scholarly journals Growth of tumor emboli within a vessel model reveals dependence on the magnitude of mechanical constraint

2021 ◽  
Vol 13 (1) ◽  
pp. 1-16
Author(s):  
Jonathan Kulwatno ◽  
Jamie Gearhart ◽  
Xiangyu Gong ◽  
Nora Herzog ◽  
Matthew Getzin ◽  
...  
Keyword(s):  
Elastic Modulus ◽  
Tumor Cell ◽  
Tumor Burden ◽  
Cell Aggregates ◽  
Continuous Growth ◽  
Soft Matrix ◽  
The Matrix ◽  
Tumor Emboli ◽  
Constraint Model ◽  
Mechanical Constraint

ABSTRACT Tumor emboli—aggregates of tumor cells within vessels—pose a clinical challenge as they are associated with increased metastasis and tumor recurrence. When growing within a vessel, tumor emboli are subject to a unique mechanical constraint provided by the tubular geometry of the vessel. Current models of tumor emboli use unconstrained multicellular tumor spheroids, which neglect this mechanical interplay. Here, we modeled a lymphatic vessel as a 200 μm-diameter channel in either a stiff or soft, bioinert agarose matrix to create a vessel-like constraint model (VLCM), and we modeled colon or breast cancer tumor emboli with aggregates of HCT116 or SUM149PT cells, respectively. The stiff matrix VLCM constrained the tumor emboli to the cylindrical channel, which led to continuous growth of the emboli, in contrast to the growth rate reduction that unconstrained spheroids exhibit. Emboli morphology in the soft matrix VLCM, however, was dependent on the magnitude of mechanical mismatch between the matrix and the cell aggregates. In general, when the elastic modulus of the matrix of the VLCM was greater than the emboli (EVLCM/Eemb > 1), the emboli were constrained to grow within the channel, and when the elastic modulus of the matrix was less than the emboli (0 < EVLCM/Eemb < 1), the emboli bulged into the matrix. Due to a large difference in myosin II expression between the cell lines, we hypothesized that tumor cell aggregate stiffness is an indicator of cellular force-generating capability. Inhibitors of myosin-related force generation decreased the elastic modulus and/or increased the stress relaxation of the tumor cell aggregates, effectively increasing the mechanical mismatch. The increased mechanical mismatch after drug treatment was correlated with increased confinement of tumor emboli growth along the channel, which may translate to increased tumor burden due to the increased tumor volume within the diffusion distance of nutrients and oxygen.

scholarly journals Growth of tumor emboli within a vessel model reveals dependence on the magnitude of mechanical constraint

2020 ◽  
Author(s):  
Jonathan Kulwatno ◽  
Jamie Gearhart ◽  
Xiangyu Gong ◽  
Nora Herzog ◽  
Matthew Getzin ◽  
...  
Keyword(s):  
Elastic Modulus ◽  
Tumor Cell ◽  
Cancer Progression ◽  
Tumor Burden ◽  
Cell Aggregates ◽  
Continuous Growth ◽  
The Matrix ◽  
Tumor Emboli ◽  
Growth Of Tumor ◽  
Mechanical Constraint

ABSTRACTTumor emboli – aggregates of tumor cell within vessels – pose a clinical challenge as they are associated with increased metastasis and tumor recurrence. When growing within a vessel, tumor emboli are subject to a unique mechanical constraint provided by the tubular geometry of the vessel. Current models of tumor emboli use unconstrained multicellular tumor spheroids, which neglect this mechanical interplay. Here, we modelled a lymphatic vessel as a 200 μm-diameter channel in either a stiff or soft, bioinert agarose matrix, and we modelled colon or breast cancer tumor emboli with aggregates of HCT116 or SUM149PT cells, respectively. The stiff vessel model constrained the tumor emboli to the cylindrical geometry, which led to continuous growth of the emboli, in contrast to the growth plateau that unconstrained spheroids exhibit. Emboli morphology in the soft vessel model, however, was dependent on the magnitude of mechanical mismatch between the vessel matrix and the cell aggregates. In general, when the elastic modulus of the vessel was greater than the emboli (Eves / Eemb > 1), the emboli were constrained to grow within the vessel geometry, and when the elastic modulus of the vessel was less than the emboli (0 < Eves / Eemb < 1), the emboli bulged into the matrix. Inhibitors of myosin-related force generation decreased the elastic modulus and/or increased the stress relaxation of the tumor cell aggregates, effectively increasing the mechanical mismatch. The increased mechanical mismatch after drug treatment was correlated with increased confinement of tumor emboli growth along the vessel, which may translate to increased tumor burden due to the increased tumor volume within the diffusion distance of nutrients and oxygen.INSIGHT BOXThe growth of tumor emboli—aggregates of tumor cells within vessels—is associated with aggressive cancer progression and metastasis. Models of their growth have not taken into account their biomechanical context, where radial expansion is constrained, but lengthwise expansion is free in the vessel. Here, we modelled the vessel geometry with a cylindrical microchannel in a hydrogel. In contrast to unconstrained or fully embedded aggregates, vessel-like constraint promotes growth of emboli in our model. The growth advantage is increased when the matrix is stiffened or actomyosin contractility weakened, both of which effectively increase the magnitude of mechanical constraint. This study sheds light on increased tumor burden in vessel-based growth and indicates a need to study tumor progression in similar environments.

