bluuebunny/crossref_metadata_2025_split huggingface dataset:
On the Interaction of Damage Evolution and Thermal Buckling in Stepped Circular Bilaminates
Authors: Xu S. , Bottega W. J. 
Published: July 2023

Abstract
The behavior and evolution of stepped circular bi-laminates with edge damage are studied for structures subjected to uniform thermal load. The problem is formulated as a moving intermediate boundaries problem in the calculus of variations, where the boundary of an evolving region of damage emanating from the edge of the smaller substructure, as well as the boundary of a progressing/regressing region of sliding contact adjacent to the intact region of the composite structure are each allowed to vary along with the displacements. This yields the associated transversality conditions that define the locations of the propagating boundaries that correspond to equilibrium configurations of the evolving composite structure, as well as the equations of equilibrium and the associated interior and exterior boundary conditions. Various configurations of contact of the detached segments of the composite structure and the associated behavior are considered, and the influence and progression of contact on the overall evolution of the composite structure are assessed. Closed-form analytical solutions to the geometrically nonlinear problem are obtained, and expressions for the critical buckling load are developed. The explicit forms of the total energy release rate along the delamination front, as well as of the conditions for propagation of the contact zone boundary, are obtained from the analytical solutions and the corresponding transversality conditions. Results of numerical simulations based on the analytical solutions are presented and are seen to unveil a rich evolution process involving contact progression/recession and metamorphosis, buckling, and detachment progression during the prebuckling phase, during sling-shot buckling, and during the postbuckling phase, depending on the material properties of the sublaminates, the geometry of the sublaminates, the initial size of the damage, and the strength of the interfacial bond. Characteristic behavior of damage propagation is found to be quite robust and is seen to include stable propagation, stable followed by unstable progression, arrest, and catastrophic propagation.
Biomechanical Evaluation of an Adaptive-Motion Pedicle Screw Fixation System: Experimental and Numerical Analysis
Authors: Zou Renling , Zhang Xuan , Li Yuchen , Wang Jiaqing , Hu Xiufang 
Published: July 2023

Abstract
Rigid fixation is mostly used in thoracolumbar spine surgery, which restricts the thoracolumbar spine segments moving and is not conducive to postoperative rehabilitation. We developed an adaptive-motion pedicle screw and established a finite element model of the T12-L3 segments of the thoracolumbar spine in osteoporosis patients based on the CT image data. A variety of internal fixation finite element models were established for mechanical simulation analysis and comparison. The simulation results showed that compared with the conventional internal fixation system, the mobility of the new adaptive-motion internal fixation system was improved by about 13.8% and 7.7% under the classic conditions such as lateral bending and flexion. in vitro experiments were conducted simultaneously with fresh porcine thoracolumbar spine vertebrae, and the axial rotation condition was taken as an example to analyze the mobility. The in vitro results showed that the mobility of the adaptive-motion internal fixation system had better mobility characteristics under axial rotation conditions, which was consistent with the finite element analysis. The adaptive-motion pedicle screws can preserve a certain degree of vertebral mobility, and avoid excessive vertebral restriction. It also increases the stress value of the intervertebral disk, which is closer to the normal mechanical transmission of the human body, avoiding stress masking and slowing down the degeneration of the intervertebral disk. The adaptive-motion pedicle screws can reduce the peak stress of the implant and avoid surgical failure due to implant fracture.
A New Error Compensation Method for Delta Robots Combining Geometric Error Modeling With Spatial Interpolating
Authors: Ma Jianwei , Shen Yabin , Zhang Shumei , Yan Huiteng , Jia Zhenyuan 
Published: July 2023

