Kirchhoff's law-based velocity-controlled motion models to predict real-time cutting forces in minimally invasive surgeries.

A theoretical framework, united by a "system effect" is formulated to model the cutting/haptic force evolution at the cutting edge of a surgical cutting instrument during its penetration into soft biological tissue in minimally invasive surgery. Other cutting process responses, including tissue fracture force, friction force, and damping, are predicted by the model as well. The model is based on a velocity-controlled formulation of the corresponding equations of motion, derived for a surgical cutting instrument and tissue based on Kirchhoff's fundamental energy conservation law.

Atomistic modeling of the mechanical properties: the rise of machine learning interatomic potentials.

Since the birth of the concept of machine learning interatomic potentials (MLIPs) in 2007, a growing interest has been developed in the replacement of empirical interatomic potentials (EIPs) with MLIPs, in order to conduct more accurate and reliable molecular dynamics calculations. As an exciting novel progress, in the last couple of years the applications of MLIPs have been extended towards the analysis of mechanical and failure responses, providing novel opportunities not heretofore efficiently achievable, neither by EIPs nor by density functional theory (DFT) calculations. In this minireview, we first briefly discuss the basic concepts of MLIPs and outline popular strategies for developing a MLIP.

Modeling neuron growth using isogeometric collocation based phase field method.

We present a new computational framework of neuron growth based on the phase field method and develop an open-source software package called "NeuronGrowth_IGAcollocation". Neurons consist of a cell body, dendrites, and axons. Axons and dendrites are long processes extending from the cell body and enabling information transfer to and from other neurons.

A first-principles and machine-learning investigation on the electronic, photocatalytic, mechanical and heat conduction properties of nanoporous CN monolayers.

Carbon nitride nanomembranes are currently among the most appealing two-dimensional (2D) materials. As a nonstop endeavor in this field, a novel 2D fused aromatic nanoporous network with a CN stoichiometry has been most recently synthesized. Inspired by this experimental advance and exciting physics of nanoporous carbon nitrides, herein we conduct extensive density functional theory calculations to explore the electronic, optical and photocatalytic properties of the CN monolayer.

Intelligent on-demand design of phononic metamaterials.

With the growing interest in the field of artificial materials, more advanced and sophisticated functionalities are required from phononic crystals and acoustic metamaterials. This implies a high computational effort and cost, and still the efficiency of the designs may be not sufficient. With the help of third-wave artificial intelligence technologies, the design schemes of these materials are undergoing a new revolution.

A 3D nano scale IGA for free vibration and buckling analyses of multi-directional FGM nanoshells.

This article explores a three-dimensional solid isogeometric analysis (3D-IGA) approach based on a nonlocal elasticity theory to investigate size effects on natural frequency and critical buckling load for multi-directional functionally graded (FG) nanoshells. The multi-directional FG material uses a power law rule with three power exponent indexes concerning three parametric coordinates. Nanoshell's geometries include the square plate, cylindrical and spherical panels with the side length considered in a nanoscale with various thickness ratios.

First-Principles Multiscale Modeling of Mechanical Properties in Graphene/Borophene Heterostructures Empowered by Machine-Learning Interatomic Potentials.

Density functional theory calculations are robust tools to explore the mechanical properties of pristine structures at their ground state but become exceedingly expensive for large systems at finite temperatures. Classical molecular dynamics (CMD) simulations offer the possibility to study larger systems at elevated temperatures, but they require accurate interatomic potentials. Herein the authors propose the concept of first-principles multiscale modeling of mechanical properties, where ab initio level of accuracy is hierarchically bridged to explore the mechanical/failure response of macroscopic systems.

A Multiscale Investigation on the Thermal Transport in Polydimethylsiloxane Nanocomposites: Graphene vs. Borophene.

Graphene and borophene are highly attractive two-dimensional materials with outstanding physical properties. In this study we employed combined atomistic continuum multi-scale modeling to explore the effective thermal conductivity of polymer nanocomposites made of polydimethylsiloxane (PDMS) polymer as the matrix and graphene and borophene as nanofillers. PDMS is a versatile polymer due to its chemical inertia, flexibility and a wide range of properties that can be tuned during synthesis.

Exploration of mechanical, thermal conductivity and electromechanical properties of graphene nanoribbon springs.

Recent experimental advances [Liu , , 2019, , 23] propose the design of graphene nanoribbon springs (GNRSs) to substantially enhance the stretchability of pristine graphene. A GNRS is a periodic undulating graphene nanoribbon, where undulations are of sinus or half-circle or horseshoe shapes. Besides this, the GNRS geometry depends on design parameters, like the pitch's length and amplitude, thickness and joining angle.

Evaluation of the efficiency of various force configurations on scoliotic, lordotic and kyphotic curves in the subjects with scoliosis.

Background: The efficiency of the braces designed for scoliotic subjects depends on configurations and also magnitudes of the forces used to stabilize and correct scoliotic curve. However, the effects of various force configurations on the spinal curves in sagittal plane should also be considered. The aim of this study was to determine the efficiency of various force configurations on scoliotic, lordotic and kyphotic curves.

An evaluation of the efficiency of endpoint control on the correction of scoliotic curve with brace. A case study.

Purpose: The use of braces is one of the conservative treatment approaches recommended for scoliotic subjects. However, the main question posted here is how to improve the efficiency of braces to control the scoliotic curve or to decrease its progression. The aim of this study was to evaluate the efficiency of various boundary conditions (endpoint control) of brace on the correction of scoliotic curves.

Sensitivity analysis for the mechanics of tendons and ligaments: Investigation on the effects of collagen structural properties via a multiscale modeling approach.