scholarly journals Influence of Alumina Nanofibers Sintered by the Spark Plasma Method on Nickel Mechanical Properties

Metals ◽  
2021 ◽  
Vol 11 (4) ◽  
pp. 548 ◽  
Author(s):  
Leonid Agureev ◽  
Valeriy Kostikov ◽  
Zhanna Eremeeva ◽  
Svetlana Savushkina ◽  
Boris Ivanov ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Tensile Strength ◽  
Elastic Modulus ◽  
Strength Properties ◽  
Alumina Nanoparticles ◽  
Metal Powders ◽  
Wide Range ◽  
The Matrix ◽  
Spark Plasma ◽  
Average Size

The article presents the study of alumina nanoparticles’ (nanofibers) concentration effect on the strength properties of pure nickel. The samples were obtained by spark plasma sintering of previously mechanically activated metal powders. The dependence of the grain size and the relative density of compacts on the number of nanofibers was investigated. It was found that with an increase in the concentration of nanofibers, the average size of the matrix particles decreased. The effects of the nanoparticle concentration (0.01–0.1 wt.%) on the elastic modulus and tensile strength were determined for materials at 25 °C, 400 °C, and 750 °C. It was shown that with an increase in the concentration of nanofibers, a 10–40% increase in the elastic modulus and ultimate tensile strength occurred. A comparison of the mechanical properties of nickel in a wide range of temperatures, obtained in this work with materials made by various technologies, is carried out. A description of nanofibers’ mechanisms of influence on the structure and mechanical properties of nickel is given. The possible impact of impurity phases on the properties of nickel is estimated. The tendency of changes in the mechanical properties of nickel, depending on the concentration of nanofibers, is shown.

scholarly journals Wear Resistance of TiC Reinforced Cast Steel Matrix Composite

2017 ◽  
Vol 17 (1) ◽  
pp. 143-146 ◽  
Author(s):  
S. Sobula ◽  
E. Olejnik ◽  
T. Tokarski
Keyword(s):  
Wear Resistance ◽  
Matrix Composite ◽  
Base Alloy ◽  
Cast Steel ◽  
Composite Layer ◽  
Wear Loss ◽  
Steel Matrix ◽  
Soft Matrix ◽  
Base Steel ◽  
The Matrix

Abstract Wear resistance of TiC-cast steel metal matrix composite has been investigated. Composites were obtained with SHSB method known as SHS synthesis during casting. It has been shown the differences in wear between composite and base cast steel. The Miller slurry machine test were used to determine wear loss of the specimens. The slurry was composed of SiC and water. The worn surface of specimens after test, were studied by SEM. Experimental observation has shown that surface of composite zone is not homogenous and consist the matrix lakes. Microscopic observations revealed the long grooves with SiC particles indented in the base alloy area, and spalling pits in the composite area. Due to the presence of TiC carbides on composite layer, specimens with TiC reinforced cast steel exhibited higher abrasion resistance. The wear of TiC reinforced cast steel mechanism was initially by wearing of soft matrix and in second stage by polishing and spalling of TiC. Summary weight loss after 16hr test was 0,14÷0,23 g for composite specimens and 0,90 g for base steel.

