scholarly journals Viscoelastic properties of ECM-rich embryonic microenvironments

2019 ◽  
Author(s):  
Zsuzsa Akos ◽  
Dona G. Isai ◽  
Sheeja Rajasingh ◽  
Edina Kosa ◽  
Saba Ghazvini ◽  
...  
Keyword(s):  
Material Properties ◽  
Viscoelastic Properties ◽  
Viscoelastic Behavior ◽  
Characteristic Relaxation Time ◽  
Solid Model ◽  
Mechanical State ◽  
Total Response ◽  
Rich Region ◽  
Embryonic Tissues ◽  
Nickel Particles

AbstractThe material properties of tissues and their mechanical state is an important factor during development, disease, regenerative medicine and tissue engineering. Here we describe a microrheological measurement technique utilizing aggregates of microinjected ferromagnetic nickel particles to probe the viscoelastic properties of embryonic tissues. Quail embryos were cultured in a plastic incubator chamber located at the center of two pairs of crossed electromagnets. We estimate the Young’s modulus of the ECM-rich region separating the mesoderm and endoderm in Hamburger Hamilton stage 6-10 quail embryos as 300±100 Pa. We found a pronounced viscoelastic behavior consistent with a Zener (standard generalized solid) model. The viscoelastic response is about 45% of the total response, with a characteristic relaxation time of 1.3 sec.

scholarly journals 3D Plotting of Silica/Collagen Xerogel Granules in an Alginate Matrix for Tissue-Engineered Bone Implants

Materials ◽  
2021 ◽  
Vol 14 (4) ◽  
pp. 830
Author(s):  
Sina Rößler ◽  
Andreas Brückner ◽  
Iris Kruppke ◽  
Hans-Peter Wiesmann ◽  
Thomas Hanke ◽  
...  
Keyword(s):  
Additive Manufacturing ◽  
Bone Regeneration ◽  
Material Properties ◽  
Viscoelastic Properties ◽  
Viscoelastic Behavior ◽  
Matrix Phase ◽  
Patient Specific ◽  
Active Player ◽  
Alginate Concentration ◽  
Alginate Matrix

Today, materials designed for bone regeneration are requested to be degradable and resorbable, bioactive, porous, and osteoconductive, as well as to be an active player in the bone-remodeling process. Multiphasic silica/collagen Xerogels were shown, earlier, to meet these requirements. The aim of the present study was to use these excellent material properties of silica/collagen Xerogels and to process them by additive manufacturing, in this case 3D plotting, to generate implants matching patient specific shapes of fractures or lesions. The concept is to have Xerogel granules as active major components embedded, to a large proportion, in a matrix that binds the granules in the scaffold. By using viscoelastic alginate as matrix, pastes of Xerogel granules were processed via 3D plotting. Moreover, alginate concentration was shown to be the key to a high content of irregularly shaped Xerogel granules embedded in a minimum of matrix phase. Both the alginate matrix and Xerogel granules were also shown to influence viscoelastic behavior of the paste, as well as the dimensionally stability of the scaffolds. In conclusion, 3D plotting of Xerogel granules was successfully established by using viscoelastic properties of alginate as matrix phase.

Properties of Mouse Cutaneous Rapidly Adapting Afferents: Relationship to Skin Viscoelasticity

2004 ◽  
Vol 92 (2) ◽  
pp. 1236-1240 ◽  
Author(s):  
P. Grigg ◽  
D. R. Robichaud ◽  
Z. Del Prete
Keyword(s):  
Viscoelastic Material ◽  
Material Properties ◽  
Viscoelastic Properties ◽  
Mechanical Response ◽  
Loss Modulus ◽  
Multiple Logistic Regression Analysis ◽  
Rate Of Change ◽  
Volterra Model ◽  
Lower Sensitivity ◽  
Dynamic Stimuli

