Displaying publications 1 - 20 of 300 in total

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  1. Jaganathan SK, Mani MP
    3 Biotech, 2018 Aug;8(8):327.
    PMID: 30073112 DOI: 10.1007/s13205-018-1356-2
    In this study, a wound dressing based on polyurethane (PU) blended with copper sulphate nanofibers was developed using an electrospinning technique. The prepared PU and PU nanocomposites showed smooth fibers without any bead defects. The prepared nanocomposites showed smaller fiber (663 ± 156.30 nm) and pore (888 ± 70.93 nm) diameter compared to the pristine PU (fiber diameter 1159 ± 147.48 nm and pore diameter 1087 ± 62.51 nm). The interaction of PU with copper sulphate was evident in the infrared spectrum through hydrogen-bond formation. Thermal analysis displayed enhanced weight residue at higher temperature suggesting interaction of PU with copper sulphate. The contact angle measurements revealed the hydrophilic nature of the prepared nanocomposites (71° ± 2.309°) compared with pure PU (100° ± 0.5774°). The addition of copper sulphate into the PU matrix increased the surface roughness, as revealed in the atomic force microscopy (AFM) analysis. Mechanical testing demonstrated the enhanced tensile strength behavior of the fabricated nanocomposites (18.58 MPa) compared with the pristine PU (7.12 MPa). The coagulation assays indicated the enhanced blood compatibility of the developed nanocomposites [activated partial thromboplastin time (APTT)-179 ± 3.606 s and partial thromboplastin time (PT)-105 ± 2.646 s] by showing a prolonged blood clotting time compared with the pristine PU (APTT-147.7 ± 3.512 s and PT-84.67 ± 2.517 s). Furthermore, the hemolysis and cytotoxicity studies suggested a less toxicity nature of prepared nanocomposites by displaying low hemolytic index and enhanced cell viability rates compared with the PU membrane. It was observed that the fabricated novel wound dressing possesses better physicochemical and enhanced blood compatibility properties, and may be utilized for wound-healing applications.
    Matched MeSH terms: Tensile Strength
  2. Hassan MI, Sultana N
    3 Biotech, 2017 Aug;7(4):249.
    PMID: 28714045 DOI: 10.1007/s13205-017-0889-0
    Considering the important factor of bioactive nanohydoxyapatite (nHA) to enhance osteoconductivity or bone-bonding capacity, nHA was incorporated into an electrospun polycaprolactone (PCL) membrane using electrospinning techniques. The viscosity of the PCL and nHA/PCL with different concentrations of nHA was measured and the morphology of the electrospun membranes was compared using a field emission scanning electron microscopy. The water contact angle of the nanofiber determined the wettability of the membranes of different concentrations. The surface roughness of the electrospun nanofibers fabricated from pure PCL and nHA/PCL was determined and compared using atomic force microscopy. Attenuated total reflectance Fourier transform infrared spectroscopy was used to study the chemical bonding of the composite electrospun nanofibers. Beadless nanofibers were achieved after the incorporation of nHA with a diameter of 200-700 nm. Results showed that the fiber diameter and the surface roughness of electrospun nanofibers were significantly increased after the incorporation of nHA. In contrast, the water contact angle (132° ± 3.5°) was reduced for PCL membrane after addition of 10% (w/w) nHA (112° ± 3.0°). Ultimate tensile strengths of PCL membrane and 10% (w/w) nHA/PCL membrane were 25.02 ± 2.3 and 18.5 ± 4.4 MPa. A model drug tetracycline hydrochloride was successfully loaded in the membrane and the membrane demonstrated good antibacterial effects against the growth of bacteria by showing inhibition zone for E. coli (2.53 ± 0.06 cm) and B. cereus (2.87 ± 0.06 cm).
    Matched MeSH terms: Tensile Strength
  3. Liew KB, Tan YT, Peh KK
    AAPS PharmSciTech, 2012 Mar;13(1):134-42.
    PMID: 22167416 DOI: 10.1208/s12249-011-9729-4
    The aim of this study was to develop a taste-masked oral disintegrating film (ODF) containing donepezil, with fast disintegration time and suitable mechanical strength, for the treatment of Alzheimer's disease. Hydroxypropyl methylcellulose, corn starch, polyethylene glycol, lactose monohydrate and crosspovidone served as the hydrophilic polymeric bases of the ODF. The uniformity, in vitro disintegration time, drug release and the folding endurance of the ODF were examined. The in vitro results showed that 80% of donepezil hydrochloride was released within 5 minutes with mean disintegration time of 44 seconds. The result of the film flexibility test showed that the number of folding time to crack the film was 40 times, an indication of sufficient mechanical property for patient use. A single-dose, fasting, four-period, eight-treatment, double-blind study involving 16 healthy adult volunteers was performed to evaluate the in situ disintegration time and palatability of ODF. Five parameters, namely taste, aftertaste, mouthfeel, ease of handling and acceptance were evaluated. The mean in situ disintegration time of ODF was 49 seconds. ODF containing 7 mg of sucralose were more superior than saccharin and aspartame in terms of taste, aftertaste, mouthfeel and acceptance. Furthermore, the ODF was stable for at least 6 months when stored at 40°C and 75% relative humidity.