Abstract
Robots are playing an important role in precision manufacturing and automated inspection, which places higher demands on the positioning accuracy. The Delta robot is the most widely used parallel robot with high speed and small cumulative error. In this way, improving the positioning accuracy of the Delta robot can expand its application scenarios. According to the parameter mapping relationship, the position error can be divided into geometric error and non-geometric error. Considering the influence of the orientation errors on the actual position of the robot end, an error model to recognize the geometric error is established, and the parameter identification is performed based on an iterative approach. For the non-geometric error, the 3D annular sector grid division method and the interpolation rule are established based on the error similarity. And then, a new error compensation method for Delta robots is proposed by combining geometric error modeling with spatial interpolating. After compensation, the positioning accuracy of the Delta robot is improved significantly. The maximum absolute positioning error of the robot is reduced by 86.08% from 2.084 mm to 0.290 mm, the average absolute positioning error of the robot is reduced by 81.77% from 0.790 mm to 0.144 mm, and the error trend in the workspace is eliminated, so as to enable the expansion of Delta robot applications.
Continuum Damage Mechanics Modeling of High-Temperature Flaw Propagation: Application to Creep Crack Growth in 316H Standardized Specimens and Nuclear Reactor Components
Authors: Recuero Antonio M. , Petkov Markian , Spencer Benjamin W. , Juan Pierre-Alexandre 
Published: July 2023

Abstract
Predicting creep crack growth (CCG) of flaws found during operation in high-temperature alloy components is essential for assessing the remaining lifetime of those components. While defect assessment procedures are available for this purpose in design codes, these are limited in their range of applicability. This study assesses the application of a local damage-based finite element methodology as a more general technique for the prediction of CCG at high temperatures on a variety of structural configurations. Numerical results for stainless steel 316H, which are validated against experimental data, show the promise of this approach. This integration of continuum damage mechanics (CDM) based methodologies, together with adequate inelastic models; into assessment procedures can therefore inform the characterization of CCG under complex operating conditions while avoiding excessive conservatism. This article shows that such modeling frameworks can be calibrated to experimental data and used to demonstrate that the degree of triaxiality ahead of a growing creep crack affects its rate of growth. The framework is also successfully employed in characterizing CCG in realistic reactor pressure vessel geometry under an arbitrary loading condition. These results are particularly relevant to the nuclear power industry for defect assessment and inspections as part of codified practices of structural components with flaws in high-temperature reactors.
Variational Bayesian Calibration of a PTW Material Strength Model for OFHC Copper
Authors: Andrews Stephen A. , Wilson Brandon M. 
Published: July 2023

Abstract
The strength of materials at high strain rates is a challenging problem for model development and calibration. Such models can span a regime in strain rate from 1 × 10−3 s−1 to 1 × 1012 s−1 and a regime in temperature of 0K to up to the material’s melting temperature. The limits of these regimes can be difficult and expensive to access experimentally. There is interest in understanding how well calibrations made at moderate strain rates and temperature can perform when applied to more extreme regimes. Variational Bayesian techniques have been shown to be computationally inexpensive methods to both calibrate a model and understand the uncertainties in model parameters. This investigation will calibrate the parameters of a Peston-Tonks-Wallace (PTW) material strength model to low and moderate strain rate experiments from quasi-static, and Hopkinson bar experiments performed on fully annealed Oxygen Free High Conductivity (OFHC) copper. Bayesian methods will be used to quantify the correlated uncertainty in these parameters. These uncertainties will propagated forward to a simulation of a Richtmyer-Meshkov instability experiment which exercise a higher strain rate regime. The effects of the model uncertainties on the predictive ability of the simulation will be observed. This will demonstrate a strategy for Bayesian model calibration and uncertainty quantification for parametric models with applications to physics processes outside high strain rate plastic deformation.
A deep learning method for predicting the minimum inhibitory concentration of antimicrobial peptides against
Escherichia coli
using Multi-Branch-CNN and Attention
Authors: Yan Jielu , Zhang Bob , Zhou Mingliang , Campbell-Valois François-Xavier , Siu Shirley W. I. 
Published: July 2023