When skin is stretched, stimuli experienced by a cutaneous mechanoreceptor neuron are transmitted to the nerve ending through the skin. In these experiments, we tested the hypothesis that the viscoelastic response of the skin influences the dynamic response of cutaneous rapidly adapting (RA) neurons. Cutaneous RA afferent neurons were recorded in 3 species of mice (Tsk, Pallid, and C57BL6) whose skin has different viscoelastic properties. Isolated samples of skin and nerve were stimulated mechanically with a dynamic stretch stimulus, which followed a pseudo Gaussian waveform with a bandwidth of 0–60 Hz. The mechanical response of the skin was measured as were responses of single RA cutaneous mechanoreceptor neurons. For each neuron, the strength of association between spike responses and the dynamic and static components of stimuli were determined with multiple logistic regression analysis. The viscoelastic material properties of each skin sample were determined indirectly, by creating a nonlinear (Wiener–Volterra) model of the stress–strain relationship, and using the model to predict the complex compliance (i.e., the viscoelastic material properties). The dynamic sensitivity of RA mechanoreceptor neurons in mouse hairy skin was weakly related to the viscoelastic properties of the skin. Loss modulus and phase angle were lower (indicating a decreased viscous component of response) in Tsk and Pallid than in C57BL6 mice. However, RA mechanoreceptor neurons in Tsk and Pallid skin did not differ from those in C57 skin with regard to their sensitivity to the rate of change of stress or to the rate of change of incremental strain energy. They did have a decreased sensitivity to the rate of change of tensile strain. Thus the skin samples with lower dynamic mechanical response contained neurons with a somewhat lower sensitivity to dynamic stimuli.

Viscoelastic Properties of Phagocytes in Arteriosclerotic Origin

2014 ◽  
Vol 540 ◽  
pp. 321-325
Author(s):  
Wei Zeng ◽  
Yan Rong Shi ◽  
Xiao Yan Deng
Keyword(s):  
Experimental Data ◽  
Viscoelastic Properties ◽  
Important Implication ◽  
Research Field ◽  
Solid Model ◽  
Initial Stage ◽  
Standard Linear Solid Model ◽  
Aspiration Technique ◽  
Standard Linear Solid ◽  
Standard Linear

A micropipette aspiration technique was adopted to investigate the viscoelastic properties of phagocytes of arteriosclerotic origin. A standard linear solid model was employed to fit the experimental data and three viscoelastic coefficients were used to compare the mechanical properties of the phagocytes in different phases during arteriosclerostic development. The experimental results indicated that prior to the formation of arteriosclerosis, the mobility and deformability of the marcopahges matured from monocytes decreased, and their rigidity increased. At the initial stage of arteriosclerosis formation, the mobility and deformability of the foam-cells further decreased. This finding may have important implication in the research field of arteriosclerosis.

The Mechanical and Viscoelastic Properties of the Healing Rabbit Patellar Tendon

2007 ◽  
Author(s):  
Steven D. Abramowitch ◽  
Matthew B. Fisher ◽  
Sinan Karaoglu ◽  
Savio L.-Y. Woo
Keyword(s):  
Patellar Tendon ◽  
Viscoelastic Properties ◽  
Cruciate Ligament ◽  
Donor Site ◽  
Viscoelastic Behavior ◽  
Surgery Complications ◽  
Contributing Factors ◽  
Anterior Cruciate ◽  
Anterior Knee ◽  
Bone Patellar Tendon

Central third bone-patellar tendon-bone (BPTB) autografts are commonly used for anterior cruciate ligament (ACL) reconstructions. Following surgery, complications arise at the donor site, including extension deficits and anterior knee pain [1]. These complications are partially caused by inadequate healing of the patellar tendon (PT) as well as adhesions in the anterior interval. Recent clinical data have suggested these are contributing factors in the early development of osteoarthrosis following ACL reconstruction [2]. Thus, it is necessary to understand the changes in mechanical and viscoelastic behavior in the healing PT.

Impact of material concentration and distribution on composite parts manufactured via multi-material jetting

2018 ◽  
Vol 24 (5) ◽  
pp. 872-879 ◽  
Author(s):  
Nicholas Alexander Meisel ◽  
David A. Dillard ◽  
Christopher B. Williams
Keyword(s):  
Material Properties ◽  
Viscoelastic Properties ◽  
Design Space ◽  
Base Material ◽  
Material Design ◽  
Mechanical Analysis ◽  
Material Composition ◽  
Significant Shift ◽  
Content Type ◽  
Property Changes

Purpose Material jetting approximates composite material properties through deposition of base materials in a dithered pattern. This microscale, voxel-based patterning leads to macroscale property changes, which must be understood to appropriately design for this additive manufacturing (AM) process. This paper aims to identify impacts on these composites’ viscoelastic properties due to changes in base material composition and distribution caused by incomplete dithering in small features. Design/methodology/approach Dynamic mechanical analysis (DMA) is used to measure viscoelastic properties of two base PolyJet materials and seven “digital materials”. This establishes the material design space enabled by voxel-by-voxel control. Specimens of decreasing width are tested to explore effects of feature width on dithering’s ability to approximate macroscale material properties; observed changes are correlated to multi-material distribution via an analysis of ingoing layers. Findings DMA shows storage and loss moduli of preset composites trending toward the iso-strain boundary as composition changes. An added iso-stress boundary defines the property space achievable with voxel-by-voxel control. Digital materials exhibit statistically significant changes in material properties when specimen width is under 2 mm. A quantified change in same-material droplet groupings in each composite’s voxel pattern shows that dithering requires a certain geometric size to accurately approximate macroscale properties. Originality/value This paper offers the first quantification of viscoelastic properties for digital materials with respect to material composition and identification of the composite design space enabled through voxel-by-voxel control. Additionally, it identifies a significant shift in material properties with respect to feature width due to dithering pattern changes. This establishes critical design for AM guidelines for engineers designing with digital materials.