    Matched MeSH terms: Tensile Strength
  4. Zeeshan F, Peh KK, Tan YT
    AAPS PharmSciTech, 2009;10(3):850-7.
    PMID: 19554454 DOI: 10.1208/s12249-009-9278-2
    Compaction of controlled-release coated pellets into tablets is challenging because of the fusion of pellets and the rupturing of coated film. The difficulty in compaction intensifies with the use of extremely water-soluble drugs. Therefore, the present study was conducted to prepare and compact pellets containing pseudoephedrine hydrochloride as an extremely water-soluble model drug. The pellets were produced using an extrusion-spheronization technique. The drug-loaded pellets were coated to extend the drug release up to 12-h employing various polymers, and then they were compressed into tablets using microcrystalline cellulose Ceolus KG-801 as a novel tabletting excipient. The in vitro drug release studies of coated pellets and tablets were undertaken using the USP basket method in dissolution test apparatus I. The amount of drug released was analyzed at a wavelength of 215 nm. The combined coatings of hydroxypropyl methylcellulose and Kollicoat SR-30D yielded 12-h extended-release pellets with drug release independent of pH of dissolution medium following zero-order kinetics. The drug release from the tablets prepared using inert Celous KG-801 granules as tabletting excipient was found faster than that of coated pellets. However, a modification in drug release rate occurred with the incorporation of inert Ceolus KG-801 pellets. The drug dissolution profile from tablets containing 40% w/w each of coated pellets and inert granules along with 20% w/w inert pellets was found to be closely similar to that of coated pellets. Furthermore, the friability, tensile strength, and disintegration time of the tablets were within the USP specifications.
    Matched MeSH terms: Tensile Strength
  5. Ab Rahman MF, Rusli A, Misman MA, Rashid AA
    ACS Omega, 2020 Nov 24;5(46):30329-30335.
    PMID: 33251468 DOI: 10.1021/acsomega.0c04964
    With increased awareness on the importance of gloves arising from the COVID-19 pandemic, people are expected to continue using them even after the pandemic recedes. This scenario in a way increased the rubber solid waste disposal problem; therefore, the production of biodegradable gloves may be an option to overcome this problem. However, the need to study the shelf life of biodegradable gloves is crucial before commercialization. There are well-established models to address the failure properties of gloves as stated in the American Society for Testing and Material (ASTM) D7160. In this study, polysaccharide-based material-filled natural rubber latex (PFNRL) gloves, which are biodegradable gloves, were subjected to an accelerated aging process at different temperatures of 50-80 °C for 1-120 days. Prediction models based on Arrhenius and shift factors were used to estimate the shelf life of the PFNRL gloves. Based on the results obtained, the estimated time for the PFNRL gloves to retain 75% of their tensile strength at shelf temperature (30 °C) based on Arrhenius and shift factor models was 2.8 years. Verification on the activation energy based on the shift factor model indicated that the shelf life of PFNRL gloves is 2.9 years, which is only a 3.6% difference. The value obtained is aligned with the requirement in accordance with ASTM D7160, which states that only up to a maximum of 3 years' shelf life is allowed for the gloves under accelerated aging conditions.
    Matched MeSH terms: Tensile Strength
  6. Jamuna, K., Noorsal, K., Zakaria, F.A., Hussin, Z.H.
    ASM Science Journal, 2010;4(1):41-47.
    MyJurnal
    Introducing CO2 flux as the carbonate source had an effect on the carbonate content of carbonate apatite (CAp) synthesized by solid state reaction. The reactants were CaCO3 and beta-tricalcium phosphate (β-TCP) and the heat treatment in air was performed at 1250ºC followed by instant cooling in CO2 flux for temperatures ranging from 800ºC room temperature (RT) . The influence of CO2 flux at various temperature drop differences in the cooling process (1250ºC RT, 1250ºC–500ºC, 1250ºC–600ºC, 1250ºC–700ºC, and 1250ºC–800ºC) was tested to optimize the carbonation degree and subsequent effects on the physical and mechanical properties of CAp. Thermally treated samples revealed an increasing degree of carbonation, achieving a maximum of 5.2 wt% at the highest (1250ºC RT) and a minimum of 2.7 wt% at the lowest (1250ºC–800ºC) temperature drop differences, respectively. This showed that the carbonate content was correlated with the increase in exposure to CO2 flux. However, consistent compressive strength, tensile strength, density and porosity were observed against increasing temperature drop differences which indicated that the degree of carbonation exerted no influence on the physical and mechanical properties of CAp. This method enabled the synthesis of solid state CAp simply by exposing calcium phosphate mixtures to CO2 flux. It also allowed the control of carbonate content for desired medical applications.
