bluuebunny/crossref_metadata_2025 huggingface dataset:
Synthesis and Properties of Bipolar Ladder‐Like Polysiloxane with Carbazole and Triphenylphosphine Oxygen Groups
Authors: Zhao Zhennan , Zhao Haisong , Liu Junteng , Ren Zhongjie
Published: June 2023

In this study, a series of ladder‐like polysiloxanes are synthesized by introducing double‐chain Si–O–Si polymer as the backbone and the carbazole and triphenylphosphine oxide with high triplet energy as side groups. The ladder‐like structures of polysiloxanes are achieved through a controlled polymerization method that involves the monomer self‐assembly and subsequent surface‐restricted solid‐phase in situ condensation through freeze‐drying. The introduction of siloxane improves thermal stability of the polymers and inhibits the conjugation of the polymers between the side groups, leading to an increase in the triplet energy level. Therefore, all these polymers perform higher triplet energy levels than phosphorescent emitter (FIrpic). The cyclic voltammetry measurements demonstrate that the bipolar polymer exhibits a high highest occupied molecular orbital (HOMO) value of −5.32 eV, which is consistent with the work function of ITO/PEDOT:PSS, consequently facilitating hole injection. Furthermore, the incorporation of triphenylphosphine oxide promotes electron injection. Molecular simulations reveal that the frontier orbital distributions of the bipolar polymer are located on the carbazole and triphenylphosphine groups, respectively, which facilitate the transport of electrons and holes.
Predictors of Burden in Carers of Patients with Impulse Control Behaviors in Parkinson's Disease
Authors: Johnson Daniel , Townsend Leigh , David Anthony S. , Askey‐Jones Sally , Brown Richard , Samuel Mike , Okai David
Published: June 2023

Background

Impulse control behaviors (ICBs) are problematic, reward‐based behaviors, affecting 15% to 35% of patients with Parkinson's disease. Evidence exists of increased carer burden as a result of these behaviors; however, little is known about the variables mediating this effect and their management.

Objective

To identify factors predictive of carer burden in a cohort of patients with Parkinson's disease with ICBs to enable the development of targeted therapeutic interventions for carers.

Methods

Data were collected from 45 patients with clinically significant ICBs and their carers, including levodopa equivalent daily dosage, motor and neuropsychiatric symptoms, cognitive function, and ICB severity. Carer burden was quantified by Zarit Burden Interview (ZBI). Univariate analyses were performed using the Spearman rank correlation. Linear regression was used to create a multivariate model for predicting ZBI.

Results

Univariate analysis identified significant correlations between ZBI and patient total Neuropsychiatric Inventory (NPI) (rs = 0.50), 4 NPI subscores (agitation/aggression, rs = 0.41; depression/dysphoria, rs = 0.47; apathy/indifference, rs = 0.49; and irritability/lability, rs = 0.38; all P < 0.02), and the carer 28‐item General Health Questionnaire (GHQ‐28) (rs = 0.52, P < 0.0005). Multivariate linear regression retained total NPI and GHQ‐28 scores and were collectively predictive of 36.6% of the variance in the ZBI.

Conclusions

Our study suggests that depressive symptoms and aspects of executive dysfunction (apathy and disinhibition) in the patient are potential drivers of carer burden in patients with ICBs. Such findings suggest the presence of executive difficulties and/or mood disturbance should point the clinician to inquire about burden in the caring role and encourage the carer to seek help for any of their own general health problems, which may compound carer burden.
Asymptotic behavior of stationary solutions to elastic wave equations in a perturbed half‐space in ℝ3
Authors: Isozaki Hiroshi , Kadowaki Mitsuteru , Watanabe Michiyuki
Published: June 2023

We study the stationary elastic wave equation with free boundary condition in a locally perturbed half‐space in
. Using the stationary phase method, we derive an asymptotic behavior at infinity of the resolvent of the elastic operator uniformly with respect to the direction in
. Consequently, the body waves and the Rayleigh surface waves appear simultaneously in the expansion. From the far‐field pattern of the expansion, we obtain the scattering amplitude. We also characterize the space of generalized eigenfunctions in terms of Agmon–Hörmander space
and derive their spatial asymptotics.
A mathematical model for precise predicting microbial propagation based on solving variable‐order fractional diffusion equation
Authors: Bavi O. , Hosseininia M. , Heydari M. H.
Published: June 2023

Continued mortality from Covid‐19 disease and environmental considerations resulting from the cemetery, landfill, wastewater treatment plants, and mass personal protective equipment (PPE) disposal sites demonstrate the importance of carefully studying how microorganisms spread in and across the soil, surface water, and groundwater. In this research, fractional diffusion equation for different functions has been solved using fractional derivative form with variable‐order (VO) to predict the diffusion of the SARS‐CoV‐2 virus. Comparison of the obtained results with the available experimental data and mathematical calculations shows that the use of VO form can predict the viral behavior more accurately. The main advantage of considering a VO fractional derivatives instead of a constant‐order fractional derivative or classical derivative is accurately predicting the behavior of propagation of microorganisms over large time and dimensional scales. In addition, to the specified SARS‐CoV‐2 virus, the method presented in this study will be able to investigate the diffusion pattern of all environmental pollutants at the nanoscale/microscale, including carcinogenic compounds, such as biogenic amines in aqueous and porous media. The obtained results manifest a high accuracy of mathematical approach which provides helpful information to urban and health planners/managers worldwide to manage other possible outbreaks.
Associations of Meat and Fish/Seafood Intake with All‐Cause and Cause‐Specific Mortality from Three Prospective Cohort Studies in Korea
Authors: Chung Sangwon , Hwang Jin‐Taek , Joung Hyojee , Shin Sangah
Published: June 2023

Scope

Animal protein intake among Koreans has recently increased. However, there is limited evidence on the association of meat and fish/seafood intake and mortality.

