YuanTong Gu

Bio: YuanTong Gu is an academic researcher from Queensland University of Technology. The author has contributed to research in topics: Finite element method & Meshfree methods. The author has an hindex of 52, co-authored 550 publications receiving 12583 citations. Previous affiliations of YuanTong Gu include Nanjing Medical University & National University of Singapore.

Determination of strain-rate-dependent mechanical behavior of living and fixed osteocytes and chondrocytes using atomic force microscopy and inverse finite element analysis

Abstract: The aim of this paper is to determine the strain-rate-dependent mechanical behavior of living and fixed osteocytes and chondrocytes, in vitro Firstly, Atomic Force Microscopy (AFM) was used to obtain the force-indentation curves of these single cells at four different strain-rates These results were then employed in inverse finite element analysis (FEA) using Modified Standard neo-Hookean Solid (MSnHS) idealization of these cells to determine their mechanical properties In addition, a FEA model with a newly developed spring element was employed to accurately simulate AFM evaluation in this study We report that both cytoskeleton (CSK) and intracellular fluid govern the strain-rate-dependent mechanical property of living cells whereas intracellular fluid plays a predominant role on fixed cells’ behavior In addition, through the comparisons, it can be concluded that osteocytes are stiffer than chondrocytes at all strain-rates tested indicating that the cells could be the biomarker of their tissue origin Finally, we report that MSnHS is able to capture the strain-rate-dependent mechanical behavior of osteocyte and chondrocyte for both living and fixed cells Therefore, we concluded that the MSnHS is a good model for exploration of mechanical deformation responses of single osteocytes and chondrocytes This study could open a new avenue for analysis of mechanical behavior of osteocytes and chondrocytes as well as other similar types of cells

Deformation of a single red blood cell in a microvessel

Abstract: Red blood cells (RBCs) are the most common type of cells in human blood and they exhibit different types of motions and deformed shapes in capillary flows. The behaviour of the RBCs should be studied in order to explain the RBC motion and deformation mechanism. This article presents a numerical simulation method for RBC deformation in microvessels. A two dimensional spring network model is used to represent the RBC membrane, where the elastic stretch/compression energy and the bending energy are considered with the constraint of constant RBC surface area. The forces acting on the RBC membrane are obtained from the principle of virtual work. The whole fluid domain is discretized into a finite number of particles using smoothed particle hydrodynamics concepts and the motions of all the particles are solved using Navier--Stokes equations. Minimum energy concepts are used to simulate the deformed shape of the RBC model. To verify the model, the motion of a single RBC is simulated in a Poiseuille flow and the characteristic parachute shape of the RBC is observed. Further simulations reveal that the RBC shows a tank treading motion when it flows in a linear shear flow. References D. A. Fedosov, B. Caswell, and G. E. Karniadakis. A multiscale red blood cell model with accurate mechanics, rheology, and dynamics. Biophys. J. , 98(10):2215–2225, 2010. doi:10.1016/j.bpj.2010.02.002 T. M. Fischer, M. Stohr-Lissen, and H. Schmid-Schonbein. The red cell as a fluid droplet: tank tread-like motion of the human erythrocyte membrane in shear flow. Science , 202(4370):894–896, 1978. doi:10.1126/science.715448 R. A. Frcitas. Exploratory design in medical nanotechnology: a mechanical artificial red cell. Artif. Cell. Blood. Sub. , 26(4):411–430, 1998. doi:10.3109/10731199809117682 H. N. P. Gallage, Y. T. Gu, S. C. Saha, W. Senadeera, and A. Oloyede. Numerical simulation of red blood cells' deformation using SPH method. In Y. T. Gu and S. C. Saha, editors, 4th International Conference on Computational Methods (ICCM 2012) , Crowne Plaza, Gold Coast, QLD, November 2012. H. N. P. Gallage, Y. T. Gu, S. C. Saha, W. Senadeera, and A. Oloyede. Numerical simulation of red blood cells' motion : a review. In Y. T. Gu and S. C. Saha, editors, 4th International Conference on Computational Methods (ICCM 2012) , Crowne Plaza, Gold Coast, QLD, November 2012. Y. T. Gu. Meshfree methods and their comparisons. Int. J. Comput. Meth. , 2(04):477–515, 2005. doi:10.1142/S0219876205000673 D. V. Le, J. White, J. Peraire, K. M. Lim, and B. C. Khoo. An implicit immersed boundary method for three-dimensional fluid–membrane interactions. J. Comput. Phys. , 228(22):8427–8445, 2009. doi:10.1016/j.jcp.2009.08.018 G. R. Liu and Y. T. Gu. An introduction to meshfree methods and their programming . Springer, 2005. G. R. Liu and M. B. Liu. Smoothed particle hydrodynamics: a meshfree particle method . World Scientific, 2003. doi:10.1142/5340 T. W. Pan and T. Wang. Dynamical simulation of red blood cell rheology in microvessels. Int. J. Numer. Anal. Mod. , 6:455–473, 2009. L. Shi, T. W. Pan, and R. Glowinski. Deformation of a single red blood cell in bounded Poiseuille flows. Phys. Rev. E , 85(1):016307, 2012. doi:10.1103/PhysRevE.85.016307 C. Sun and L. L. Munn. Particulate nature of blood determines macroscopic rheology: a 2-D lattice Boltzmann analysis. Biophys. J. , 88(3):1635–1645, 2005. doi:10.1529/biophysj.104.051151 K. I. Tsubota, S. Wada, and T. Yamaguchi. Particle method for computer simulation of red blood cell motion in blood flow. Comput. Meth. Prog. Bio. , 83(2):139–146, 2006. doi:10.1016/j.cmpb.2006.06.005 K. I. Tsubota, S. Wada, and T. Yamaguchi. Simulation study on effects of hematocrit on blood flow properties using particle method. J. Biomech. Sci. Eng. , 1(1):159–170, 2006. doi:10.1299/jbse.1.159 A. Vadapalli, D. Goldman, and A. S. Popel. Calculations of oxygen transport by red blood cells and hemoglobin solutions in capillaries. Artif. Cell. Blood. Sub. , 30(3):157–188, 2002. doi:10.1081/BIO-120004338

