scholarly journals Homogeneous Deformation of Native Erythrocytes During Long-Term Storage

2019 ◽  
Vol 15 (5) ◽  
pp. 4-10 ◽  
Author(s):  
E. A. Manchenko ◽  
E. K. Kozlova ◽  
V. A. Sergunova ◽  
A. M. Chernysh
Keyword(s):  
Young’S Modulus ◽  
Young's Modulus ◽  
Homogeneous Medium ◽  
Fold Increase ◽  
Interaction Force ◽  
Erythrocyte Membranes ◽  
Erythrocyte Suspension ◽  
Theoretical Dependence ◽  
Long Term Storage

Purpose of the study — to evaluate biomechanical regularities of deep deformation of native erythrocytes’ membranes during long-term (up to 32 days) storage of erythrocyte suspension.Materials and methods. The method for addressing the said problem was atomic-force spectroscopy. The measured value was hHz comprizing the depth to which the probe immersion process was described by interaction with a homogeneous medium. Empirical and theoretical dependence of the interaction force F (nN) on the probe immersion depth h (nm) — F (h) were obtained. Bar charts of relative frequency density of Young’s modulus E were built.Results. Modulus E changed from 9.3±3.2 kPa — for 3 days of storage, to 22.7±8.7 kPa — for 32 days. Coefficients of skewness were 0.52±0.04 (for day 3) and 0.82±0.09 (for day 32 d), hHz value remaining constant.Conclusion. Progressively as erythrocyte suspension was stored, erythrocyte membranes to the depth of 700 nm deflected homogeneously in spite of 2.4-fold increase of Young’s modulus.

scholarly journals Atomic force microscopy in the assessment of erythrocyte membrane mechanical properties with exposure to various physicochemical agents

2021 ◽  
Vol 49 (6) ◽  
pp. 427-434
Author(s):  
E. A. Sherstyukova ◽  
V. A. Inozemtsev ◽  
A. P. Kozlov ◽  
O. E. Gudkova ◽  
V. A. Sergunova
Keyword(s):  
Mechanical Properties ◽  
Young’S Modulus ◽  
Erythrocyte Membrane ◽  
Uv Radiation ◽  
Structural Organization ◽  
Young's Modulus ◽  
Homogeneous Medium ◽  
Topological Defects ◽  
Erythrocyte Membranes ◽  
Atomic Force

Background: Mechanical properties of cell membranes and their structural organization are considered among the most important biological parameters affecting the functional state of the cell. Under the influence of various pathogenic factors, erythrocyte membranes lose their elasticity. The resulting changes in their biomechanical characteristics is an important, but poorly studied topic. It is of interest to study the deformation of native erythrocytes to a depth compatible with their deformation in the bloodstream.Aim: To investigate the patterns of deep deformation and the particulars of structural organization of native erythrocyte membranes before and after their exposure to physicochemical agents in vitro.Materials and methods: Cell morphology, nanostructure characteristics, and membrane deformation of native erythrocytes in a  solution of hemoconservative CPD/SAGM were studied with atomic force microscope NTEGRA Prima. Hemin, zinc ions (Zn2+), and ultraviolet (UV) radiation were used as modifiers. To characterize the membrane stiffness, we measured the force curves F(h), hHz (the depth to which the probe immersion is described by interaction with a homogeneous medium), and the Young's modulus values of the erythrocyte membrane.Results: Exposure to hemin, Zn2+ and UV radiation led to transformation of the cell shape, appearance of topological defects and changes in mechanical characteristics of erythrocyte membranes. Under exposure to hemin, Young's modulus increased from 10±4  kPa to 27.2±8.6  kPa (p<0.001), exposure to Zn2+, to 21.4±8.7  kPa (p=0.002), and UV, to 18.8±5.6  kPa (p=0.001). The hHz value was 815±210  nm for the control image and decreased under exposure to hemin to 420±80 nm (p<0.001), Zn2+, to 370±90 nm (p<0.001), and UV, to 614±120 nm (p=0.001).Conclusion: The results obtained contribute to a  deeper understanding of interaction between membrane surfaces of native erythrocytes and small vessel walls. They can be useful in clinical medicine as additional characteristics for assessment of the quality of packed red blood cells, as well as serve as a basis for biophysical studies into the mechanisms of action of oxidative processes of various origins.

