scholarly journals Biomechanically Tunable Nano-Silica/P-HEMA Structural Hydrogels for Bone Scaffolding

2021 ◽  
Author(s):  
Raffaella Aversa ◽  
Relly Victoria Petrescu ◽  
Florian Ion T. Petrescu ◽  
Davide Apicella ◽  
and Antonio Apicella
Keyword(s):  
Mechanical Properties ◽  
Tissue Engineering ◽  
Bulk Modulus ◽  
Physical And Mechanical Properties ◽  
Sorption Kinetics ◽  
Swelling Kinetics ◽  
Swelling Rate ◽  
Biomimetic Scaffold ◽  
The Difference ◽  
Saline Solutions

Innovative tissue engineering biomimetic hydrogels based on hydrophilic polymers have been investigated for their physical and mechanical properties. 5% to 25% by volume loading PHEMA-nanosilica glassy hybrid samples were equilibrated at 37°C in aqueous physiological isotonic and hypotonic saline solutions (0.15 and 0.05 M NaCl) simulating two limiting possible compositions of physiological extracellular fluids. The glassy and hydrated hybrid materials were characterized both for dynamo-mechanical properties and equilibrium absorptions in the two physiological-like aqueous solutions. Mechanical and the morphological modifications occurring in the samples have been described. The 5% volume nanosilica loading hybrid nanocomposite composition showed mechanical characteristics in the dry and hydrated states that were comparable to those of cortical bone and articular cartilage, respectively, and then chosen for further sorption kinetics characterization. Sorption and swelling kinetics were monitored up to equilibrium. Changes in water activities and osmotic pressures in the water-hybrid systems equilibrated at the two limiting solute molarities of the physiological solutions have been related to the observed anomalous sorption modes using the Flory-Huggins interaction parameter approach. The bulk modulus of the dry and glassy PHEMA-5% nanosilica hybrid at 37°C has been observed to be comparable with the values of the osmotic pressures generated from the sorption of isotonic and hypotonic solutions. The anomalous sorption modes and swelling rates are coherent with the difference between osmotic swelling pressures and hybrid glassy nano-composite bulk modulus: the lower the differences the higher the swelling rate and equilibrium solution uptakes. Bone tissue engineering benefits of use of tuneable biomimetic scaffold biomaterials that can be “designed” to act as biocompatible and biomechanically active hybrid interfaces are discussed.

scholarly journals Biomechanically Tunable Nano-Silica/P-HEMA Structural Hydrogels for Bone Scaffolding

2021 ◽  
Vol 8 (4) ◽  
pp. 45
Author(s):  
Raffaella Aversa ◽  
Relly Victoria Petrescu ◽  
Florian Ion T. Petrescu ◽  
Valeria Perrotta ◽  
Davide Apicella ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Tissue Engineering ◽  
Bulk Modulus ◽  
Physical And Mechanical Properties ◽  
Sorption Kinetics ◽  
Swelling Kinetics ◽  
Swelling Rate ◽  
Biomimetic Scaffold ◽  
The Difference ◽  
Saline Solutions

Innovative tissue engineering biomimetic hydrogels based on hydrophilic polymers have been investigated for their physical and mechanical properties. 5% to 25% by volume loading PHEMA-nanosilica glassy hybrid samples were equilibrated at 37 °C in aqueous physiological isotonic and hypotonic saline solutions (0.15 and 0.05 M NaCl) simulating two limiting possible compositions of physiological extracellular fluids. The glassy and hydrated hybrid materials were characterized by both dynamo-mechanical properties and equilibrium absorptions in the two physiological-like aqueous solutions. The mechanical and morphological modifications occurring in the samples have been described. The 5% volume nanosilica loading hybrid nanocomposite composition showed mechanical characteristics in the dry and hydrated states that were comparable to those of cortical bone and articular cartilage, respectively, and then chosen for further sorption kinetics characterization. Sorption and swelling kinetics were monitored up to equilibrium. Changes in water activities and osmotic pressures in the water-hybrid systems equilibrated at the two limiting solute molarities of the physiological solutions have been related to the observed anomalous sorption modes using the Flory-Huggins interaction parameter approach. The bulk modulus of the dry and glassy PHEMA-5% nanosilica hybrid at 37 °C has been observed to be comparable with the values of the osmotic pressures generated from the sorption of isotonic and hypotonic solutions. The anomalous sorption modes and swelling rates are coherent with the difference between osmotic swelling pressures and hybrid glassy nano-composite bulk modulus: the lower the differences the higher the swelling rate and equilibrium solution uptakes. Bone tissue engineering benefits of the use of tuneable biomimetic scaffold biomaterials that can be “designed” to act as biocompatible and biomechanically active hybrid interfaces are discussed.

