophytic fungus Alternaria oxytropis. The structure (including planar structure and relative configuration) was systematically elucidated by NMR spectra (including 1H, 13C, 1H‐1H COSY, HMQC, HMBC, and NOESY spectra in DMSO‐d6 and in CD3OD); 1H NMR spectra of the modified Mosher's products were first used to determine the absolute configuration of SW. More importantly, the complex coupled features of H‐7α, H‐7β, and H‐6α in the 1H NMR spectrum of (1) were analyzed in details, which will provide aids for the planar and relative configuration determination of analogs.
Voters' voting intention: The salience of celebrity endorsement—Evidence from Ghana
Authors: Arkorful Vincent Ekow , Lugu Benjamin Kweku , Tetteh Evans , Arkorful Vincent Ansah
Published: December 2021

Partly spurred by the notion that celebrities wield potentials leverageable for political gains, the phenomenon of celebrity endorsement has become emblematic of political campaigns. While the use of celebrities in politics is on the ascendancy, its impact on electoral fortunes in bourgeoning democracies like Ghana where the concept is nascent, has received little research focus. Considering the anticipated gains, an empirical investigation in this regard will be imperative to the politics of transitioning polities. Against this backdrop, our study investigates the salience of celebrity endorsement to voters' voting intention. Employing a questionnaire‐drawn data via the survey method, with a sample of 745, results of data analysis anchored on the structural equation modeling technique revealed a significant positive relationship between endorser credibility and political brand credibility. Similarly, study results confirmed the significant positive relationship between political brand credibility and voting intention. Finally, the significant positive relationship between endorser credibility and voting intention was affirmed. Overall, the study outcomes verify the usefulness and appropriateness of the proposed model. Based on the results, implications for political strategy and suggestions for further research are subsequently delineated.
The contribution of Theodore von Kármán to the development of metal forming technology and the controversy with Erich Siebel
Authors: Bruhns Otto T.
Published: December 2021

In 1925, Theodore von Kármán publishes an article in [1] where he presents a simple method for calculating strip rolling. This procedure (later called elementary theory), can today be regarded as the starting point for the theoretical treatment of many metal forming technology problems. Von Kármán pursues two objectives: On the one hand, he illuminates the rolling process from the point of view of a mechanic and wants to make this comprehensible to the practical engineer. On the other hand, he wants to create the basis for further investigations. For describing the state in the rolling gap, he introduces a number of simplifying assumptions, which lead to the fact that the compressive stresses in the rolled material can be represented directly as the solution of a statically determinate problem. Although this work is published in German, it received rapid acceptance, particularly in the English‐speaking world.
Least‐squares formulation to solve non‐Newtonian fluid flow and application of data assimilation in 2D
Authors: Averweg Solveigh , Schwarz Alexander , Schwarz Carina , Schröder Jörg
Published: December 2021

In this contribution, we present an approach to model steady flow of incompressible non‐Newtonian fluids with data assimilation into the numerical solution based on the least‐squares finite element method (LSFEM). The assimilation of data (e.g. experimental or analytical) into numerical simulations offers promising possibilities when examining complex problems. Potential applications include the enhancement of numerical models using measured data or the completion of experimental data using numerical methods, e.g. the determination of non‐measured quantities such as pressure. In particular for the field of fluid mechanics, the implemented LSFEM has some theoretical advantages compared to the well‐known (mixed) Galerkin finite element method, since it is not restricted to the LBB‐condition. Additionally, it results in a minimization problem with symmetric positive (semi‐)definite equation systems also for differential equations with non‐self‐adjoint operators. A further advantage in this context is that the assimilation of data can easily be performed by adding a term to the least‐squares (LS) functional such that it does not significantly increase the computational cost. The approach of data assimilation is shown by solving steady flow of a non‐Newtonian fluid through a channel with a smooth contraction.
Ray tracing in thermally loaded optical systems
Authors: Rall Phillip Lino , Pflaum Christoph
Published: December 2021