scholarly journals A study into the structure and physical properties of the Cr18Ni9-grade steel following long-term irradiation as part of the BN-600 reactor internals

2020 ◽  
Vol 6 (1) ◽  
pp. 1-6
Author(s):  
Irina A. Portnykh ◽  
Aleksandr V. Kozlov ◽  
Valery L. Panchenko ◽  
Vyacheslav S. Shikhalev
Keyword(s):  
Physical Properties ◽  
Young’S Modulus ◽  
Structural Changes ◽  
Young's Modulus ◽  
Void Size ◽  
Initial State ◽  
Porosity Distribution ◽  
Grade Steel ◽  
Reactor Internals

The microstructures and physical properties of the austenitic Cr18Ni9-grade steel after 22 and 33 years of operation as part of the reactor internals were tested for assessing the conditions of the BN-600 reactor non-replaceable components (internals) and the potential of their subsequent use in predicting the reactor ultimate life. The paper presents histograms of the porosity distribution depending on the void size, in samples taken from portions that were subjected to neutron irradiation with displacement rates ranging from 1.0×10–9 to 4.3×10–8 dpa/s at temperatures from 370 to 440 °C. The elasticity characteristics were measured by resonance-type ultrasonic technique for the samples taken from the same portions of material. It was demonstrated that swelling calculated using the histograms of the porosity distribution depending on the void size has the maximum value at ~415 °C and after 33 years of irradiation reaches values of ~3%. Long-term variations of Young’s modulus demonstrate non-monotonous dependence on the damage dose. The maximum relative variation of Young’s modulus after 22 and 33 years of operation does not exceed 2% and 6%, respectively, of the values corresponding to the initial state. It was shown that along with the irradiation-induced swelling the changes in the physical properties are also affected in the process of irradiation by other structural changes and, in particular, by the formation of secondary phases. As shown by the results of the studies, operation of the BN-600 reactor internals made of Cr18Ni9-grade steel can be extended beyond 33 years of service. The comparison of the results obtained for the material after 22 and 33 years of operation contains information required for describing subsequent changes of the structure and properties of the Cr18Ni9 internals. The obtained results can be used for forecasting the reactor ultimate life within the framework of existing and developed models.

scholarly journals Experimental Investigation on Mechanical Properties of In Situ Cemented Paste Backfill Containing Coal Gangue and Fly Ash

2020 ◽  
Vol 2020 ◽  
pp. 1-12
Author(s):  
Xinguo Zhang ◽  
Shichuan Zhang
Keyword(s):  
Mechanical Properties ◽  
Tensile Strength ◽  
Fly Ash ◽  
Young’S Modulus ◽  
Young's Modulus ◽  
Friction Angle ◽  
Coal Gangue ◽  
Cemented Paste Backfill ◽  
Paste Backfill

Cemented paste backfill containing coal gangue and fly ash (CGFACPB) is an emerging backfill technique for coal mines that allows environmentally hazardous coal gangue and fly ash to be reused in the underground goaf. Meanwhile, CGFACPB can provide an efficient ground support and reduce the surface subsidence. Due to the difference of consolidation environment between the laboratory and the field, the mechanical properties of the cemented paste backfill vary significantly. In this paper, the core specimens were collected from an underground coal mine where the CGFACPB was used for coal mining, and the mechanical properties of the collected specimens were investigated. The cores were obtained from the underground coal mine, and then the standard cylinders or discs were prepared in laboratory. The uniaxial compressive strength (UCS), Young’s modulus, and Poisson’s ratio were determined by the compression tests, and the tensile strength was achieved by the Brazilian test. Then the internal friction angle and cohesion were calculated using the improved Mohr–Coulomb strength criterion. The results showed the development of UCS can be divided into four stages, and the final long-term stable value was about 5.1 MPa. The development of Young’s modulus had similar trend. Young’s modulus had a range from 550 MPa to 750 MPa and the mean value of 675 MPa. Poisson’s ratio gradually increased with the underground curing duration and eventually approached the stable value of 0.18. The failure type of compression samples was mainly single-sided shear failure. The development of tensile strength can be divided into two stages, and the stable value of the tensile strength was about 1.05 MPa. The development of cohesion can be divided into four stages, and the stable value was about 1.75 MPa. The stable value of the internal friction angle was about 25°. This study can provide significant references for not only the long-term stability evaluation of CGFACPB in the field but also the design of optimal recipe of the cemented paste backfill (CPB).