ABSTRACT

Antimicrobial peptides (AMPs) are a promising alternative to antibiotics to combat drug resistance in pathogenic bacteria. However, the development of AMPs with high potency and specificity remains a challenge, and new tools to evaluate antimicrobial activity are needed to accelerate the discovery process. Therefore, we proposed MBC-Attention, a combination of a multi-branch convolution neural network architecture and attention mechanisms to predict the experimental minimum inhibitory concentration of peptides against
Escherichia coli
. The optimal MBC-Attention model achieved an average Pearson correlation coefficient (PCC) of 0.775 and a root mean squared error (RMSE) of 0.533 (log μM) in three independent tests of randomly drawn sequences from the data set. This results in a 5–12% improvement in PCC and a 6–13% improvement in RMSE compared to 17 traditional machine learning models and 2 optimally tuned models using random forest and support vector machine. Ablation studies confirmed that the two proposed attention mechanisms, global attention and local attention, contributed largely to performance improvement.

IMPORTANCE

Antimicrobial peptides (AMPs) are potential candidates for replacing conventional antibiotics to combat drug resistance in pathogenic bacteria. Therefore, it is necessary to evaluate the antimicrobial activity of AMPs quantitatively. However, wet-lab experiments are labor-intensive and time-consuming. To accelerate the evaluation process, we develop a deep learning method called MBC-Attention to regress the experimental minimum inhibitory concentration of AMPs against
Escherichia coli
. The proposed model outperforms traditional machine learning methods. Data, scripts to reproduce experiments, and the final production models are available on GitHub.
Paired associated SARS-CoV-2 spike variable positions: a network analysis approach to emerging variants
Authors: Manoussopoulos Yiannis , Anastassopoulou Cleo , Ioannidis John P. A. , Tsakris Athanasios 
Published: July 2023

ABSTRACT

Amino acids in variable positions of proteins may be correlated, with potential structural and functional implications. Here, we apply exact tests of independence in R × C contingency tables to examine noise-free associations between variable positions of the SARS-CoV-2 spike protein, using as a paradigm sequences from Greece deposited in GISAID (
N
= 6,683/1,078 full length) for the period 29 February 2020 to 26 April 2021 that essentially covers the first three pandemic waves. We examine the fate and complexity of these associations by network analysis, using associated positions (exact
P
≤ 0.001 and Average Product Correction ≥ 2) as links and the corresponding positions as nodes. We found a temporal linear increase of positional differences and a gradual expansion of the number of position associations over time, represented by a temporally evolving intricate web, resulting in a non-random complex network of 69 nodes and 252 links. Overconnected nodes corresponded to the most adapted variant positions in the population, suggesting a direct relation between network degree and position functional importance. Modular analysis revealed 25
k
-cliques comprising 3 to 11 nodes. At different
k
-clique resolutions, one to four communities were formed, capturing epistatic associations of circulating variants (Alpha, Beta, B.1.1.318), but also Delta, which dominated the evolutionary landscape later in the pandemic. Cliques of aminoacidic positional associations tended to occur in single sequences, enabling the recognition of epistatic positions in real-world virus populations. Our findings provide a novel way of understanding epistatic relationships in viral proteins with potential applications in the design of virus control procedures.

IMPORTANCE

Paired positional associations of adapted amino acids in virus proteins may provide new insights for understanding virus evolution and variant formation. We investigated potential intramolecular relationships between variable SARS-CoV-2 spike positions by exact tests of independence in R × C contingency tables, having applied Average Product Correction (APC) to eliminate background noise. Associated positions (exact
P
≤ 0.001 and APC ≥ 2) formed a non-random, epistatic network of 25 cliques and 1–4 communities at different clique resolutions, revealing evolutionary ties between variable positions of circulating variants and a predictive potential of previously unknown network positions. Cliques of different sizes represented theoretical combinations of changing residues in sequence space, allowing the identification of significant aminoacidic combinations in single sequences of real-world populations. Our analytic approach that links network structural aspects to mutational aminoacidic combinations in the spike sequence population offers a novel way to understand virus epidemiology and evolution.
Challenger Deep basalts reveal Indian-type Early Cretaceous oceanic crust subducting in the southernmost Mariana Trench
Authors: Xu Wenjing , Peng Xiaotong , Stern Robert J. , Xu Xisheng , Xu Hengchao 
Published: July 2023