Deformation Properties of Single Red Blood Cell in a Stenosed Microchannel

Abstract: Red Blood Cells (RBCs) exhibit different types of motions and different deformed shapes, when they move through capillaries. RBCs can travel through capillaries having smaller diameters than RBCs’ diameter, due to the capacity of high deformability of the viscoelastic RBC membrane. The motion and the steady state shape of the RBCs depend on many factors, such as the geometrical parameters of the microvessel through which blood flows, the RBC membrane bending stiffness and the flow velocity. In this study, the effect of the RBC’s membrane stiffness on the deformation of a single RBC in a stenosed capillary is comprehensively examined. Smoothed Particle Hydrodynamics (SPH) in combination with the two-dimensional spring network membrane model is used to investigate the motion and the deformation property of the RBC. The simulation results demonstrate that the membrane bending stiffness of the RBC has a significant impact on the RBCs’ deformability.

Tensile properties of graphene-nanotube hybrid structures: a molecular dynamics study

Abstract: Graphene has been reported with record-breaking properties which have opened up huge potential applications. A considerable research has been devoted to manipulate or modify the properties of graphene to target a more smart nanoscale device. Graphene and carbon nanotube hybrid structure (GNHS) is one of the promising graphene derivates, while their mechanical properties have been rarely discussed in literature. Therefore, such a studied is conducted in this paper basing on the large-scale molecular dynamics simulation. The target GNHS is constructed by considering two separate graphene layers that being connected by single-wall carbon nanotubes (SWCNTs) according to the experimental observations. It is found that the GNHSs exhibit a much lower yield strength, Young’s modulus, and earlier yielding comparing with a bilayer graphene sheet. Fracture of studied GNHSs is found to fracture located at the connecting region between carbon nanotubes (CNTs) and graphene. After failure, monatomic chains are normally observed at the front of the failure region, and the two graphene layers at the failure region without connecting CNTs will adhere to each other, generating a bilayer graphene sheet scheme (with a layer distance about 3.4 A). This study will enrich the current understanding of the mechanical performance of GNHS, which will guide the design of GNHS and shed lights on its various applications.

Atomistic exploration of deformation properties of copper nanowires with pre-existing defects

Abstract: Free to read full-text Based on the embedded atom method (EAM) and molecular dynamics (MD) method, in this paper, the tensile deformation properties of Cu nanowires (NWs) with different pre-existing defects, including single surface defects, surface bi-defects and single internal defects, are systematically studied. In-depth deformation mechanisms of NWs with pre-existing defects are also explored. It is found that Young's modulus is insensitive to different pre-existing defects, but yield strength shows an obvious decrease. Defects are observed influencing greatly on NWs' tensile deformation mechanisms, and playing a role of dislocation sources. Besides of the traditional deformation process dominated by the nucleation and propagation of partial dislocations, the generations of twins, grain boundaries, fivefold deformation twins, hexagonal close-packed (HCP) structure and phase transformation from face-centred cubic (FCC) structure to HCP structure have been triggered by pre-existing defects. It is found that surface defect intends to induce larger influence to yield strength than internal defect. Most importantly, the defect that lies on slip planes exerts larger influence than other defects. As expected, it is also found that the more or longer of the defect, the bigger influence will be induced.

I and i

Abstract: There is, I think, something ethereal about i —the square root of minus one. I remember first hearing about it at school. It seemed an odd beast at that time—an intruder hovering on the edge of reality. Usually familiarity dulls this sense of the bizarre, but in the case of i it was the reverse: over the years the sense of its surreal nature intensified. It seemed that it was impossible to write mathematics that described the real world in …

Fast parallel algorithms for short-range molecular dynamics

Abstract: Three parallel algorithms for classical molecular dynamics are presented. The first assigns each processor a fixed subset of atoms; the second assigns each a fixed subset of inter-atomic forces to compute; the third assigns each a fixed spatial region. The algorithms are suitable for molecular dynamics models which can be difficult to parallelize efficiently—those with short-range forces where the neighbors of each atom change rapidly. They can be implemented on any distributed-memory parallel machine which allows for message-passing of data between independently executing processors. The algorithms are tested on a standard Lennard-Jones benchmark problem for system sizes ranging from 500 to 100,000,000 atoms on several parallel supercomputers--the nCUBE 2, Intel iPSC/860 and Paragon, and Cray T3D. Comparing the results to the fastest reported vectorized Cray Y-MP and C90 algorithm shows that the current generation of parallel machines is competitive with conventional vector supercomputers even for small problems. For large problems, the spatial algorithm achieves parallel efficiencies of 90% and a 1840-node Intel Paragon performs up to 165 faster than a single Cray C9O processor. Trade-offs between the three algorithms and guidelines for adapting them to more complex molecular dynamics simulations are also discussed.

Mitigation and Adaptation Strategies for Global Change

Abstract: ▶ Addresses a wide range of timely environment, economic and energy topics ▶ A forum to review, analyze and stimulate the development, testing and implementation of mitigation and adaptation strategies at regional, national and global scales ▶ Contributes to real-time policy analysis and development as national and international policies and agreements are discussed and promulgated ▶ 94% of authors who answered a survey reported that they would definitely publish or probably publish in the journal again