Methods and results

This study uses three representative prospective cohorts in Korea and 134,586 eligible participants are selected. Food intake is assessed using a food frequency questionnaire. Outcomes are classified as death from cardiovascular disease (CVD), cancer, and all‐causes. Red meat intake shows a marginally negative association with all‐cause mortality in the median intake group and a positive association in the highest intake group. Processed meat intake in the highest quintile group is positively associated with all‐cause mortality compared to that of the lowest quintile group. Fish intake in the highest quintile group is negatively associated with CVD mortality in men, and all‐cause mortality in women, compared to those in the lowest quintile group, while processed fish intake has unfavorable effects on mortality. In addition, substitution of one serving per week of red and processed meat, and processed fish with fish is negatively associated with all‐cause and CVD mortality.

Conclusion

Reduction of red and processed meat, and processed fish consumption or replacement of these foods with fish may be beneficial for longevity in Korean adults.
Influence of Channel Catfish and Channel × Blue Catfish Hybrids on Myxozoan Community Composition in Catfish Aquaculture Ponds
Authors: Stilwell Justin M. , Camus Alvin C. , Ware Cynthia , Walker Charles M. , Stanton James B. , Leary John H. , Khoo Lester H. , Wise David J. , Waldbieser Geoffrey C. , Griffin Matt J.
Published: June 2023

The myxozoan Henneguya ictaluri is cited as the cause of proliferative gill disease (PGD) in Channel Catfish Ictalurus punctatus and Channel × Blue Catfish I. furcatus hybrids. Differences in host susceptibility result in decreased transmission rates, reduced sporogenesis, and lesser incidence of PGD in hybrid catfish. In experimental pond trials, continuous monoculture of hybrid catfish suppressed H. ictaluri abundance in pond systems compared to Channel Catfish monoculture. The present study examined differences in myxozoan community structure in catfish ponds stocked with Channel Catfish or hybrid catfish. Experimental ponds (0.4 ha) dedicated to Channel Catfish or hybrid catfish monoculture were maintained over three production cycles. Pond water collected during the spring of each year was subjected to metagenomic analysis by targeted amplicon sequencing of a diagnostic hypervariable region (DVR3) of the myxozoan 18S ribosomal RNA gene. Relative abundance of H. ictaluri was significantly greater in Channel Catfish ponds than in hybrid catfish ponds during years 2 and 3. In hybrid catfish ponds, H. ictaluri never exceeded 20% average relative abundance. Hybrid catfish ponds also revealed decreased myxozoan diversity and species evenness compared to Channel Catfish ponds, suggesting that myxozoan taxa associated with Channel Catfish may not be well adapted to the hybridized host. Results corroborate previous research indicating that hybrid catfish monoculture can suppress H. ictaluri compared to ponds that are devoted to Channel Catfish. These data imply that alternating catfish culture species in ponds (crop rotation) has the potential to mitigate PGD by precluding H. ictaluri from accumulating within ponds to levels associated with disease and catastrophic loss. Further, this work identified numerous previously unidentified taxa present within these systems that clustered phylogenetically with both catfish and noncatfish hosts. The impacts that these other myxozoans have on catfish health and production are unknown, but their presence indicates that myxozoan diversity within catfish aquaculture ponds has been greatly underestimated and is significantly influenced by stocking choice.
Emerging Relations among Cognitive Constructs and Cochlear Implant Outcomes: A Systematic Review and Meta‐Analysis
Authors: Amini Andrew E. , Naples James G. , Hwa Tiffany , Larrow Danielle C. , Campbell Frank M. , Qiu Maylene , Castellanos Irina , Moberly Aaron C.
Published: June 2023

Objective

Hearing loss has a detrimental impact on cognitive function. However, there is a lack of consensus on the impact of cochlear implants on cognition. This review systematically evaluates whether cochlear implants in adult patients lead to cognitive improvements and investigates the relations of cognition with speech recognition outcomes.

Data Sources

A literature review was performed following the Preferred Reporting Items for Systematic Reviews and Meta‐Analyses guidelines. Studies evaluating cognition and cochlear implant outcomes in postlingual, adult patients from January 1996 to December 2021 were included. Of 2510 total references, 52 studies were included in qualitative analysis and 11 in meta‐analyses.

Review Methods

Proportions were extracted from studies of (1) the significant impacts of cochlear implantation on 6 cognitive domains and (2) associations between cognition and speech recognition outcomes. Meta‐analyses were performed using random effects models on mean differences between pre‐ and postoperative performance on 4 cognitive assessments.