Evaluation of the Temperature Effect on the Viscoelastic Responses of Flexible Risers

2019 ◽  
Author(s):  
Junpeng Liu ◽  
Jinsheng Ma ◽  
Murilo Augusto Vaz ◽  
Menglan Duan
Keyword(s):  
Material Properties ◽  
Global Analysis ◽  
Viscoelastic Behavior ◽  
Step Test ◽  
Nonlinear Material ◽  
Polymer Layer ◽  
Axial Stiffness ◽  
Loading Frequency ◽  
Flexible Risers ◽  
Improved Model

Abstract Mechanical behavior of flexible risers can be challenging due largely to its complex design generating strong nonlinear problems. Nonlinear material properties, as one of them, from polymer layers dominate the overall viscoelastic responses of flexible risers which may play an inevitable role on the global analysis in deepwater application. An alternative to predict the viscoelastic behavior comprising of the time domain and the frequency domain has been proposed recently by the authors (Liu and Vaz, 2016). Given the fact that polymeric material properties are temperature-dependent and that the temperature profiles in flexile risers vary continuously in both axial and radial direction, the temperature of the internal hydrocarbons must affect the viscoelastic responses. However, such phenomenon dose not draw much attention in previous studies. This paper presents an improved model for overcoming some drawbacks in the proposed model involving assumption of steady temperature distribution in polymer layer and no gap appearance between the adjacent layers. The computing method of model is developed by using a step by step test approach. Consequently, some important parameters like equivalent axial stiffness, contact pressure or gap between the near layers, and force-deformation relationship can be observed. Parametric studies are conducted on the axisymmetric viscoelastic behavior of flexible risers to study the role of input temperature and loading frequency. Results show that equivalent axial stiffness given by the improved model is smaller than before. It can also be found that the gap between metal layer and polymer layer appear easily and increases as time goes on.

scholarly journals Physical and Dynamic Oscillatory Shear Properties of Gluten-Free Red Kidney Bean Batter and Cupcakes Affected by Rice Flour Addition

Foods ◽  
2020 ◽  
Vol 9 (5) ◽  
pp. 616 ◽  
Author(s):  
Pavalee Chompoorat ◽  
Napong Kantanet ◽  
Zorba J. Hernández Estrada ◽  
Patricia Rayas-Duarte
Keyword(s):  
Viscoelastic Properties ◽  
Structural Characteristics ◽  
Viscoelastic Behavior ◽  
Rice Flour ◽  
Quality Parameters ◽  
Kidney Bean ◽  
Heterogeneous Structure ◽  
Gluten Free ◽  
Red Kidney Bean ◽  
Better Than

Red kidney bean (RKB) flour is a nutrient-rich ingredient with potential use in bakery products. The objective of this study was to investigate the viscoelastic properties and key quality parameters of a functional RKB flour in gluten-free cupcakes with different rice flour levels. A 10 g model batter was developed for analyzing the viscoelastic properties of RKB with rice incorporation, in a formula containing oil, liquid eggs, and water. Rice flour was added at five levels 0%, 5%, 10%, 15%, and 25% (w/w, g rice flour/100 g RKB flour). Rice flour increased RKB batter consistency, solid- and liquid-like viscoelastic behavior and revealed a heterogeneous structure, based on the sweep frequency test. Rice flour at the 25% level increased the shear modulus and activation energy of gelatinization, compared to 0% rice flour addition. Rice flour levels in the RKB batter decreased the inflection gelation temperature from 63 to 56 °C. In addition, the texture of RKB cupcakes with 25% rice flour were 46% softer, compared to the control. The scores from all sensory attributes of cupcakes increased with the addition of rice flour. Rice flour addition improved solid- and liquid-like behavior of the RKB batter and improved the cupcake’s macro-structural characteristics. Overall, 25% rice flour addition performed better than the lower levels. This study confirmed the potential of RKB as a functional ingredient and its improvement in cupcake application with the addition of rice flour.