    Matched MeSH terms: Tensile Strength
  7. Ahmad, Z., Wee, L.S., Fauzi, M.A.
    ASM Science Journal, 2011;5(1):27-35.
    MyJurnal
    This paper reports the mechanical properties of cement composite boards made using wood-wool from a lesser known Malaysian timber species. A total of 108 specimens were fabricated using Portland cement (Type I) and wood-wool from Kelampayan (Neolamarckia cadamba). The cement to wood ratio of the specimens was 2 to 1 by weight. The aim of the study was to determine the density; flexural, compressive and tensile strength of wood-wool cement composite boards (WWCCB) by studying boards with wood-wool sized 1.5 mm, 2.5 mm and 3.5 mm and board thickness 25 mm, 50 mm and 75mm. The physical and mechanical properties of the boards were evaluated according to ASTM D 1037-96a (Standard testing method for evaluating properties of wood-based fibre and particle panel materials) and MS934:1986. Results showed that mechanical properties of WWCCB were greatly influenced by the density; as the density decreased, the mechanical strengths also decreased. However, the strength properties of the composite boards did not display a similar trend when subjected to different types of loading conditions. The compressive strength increased with thicker boards (50 mm and 75 mm) but the modulus of elasticity and modulus of rupture declined as the thickness of the board was increased.
    Matched MeSH terms: Tensile Strength
  8. Abdullah, M.A.A., Mamat, M., Rusli, S.A., Kassim, A.A.
    ASM Science Journal, 2018;11(101):96-104.
    MyJurnal
    Considering its excellent thermal stability, alkyl phosphonium surfactant: triisobutyl(methyl)phosphonium
    (TIBMP) was used in this research as an intercalant for surface
    modification of Na+-MMT via ion exchange process forming organomontmorillonite
    (OMMT). The OMMT was then used as filler in poly(methyl methacrylate) (PMMA) via
    melt intercalation technique. OMMT decomposed at a higher temperature than commercial
    alkyammonium modified MMT. Exfoliated and intercalated types of nanocomposites
    are obtained from PMMA/OMMTs at low and high content of OMMT loading, depending
    on the space of those clay platelets had to disperse in PMMA. The ability of OMMT to
    carry a certain load applied in PMMA matrix enhances the tensile strength in all composites.
    TIBMP are compatible with PMMA matrix, and significantly improves the tensile
    properties of PMMA composites.
    Matched MeSH terms: Tensile Strength
  9. Razali, M.H., Ismail, N.A., Osman, U.M., Amin, K.A.M.
    ASM Science Journal, 2018;11(101):158-165.
    MyJurnal
    The aim of this work was to investigate the effect of glycerol concentration on mechanical
    and physical properties of gellan gum (GG) biofilm. The biofilm was prepared using solvent
    casting method and the effective glycerol concentration was found to be within 30-50%
    w/w (based on GG weight). At 60 and 70 w/w% of glycerol, the films started to distort
    because the films was flexible and brittle. As glycerol concentration was increased the tensile
    strength (TS) and Youngs modulus (E) of films decreased. Somehow, elongation at break
    (EAB), water vapor transmission rate (WVTR) and swelling of films was increased. Glycerol
    plasticized GG biofilm was thermally stable and flexible, proposed its can be exploited as
    film-forming material and with optimized glycerol concentration it has good mechanical and
    physical properties for edible biofilm.
    Matched MeSH terms: Tensile Strength
  10. Sofian Ibrahim, Keong, Chai Chee, Ratnam, Chantara Thevy, Khairiah Badri
    ASM Science Journal, 2018;11(2):67-75.
    MyJurnal
    Radiation pre-vulcanised natural rubber latex (RVNRL) prepared by using gamma irradiation technique has many advantages over the conventionally prepared sulphur pre-vulcanised natural rubber latex (SPVL). Despite the fact that many potential latex dipped products can be made from RVNRL, little effort was made to fully commercialise the products because of the inferior strength of RVNRL products compared to SPVL products. An attempt was made to improve the tensile strength of RVNRL by combining both radiation and peroxide vulcanisation in order to ensure that the products will not tear or fail, and has sufficient stretch. Hexanediol diacrylate (HDDA) plays the main role as sensitizer during radiation vulcanisation and tert-butyl hydroperoxide (t-BHPO) as the co-sensitizer in peroxide vulcanisation. Pre-vulcanised natural rubber latex dipped films via hybrid radiation and peroxidation vulcanisations obtained showed tensile strength of 26.7 MPa, an increment of more than 15% compared to controlled film (22.5 MPa). Besides, the crosslink percentage of the rubber films also showed around 5% increment from 90.7% to 95.6%.