Results

Only half of the outcomes reported suggested cochlear implantation had a significant impact on cognition (50.8%), with the highest proportion in assessments of memory & learning and inhibition‐concentration. Meta‐analyses revealed significant improvements in global cognition and inhibition‐concentration. Finally, 40.4% of associations between cognition and speech recognition outcomes were significant.

Conclusion

Findings relating to cochlear implantation and cognition vary depending on the cognitive domain assessed and the study goal. Nonetheless, assessments of memory & learning, global cognition, and inhibition‐concentration may represent tools to assess cognitive benefit after implantation and help explain variability in speech recognition outcomes. Enhanced selectivity in assessments of cognition is needed for clinical applicability.
Long‐Term Chondrocyte Retention in Partially Decellularized Tracheal Grafts
Authors: Bergman Maxwell , Harwood Jacqueline , Liu Lumei , Shontz Kimberly M. , Chan Coreena , Chiang Tendy
Published: June 2023

Objective

Decellularized tracheal grafts possess the biological cues necessary for tissue regeneration. However, conventional decellularization approaches to target the removal of all cell populations including chondrocytes lead to a loss of mechanical support. We have created a partially decellularized tracheal graft (PDTG) that preserves donor chondrocytes and the mechanical properties of the trachea. In this study, we measured PDTG chondrocyte retention with a murine microsurgical model.

Study Design

Murine in vivo time‐point study.

Setting

Research Institute affiliated with Tertiary Pediatric Hospital.

Methods

PDTG was created using a sodium dodecyl sulfate protocol. Partially decellularized and syngeneic grafts were orthotopically implanted into female C57BL/6J mice. Grafts were recovered at 1, 3, and 6 months postimplant. Pre‐ and postimplant grafts were processed and analyzed via quantitative immunofluorescence. Chondrocytes (SOX9+, DAPI+) present in the host and graft cartilage was evaluated using ImageJ.

Results

Partial decellularization resulted in the maintenance of gross tracheal architecture with the removal of epithelial and submucosal structures on histology. All grafts demonstrated SOX9+ chondrocytes throughout the study time points. Chondrocytes in PDTG were lower at 6 months compared to preimplant and syngeneic controls.

Conclusion

PDTG retained donor graft chondrocytes at all time points. However, PDTG exhibits a reduction in chondrocytes at 6 months. The impact of these histologic changes on cartilage extracellular matrix regeneration and repair remains unclear.
Unconventional microdomains of block copolymers
Authors: Woo Dokyung , Yoon Hyeongkeon , Kim Jin Kon
Published: June 2023

Block copolymers (BCPs) have attracted significant interest due to their ability to form various nanostructures, including lamellae, cylinders, gyroids, and spheres. But these nanostructures are only observed for limited range of the volume fraction of one block. Namely, lamellar microdomains are observed for symmetric volume fraction, whereas spherical microdomains are found for highly asymmetric volume fraction. To increase the potential applications of these nanostructures for next‐generation lithography, advanced optical materials, and high‐performance membranes, one should have these nanostructures beyond the limitation of the volume fraction. During the past decades, many directions, such as blends of two BCPs, design of complex chain architecture of BCP and introduction of favorable interactions between block components, have been suggested to greatly change the phase boundaries of conventional nanostructures. In this review, we focus on unconventional nanostructures, such as highly asymmetric lamellae, inverted cylinders and gyroids, and spherical microdomains at nearly symmetric volume fraction.
De novo design of stable proteins that efficaciously inhibit oncogenic G proteins
Authors: Cummins Matthew C. , Tripathy Ashutosh , Sondek John , Kuhlman Brian
Published: June 2023

Many protein therapeutics are competitive inhibitors that function by binding to endogenous proteins and preventing them from interacting with native partners. One effective strategy for engineering competitive inhibitors is to graft structural motifs from a native partner into a host protein. Here, we develop and experimentally test a computational protocol for embedding binding motifs in de novo designed proteins. The protocol uses an “inside‐out” approach: Starting with a structural model of the binding motif docked against the target protein, the de novo protein is built by growing new structural elements off the termini of the binding motif. During backbone assembly, a score function favors backbones that introduce new tertiary contacts within the designed protein and do not introduce clashes with the target binding partner. Final sequences are designed and optimized using the molecular modeling program Rosetta. To test our protocol, we designed small helical proteins to inhibit the interaction between Gαq and its effector PLC‐β isozymes. Several of the designed proteins remain folded above 90°C and bind to Gαq with equilibrium dissociation constants tighter than 80 nM. In cellular assays with oncogenic variants of Gαq, the designed proteins inhibit activation of PLC‐β isozymes and Dbl‐family RhoGEFs. Our results demonstrate that computational protein design, in combination with motif grafting, can be used to directly generate potent inhibitors without further optimization via high throughput screening or selection.
A customized multimodality approach for prolonged air leaks (PAL) in mechanically ventilated patients
Authors: Bansal Sameer , Furtado Arul , Kalpakam Hariprasad , Loknath Chakravarthi , Mehta Ravindra M.
Published: June 2023

