Finite growth models

The parametric estimators applied by rolling are commonly used for the analysis of time series with nonlinear patterns, including time varying parameters and local trends. This paper examines the properties of rolling estimators in the class of temporally local maximum likelihood (TLML) estimators. We consider the TLML estimators of (a) constant parameters, (b) stochastic, stationary parameters and (c) parameters with the ultra-long run (ULR) dynamics bridging the gap between the constant and stochastic parameters...

As a result of the complexity and difficulty of the lifetime assessment of the thermoelectric (TE) module, the related research is still immature. In this work, to predict the lifetime of the Bi2 Te3 -based TE module from the perspective of cyclic thermal stress leading to interface cracking, the viscoplastic behavior of the solder layer is first described by the Anand material ontology model, and then the sprouting and expansion of interface cracking of the module are simulated by combining the Darveaux model and the viscoplastic dissipation energy accumulated during the thermal stress cyclic loading...

Atherosclerosis is a disease in blood vessels that often results in plaque formation and lumen narrowing. It is an inflammatory response of the tissue caused by disruptions in the vessel wall nourishment. Blood vessels are nourished by nutrients originating from the blood of the lumen. In medium-sized and larger vessels, nutrients are additionally provided from outside through a network of capillaries called vasa vasorum. It has recently been hypothesized (Haverich in Circulation 135:205-207, 2017) that the root of atherosclerotic diseases is the malfunction of the vasa vasorum...

The indirect tensile test plays a crucial role in experimental investigations of brittle material properties. In this study, a mechanical analysis model of the rectangular test block is established based on the theory of elastic mechanics for the characteristics of the indirect tensile test. The theoretical solution of the triangular series is derived for the rectangular test block under the locally distributed load. The finite element simulation results and splitting test results were compared with the theoretical results...

Conical surfaces pose an interesting challenge to crystal growth: A crystal growing on a cone can wrap around and meet itself at different radii. We use a disk-packing algorithm to investigate how this closure constraint can geometrically frustrate the growth of single crystals on cones with small opening angles. By varying the crystal seed orientation and cone angle, we find that-except at special commensurate cone angles-crystals typically form a seam that runs along the axial direction of the cone, while near the tip, a disordered particle packing forms...

Anterior Vertebral Body Tethering (VBT) is a novel fusionless treatment option for selected adolescent idiopathic scoliosis patients which is gaining widespread interest. The primary objective of this study is to investigate the effects of tether pre-tension within VBT on the biomechanics of the spine including sagittal and transverse parameters as well as primary motion, coupled motion, and stresses acting on the L2 superior endplate. For that purpose, we used a calibrated and validated Finite Element model of the L1-L2 spine...

Anoikis resistance or evasion of cell death triggered by cell detachment into suspension is a hallmark of cancer that is concurrent with cell survival and metastasis. The effects of frequent matrix detachment encounters on the development of anoikis resistance in cancer remains poorly defined. Here we show using a panel of ovarian cancer models, that repeated exposure to suspension stress in vitro followed by attached recovery growth leads to the development of anoikis resistance paralleling in vivo development of anoikis resistance in ovarian cancer ascites...

Phosphorus is a nonrenewable material with a finite supply on Earth; however, due to the rapid growth of the manufacturing industry, phosphorus contamination has become a global concern. Therefore, this study highlights the remarkable potential of ranunculus-like MgO (MO4-MO6) as superior adsorbents for phosphate removal and recovery. Furthermore, MO6 stands out with an impressive adsorption capacity of 596.88 mg/g and a high efficacy across a wide pH range (2-10) under varying coexisting ion concentrations...

Colorectal cancer (CRC) involves epigenetic alterations. Irregular gene-methylation alteration causes and advances CRC tumor growth. Detecting differentially methylated genes (DMGs) in CRC and patient survival time paves the way to early cancer detection and prognosis. However, CRC data including survival times are heterogeneous. Almost all studies tend to ignore the heterogeneity of DMG effects on survival. To this end, we utilized a sparse estimation method in the finite mixture of accelerated failure time (AFT) regression models to capture such heterogeneity...

Consider the diffusion process defined by the forward equation ut (t,x)=12{xu(t,x)}xx -α{xu(t,x)}x for t,x≥0 and -∞<α<∞, with an initial condition u(0,x)=δ(x-x0 ). This equation was introduced and solved by Feller to model the growth of a population of independently reproducing individuals. We explore important coalescent processes related to Feller's solution. For any α and x0 >0 we calculate the distribution of the random variable An (s;t), defined as the finite number of ancestors at a time s in the past of a sample of size n taken from the infinite population of a Feller diffusion at a time t since since its initiation...