The effects of the stochasticity of collagen-related structural properties on the biomechanical properties of tendons and ligaments are investigated in this study. The tissue mechanics is modeled by means of a macroscale constitutive model based on a multiscale structural approach. This rationale allows to introduce model parameters directly associated with tissue structural and biochemical features, opening to physically motivated parametric studies.

Evaluation of the efficiency of Boston brace on scoliotic curve control: A review of literature.

Bracing is one of the most important treatment approaches that have been utilized in patients with scoliosis. Boston brace used to manage a scoliotic curve especially in lumbar and thoracolumbar areas. The aim of this review was to evaluate the efficiency of Boston brace to control the progression of the curve based on the available literature.

A nanoscale study of the negative strain rate dependency of the strength of metallic glasses by molecular dynamics simulations.

Compressive strength and deformation characteristics of a metallic glassy alloy related to strain rate are studied by molecular dynamics simulations. The negative strain rate dependency of strength is presented, i.e.

The effect of plaque eccentricity on blood hemodynamics and drug release in a stented artery.

Atherosclerosis in the coronary arteries is one of the leading causes of death in the world. Percutaneous coronary interventions (PCI) associated with the implantation of drug eluting stents (DES) is one of the most common forms of revascularization in patients with atherosclerotic coronary artery disease. The use of DES is considered as an effective tool to reduce restenosis after PCI.

Scoliosis conservative treatment: A review of literature.

Background: Scoliosis is defined as lateral curvature of the spine which is also associated with a change in the curves in sagittal plane and vertebral rotation. Various types of conservative treatment approaches have been recommended for the patients with scoliosis. The aim of this review article was to introduce the various methods of conservative treatment which can be used for the patients with scoliosis.

Borophene hydride: a stiff 2D material with high thermal conductivity and attractive optical and electronic properties.

Two-dimensional (2D) structures of boron atoms, so-called borophene, have recently attracted remarkable attention. In a recent exciting experimental study, a hydrogenated borophene structure was realized. Motivated by this success, we conducted extensive first-principles calculations to explore the mechanical, thermal conduction, electronic and optical responses of borophene hydride.

Evaluation of the efficiency of the Chêneau brace on scoliosis deformity : A systematic review of the literature.

Background: Scoliosis is a three-dimensional deformity of the spine and rib cage. Depending on the severity of this disease, various kinds of treatment methods have been used and bracing is among the most common. One of the braces which has been used for subjects with scoliosis is the Chêneau brace.

Thermal and electronic transport characteristics of highly stretchable graphene kirigami.

For centuries, cutting and folding papers with special patterns have been used to build beautiful, flexible and complex three-dimensional structures. Inspired by the old idea of kirigami (paper cutting), and the outstanding properties of graphene, recently graphene kirigami structures were fabricated to enhance the stretchability of graphene. However, the possibility of further tuning the electronic and thermal transport along the 2D kirigami structures has remained original to investigate.

A mechanistic model for drug release from PLGA-based drug eluting stent: A computational study.

Atherosclerosis in the coronary artery is one of the leading causes of death in the world. The stenting as a minimally invasive technique was considered as an effective tool to reduce the severity of atherosclerotic stenosis. In-stent restenosis is the main drawback of the stenting in the coronary artery.

Anisotropic mechanical and optical response and negative Poisson's ratio in MoC nanomembranes revealed by first-principles simulations.

Transition metal carbides include a wide variety of materials with attractive properties that are suitable for numerous and diverse applications. A most recent experimental advance could provide a path toward the successful synthesis of large-area and high-quality ultrathin MoC membranes with superconducting properties. In the present study, we used first-principles density functional theory calculations to explore the mechanical and optical response of single-layer and free-standing MoC.

Electrical and Thermal Transport in Coplanar Polycrystalline Graphene-hBN Heterostructures.

We present a theoretical study of electronic and thermal transport in polycrystalline heterostructures combining graphene (G) and hexagonal boron nitride (hBN) grains of varying size and distribution. By increasing the hBN grain density from a few percent to 100%, the system evolves from a good conductor to an insulator, with the mobility dropping by orders of magnitude and the sheet resistance reaching the MΩ regime. The Seebeck coefficient is suppressed above 40% mixing, while the thermal conductivity of polycrystalline hBN is found to be on the order of 30-120 Wm K.

Thermal conductivity of graphene nanoribbons under shear deformation: A molecular dynamics simulation.

Tensile strain and compress strain can greatly affect the thermal conductivity of graphene nanoribbons (GNRs). However, the effect of GNRs under shear strain, which is also one of the main strain effect, has not been studied systematically yet. In this work, we employ reverse nonequilibrium molecular dynamics (RNEMD) to the systematical study of the thermal conductivity of GNRs (with model size of 4 nm × 15 nm) under the shear strain.

A structural insight into mechanical strength of graphene-like carbon and carbon nitride networks.

Graphene, one of the strongest materials ever discovered, triggered the exploration of many 2D materials in the last decade. However, the successful synthesis of a stable nanomaterial requires a rudimentary understanding of the relationship between its structure and strength. In the present study, we investigate the mechanical properties of eight different carbon-based 2D nanomaterials by performing extensive density functional theory calculations.

The influence of atherosclerotic plaques on the pharmacokinetics of a drug eluted from bioabsorbable stents.

In this paper the effect of plaque composition, on the accumulation of drug released by a drug eluting stent, is analyzed. The mathematical model is represented by two coupled systems of partial differential equations that describe the pharmacokinetics of drug in the stent coating and in the arterial wall. The influence of the stiffness and porosity of soft and hard plaques is studied.