Influence of different concentrations of fibrinogen on the properties of a fibrin matrix for vascular tissue engineering

2021 ◽  
Vol 29 (1) ◽  
pp. 21-34
Author(s):  
Vera G. Matveeva ◽  
Mariam Yu. Khanova ◽  
Tatyana V. Glushkova ◽  
Larisa V. Antonova
Keyword(s):  
Mechanical Properties ◽  
Tissue Engineering ◽  
Metabolic Activity ◽  
Vascular Tissue ◽  
Physical And Mechanical Properties ◽  
Vascular Tissue Engineering ◽  
Test Machine ◽  
Fibrin Matrix ◽  
Before And After ◽  
The Difference

Aim. To evaluate the potential utility of fibrin matrices containing 10, 20, and 25 mg/ml of fibrinogen (fibrin-10, fibrin-20, and fibrin-30, respectively) in vascular tissue engineering (VTE). Materials and Methods. Fibrinogen was isolated using the method of ethanol cryoprecipitation and polymerized using a solution of thrombin and CaCl2. The fibrin structure was studied in a scanning electron microscope, and the physical and mechanical properties of the material were tested on a Zwick/Roell test machine. The metabolic activity of endothelial cells (EC) on the fibrin surface was evaluated by the MTT assay, and the viability of fibroblasts in the thickness of fibrin and possibility for migration by in fluorescent and light microscopy. Percent of fibrin shrinkage was determined from the difference in the sample volumes before and after removal of moisture. Results. The fiber diameter did not differ among all fibrin samples, but the pore diameter in fibrin-30 was smaller than those in fibrin-10 and fibrin-20. A possibility for migration of fibroblasts into the depth of the fibrin matrix and preservation of 97-100% viability of cells at a depth 5 mm was confirmed. The metabolic activity of EC on the surface of fibrin-20 and fibrin-30 exceeded that on collagen, fibronectin, and fibrin-10. All fibrin samples shrank in volume to 95.5-99.5%, and the highest shrinkage was seen in fibrin-10. The physical and mechanical properties of fibrin were inferior to those of human A. mammaria by a factor of 10. Conclusion. Fibrin with fibrinogen concentrations of 20 and 30 mg/ml maintains a high metabolic and proliferative activity of EC on the surface and also a high viability of fibroblasts in the matrix. Its availability, ease of preparation, and a number of other favorable properties make fibrin a promising material for VTE. However, the problem of insufficient strength requires further investigations.

Differences in petrophysical and mechanical properties between low- and middle-rank coal subjected to liquid nitrogen cooling in coalbed methane mining

2021 ◽  
pp. 1-10
Author(s):  
Menglin Du ◽  
Feng Gao ◽  
Chengzheng Cai ◽  
Shanjie Su ◽  
Zekai Wang
Keyword(s):  
Mechanical Properties ◽  
Pore Structure ◽  
Liquid Nitrogen ◽  
Coalbed Methane ◽  
Bituminous Coal ◽  
Thermal Damage ◽  
Physical And Mechanical Properties ◽  
Damage Degree ◽  
Lignite Coal ◽  
The Difference

Abstract Exploring the damage differences between different coal rank coal reservoirs subjected to liquid nitrogen (LN2) cooling is of great significance to the rational development and efficient utilization of coalbed methane. For this purpose, the mechanical properties, acoustic emission (AE) characteristics and energy evolution law of lignite and bituminous coal subjected to LN2 cooling were investigated based on the Brazilian splitting tests. Then, pore structure changes were analyzed to reveal the difference in the microscopic damage between lignite and bituminous coal after LN2 cooling. The results showed that compared with bituminous coal, the pore structure of lignite coal changed more obviously, which was manifested as follows: significant increases in porosity, pore diameters, and pore area; a larger transformation from micropores and transition pores to mesopores and macropores. After LN2 cooling, the thermal damage inside lignite and bituminous coal was 0.412 and 0.069, respectively. The thermal damage reduced the cohesive force between mineral particles, leading to the deterioration of the macroscopic physical and mechanical properties. Simultaneously, denser AE ringing counts and larger accumulated ringing counts were observed after LN2 cooling. Moreover, the random distribution of thermal damage enhanced the randomness of the macrocrack propagation direction, resulting in an increase in the crack path tortuosity. With more initial defects inside coal, a more obvious thermal damage degree and wider damage distribution will be induced by LN2 cooling, leading to more complicated crack formation paths and a higher fragmentation degree, such as that of lignite coal.