ARDS in general and severe COVID ARDS (CARDS) is particularly associated with high rates of barotrauma. Two cases with severe CARDS developed bilateral pneumothorax with persistent air leak (PAL). Conservative management with prolonged chest tube drainage did not help in PAL resolution and both patients continued to be on high‐end ventilatory support. The course was further complicated by the presence of septic shock. The 1st patient was taken up for a challenging procedure after spending 23 days on the mechanical ventilator. Diagnostic pleuroscopy revealed left‐sided bullae and a surgical staple bullectomy was done. The right side showed a large bronchopleural fistula (BPF) on pleuroscopy, which was occluded using a customized endobronchial silicone blocker (CESB, described in 2018). This led to the reduction and finally, resolution of the bilateral PAL with subsequent removal of chest drains and weaning off the ventilator and oxygen. The second patient was managed with 2 CESB devices for occlusion of RUL anterior and posterior segment fistulae, followed by chest drain removal. These cases highlight effective out‐of‐the‐box multimodality treatment using a combination of interventional pulmonary techniques and surgical stapling for a life‐threatening bilateral PAL secondary to CARDS.
Teachers' multilingual beliefs and practices in English classrooms: A scoping review
Authors: Burner Tony , Carlsen Christian
Published: June 2023

The past decade has witnessed an unprecedented growth in the field of research on multilingualism in English as a second and foreign language (ESL/EFL) classrooms. This scoping review evaluates research conducted on multilingualism and the teaching and learning of English. Three search methods were used: a database search in three major databases for education; a manual search in six most prominent and relevant journals; and a citation search in the articles found through database and manual search. A total of 2282 articles were scanned. Based on inclusion and exclusion criteria and several rounds of selections, 56 articles were found relevant for the purpose of this review. The articles were analysed and discussed according to their research questions/aims, context and methods, evidence, and findings. The findings from the reviewed studies indicate that English teachers' multilingual beliefs and practices vary considerably within national contexts, that they possess more positive beliefs about multilingualism than what they practise in their teaching, and that translanguaging occurs mainly with reference to the language of instruction or students' first language. The study also underlines the importance of arriving at a shared understanding of research concepts when researching multilingual teachers and breaking down barriers between language subjects. Finally, there is little knowledge about the long‐term effects of various interventionist or long‐term continual professional development programmes when it comes to teachers' multilingual beliefs and practices.
Concentration estimates for functions of finite high‐dimensional random arrays
Authors: Dodos Pandelis , Tyros Konstantinos , Valettas Petros
Published: June 2023

Let be a ‐dimensional random array on whose entries take values in a finite set , that is, is an ‐valued stochastic process indexed by the set of all ‐element subsets of . We give easily checked conditions on that ensure, for instance, that for every function that satisfies and for some , the random variable becomes concentrated after conditioning it on a large subarray of . These conditions cover several classes of random arrays with not necessarily independent entries. Applications are given in combinatorics, and examples are also presented that show the optimality of various aspects of the results.
Nanocomposite Hydrogel Actuators with Ordered Structures: From Nanoscale Control to Macroscale Deformations
Authors: Yao Xin , Chen Hong , Qin Haili , Cong Huai‐Ping
Published: June 2023

Flexible intelligent actuators with the characteristics of flexibility, safety and scalability, are highly promising in industrial production, biomedical fields, environmental monitoring, and soft robots. Nanocomposite hydrogels are attractive candidates for soft actuators due to their high pliability, intelligent responsiveness, and capability to execute large‐scale rapid reversible deformations under external stimuli. Here, the recent advances of nanocomposite hydrogels as soft actuators are reviewed and focus is on the construction of elaborate and programmable structures by the assembly of nano‐objects in the hydrogel matrix. With the help of inducing the gradient or oriented distributions of the nanounits during the gelation process by the external forces or molecular interactions, nanocomposite hydrogels with ordered structures are achieved, which can perform bending, spiraling, patterned deformations, and biomimetic complex shape changes. Given great advantages of these intricate yet programmable shape‐morphing, nanocomposite hydrogel actuators have presented high potentials in the fields of moving robots, energy collectors, and biomedicines. In the end, the challenges and future perspectives of this emerging field of nanocomposite hydrogel actuators are proposed.
Over 13% Efficient, Ambient Air‐Processed CuIn(S,Se)2 Solar Cells via Compositional Engineering of Molecular Inks
Authors: Suresh Sunil , Abou-Ras Daniel , Chowdhury Towhid H. , Uhl Alexander R.
Published: June 2023

A dimethylformamide (DMF) and thiourea (TU)‐based ink deposition route is used to fabricate narrow bandgap (≈1.0 eV) CuIn(S,Se)2 (CISSe) films with Cu‐poor ([Cu]/[In] = 0.85), stoichiometric ([Cu]/[In] = 1.0), and Cu‐rich ([Cu]/[In] = 1.15) compositions for photovoltaic applications. Characterization of KCN‐ or (NH4)2S‐treated Cu‐rich absorber films using X‐ray diffraction and scanning electron microscopy confirms the removal of copper‐selenide phases from the film surface, while electron backscatter diffraction measurements and depth‐dependent energy‐dispersive X‐ray spectroscopy indicate remnant copper‐selenides in the absorber layer bulk. Contrary to best practice for vacuum‐processed cells, optimum [Cu]/[In] ratios appear to be stoichiometric, rather than Cu‐poor, in DMF–TU‐based CISSe devices. Accordingly, stoichiometric film compositions yield large‐grained (≈2 μm) absorber layers with smooth absorber surfaces (root mean square roughness <20 nm) and active area device efficiencies of 13.2% (without antireflective coating). Notably, these devices reach 70.0% of the Shockley–Queisser limit open‐circuit voltage (i.e., 526 mV at Eg of 1.01 eV), which is among the highest for ink‐based CISSe devices.
Teaching Up: The Intersection of Impression Management and Controlling Images for Black, Cisgender, Women Faculty
Authors: Atkins Celeste , Kalel Christina
Published: June 2023