High‐power laser beams are usually imaged with the help of suitable optics. The propagation of such beams, through optical systems, often result in a focus shift. This is mainly due to the deposited power in the beam acting as a heat source in the optical elements. Finally, the resulting change in temperature leads to both, a deformation of the lens surface, and a change of the refractive index in the lens. Ray tracing and the finite element method are needed in order to analyze the above effects. The accuracy and the computational time of focus shift calculations, in both simulation techniques, are strongly influenced by the interpolation of the data. This paper will present, a newly proposed interpolation method, allowing a fast and accurate interpolation of data using an unstructured finite element grid. This method will specifically focus on the accurate calculation of laser beam thermal load inside an optical lens.
Freezing of sea ice with an inhomogeneous material distribution using the Theory of Porous Media
Authors: Schwarz Alexander , Bluhm Joachim , Schröder Jörg , Skatulla Sebastian
Published: December 2021

In this paper, we present results of a four‐field finite element formulation in the context of the Theory of Porous Media for the modeling of freezing processes. The primary solution variables are ice displacements, fluid pressure, temperature, and volume fraction ice. In detail, we show results on ice formation (mass transfer from liquid to solid constitutents) and temperature distribution. Special attention is given to the modeling of the heat of solidification. A thermodynamically consistent approach is used for the energetic effects to characterize and control the phase transition, see [1]. Finally, a numerical example of a freezing process with an inhomogeneous material distribution is shown.
Reduced integration‐based solid and solid‐shell finite elements for gradient‐extended damage
Authors: Barfusz Oliver , van der Velden Tim , Brepols Tim , Reese Stefanie
Published: December 2021

The present contribution is concerned with the incorporation of gradient‐extended damage into reduced integration‐based continuum finite elements. To this end, the purely mechanical low‐order solid and solid‐shell elements based on the isoparametric concept are combined with a gradient extended two‐surface damage plasticity model. Due to a tailored combination of reduced integration with hourglass stabilization, the enhanced assumed strain (EAS) method and in case of the solid‐shell 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 hourglass stabilization. In this way, the element stiffness contributions coming from the hourglass stabilization can be determined analytically, since they represent polynomials with respect to Cartesian coordinates. Two representative numerical examples of an elasto‐plastic asymmetrically notched specimen as well as an elastic thin annular plate reveal the accuracy and efficiency of the proposed methodology. Besides the ability to deliver mesh independent results, the framework is especially suitable for constrained situations in which conventional low‐order finite elements suffer from well‐known locking phenomena.
Optimal sensor placement for stochastic sources in machine tools
Authors: Herzog Roland , Naumann Andreas
Published: December 2021

Accuracy requirements for machine tools demand an accurate positioning of the tool center point. Due to the heat sources, for example the friction and heat loss of motors, a machine can undergo complicated deformations during operation. While the location of mounted sources are known in advance, there are also process dependent sources, like hot chips after chip off. Furthermore many material parameters and most coupling parameters are not known exactly, or have an unknown temperature dependency. We consider a coupled thermo‐elastic finite element model of a simplified machine tool. We include uncertain heat sources and exchange parameters and present an optimal sensor placement approach to capture the sources.
A Proof of Concept for Very Fast Finite Element Poisson Solvers on Accelerator Hardware
Authors: Ruda Dustin , Turek Stefan , Ribbrock Dirk , Zajac Peter
Published: December 2021

It is demonstrated that modern accelerator hardware specialized in AI, e.g., “next gen GPUs” equipped with Tensor Cores, can be profitably used in finite element simulations by means of a new hardware‐oriented method to solve linear systems arising from Poisson's equation in 2D. We consider the NVIDIA Tesla V100 Tensor Core GPU with a peak performance of 125 TFLOP/s, that is only achievable in half precision and if operations with high arithmetic intensity, such as dense matrix multiplications, are executed, though. Its computing power can be exploited to a great extent by the new method based on “prehandling” without loss of accuracy. We obtain a significant reduction of computing time compared to a standard geometric multigrid solver on standard x64 hardware.
A NURBS enhanced polygonal element formulation based on the scaled boundary method for the analysis of solids in boundary representation
Authors: Reichel Rainer , Klarmann Simon , Klinkel Sven
Published: December 2021