Thermal and Mechanical Properties of Cyclized Polybutadiene Dielectrics

1986 ◽  
Vol 76 ◽  
Author(s):  
C. W. Wilkins ◽  
H. E. Bair ◽  
M. G. Chan ◽  
R. S. Hutton
Keyword(s):  
Mechanical Properties ◽  
Differential Scanning Calorimetry ◽  
Physical And Mechanical Properties ◽  
Mechanical Analysis ◽  
Infrared Analysis ◽  
Thermal And Mechanical Properties ◽  
Scanning Calorimetry ◽  
The Difference ◽  
Thermal Mechanical Analysis ◽  
Lower Glass Transition Temperature

ABSTRACTWe have studied some of the physical and mechanical properties of cyclized polybutadiene (CBR) dielectrics by dynamic mechanical analysis, thermal mechanical analysis, thermogravimetry, infrared analysis, and differential scanning calorimetry. Of interest is the difference in properties between thin (<30 μm) films which have been cured under vacuum and those which have been cured in air. Our results indicate that curing under vacuum prevents oxidation and reduces crosslinking. Vacuum cured films have 20% smaller moduli and 200 lower glass transition temperature than do films produced in air.

Structure and Mechanical Properties of Retrograded Rice Starch and Cow Bone Powder Composite Sponge

2018 ◽  
Vol 923 ◽  
pp. 84-88
Author(s):  
Sittiporn Punyanitya ◽  
Rungsarit Koonawoot ◽  
Anucha Ruksanti ◽  
Sakdiphon Thiensem ◽  
Anirut Raksujarit
Keyword(s):  
Mechanical Properties ◽  
Compressive Strength ◽  
Porous Material ◽  
Bone Repair ◽  
Physical And Mechanical Properties ◽  
Powder Composite ◽  
Rice Starch ◽  
Bone Powder ◽  
Swelling Rate ◽  
Cow Bone

To study the effect of addition purified cow bone (CB) powder (20, 30, 40 and 50 wt%) in slurry suspension of retrograded rice starch (RRS). The composite sponges were used as in bone repair. The RRS-CB composite sponges were prepared from the mixture of RRS, CB and additive into distill water. The prepared samples were characterized including SEM, XRD, physical and mechanical properties. The results of optimized condition have shown the samples of 40 wt% CB that had the swelling rate as 102± 0.01%, area of expansion was 20 ± 0.03 % for 72 hours and the compressive strength was 64.35±0.05KPa. In addition, it was found that this content resulted in sufficient soft porous material, foldable by hand and self recovered body.

Physical and Mechanical Properties of Co3(Al,W) with the L12 Structure in Single and Polycrystalline Forms

2011 ◽  
Vol 465 ◽  
pp. 9-14 ◽  
Author(s):  
Haruyuki Inui ◽  
Takashi Oohashi ◽  
Norihiko L. Okamoto ◽  
Kyosuke Kishida ◽  
Katsushi Tanaka
Keyword(s):  
Mechanical Properties ◽  
Shear Modulus ◽  
Bulk Modulus ◽  
Single Crystal ◽  
Elastic Constants ◽  
Tensile Elongation ◽  
Physical And Mechanical Properties ◽  
Helium Temperature ◽  
Cauchy Pressure ◽  
L12 Structure

The physical and mechanical properties of Co3(Al,W) with the L12 structure have been investigated both in single and polycrystalline forms. The values of all the three independent single-crystal elastic constants and polycrystalline elastic constants of Co3(Al,W) experimentally determined by resonance ultrasound spectroscopy at liquid helium temperature are 15~25% larger than those of Ni3(Al,Ta) but are considerably smaller than those previously calculated. When judged from the values of Poisson’s ratio, Cauchy pressure and Gh (shear modulus)/Bh (bulk modulus), the ductility of Co3(Al,W) is expected to be sufficiently high. Indeed, the value of tensile elongation obtained in air is as large as 28 %, which is far larger than that obtained in Ni3Al polycrystals under similar conditions.