This is a qualitative study of Black cisgender women's faculty experiences using an interactionist framework. Relying on in‐depth interviews, we explore the experiences of eight Black, cisgender, women, sociology faculty across the United States in various tenure and non‐tenure roles at different institutions (community college, teaching college, and research universities). Participants engaged in a variety of impression management techniques to overcome implicit biases and controlling images that shaped their students', and their colleagues', perceptions. While women in our study had agency, they were limited in the ways they could present themselves, a phenomenon Deil‐Amen and Tevis describe as circumscribed agency. Once women in our study had achieved seniority they were able to express themselves in culturally authentic ways. Theoretically, this study shows how interpretive sociology can overcome its theoretical limitations in dealing with race, and shows that the interactionist perspective is actually well suited towards discussing this matters in a meaningful way. We conclude by advocating for greater awareness surrounding the lived experience of Black, women faculty, especially by those who mentor and evaluate them.
Simulating a sterilization processing department to evaluate block schedules and tray configurations
Authors: Harris Sean , Nino Valentina , Claudio David
Published: June 2023

Discrete event simulation is a well‐established tool for examining the effect of different operating room (OR) block schedules on various performance metrics within the OR suite and adjacent units. However, one unit that has rarely been studied is the sterilization processing department (SPD), which cleans and assembles reusable OR instruments. As part of a larger research study, we developed a series of OR block assignment models that sought to reduce the workload of the SPD and developed a tray optimization model to reduce the number of instruments on increasingly bloated instrument trays. While initial numerical experiments were promising, a comprehensive simulation model of the OR and SPD was needed to more thoroughly examine how potential changes to the block schedule and/or more efficient tray configurations could improve SPD processing times. In this article, we incorporate the SPD into an existing simulation model of an OR suite, which is the first of its kind, and examine the effect that different block schedules and tray configurations have on SPD processing times. Simulation results confirm earlier numerical computations. Furthermore, simulation results suggest that more efficient instrument tray configurations are a much better and more viable method for improving SPD processing time than reconfiguring block schedules.
Donanemab exposure and efficacy relationship using modeling in Alzheimer's disease
Authors: Gueorguieva Ivelina , Willis Brian A. , Chua Laiyi , Chow Kay , Ernest C. Steven , Wang Jian , Shcherbinin Sergey , Sims John R. , Chigutsa Emmanuel
Published: June 2023

INTRODUCTION

Donanemab is an amyloid‐targeting therapy that specifically targets brain amyloid plaques. The objective of these analyses was to characterize the relationship of donanemab exposure with plasma biomarkers and clinical efficacy through modeling.

METHODS

Data for the analyses were from participants with Alzheimer's disease from the phase 1 and TRAILBLAZER‐ALZ studies. Indirect‐response models were used to fit plasma phosphorylated tau 217 (p‐tau217) and plasma glial fibrillated acidic protein (GFAP) data over time. Disease‐progression models were developed using pharmacokinetic/pharmacodynamic modeling.

RESULTS

The plasma p‐tau217 and plasma GFAP models adequately predicted the change over time, with donanemab resulting in decreased plasma p‐tau217 and plasma GFAP concentrations. The disease‐progression models confirmed that donanemab significantly reduced the rate of clinical decline. Simulations revealed that donanemab slowed disease progression irrespective of baseline tau positron emission tomography (PET) level within the evaluated population.

DISCUSSION

The disease‐progression models show a clear treatment effect of donanemab on clinical efficacy regardless of baseline disease severity.
Lightweight and flame retardant fluorosilicone rubber composited foam prepared by supercritical nitrogen
Authors: Yu Zhen , Song Yifa , Yang Lijuan , Wen Shibao , Zhao Yingjie , Zhao Yongxian , Zhang Zhenxiu
Published: June 2023

Improving the flame retardancy and lightweight of fluorosilicone rubber (FSR) foam is important for its application in aerospace, rail transportation, petrochemical equipment, etc. In this work, ammonium polyphosphate (APP) and expandable graphite (EG) were used as synergistic flame retardants, and the lightweight FSR composite foam with flame retardancy was prepared by supercritical N2 foaming. When there were 12.5 phr APP and 7.5 phr EG, the composite foam with density of 0.254 g/cm3 showed superiority in foaming performance and flame retardancy, and the limit oxygen index was 36.4%, the UL‐94 grade reached V‐0, the ignition time was 12 s and the fire performance index was 0.071 s·m2/kW. In addition, the aging, oil and solvent resistance of FSR foam was not affected. This work provided data support for the production and application of the flame retardant FSR foam.
A fully coupled level set-based topology optimization of flexible components in multibody systems
Authors: Azari Nejat Ali , Held Alexander , Seifried Robert
Published: June 2023