The local charge density and distribution of extracellular membranes play a crucial role in the various cellular processes, such as regulation and localization of membrane proteins, electrophysiological signal transduction, transcriptional control, cell growth, and cell death. In this study, a novel scanning ion conductance microscopy-based method is employed to extracellular membrane mapping. This method allows to not only visualize the dynamic topography and surface charge distribution around individual cells, but also distinguish the charge difference...

A central task in finite-time thermodynamics is to minimize the excess or dissipated work W_{diss} when manipulating the state of a system immersed in a thermal bath. We consider this task for an N-body system whose constituents are identical and uncorrelated at the beginning and end of the process. In the regime of slow but finite-time processes, we show that W_{diss} can be dramatically reduced by considering collective protocols in which interactions are suitably created along the protocol. This can even lead to a sublinear growth of W_{diss} with N: W_{diss}∝N^{x} with x<1; to be contrasted to the expected W_{diss}∝N satisfied in any noninteracting protocol...

This study analyzed the mechanical and physiological strategies associated with four features in the branch-stem junction of a tree, namely the U-shaped branch attachment, the branch collar, the branch bark ridge, and the roughened lower stem. Models were established for each stage of tree growth by adding these four features sequentially to a base model, and the finite element method (FEM) was employed to create three-dimensional models of an Acer tree's branch-stem structure for static force analysis. According to the results, the development of the branch collar shifted the point of breakage to the outer part of the collar and, thus, constituted a physiological strategy that prevented decay in the stem...

We implement full, three-dimensional constrained mixture theory for vascular growth and remodeling into a finite element fluid-structure interaction (FSI) solver. The resulting "fluid-solid-growth" (FSG) solver allows long term, patient-specific predictions of changing hemodynamics, vessel wall morphology, tissue composition, and material properties. This extension from short term (FSI) to long term (FSG) simulations increases clinical relevance by enabling mechanobioloigcally-dependent studies of disease progression in complex domains...

We conducted a comprehensive analysis of optical and photoluminescence images obtained from practical multicrystalline silicon wafers, utilizing various machine learning models for dislocation cluster region extraction, grain segmentation, and crystal orientation prediction. As a result, we were able to build a realistic three-dimensional (3D) model that includes the generation point of dislocation clusters. Finite element stress analysis on the 3D model coupled with crystal growth simulation revealed inhomogeneous and complex stress distribution and that dislocation clusters are frequently formed along the slip plane with the highest shear stress among twelve equivalents, concentrated along bending grain boundaries (GBs)...

Bio reciprocal symbiosis is very common in nature, such as soybeans providing food for rhizobia, which uses atmospheric nitrogen to synthesize nitrogen to provide nutrients to soybeans. This paper proposes an advanced Logistic model that adjusts to changes in precipitation and an environmental capacity parameter that varies with the level of symbiosis. The aim is to precisely depict the symbiotic relationship between plants and the interplay among symbiosis, competition, and independent growth of each population in the plant community, as precipitation changes by adapting finite difference method and tertiary Hermit interpolation...

The hardest anatomical components of many animals are connected at thin seams known as sutures, which allow for growth and compliance required for respiration and movement and serve as a defense mechanism by absorbing energy during impacts. We take a bio-inspired approach and parameterize suture geometries to utilize geometric connections, rather than new engineering materials, to absorb high-impact loads. This study builds upon our work that investigated the effects of the dovetail suture contact angle, tangent length, and tab radius on the stiffness and toughness of an archway structure using finite element analysis...

The mechanical behavior of each type of pacifier on rigid structures and their various impacts on orofacial growth have yet to be discovered. The study aimed to evaluate the stress distribution over a child's palate by three types of pacifiers using finite element analysis and clinical and laboratory data. Modulus of elasticity was obtained from 30 specimens comprising 10 of each conventional (A), orthodontic (B), and breast-shaped (C) pacifiers. Tongue strength was assessed in eight 3-year-old children (kPa)...

Cardiovascular function is regulated by a short-term hemodynamic baroreflex loop, which tries to maintain arterial pressure at a normal level. In this study, we present a new multiscale model of the cardiovascular system named MyoFE. This framework integrates a mechanistic model of contraction at the myosin level into a finite-element-based model of the left ventricle pumping blood through the systemic circulation. The model is coupled with a closed-loop feedback control of arterial pressure inspired by a baroreflex algorithm previously published by our team...

The study of how children learn numbers has yielded one of the most productive research programs in cognitive development, spanning empirical and computational methods, as well as nativist and empiricist philosophies. This paper provides a tutorial on how to think computationally about learning models in a domain like number, where learners take finite data and go far beyond what they directly observe or perceive. To illustrate, this paper then outlines a model which acquires a counting procedure using observations of sets and words, extending the proposal of Piantadosi et al...