Abstract
Why the Challenger Deep, the deepest point on Earth’s solid surface, is so deep is unclear, but part of the reason must be the age and density of the downgoing plate. Northwest Pacific oceanic crust subducting in the Izu-Bonin-Mariana Trench is Cretaceous and Jurassic, but the age and nature of Pacific oceanic crust subducting in the southernmost Mariana Trench remains unknown. Here we present the first study of seafloor basalts recovered by the full-ocean-depth crewed submersible Fendouzhe from the deepest seafloor around the Challenger Deep, from both the overriding and downgoing plates. 40Ar/39Ar ages indicate that downgoing basalts are Early Cretaceous (ca. 125 Ma), indicating they are part of the Pacific plate rather than the nearby Oligocene Caroline microplate. Downgoing-plate basalts are slightly enriched in incompatible elements but have similar trace element and Hf isotope compositions to other northwest Pacific mid-ocean ridge basalts (MORBs). They also have slightly enriched Sr-Nd-Pb isotope compositions like those of the Indian mantle domain. These features may have formed with contributions from plume-derived components via plume-ridge interactions. One sample from the overriding plate gives an 40Ar/39Ar age of ca. 55 Ma, about the same age as subduction initiation, to form the Izu-Bonin-Mariana convergent margin. Our results suggest that 50%–90% of the Pb budget of Mariana arc magmas is derived from the subducted MORBs with Indian-type isotope affinity.
Adenomas of the ciliary body epithelium: clinics, histopathology and management
Authors: Zheng Yue , Gu Xiang , Yao Yiran , Pan Hui , Jia Renbing , Xu Xiaofang , Zhuang Ai 
Published: July 2023

AimsAdenomas of the ciliary body epithelium, including adenoma of the pigmented ciliary body epithelium (APCE) and adenoma of the non-pigmented ciliary body epithelium (ANPCE), are extremely rare, and most knowledge about them comes from sporadic case reports. The purpose of this study was to provide a comprehensive understanding of adenomas of the ciliary body epithelium and to identify the similarities and differences between APCE and ANPCE.MethodsThis study was a retrospective case series comprising data from 41 patients obtained from retrieved publications and five cases diagnosed at the Shanghai Ninth People’s Hospital. The clinicopathological features, treatment and prognosis of APCE and ANPCE were compared using the non-parametric rank sum test, t-test and the χ2test.ResultsThe clinical and histopathological features and treatment were analogous between APCE (n=23) and ANPCE (n=23). The overall visual prognosis associated with the two tumours was good, with 63% of the patients having stable or improved vision after treatment. Enucleation was the primary cause of eventual vision loss (three in APCE vs two in ANPCE, p=0.001). Notably, iris invasion was commonly observed in patients with APCE (six in APCE vs zero in ANPCE, p=0.014), and iris invasion was associated with decreased vision eventually (p=0.003). Tumour size was irrelevant to the vision outcome (p=0.65). Metastasis or recurrence did not occur in any of the patients.ConclusionIn most cases, the clinicopathological features of ANPCE and APCE were similar. Iris invasion was commonly observed in patients with APCE, which was associated with poor visual prognosis.
Visual function resists early neurodegeneration in the visual system in primary progressive multiple sclerosis
Authors: Rosenkranz Sina C , Gutmann Lilija , Has Silemek Arzu Ceylan , Dorr Michael , Häußler Vivien , Lüpke Margareta , Mönch Andrea , Reinhardt Stefanie , Kuhle Jens , Tilsley Penelope , Heesen Christoph , Friese Manuel A , Brandt Alexander , Paul Friedemann , Zimmermann Hanna , Stellmann Jan-Patrick 
Published: July 2023