Nanosized Magnesium Oxide With Engineered Expansive Property for Enhanced Cement-System Performance

SPE Journal ◽  
2017 ◽  
Vol 22 (05) ◽  
pp. 1681-1689 ◽  
Author(s):  
Narjes Jafariesfad ◽  
Mette Rica Geiker ◽  
Pål Skalle
Keyword(s):  
Heat Treatment ◽  
Young’S Modulus ◽  
Magnesium Oxide ◽  
Young's Modulus ◽  
Oil Well ◽  
Cement Slurry ◽  
Expansive Agent ◽  
Cement System ◽  
Zonal Isolation

Summary The bulk shrinkage of cement sheaths in oil wells can result in loss of long-term zonal isolation. Expansive additives are used to mitigate bulk shrinkage. To compensate effectively for bulk shrinkage during the late plastic phase and the hardening phase of the cement system, the performance of the expansive additive needs to be regulated considering the actual cement system and placement conditions. This paper presents an introductory investigation on the potential engineering of nanosized magnesium oxide (MgO) (NM) through heat treatment for use as an expansive agent in oilwell-cement systems. In this study, the bulk shrinkage of a cement system was mitigated by introducing NM with designed reactivity to the fresh cement slurry. The reactivity of NM was controlled by heat treatment. A dilatometer with corrugated molds was used to measure the linear strain of samples cured at 40°C and atmospheric pressure. The effect of NMs differing in reactivity on tensile properties of cement systems cured for 3 days at 40°C was examined by use of the flattened Brazilian test. The reactivity of the NM played a key role in controlling the bulk shrinkage of the cement system. Addition of only 2% NM by weight of cement (BWOC) with appropriate reactivity was sufficient to maintain expansion of the cement system. Adding NM to the cement system also resulted in improved mechanical flexibility. The NM with highest reactivity caused the largest reduction in Young's modulus at 3 days and, in general, the ratio of tensile strength to Young's modulus improved through the addition of NM to the cement system. Our work demonstrates that controlling the reactivity of the additive is a promising method to mitigate bulk shrinkage of cement systems and thereby to sustain the mechanical properties of the cement sheath in the oil well at an acceptable level.

Strength and Young's modulus change in concrete due to long-term drying and heating up to 90°C

2014 ◽  
Vol 66 ◽  
pp. 48-63 ◽  
Author(s):  
Ippei Maruyama ◽  
Hiroshi Sasano ◽  
Yukiko Nishioka ◽  
Go Igarashi
Keyword(s):  
Young’S Modulus ◽  
Young's Modulus ◽  
Heating Up

Threading and Interlocking: A Mechanism for the Simultaneous Enhancement of Polymer Stiffness, Strength, and Ductility

2008 ◽  
Vol 1086 ◽  
Author(s):  
Lokman Torun ◽  
Alex J. Paraskos ◽  
Nicholas T. Tsui ◽  
Timothy M. Swager ◽  
Edwin L. Thomas
Keyword(s):  
Mechanical Properties ◽  
Young’S Modulus ◽  
Structural Properties ◽  
Free Volume ◽  
Polymer Chain ◽  
Young's Modulus ◽  
Fold Increase ◽  
Processing Conditions ◽  
Strength And Ductility

AbstractWe have synthesized polyester systems containing pendant iptycene units and compared their mechanical/structural properties to a homologous reference polymer wherein benzene replaces iptycene units. Iptycenes have unique structural properties called internal molecular free volume (IMFV). The incorporation of iptycene into polyester backbones results in a polymer chain contour resembling “molecular barbed wire.” The contribution of iptycene to the mechanical properties of polyesters is significant and robust across concentration and processing conditions. The triptycene polyester films displayed a nearly 3-fold increase in Young's modulus, an approximately 3-fold increase in strength, and a more than 20-fold increase in strain to failure. We proposed that the presence of triptycene introduces two mechanisms for the enhancement of tensile mechanical properties: molecular threading and molecular interlocking.