A fully coupled level set-based topology optimization of flexible components in multibody systems is considered. Thereby, using the floating frame of reference approach, the flexible components are efficiently modeled and incorporated in multibody systems. An adjoint sensitivity analysis is utilized to obtain the gradient of the objective function with respect to a set of density-like design variables assigned to elements included in the underlying finite element model. The utilized adjoint sensitivity analysis provides a gradient, which is within numerical limits exact. In this process, the parametrization of material properties of finite elements has a significant influence on the calculated gradient, in particular for poorly filled elements. These influences are studied in detail. As an application example, the compliance minimization problem of a flexible piston rod in a transient slider-crank mechanism is considered. For this model, the influence of different parametrization methods on the obtained gradient is discussed, and a gradient strategy is proposed to overcome numerical issues included in different parametrization laws. Using this gradient strategy within a level set-based algorithm, a topology optimization of the flexible piston rod is performed. The corresponding results are then compared with optimization results provided by the method of moving asymptotes (MMA). Moreover, the computational effort of the sensitivity analysis is high and scales with the number of design variables. In this work, a gradient approximation is introduced using radial basis functions (RBFs). This helps to develop an appropriate gradient for a level set-based topology optimization of the flexible components in multibody systems, where the RBF-based design space reduction decreases the computational effort of the utilized sensitivity analysis. Finally, the efficiency gain obtained by the introduced design space reduction is demonstrated by optimization examples.
Efficient buckling constrained topology optimization using reduced order modeling
Authors: Dahlberg Vilmer , Dalklint Anna , Spicer Matthew , Amir Oded , Wallin Mathias
Published: June 2023

We present an efficient computational approach to continuum topology optimization with linearized buckling constraints, using Reduced Order Models (ROM). A reanalysis technique is employed to generate basis vectors that subsequently are used to significantly reduce the size of the generalized eigenvalue problems. We demonstrate the efficacy of this approach by optimizing for stiffness with buckling constraints and show results for several test cases. Based on our findings, we conclude that the ROM can potentially save significant computational effort without compromising the quality of the results.
Boundedness and Unboundedness in Total Variation Regularization
Authors: Bredies Kristian , Iglesias José A. , Mercier Gwenael
Published: June 2023

We consider whether minimizers for total variation regularization of linear inverse problems belong to$$L^\infty $$L∞even if the measured data does not. We present a simple proof of boundedness of the minimizer for fixed regularization parameter, and derive the existence of uniform bounds for sufficiently small noise under a source condition and adequate a priori parameter choices. To show that such a result cannot be expected for every fidelity term and dimension we compute an explicit radial unbounded minimizer, which is accomplished by proving the equivalence of weighted one-dimensional denoising with a generalized taut string problem. Finally, we discuss the possibility of extending such results to related higher-order regularization functionals, obtaining a positive answer for the infimal convolution of first and second order total variation.
Real-time, acquisition parameter-free voxel-wise patient-specific Monte Carlo dose reconstruction in whole-body CT scanning using deep neural networks
Authors: Salimi Yazdan , Akhavanallaf Azadeh , Mansouri Zahra , Shiri Isaac , Zaidi Habib
Published: June 2023

Objective

We propose a deep learning-guided approach to generate voxel-based absorbed dose maps from whole-body CT acquisitions.

Methods

The voxel-wise dose maps corresponding to each source position/angle were calculated using Monte Carlo (MC) simulations considering patient- and scanner-specific characteristics (SP_MC). The dose distribution in a uniform cylinder was computed through MC calculations (SP_uniform). The density map and SP_uniform dose maps were fed into a residual deep neural network (DNN) to predict SP_MC through an image regression task. The whole-body dose maps reconstructed by the DNN and MC were compared in the 11 test cases scanned with two tube voltages through transfer learning with/without tube current modulation (TCM). The voxel-wise and organ-wise dose evaluations, such as mean error (ME, mGy), mean absolute error (MAE, mGy), relative error (RE, %), and relative absolute error (RAE, %), were performed.

Results

The model performance for the 120 kVp and TCM test set in terms of ME, MAE, RE, and RAE voxel-wise parameters was  − 0.0302 ± 0.0244 mGy, 0.0854 ± 0.0279 mGy,  − 1.13 ± 1.41%, and 7.17 ± 0.44%, respectively. The organ-wise errors for 120 kVp and TCM scenario averaged over all segmented organs in terms of ME, MAE, RE, and RAE were  − 0.144 ± 0.342 mGy, and 0.23 ± 0.28 mGy,  − 1.11 ± 2.90%, 2.34 ± 2.03%, respectively.

Conclusion

Our proposed deep learning model is able to generate voxel-level dose maps from a whole-body CT scan with reasonable accuracy suitable for organ-level absorbed dose estimation.

Clinical relevance statement

We proposed a novel method for voxel dose map calculation using deep neural networks. This work is clinically relevant since accurate dose calculation for patients can be carried out within acceptable computational time compared to lengthy Monte Carlo calculations.