BackgroundNeurodegeneration in multiple sclerosis (MS) affects the visual system but dynamics and pathomechanisms over several years especially in primary progressive MS (PPMS) are not fully understood.MethodsWe assessed longitudinal changes in visual function, retinal neurodegeneration using optical coherence tomography, MRI and serum NfL (sNfL) levels in a prospective PPMS cohort and matched healthy controls. We investigated the changes over time, correlations between outcomes and with loss of visual function.ResultsWe followed 81 patients with PPMS (mean disease duration 5.9 years) over 2.7 years on average. Retinal nerve fibre layer thickness (RNFL) was reduced in comparison with controls (90.1 vs 97.8 µm; p<0.001). Visual function quantified by the area under the log contrast sensitivity function (AULCSF) remained stable over a continuous loss of RNFL (0.46 µm/year, 95% CI 0.10 to 0.82; p=0.015) up until a mean turning point of 91 µm from which the AULCSF deteriorated. Intereye RNFL asymmetry above 6 µm, suggestive of subclinical optic neuritis, occurred in 15 patients and was related to lower AULCSF but occurred also in 5 out of 44 controls. Patients with an AULCSF progression had a faster increase in Expanded Disability Status Scale (beta=0.17/year, p=0.043). sNfL levels were elevated in patients (12.2 pg/mL vs 8.0 pg/mL, p<0.001), but remained stable during follow-up (beta=–0.14 pg/mL/year, p=0.291) and were not associated with other outcomes.ConclusionWhereas neurodegeneration in the anterior visual system is already present at onset, visual function is not impaired until a certain turning point. sNfL is not correlated with structural or functional impairment in the visual system.
Virial theorem for a cloud of stars obtained from the Jeans equations with second correlation moments
Authors: Stupka A. A. , Kopteva E. M. , Saliuk M. A. , Bormotova I. M. 
Published: July 2023

AbstractA hydrodynamic model for small acoustic oscillations in a cloud of stars is built, taking into account the self-consistent gravitational field in equilibrium with a non-zero second correlation moment. It is assumed that the momentum flux density tensor should include the analog of the anisotropic pressure tensor and the second correlation moment of both longitudinal and transverse gravitational field strength. The non-relativistic temporal equation for the second correlation moment of the gravitational field strength is derived from the Einstein equations using the first-order post-Newtonian approximation. One longitudinal and two transverse branches of acoustic oscillations are found in a homogeneous and isotropic star cloud. The requirement for the velocity of transverse oscillations to be zero provides the boundary condition for the stability of the cloud. The critical radius of the spherical cloud of stars is obtained, which is precisely consistent with the virial theorem.
Constraining the transitional magnetic dipole moment interaction between active and heavy neutrinos with the $$Z'$$ at FASER$$\nu $$
Authors: Cheung Kingman , Ouseph C. J. 
Published: July 2023

AbstractWe investigate the effects of the transitional magnetic dipole type interactions of the active-to-heavy-neutrino associated with a new neutral gauge boson $$Z'$$

Z
′

on neutrino-nucleon scattering at the ForwArd Search ExpeRiment-$$\nu $$
ν
(FASER$$\nu $$
ν
). We consider the neutral-current neutrino-nucleon scattering ($$\nu A\rightarrow N A'$$

ν
A
→
N

A
′

, where $$A'$$

A
′

denotes the disintegrated nuclei) as the production mechanism of the heavy neutrino N at FASER$$\nu $$
ν
and estimate the sensitivity reach on the magnetic-type dipole coupling $$\omega _{\nu _\alpha }$$

ω

ν
α

for a range of heavy neutrino mass ($$1\,\textrm{GeV}< \textrm{M}_{\textrm{N}} < 70 \mathrm{~GeV}$$

1

GeV
<

M
N

<
70

GeV

). In this study, we consider three benchmark models, in which the heavy neutrino is coupled to $$L_e$$

L
e

, $$L_\mu $$

L
μ

or $$L_\tau $$

L
τ

doublet, respectively.