scholarly journals Effect of the material’s stiffness on stress-shielding in osseointegrated implants for bone-anchored prostheses: a numerical analysis and initial benchmark data

2020 ◽  
Vol 22 (2) ◽  
Author(s):  
Piotr Prochor ◽  
Laurent Frossard ◽  
Eugeniusz Sajewicz
Keyword(s):  
Bone Mass ◽  
Young’S Modulus ◽  
Distal Femur ◽  
Young's Modulus ◽  
Stress Shielding ◽  
Term Stability ◽  
Long Term Stability ◽  
Press Fit ◽  
Material Stiffness

Purpose: This study attempted to establish the link between design of implants for bone-anchored prostheses and stress-shielding, affecting the stability of the bone-implant coupling using numerical approach. The objectives were to share a numerical model capable to evaluate the long-term stability of implants and to use this model to extract data sets showing how shape and material stiffness of threaded, press-fit and modular press-fit implants affect stress-shielding intensity. Methods: Three designs were considered: threaded, press-fit and modular press-fit. The effect of shape and material stiffness of each design on stress-shielding intensity was assessed using Young’s modulus (10 to 210 GPa). Furthermore, the impact of the diameter of percutaneous part (10 to 18 mm) and thickness of medullar part (5 to 1 mm) was investigated for the modular press-fit implant. Results: The threaded design generated 4% more bone mass loss at the distal femur but an overall loss of bone mass was by 5% lower to press-fit design. The influence of Young’s modulus on bone mass changes was noticeable for modular press-fit implant, depending on diameter of percutaneous or medullary part. A 20 GPa change of stiffness caused a bone mass change from 0.65% up to 2.45% and from 0.07% up to 0.32% for percutaneous parts with 18 mm and 10 mm diameter, respectively. Conclusions: Results suggested that threaded implant provides greater stability despite an increased bone loss at the distal femur. Altogether, this work provided an initial model that could be applied in subsequent studies on the long-term stability of current and upcoming implants.

scholarly journals Investigating the potential for reversal of myofibroblast activation in human cardiac fibroblasts in 2D culture

EP Europace ◽  
2021 ◽  
Vol 23 (Supplement_3) ◽  
Author(s):  
C Hall ◽  
JP Law ◽  
JS Reyat ◽  
L Fabritz ◽  
P Kirchhof ◽  
...  
Keyword(s):  
Confocal Microscopy ◽  
Protein Expression ◽  
Young’S Modulus ◽  
Western Blotting ◽  
Young's Modulus ◽  
Cardiac Fibroblasts ◽  
Public Institution ◽  
Young’S Moduli ◽  
Human Cardiac Fibroblasts