Key Points

• We proposed a deep neural network approach as an alternative to Monte Carlo dose calculation.

• Our proposed deep learning model is able to generate voxel-level dose maps from a whole-body CT scan with reasonable accuracy, suitable for organ-level dose estimation.

• By generating a dose distribution from a single source position, our model can generate accurate and personalized dose maps for a wide range of acquisition parameters.
Inter-software and inter-scan variability in measurement of epicardial adipose tissue: a three-way comparison of a research-specific, a freeware and a coronary application software platform
Authors: Chan Jasmine , Thakur Udit , Tan Sean , Muthalaly Rahul G. , Thakkar Harsh , Goel Vinay , Cheen Yeong-Chee , Dey Damini , Brown Adam J. , Wong Dennis T. L. , Nerlekar Nitesh
Published: June 2023

Objectives

Epicardial adipose tissue (EAT) is a proposed marker of cardiovascular risk; however, clinical application may be limited by variability in post-processing software platforms. We assessed inter-vendor agreement of EAT volume (EATv) and attenuation on both contrast-enhanced (CE) and non-contrast CT (NCT) using a standard coronary CT reporting software (Vitrea), an EAT research-specific software (QFAT) and a freeware imaging software (OsiriX).

Methods

Seventy-six consecutive patients undergoing simultaneous CE and NCT had complete volumetric EAT measurement. Between-software, within-software NCT vs. CE, and inter- and intra-observer agreement were evaluated with analysis by ANOVA (with post hoc adjustment), Bland-Altman with 95% levels of agreement (LoA) and intraclass correlation coefficient (ICC).

Results

Mean EATv (freeware 53 ± 31 mL vs. research 93 ± 43 mL vs. coronary 157 ± 64 mL) and attenuation (freeware  − 72 ± 25 HU vs. research  − 75 ± 3 HU vs. coronary  − 61 ± 10 HU) were significantly different between all vendors (ANOVA p < 0.001). EATv was consistently higher in NCT vs. CE for all software packages, with most reproducibility found in research software (bias 26 mL, 95% LoA: 2 to 56 mL), compared to freeware (bias 11 mL 95% LoA: − 46 mL to 69 mL) and coronary software (bias 10 mL 95% LoA: − 127 to 147 mL). Research software had more comparable NCT vs. CE attenuation (− 75 vs. − 72 HU) compared to freeware (− 72 vs. − 57 HU) and coronary (− 61 vs.  − 39 HU). Excellent inter-observer agreement was seen with research (ICC 0.98) compared to freeware (ICC 0.73) and coronary software (ICC 0.75) with narrow LoA on Bland-Altman analysis.

Conclusion

There are significant inter-vendor differences in EAT assessment. Our study suggests that research-specific software has better agreement and reproducibility compared to freeware or coronary software platforms.

Key Points

• There are significant differences between EAT volume and attenuation values between software platforms, regardless of scan type.

• Non-contrast scans routinely have higher mean EAT volume and attenuation; however, this finding is only consistently seen with research-specific software.

• Of the three analyzed packages, research-specific software demonstrates the highest reproducibility, agreement, and reliability for both inter-scan and inter-observer agreement.
Sensitivity of seasonal circulation response to snow reduction in the Northern Hemisphere and Eurasia and its impact on Eurasian climate
Authors: Wang Shiyu , Wyser Klaus , Koenigk Torben
Published: June 2023

In this study, we analyze the impact of reduced snow cover in the Northern Hemisphere on the atmosphere and if the atmospheric response depends on the model resolution. We use the atmospheric component of the global climate model EC-Earth and perform three experiments: in the first experiment, we reduce the snow cover in the entire Northern Hemisphere by reducing the snow albedo to a constant value of 0.3, in the second experiment, we reduce the snow albedo only over Eurasia, and the third experiment is the control run using normal snow conditions. All experiments are integrated over the period 1980–2015 at standard resolution (~ 80 km) and high resolution (~ 40 km). Experiments comprise 11 and 5 ensemble members at standard resolution and high resolution, respectively. Reducing the snow albedo in the Northern Hemisphere leads to 5–10% snow cover reduction in winter and spring. Significant warm responses are found over northern Eurasia in spring and summer with a warm response reaching 3 °C. Similar but weaker warm temperature responses are found in the middle and upper troposphere (up to 2 °C) and reversed temperature responses in the stratosphere (up to – 2 °C), particularly over eastern Eurasia. This is closely associated with westerly jet flow response which is enhanced at high-latitude and weakened at low-latitude in winter and spring over eastern Eurasia. Reduced snow cover leads to warmer surface temperatures that accelerate snow-melting and further lead to different snow-hydrological responses in western and eastern Eurasia and more precipitation occurs over eastern Eurasia (increasing 10–20%), particularly in the Siberian region. When the snow albedo is reduced only in the Eurasian sector, the surface response pattern resembles the results of the Northern Hemisphere experiment. The warm response is slightly weakened about 0.25–0.5 °C over Eurasia and significantly weakened outside of Eurasia. However, the upper air circulation response is much less pronounced over Eurasia. The impact of resolution on the mean surface field response is small yet it is more pronounced on the large-scale circulation response, particularly in spring and winter.
Effects of exercise induced muscle damage on cardiovascular responses to isometric muscle contractions and post-exercise circulatory occlusion
Authors: Zambolin Fabio , Peçanha Tiago , Pinner Susan , Venturelli Massimo , McPhee Jamie Stewart
Published: June 2023

Purpose

The aim of the present study was to investigate whether exercise-induced muscle damage (EIMD) influences cardiovascular responses to isometric exercise and post-exercise circulatory occlusion (PECO). We hypothesized that EIMD would increase muscle afferent sensitivity and, accordingly, increase blood pressure responses to exercise and PECO.