The contribution is concerned with a numerical element formulation for the nonlinear analysis of solid in boundary representation. Its results in a polygonal element with an arbitrary number of sides. Straight edges are possible as well as curved edges, which are described by e.g. Non‐Uniform Rational B‐Splines (NURBS). The element formulation is based on the so‐called scaled boundary finite element method (SBFEM). The basic idea is to scale the domain's boundary with respect to a scaling center in order to describe the interior domain. In contrast to SBFEM, the proposed method makes use of a numerical aproximation for the displacement response in scaling direction. This enables the analysis of geometrically and physically nonlinear problems in solid mechanics. The interpolation at the boundary in circumferential direction is independent of the interpolation in scaling direction. So, different basis functions can be used for each direction, e.g. NURBS basis functions in circumferential and Lagrange basis functions in radial direction. The advantage of the presented element formulation is the flexibility in mesh generation. The avoidance of so‐called hanging node problems as arbitrary element geometries are possible. For example, using Quadtree algorithms, a fast and reliable mesh generation can be achieved. Furthermore, in connection with trimming algorithms, the element formulation allows a precise representation of the geometry even with coarse meshes. Some benchmark tests are presented to evaluate the accuracy of the proposed numerical method against analytical solutions.
Estimation of unordered core size using a robustness measure for topological defects in discretized orientation and vector fields
Authors: Hoffmann Karl B. , Sbalzarini Ivo F.
Published: December 2021

We show how the finite sizes of unordered defect cores in discretized orientation and vector fields can reliably be estimated using a robustness measure for topological defects. Topological defects, or singular points, in vector and orientation fields are considered in applications from material science to life sciences to fingerprint recognition. Their identification from discretized two‐dimensional fields must deal with discontinuities, since the estimated topological charge jumps in (half‐)integer steps upon orientation changes above a certain threshold. We use a recently proposed robustness measure [Hoffmann & Sbalzarini, Phys. Rev. E 103(1), 012602 (2021)] that exploits this effect to quantify the influence of noise in a vector field, and of the path chosen for defect estimation, on the detection reliability in two‐dimensional discrete domains. Here, we show how this robustness measure can be used to quantify the sizes of unordered regions surrounding a defect, which are known as unordered cores. We suggest that the size of an unordered core can be identified as the smallest path radius of sufficient robustness. The resulting robust core‐size estimation complements singular point and index estimation and may serve as uncertainty quantification of defect localization, or as an additional feature for defect characterization.
Phase field modeling with deformation‐dependent interface energies
Authors: Wilbuer Hendrik , Lammen Henning , Mosler Jörn
Published: December 2021

In the last years, the phase field method has established itself for the simulation of various problem types, especially in the fields of microstructure evolution and phase transformations as well as in fluid dynamics. Concerning the first two cases, usually a constant, deformation‐independent, surface energy is considered. In this work, however, deformation‐dependent surface elasticity according to [5] will be incorporated into phase field theory. In line with [4], a finite element framework for an Allen‐Cahn type phase field model coupled to continuum mechanics is presented, which is solved in a monolithic manner by means of Newton's method. The resulting model also accounts for a spatial evolution of the diffuse interface by a functional of Ginzburg–Landau type. The implemented model is employed in numerical simulations. These will be used to study the behavior of the phase field model.
Geometric and finite element modeling of biopolymer aerogels to characterize their microstructural and mechanical properties
Authors: Chandrasekaran Rajesh , Hillgärtner Markus , Rege Ameya , Milow Barbara , Itskov Mikhail
Published: December 2021

Biopolymer aerogels belong to a class of highly open‐porous cellular materials. Their macroscopic mechanical properties (such as elasticity or thermal conductivity) depend on microstructural features (namely pore size distribution (PSD), fiber diameter and solid fraction), which can be tailored by different synthesis and drying routes. The design of modern aerogel materials requires a better perception into the microstructure and its influence on the mechanical properties. To predict the material properties using simulation, it is significant to construct a geometric model which is sufficiently precise to represent the microstructure of real materials. A tessellation approach based on Voronoi diagrams is a powerful tool to model such cellular‐like materials. In this contribution, the diversified cellular morphology of aerogels is described computationally using a Voronoi tessellation‐based approach [1]. Accordingly, Voronoi tessellations are generated to create periodic representative volume elements (RVEs) resembling the microstructural properties of the cellular network. Stress‐strain curves resulting from finite element simulations of these RVEs and experiments of the aerogels under compression are compared. This work is an extension of our previous Voronoi tessellation‐based on the 2‐d description of biopolymer aerogels [2].
The First Stage of Firn Densification ‐ An Evaluation of Grain Boundary Sliding
Authors: Schultz Timm , Müller Ralf , Gross Dietmar , Humbert Angelika
Published: December 2021

Firn describes the interstage product between snow and ice in cold regions of the earth, where annual snow fall exceeds the amount of snow melting. The continuing accumulation of snow leads to its densificiation due to overburden stress until it becomes ice. In the field of glaciology various attempts on simulating firn densification have been made and new models are still developed, as the knowledge of the firn column's density structure allows important derivations.