Fabrication and Mechanical Properties of Dense/Porous β-Tricalcium Phosphate Bioceramics

2007 ◽  
Vol 330-332 ◽  
pp. 907-910
Author(s):  
Fa Ming Zhang ◽  
Jiang Chang ◽  
Jian Xi Lu ◽  
Kai Li Lin
Keyword(s):  
Mechanical Properties ◽  
Compressive Strength ◽  
Elastic Modulus ◽  
Exponential Growth ◽  
Weight Bearing ◽  
Area Ratio ◽  
Sectional Area ◽  
Cross Sectional ◽  
The Matrix ◽  
Porous Bioceramics

Attempt to increase the mechanical properties of porous bioceramics, a dense/porous structured β-TCP bioceramics that mimic the characteristics of nature bone were fabricated. Experimental results show that the dense/porous structured β-TCP bioceramics demonstrated excellent mechanical properties with compressive strength up to 74 MPa and elastic modulus up to 960 MPa, which could be tailored by the dense/porous cross-sectional area ratio obeying the rule of exponential growth. The interface between the dense and porous bioceramics is connected compactly and tightly with some micropores distributed in the matrix of both porous and dense counterparts. The dense/porous structure of β-TCP bioceramics may provide an effective way to increase the mechanical properties of porous bioceramics for bone regeneration at weight bearing sites.

FORC analysis of magnetically soft microparticles embedded in a polymeric elastic environment

2022 ◽  
Author(s):  
Dmitry Yu Borin ◽  
Mikhail V Vaganov
Keyword(s):  
Particle Concentration ◽  
Magnetic Hysteresis ◽  
Magnetic Response ◽  
Soft Matrix ◽  
First Order ◽  
Matrix Elasticity ◽  
Intrinsic Coercivity ◽  
The Matrix ◽  
Soft Particles ◽  
Elastomer Composites

Abstract First-order reversal curve (FORC) analysis allows one to investigate composite magnetic materials by decomposing the magnetic response of a whole sample into individual responses of the elementary objects comprising the sample. In this work, we apply this technique to analysing silicone elastomer composites reinforced with ferromagnetic microparticles possessing low intrinsic coercivity. Even though the material of such particles does not demonstrate significant magnetic hysteresis, the soft matrix of the elastomers allows for the translational mobility of the particles and enables their magnetomechanical hysteresis which renders into a wasp-waisted major magnetization loop of the whole sample. It is demonstrated that the FORC diagrams of the composites contain characteristic wing features arising from the collective hysteretic magnetization of the magnetically soft particles. The influence of the matrix elasticity and particle concentration on the shape of the wing feature is investigated, and an approach to interpreting experimental FORC diagrams of the magnetically soft magnetoactive elastomers is proposed. The experimental data are in qualitative agreement with the results of the simulation of the particle magnetization process obtained using a model comprised of two magnetically soft particles embedded in an elastic environment.

scholarly journals Pulmonary micro-tumor emboli resulting in paradoxical emboli: a case report

2018 ◽  
Vol 8 (2) ◽  
pp. 204589321875485
Author(s):  
Louis-Vincent Morin-Thibault ◽  
Daniel Wiseman ◽  
Michelle Fortin ◽  
Christian Couture ◽  
Steeve Provencher
Keyword(s):  
Breast Cancer ◽  
Case Report ◽  
Tumor Cell ◽  
Pulmonary Vascular Resistance ◽  
Recurrent Breast Cancer ◽  
Pulmonary Tumor ◽  
Rare Manifestation ◽  
Paradoxical Emboli ◽  
Recurrent Breast ◽  
Tumor Emboli

Pulmonary tumor embolism (PTE) is a rare manifestation of cancer. It is characterized by the presence of tumor cell emboli in the pulmonary arterioles and capillaries leading to an elevation of pulmonary vascular resistance. The ante-mortem diagnosis is difficult. We report a case of PTE associated with recurrent breast cancer that presented with neurological symptoms due to paradoxical cerebral embolism.

Modeling matrix fracture in fiber-reinforced ceramic-matrix composites with different fiber preforms

2019 ◽  
Vol 90 (7-8) ◽  
pp. 909-924 ◽  
Author(s):  
Longbiao Li
Keyword(s):  
Elastic Modulus ◽  
Ceramic Matrix Composites ◽  
Interface Debonding ◽  
Matrix Composites ◽  
Multiple Fracture ◽  
Fiber Volume ◽  
Interface Shear ◽  
Interface Shear Stress ◽  
The Matrix ◽  
Fiber Preforms

In this paper, the stress-dependent matrix multiple fracture in silicon carbide fiber-reinforced ceramic-matrix composites with different fiber preforms is investigated. The critical matrix strain energy criterion is used to determine the matrix multiple fracture considering the interface debonding. The effects of the fiber radius, fiber elastic modulus, matrix elastic modulus, fiber volume, interface shear stress, and interface debonded energy on the matrix multiple fracture and the interface debonding are analyzed. The experimental matrix multiple cracking and interface debonding of minicomposite, unidirectional, and two-dimensional woven SiC/SiC composites with different fiber volumes and interphases are predicted. The matrix cracking density increases with the increasing of the fiber volume, fiber elastic modulus, interface shear stress, and interface debonded energy, and the decreasing of the fiber radius and matrix elastic modulus.