Methods

Eleven male and nine female participants performed unilateral isometric knee extension at 30% of maximal voluntary contraction (MVC) for 3-min. A thigh cuff was rapidly inflated to 250 mmHg for two min PECO, followed by 3 min recovery. Heart rate and blood pressure were monitored beat-by-beat, with stroke volume and cardiac output estimated from the Modelflow algorithm. Measurements were taken before and 48 h after completing eccentric knee-extension contractions to induce muscle damage (EIMD).

Results

EIMD caused 21% decrease in MVC (baseline: 634.6 ± 229.3 N, 48 h: 504.0 ± 160 N), and a 17-fold increase in perceived soreness using a visual-analogue scale (0–100 mm; VASSQ) (both p < 0.001). CV responses to exercise and PECO were not different between pre and post EIMD. However, mean arterial pressure (MAP) was higher during the recovery phase after EIMD (p < 0.05). Significant associations were found between increases in MAP during exercise and VASSQ, Rate of Perceived Exertion (RPE) and Pain after EIMD only (all p < 0.05).

Conclusion

The MAP correlations with muscle soreness, RPE and Pain during contractions of damaged muscles suggests that higher afferent activity was associated with higher MAP responses to exercise.
Organ-specific responses during acclimation of mycorrhizal and non-mycorrhizal tomato plants to a mild water stress reveal differential local and systemic hormonal and nutritional adjustments
Authors: Fresno David H. , Munné-Bosch Sergi
Published: June 2023

Main conclusion

Tomato plant acclimation to a mild water stress implied tissue-specific hormonal and nutrient adjustments, being the root one of the main modulators of this response.

Phytohormones are key regulators of plant acclimation to water stress. However, it is not yet clear if these hormonal responses follow specific patterns depending on the plant tissue. In this study, we evaluated the organ-specific physiological and hormonal responses to a 14 day-long mild water stress in tomato plants (Solanum lycopersicum cv. Moneymaker) in the presence or absence of the arbuscular mycorrhizal fungus Rhizoglomus irregulare, a frequently used microorganism in agriculture. Several physiological, production, and nutritional parameters were evaluated throughout the experiments. Additionally, endogenous hormone levels in roots, leaves, and fruits at different developmental stages were quantified by ultrahigh-performance liquid chromatography coupled to tandem mass spectrometry (UHPLC–MS/MS). Water deficit drastically reduced shoot growth, while it did not affect fruit production. In contrast, fruit production was enhanced by mycorrhization regardless of the water treatment. The main tissue affected by water stress was the root system, where huge rearrangements in different nutrients and stress-related and growth hormones took place. Abscisic acid content increased in every tissue and fruit developmental stage, suggesting a systemic response to drought. On the other hand, jasmonate and cytokinin levels were generally reduced upon water stress, although this response was dependent on the tissue and the hormonal form. Finally, mycorrhization improved plant nutritional status content of certain macro and microelements, specially at the roots and ripe fruits, while it affected jasmonate response in the roots. Altogether, our results suggest a complex response to drought that consists in systemic and local combined hormonal and nutrient responses.
Vulcanian eruption processes inferred from volcanic glow analysis at Sakurajima volcano, Japan
Authors: Muramatsu Dan , Aizawa Koki , Yokoo Akihiko , Tameguri Takeshi , Iguchi Masato
Published: June 2023

Volcanic glow, which is often observed at active craters during nighttime, contains information on high-temperature zones deep in the crater that are hidden from view. We analyzed 90 eruption videos capturing volcanic glow before the onset of Vulcanian eruptions at the Showa crater of Sakurajima volcano (Japan), and found that they show clear temporal changes. The red (R)-value and the green-to-red ratio (GR ratio) are used to track glow intensity and temperature change, respectively. We found two types of temporal change in glow intensity: a short-term change approximately 1 s before the onset of explosions, and a long-term change 3 to 330 s before an explosion. Short-term changes were observed for 28 of 90 eruptions, and coincided with an increase in the GR ratio and with a modest precursory infrasound pressure increase. Since an increasing GR ratio means a temperature increase, we consider that the change was associated with the opening of tensile cracks on the crater floor before an explosion. However, the other 62 eruptions did not show short-term changes, suggesting that the opening of cracks is sporadic. Long-term changes were observed for 73 of 90 eruptions, the GR ratio did not exhibit a significant increase. We suggest that long-term changes are caused by gradual gas leakage, which precedes initiation of Vulcanian eruptions. We hypothesize that the long-term gas leakage causes gradual decompression of the conduit, which induces supersaturation of volatile-rich magma beneath the lava plug causing explosive expansion, thereby triggering an eruption.