Abstract Funding Acknowledgements Type of funding sources: Public Institution(s). Main funding source(s): BHF MRC Introduction Cardiac fibroblasts (cFbs) are responsible for deposition of extracellular matrix in the heart, providing support to the contracting myocardium and contributing to a myriad of physiological signalling processes. Prolonged and excessive activation of cFbs, via stimulation by transforming growth factor β (TGF-β), causes conversion of cFbs into myofibroblasts. Myofibroblasts are believed to cause pathological cardiac remodelling and to contribute to heart failure and arrhythmias. Reversion of myofibroblasts into cFbs has been demonstrated in rodent cells; it has yet to be explored in human cells. Purpose To characterise the effects of long-term 2D standard culture on the activation status of human cFbs. To identify the potential for human myofibroblasts to dedifferentiate back to cFbs. Methods Primary human cFbs were cultured in Corning Costar flasks (Young’s modulus E = ∼3GPa) for up to 10 passages. Cells were subsequently plated onto dishes with a Young’s modulus of ∼3GPa, 25kPa and 2kPa in the presence or absence of TGF-β (10ng/ml) and/or TGF-β receptor I inhibitor SD208 (10nM) for up to 4 days. The proliferative capacity of the cells was assessed using the CyQUANT NF® assay. Cells were assessed for mRNA and protein expression of myofibroblast activation markers α-smooth muscle actin (α-SMA) and collagen-1 by qPCR and western blotting. The localised distribution of α-SMA was assessed by confocal microscopy. Results Human cardiac fibroblasts robustly expressed α-SMA. Proliferation was significantly decreased at 2kPa compared to higher Young’s moduli (mean percentage change over 2 days: 2kPa = 115.1, 25kPa = 191.4, 3GPa = 205.9, p &lt; 0.0001). qPCR analysis revealed no significant changes in expression of myofibroblast gene markers α-SMA and collagen 1 at either ∼3GPa, 25kPa or 2kPa Young’s Moduli in the presence or absence of TGF-β treatment (median fold change (interquartile range [IQR]) versus control: TGF-β(α-SMA, 3GPa) = 1.226 (0.820); TGF-β(Collagen 1, 3GPa) = 1.636 (1.403); TGF-β(α-SMA, 25kPa) = 1.069 (7.030); TGF-β(Collagen 1, 25kPa) = 1.103 (0.411); TGF-β(α-SMA, 2kPa) = 0.800 (5.021); TGF-β(Collagen 1, 2kPa) = 1.629 (7.092); n = 2-3). These data was confirmed by western blotting (median relative protein expression (IQR) versus control: TGF-β(α-SMA, 3GPa) = 1.012 (0.500); TGF-β(Collagen 1, 3GPa) = 1.008 (1.466); TGF-β(α-SMA, 25kPa) = 1.321 (2.282); TGF-β(Collagen 1, 25kPa) = 0.944 (1.125); TGF-β(α-SMA, 2kPa) = 1.142 (0.705); TGF-β(Collagen 1, 2kPa) = 0.283 (1.127), p &gt; 0.05; n = 2-3). TGF-β or SD208 treatment did not affect α-SMA expression when assessed by confocal microscopy. Conclusions Long-term culture of human cFbs in 2D format leads to a robust and persistent activation of myofibroblasts that is unresponsive to TGF-ß activation or inhibition. Ongoing work is focussed on investigating whether human myofibroblast de-differentiation is possible.

scholarly journals Measurement of Radial Elasticity and Original Height of DNA Duplex Using Tapping-Mode Atomic Force Microscopy

Nanomaterials ◽  
2019 ◽  
Vol 9 (4) ◽  
pp. 561 ◽  
Author(s):  
Longhai Li ◽  
Xu Zhang ◽  
Hongfei Wang ◽  
Qian Lang ◽  
Haitao Chen ◽  
...  
Keyword(s):  
Atomic Force Microscopy ◽  
Young’S Modulus ◽  
Young's Modulus ◽  
Interaction Force ◽  
Dna Duplex ◽  
Tapping Mode ◽  
Force Microscopy ◽  
Atomic Force ◽  
Novel Approach ◽  
Experimental Values

Atomic force microscopy (AFM) can characterize nanomaterial elasticity. However, some one-dimensional nanomaterials, such as DNA, are too small to locate with an AFM tip because of thermal drift and the nonlinearity of piezoelectric actuators. In this study, we propose a novel approach to address the shortcomings of AFM and obtain the radial Young’s modulus of a DNA duplex. The elastic properties are evaluated by combining physical calculations and measured experimental results. The initial elasticity of the DNA is first assumed; based on tapping-mode scanning images and tip–sample interaction force simulations, the calculated elastic modulus is extracted. By minimizing the error between the assumed and experimental values, the extracted elasticity is assigned as the actual modulus for the material. Furthermore, tapping-mode image scanning avoids the necessity of locating the probe exactly on the target sample. In addition to elasticity measurements, the deformation caused by the tapping force from the AFM tip is compensated and the original height of the DNA is calculated. The results show that the radial compressive Young’s modulus of DNA is 125–150 MPa under a tapping force of 0.5–1.3 nN; its original height is 1.9 nm. This approach can be applied to the measurement of other nanomaterials.

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