Study on the Effects of the Nonhomogeneous Material Properties on the Structure Strength of the Induction Quenched Crankshaft

2014 ◽  
Vol 703 ◽  
pp. 400-405
Author(s):  
Ji Shan Li ◽  
Ri Dong Liao ◽  
Guo Hua Chen
Keyword(s):  
Elastic Modulus ◽  
Material Properties ◽  
Fem Model ◽  
Explosion Pressure ◽  
Nonhomogeneous Material ◽  
Linear Rule ◽  
Distribution Rule ◽  
The Matrix ◽  
Nonhomogeneous Properties ◽  
Structure Strength

To study the effects of the nonhomogeneous material properties on the stress in an induction quenched crankshaft, the FEM model considering the nonhomogeneous material properties was established to simulate the stress in the crankshaft under the explosion pressure. Results showed that the nonhomogeneous properties almost didn’t vary the Mises stress distribution rule in the crankshaft. The maximum Mises stress, the ratio of the elastic modulus of the surface layer and the matrix followed a linear rule nearly. Moreover, the maximum Mises stress increased with the ratio. Besides, effect of elastic modulus distribution in the transition layer on the maximum stress could be ignored. To simplify the establishment of the FEM model, the elastic modulus could be set to either equal to the surface layer’s or the matrix’s.

Magnetorheological Elastomers With Increased Structural Integrity for Multifunction Applications

2007 ◽  
Author(s):  
Zelalem Aga ◽  
Dan Feimster ◽  
LeAnn Faidley
Keyword(s):  
Elastic Modulus ◽  
Vibration Isolation ◽  
Structural Integrity ◽  
Effective Elastic Modulus ◽  
Zero Field ◽  
Magnetorheological Elastomers ◽  
The Matrix ◽  
Cure Temperature ◽  
Vibration Tests ◽  
Novel Applications

Magnetorheological Elastomers (MREs) are composite materials formed of a soft elastomer matrix and a magnetic-powder filler. The interaction of the matrix and filler in a magnetic field causes the effective elastic modulus of the MRE to be controllable by an external field. In previous studies the applications of MREs have been severely limited by their lack of structural integrity, forcing them to be applied only as soft pads or as the filler in sandwich beams. This study represents initial steps towards improving the structural integrity of MREs while retaining some level of modulus variability. Specimens are made from Sylgard 184 Silicone with a variety of cure temperatures and filler volume percentages. Longitudinal swept-sine vibration tests are performed to measure the dependence of elastic modulus on applied fields of up to 40 kA/m. It is found that the softer specimen (ie: the lowest cure temperature) with 27% percent filler exhibits the largest percent change in effective modulus of almost 40%. The zero-field modulus for this specimen is 5.7 MPa giving it the structural integrity needed for multifunction applications in which the material is both active and load bearing. Many novel applications exist including active modulus control of sound radiating plates, novel design of vibration isolation tables, and more.

Preliminary Study on Deformation and Recrystallization Behavior of Pure Tin for Mitigation of Whisker Growth

2018 ◽  
Vol 273 ◽  
pp. 107-111 ◽  
Author(s):  
Noriyuki Kuwano ◽  
Marina Binti Lias ◽  
Nur Azmah Binti Nordin ◽  
Youhei Soejima ◽  
Ahmad Rafiqan bin Nayan
Keyword(s):  
Growth Process ◽  
Room Temperature ◽  
Whisker Growth ◽  
Recrystallization Behavior ◽  
Sn Whisker ◽  
Continuous Growth ◽  
Stable Boundary ◽  
The Matrix ◽  
Small Grains ◽  
Preliminary Study

Since the mechanism of Sn-whisker growth is closely related with the behavior of deformation and recrystallization, understanding of the behavior is very important to establish the measure for mitigation of whisker growth. In this work, microstructural changes after heavy deformation by scratching were characterized by EBSD for a single crystal of β-Sn, and the following results were obtained. Three types of crystal grains appear immediately after the deformation; small grains in aggregation, large serrated grains and rim-grains. The small grains are considered to be formed by dynamic recrystallization. They continue to grow at a room temperature over a lengthy period of time. The large grain has a certain crystallographic relationship with the matrix where <100> axes of the large grain and the matrix are almost parallel to each other. The serrated boundaries of large grain are so stable that the large grain does not show a grain growth process. The stable boundary is considered to promote a continuous growth of whiskers.

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