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1. Simulation of the Childbirth Process in ls-dyna

   https://doi.org/10.1115/1.4064594  

   Tao, Ru; Grimm, Michele J (June 2024, Journal of Biomechanical Engineering)

   Abstract Childbirth or labor, as the final phase of a pregnancy, is a biomechanical process that delivers the fetus from the uterus. It mainly involves two important biological structures in the mother, the uterus—generating the pushing force on the fetus—and the pelvis (bony pelvis and pelvic floor muscles)—resisting the movement of the fetus. The existing computational models developed in this field that simulate the childbirth process have focused on either the uterine expulsion force or the resistive structures of the pelvis, not both. An FEM model including both structures as a system was developed in this paper to simulate the fetus delivery process in ls-dyna. Uterine active contraction was driven by contractile fiber elements using the Hill material model. The passive portion of the uterus and pelvic floor muscles were modeled with Neo Hookean and Mooney–Rivlin materials, respectively. The bony pelvis was modeled as a rigid body. The fetus was divided into three components: the head, neck, and body. Three uterine active contraction cycles were modeled. The model system was validated based on multiple outputs from the model, including the stress distribution within the uterus, the maximum Von Mises and principal stress on the pelvic floor muscles, the duration of the second stage of the labor, and the movement of the fetus. The developed model system can be applied to investigate the effects of pathomechanics related to labor, such as pelvic floor disorders and brachial plexus injury. 

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2. Evaluation of ETAS and STEP Forecasting Models for California Seismicity Using Point Process Residuals

   https://doi.org/10.1002/env.70014  

   Ward, Joshua; Werner, Maximilian; Savran, William; Schoenberg, Frederic (April 2025, Environmetrics)

   ABSTRACT Variants of the Epidemic‐Type Aftershock Sequence (ETAS) and Short‐Term Earthquake Probabilities (STEP) models have been used for earthquake forecasting and are entered as forecast models in the purely prospective Collaboratory Study for Earthquake Predictability (CSEP) experiment. Previous analyses have suggested the ETAS model offered the best forecast skill for the first several years of CSEP. Here, we evaluate the prospective forecasting ability of the ETAS and STEP one‐day forecast models for California from 2013 to 2017, using super‐thinned residuals and Voronoi residuals. We find very comparable performance of the two models, with slightly superior performance of the STEP model compared to ETAS according to most metrics. 

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3. A process approach to quality management doubles NEON sensor data quality

   https://doi.org/10.1111/2041-210X.13943  

   Sturtevant, Cove; DeRego, Elizabeth; Metzger, Stefan; Ayres, Edward; Allen, Dan; Burlingame, Teresa; Catolico, Nora; Cawley, Kaelin; Csavina, Janae; Durden, David; et al (September 2022, Methods in Ecology and Evolution)
4. Upcycling waste PMMA to durable composites via a transesterification‐inverse vulcanization process

   https://doi.org/10.1002/pol.20230609  

   Wijeyatunga, Shalini K; Derr, Katelyn M; Maladeniya, Charini P; Sauceda‐Oloño, Perla Y; Tennyson, Andrew G; Smith, Rhett C (February 2024, Journal of Polymer Science)

   Abstract Poly(methyl methacrylate) (PMMA) is an important commodity polymer having a wide range of applications. Currently, only about 10% of PMMA is recycled. Herein, a simple two‐stage process for the chemical upcycling of PMMA is discussed. In this method PMMA is modified by transesterification with a bio‐derived, olefin‐bearing terpenoid, geraniol. In the second stage, olefin‐derivatized PMMA is reacted with sulfur to form a network composite by an inverse vulcanization mechanism. Inverse vulcanization of PGMA with elemental sulfur (90 wt.%) yielded the durable compositePGMA‐S. This composite was characterized by NMR spectrometry, IR spectroscopy, elemental analysis, thermogravimetric analysis, and differential scanning calorimetry. Composite water uptake, compressional strength analysis, flexural strength analysis, tensile strength analysis, and thermal recyclability are presented with comparison to current commercial structural materials.PGMA‐Sexhibits a similar compressive strength (17.5 MPa) to that of Portland cement.PGMA‐Sdemonstrates an impressive flexural strength of 4.76 MPa which exceeds the flexural strength (>3 MPa) of many commercial ordinary Portland cements. This study provides a way to upcycle waste PMMA through combination with a naturally‐occurring olefin and industrial waste sulfur to yield composites having mechanical properties competitive with ecologically detrimental legacy building materials. 

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5. Hybrid PDE‐kMC modeling approach to simulate multivalent lectin‐glycan binding process

   https://doi.org/10.1002/aic.17453  

   Lee, Dongheon; Green, Aaron; Wu, Hung‐Jen; Kwon, Joseph_Sang‐Il (October 2021, AIChE Journal)

   Abstract Glycans are the major components of the cellular membranes and mediate many cellular processes via their interactions with lectins. A kinetic Monte Carlo (kMC) model was proposed previously to incorporate the key features of glycan‐lectin interactions such as multivalency and glycan diffusion, and its accuracy has been validated by experiments. However, computational cost of the kMC model is its major bottleneck. In this study, a hybrid model combining a partial differential equation (PDE) with the kMC model is proposed to greatly reduce the computational cost while preserving the accuracy. Specifically, glycan diffusion is simulated by the PDE for improving computational efficiency since the glycan diffusion execution through the kMC is computationally expensive. The hybrid PDE‐kMC model is employed to simulate the binding dynamics between cholera toxin subunit B and gangliosides on cellular membranes. The accuracy and efficiency of the proposed model was demonstrated by comparing with the sole kMC model. 

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