Interpreting research results for the physical and mechanical properties of wood: An approach not dependent on a juvenile/mature wood boundary

BioResources ◽  
2021 ◽  
Vol 16 (4) ◽  
pp. 6921-6932
Author(s):  
Tomislav Sinković ◽  
Branimir Jambreković ◽  
Tomislav Sedlar
Keyword(s):  
Mechanical Properties ◽  
Radial Direction ◽  
Statistical Tests ◽  
Physical And Mechanical Properties ◽  
Wood Properties ◽  
Mature Wood ◽  
Raw Material ◽  
Technological Properties ◽  
Wood Processing ◽  
The Difference

The interpretation and presentation of research on the physical and mechanical properties of wood in the radial direction is important for the estimation of technological properties in primary wood processing. It is common practice to define the boundary between the juvenile and mature wood zone of tree growth because of the differences in wood properties in these two zones. The juvenile and mature wood zones can be determined statistically based on the significance of the difference in the properties in a particular zone. This paper presents the insufficiency in the statistical determination of the boundary between juvenile and adult wood. Such limitations detract from the potential value and technological exploitation of wood as raw material. Statistical tests yielded zones that were too wide for the transition of juvenile wood to mature wood. Representations of the distribution of properties in the radial direction also complement the knowledge for assessing the technological properties based on the researched use of the presentation of polynomials of the second degree and the display of the Tukey HSD test in the form of comparison tables. The graphical representations by groups of the tested annual rings of fir wood also help to assess the technological properties.

scholarly journals ANÁLISE DAS PROPRIEDADES FÍSICAS E MECÂNICAS DO CONCRETO PRODUZIDO COM RESÍDUO SÓLIDO DE CERÂMICA VERMELHA

2012 ◽  
Vol 04 (02) ◽  
pp. 01-11 ◽  
Author(s):  
Cassio Fabian S. Campos ◽  
Giovane Bozette Mazini ◽  
Guilherme A. da Silva Neto
Keyword(s):  
Mechanical Properties ◽  
Construction Industry ◽  
Physical And Mechanical Properties ◽  
Specific Weight ◽  
Recycled Aggregate ◽  
Recycled Aggregates ◽  
Mechanical Compression ◽  
Conventional Concrete ◽  
The Difference ◽  
Physical Changes

The construction industry accounts for the largest share of consumption of natural resources among all other areas, about 50%. Consequently is also the largest generator of waste. One of these tailings is red ceramic, which due to its fragility break easily generate large amount of debris. This project aimed to examine the possibility of reuse of waste as aggregate for concrete comparing their physical and mechanical properties, with conventional concrete. We compared the behaviors of different traits in concrete with a gradual replacement of 20% of natural coarse aggregate by recycled aggregate red ceramic to achieve 100% recycled aggregate, evaluating possible changes in density, absorption and voids, as well as the mechanical compression. The reference concrete results presented in the order of 25 MPa at 28 days of age, since the concrete produced with recycled aggregates showed lower results of the compressive strength of up to30%. The other indices also suffered physical changes as the slump that had values 4 times higher, the level of absorption and voids which increased 2-3 three times in concrete with recycled aggregate. This happens due to the difference between the densities of crushed stone and ceramics. Although the ceramic adversely affect the mechanical properties, this difference becomes lighter concrete, or decreases its specific weight, which may be favorable in some situations.

Nanomaterials-based Cell Osteogenic Differentiation and Bone Regeneration

2021 ◽  
Vol 16 (1) ◽  
pp. 36-47
Author(s):  
Tianxu Zhang ◽  
Yang Gao ◽  
Weitong Cui ◽  
Yanjing Li ◽  
Dexuan Xiao ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Tissue Engineering ◽  
Bone Tissue Engineering ◽  
Bone Regeneration ◽  
Osteogenic Differentiation ◽  
Bone Tissue ◽  
Bone Repair ◽  
Rapid Development ◽  
Physical And Mechanical Properties ◽  
Unique Chemical

With the rapid development of nanotechnology, various nanomaterials have been applied to bone repair and regeneration. Due to the unique chemical, physical and mechanical properties, nanomaterials could promote stem cells osteogenic differentiation, which has great potentials in bone tissue engineering and exploiting nanomaterials-based bone regeneration strategies. In this review, we summarized current nanomaterials with osteo-induction ability, which could be potentially applied to bone tissue engineering. Meanwhile, the unique properties of these nanomaterials and their effects on stem cell osteogenic differentiation are also discussed. Furthermore, possible signaling pathways involved in the nanomaterials- induced cell osteogenic differentiation are also highlighted in this review.

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