Research on the Micro-Mechanical State at Tip of Environmentally Assisted Cracking Based on Latin Hypercube Sampling Method

2019 ◽  
Vol 795 ◽  
pp. 74-78
Author(s):  
Kuan Zhao ◽  
He Xue ◽  
Ling Yan Zhao
Keyword(s):  
Oxide Film ◽  
Material Properties ◽  
Nuclear Power ◽  
Power Plants ◽  
Sampling Method ◽  
Latin Hypercube Sampling ◽  
Primary Circuit ◽  
Mechanical State ◽  
Latin Hypercube ◽  
Environmentally Assisted Cracking

Environmentally assisted cracking (EAC) of nickel-based alloys is one of the most significant potential safety hazards in the primary circuit of nuclear power plants. To understand the influence of randomness on micro-mechanical state at tip of EAC, Latin hypercube sampling method is applied to analyze the uncertainty of stress-strain in the oxide film at the EAC tip considering the uncertainties of load and material properties of base metal and oxide film. Meanwhile, to improve the efficiency of numerical analysis, MATLAB is employed in the secondary development for ABAQUS. With the help of finite element numerical simulation and Latin hypercube sampling method, the uncertainty of mechanical properties at tip of EAC in one-inch compact tension specimen is simulated and analyzed in this study. The results show that the randomness of material properties and load markedly affect the uncertainty of micro-mechanical state. Among the variables, The randomness of load has the greatest influence on uncertainty of strain, and Poisson`s ratio of oxide film is the smallest effect.

scholarly journals Controlling the material properties and rRNA processing function of the nucleolus using light

2019 ◽  
Vol 116 (35) ◽  
pp. 17330-17335 ◽  
Author(s):  
Lian Zhu ◽  
Tiffany M. Richardson ◽  
Ludivine Wacheul ◽  
Ming-Tzo Wei ◽  
Marina Feric ◽  
...  
Keyword(s):  
Phase Behavior ◽  
Ribosomal Rna ◽  
Material Properties ◽  
Viscoelastic Properties ◽  
Ribosome Biogenesis ◽  
Threshold Concentration ◽  
Rrna Processing ◽  
Small Proteins ◽  
Nucleolar Material ◽  
Processing Steps

The nucleolus is a prominent nuclear condensate that plays a central role in ribosome biogenesis by facilitating the transcription and processing of nascent ribosomal RNA (rRNA). A number of studies have highlighted the active viscoelastic nature of the nucleolus, whose material properties and phase behavior are a consequence of underlying molecular interactions. However, the ways in which the material properties of the nucleolus impact its function in rRNA biogenesis are not understood. Here we utilize the Cry2olig optogenetic system to modulate the viscoelastic properties of the nucleolus. We show that above a threshold concentration of Cry2olig protein, the nucleolus can be gelled into a tightly linked, low mobility meshwork. Gelled nucleoli no longer coalesce and relax into spheres but nonetheless permit continued internal molecular mobility of small proteins. These changes in nucleolar material properties manifest in specific alterations in rRNA processing steps, including a buildup of larger rRNA precursors and a depletion of smaller rRNA precursors. We propose that the flux of processed rRNA may be actively tuned by the cell through modulating nucleolar material properties, which suggests the potential of materials-based approaches for therapeutic intervention in ribosomopathies.

Multi-Scale Analysis of Viscoelastic Behavior of Laminated Composite Structures

2010 ◽  
Vol 430 ◽  
pp. 115-132
Author(s):  
Y. Shibuya ◽  
Hideki Sekine
Keyword(s):  
Viscoelastic Properties ◽  
Composite Structures ◽  
Viscoelastic Behavior ◽  
Laminated Composite ◽  
Scale Analysis ◽  
Scale Level ◽  
Micro Scale ◽  
Multi Scale ◽  
Laminated Composite Structures ◽  
Multi Scale Analysis

For high temperature applications of laminated composite structures, viscoelastic behavior of laminated composite structures is investigated by multi-scale analysis based on a homogenization theory. Effective viscoelastic properties of the laminas are evaluated by a boundary integral method at a micro-scale level, and viscoelastic analysis for laminated composite structures is performed by a finite element method at a macro-scale level using the effective viscoelastic properties of lamina obtained by the micro-scale analysis. In the multi-scale analysis, the Laplace transformation is adopted and the correspondence principle between elastic and viscoelastic solutions in the Laplace domain is applied. The inverse Laplace transform is formulated by the Duhamel integral, and is calculated numerically. As a numerical example, a laminated composite plate with a hole is treated and the viscoelastic behavior of the laminated composite structure is elucidated.

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