The presented study reassesses a model description for low density firn based on the process of grain boundary sliding presented by Alley in 1987 [1] using an optimisation approach. By comparing simulation results to 159 measured firn density profiles from Greenland and Antarctica it finds a possible additional dependency of the constitutive relation on the mean surface mass balance. This result is interpreted as an insufficient description of the stress regime.
Parameter‐robust preconditioning for unsteady Stokes control problems
Authors: Leveque Santolo , Pearson John W.
Published: December 2021

We propose a saddle‐point preconditioner for an optimization problem constrained by the time‐dependent Stokes equations, discretized using the backward Euler method in time. The key ingredients are an inner iteration for the (1, 1)‐block, accelerated by a known preconditioner for the heat control problem, and an approximation of the Schur complement involving a commutator argument applied to a block matrix. Numerical results demonstrate the efficacy and robustness of this approach.
Numerical modeling of the receptor driven endocytosis
Authors: Klinge Sandra , Wiegold Tillmann , Aygün Serhat , Gilbert Robert P. , Holzapfel Gerhard A.
Published: December 2021

The present contribution focuses on the receptor driven endocytosis typical of viral entry into a cell. The process is characterized by a local increase in receptor density necessary to establish contact between the cell and the virus. While the receptors of the virus are fixed on its surface, the receptors of the cell are able to move over its membrane, which leads to a local change in their concentration. In the model developed, the receptor motion is described by the diffusion equation along with two boundary conditions. The boundary conditions represent the balance of fluxes at the front of the contact area, where the velocity is assumed to be proportional to the gradient of the chemical potential, and the energy balance behind and before the front, causing the fronts movement. The model provides a basis to incorporate different phenomena such as for example cooperativity. This property strongly influences the effective binder density necessary to establish contact. The moving boundary problem describing the process is numerically solved by using the finite difference method and applied to study the change of receptor density over the membrane as well as the motion of the adhesion front. Two features are investigated in particular: The process initiation is analyzed in order to obtain information on possibilities for inhibiting the viral entry, and the non‐dimensional analysis is performed to minimize the number of necessary process parameters and to check their priority.
Investigation of copper lattice structures using a Split Hopkinson Pressure Bar
Authors: Bieler Sören , Kang Sung Gyu , Heußen Daniel , Ramachandramoorthy Rajaprakash , Dehm Gerhard , Weinberg Kerstin
Published: December 2021

The paper deals with experiments on 3D printed lattices in a Split Hopkinson Pressure Bar. An energy‐based evaluation of the measured wave signals enables us to compare the damping properties of two different copper lattice structures.
Improving energy efficiency of bipedal walking using nonlinear compliant mechanisms
Authors: Luo Yinnan , Zirkel Marten , Römer Ulrich J. , Zentner Lena , Fidlin Alexander
Published: December 2021

A method to improve the energy efficiency of a bipedal robot by coupling its thighs with compliant smart mechanisms is introduced. The walking gaits are driven by electric motors in its revolute joints, whose reference trajectories are generated via numerical optimization. The optimized nonlinear characteristic of the compliant mechanism modifies the free oscillation frequency of the system that matches the current double step frequency even under different conditions, which results in a very high energy efficiency.
A mixed finite element formulation for energy‐momentum time integrations of composites with fiber bending stiffness
Authors: Dietzsch Julian , Gross Michael , Kalaimani Iniyan
Published: December 2021

We aim at dynamic simulations of 3D‐fiber‐reinforced materials in light‐weight structures, which are reinforced by fiber rovings comprised of thousands of filaments. Each roving possesses a separate bending stiffness, which has a large influence on the material behaviour on the macro scale. For the description of this material behavior, we extend a hyperelastic anisotropic Cauchy continuum formulation, which models only the macro‐scopic behaviour of a reinforcement by filaments, by a higher‐order gradient of the deformation mapping as an independent field. The new mixed finite element formulation is based on well‐known mixed finite elements for anisotropic polyconvex material formulations, but include new additional mixed fields concernd with the fiber bending stiffness. As we aim at dynamic long‐term simulations, we apply higher‐order accurate time integrators. Here, we include the new mixed finite element formulation in a variational‐based time finite element method. As numerical examples serve a simple cantilever beam. Here, we first analyze the influence of the fiber bending stiffness.