    Matched MeSH terms: Tensile Strength
  11. Tan LF, Elaine E, Pui LP, Nyam KL, Yusof YA
    Acta Sci Pol Technol Aliment, 2021 1 16;20(1):55-66.
    PMID: 33449520 DOI: 10.17306/J.AFS.0771
    BACKGROUND: Biodegradable food packaging has improved in quality with recent research incorporating natural extracts for functionality purposes. This research aims to develop chitosan film with Chrysanthemum morifolium essential oil to improve the shelf life of fresh raw chicken and beef.

    METHODS: 1.5% (w/v) chitosan films with Chrysanthemum morifolium essential oil (0% to 6% (v/v)) were produced through homogenization, the casting of a film solution in a petri dish and convection drying. The edible film was evaluated in terms of its physical (color, thickness, water vapor permeability), mechanical (puncture strength, tensile strength, elongation at break) and chemical properties (antioxidant assay, Fourier Transform Infrared Spectroscopy (FTIR)).

    RESULTS: With an increasing concentration of Chrysanthemum morifolium in the chitosan film, the test values of physical properties such as tensile strength, puncture force, and elongation at break declined significantly. However, the thickness, water permeability, and color profile (L*, a*, b*) values of the chitosan film increased. Similarly, the scavenging effect of antioxidant assay increased (from 4.97% to 18.63%) with a rise in Chrysanthemum morifolium concentration. 2%, 3%, and 4% of Chrysanthemum morifolium in the chitosan film showed a significant inhibition zone ranging from 2.67 mm to 3.82 mm against Staphylococcus aureus, a spoilage bacterium that is commonly found in chicken and beef products. The storage and pH tests showed that 4% of Chrysanthemum morifolium in the film maintained pH level (safe to consume), and the shelf life was extended from 3 days to 5 days of meat storage.

    CONCLUSIONS: This study demonstrated that the incorporation of 4% (v/v) Chrysanthemum morifolium extract into 1.5% (w/v) chitosan film extends the storage duration of raw meat products noticeably by reducing Staphylococcus aureus activity. Therefore, it increases the quality of the edible film as an environmentally friendly food packaging material so that it can act as a substitute for the use of plastic bags. Future studies will be conducted on improving the tensile strength of the edible film to increase the feasibility of using it in the food industry. In addition, the microstructure and surface morphology of the edible film can be further determined.

    Matched MeSH terms: Tensile Strength
  12. Kamalaldin N', Jaafar M, Zubairi SI, Yahaya BH
    Adv Exp Med Biol, 2019;1084:1-15.
    PMID: 29299875 DOI: 10.1007/5584_2017_130
    The use of bioceramics, especially the combination of hydroxyapatite (HA) and β-tricalcium phosphate (β-TCP), as a three-dimensional scaffold in bone engineering is essential because together these elements constitute 60% of the bone content. Different ratios of HA and β-TCP were previously tested for their ability to produce suitable bioceramic scaffolds, which must be able to withstand high mechanical load. In this study, two ratios of HA/TCP (20:80 and 70:30) were used to create pellets, which then were evaluated in vitro to identify any adverse effects of using the material in bone grafting. Diametral tensile strength (DTS) and density testing was conducted to assess the mechanical strength and porosity of the pellets. The pellets then were tested for their toxicity to normal human fibroblast cells. In the toxicity assay, cells were incubated with the pellets for 3 days. At the end of the experiment, cell morphological changes were assessed, and the absorbance was read using PrestoBlue Cell Viability Reagent™. An inversely proportional relationship between DTS and porosity percentage was detected. Fibroblasts showed normal cell morphology in both treatments, which suggests that the HA/TCP pellets were not toxic. In the osteoblast cell attachment assay, cells were able to attach to the surface of both ratios, but cells were also able to penetrate inside the scaffold of the 70:30 pellets. This finding suggests that the 70:30 ratio had better osteoconduction properties than the 20:80 ratio.
    Matched MeSH terms: Tensile Strength
  13. Seow LL, Toh CG, Fok AS, Wilson NH
    Am J Dent, 2008 Oct;21(5):331-6.
    PMID: 19024261
    PURPOSE: To investigate the level and distribution of stresses in endodontically treated maxillary premolar teeth restored using various cavity designs of bonded all-ceramic restorations. The hypothesis tested was that the various all-ceramic approaches, including incorporating a pulp chamber extension in the restoration, had no influence on the stresses in the restored tooth unit.
    METHODS: Finite element packages Patran and Abaqus were used for the stress analysis. The cavity designs investigated include: (1) inlay (I); (2) inlay with palatal cusp coverage (IPC); (3) onlay (O); (4) inlay with pulp chamber extension (IPE); (5) inlay with palatal cusp coverage and pulp chamber extension (IPCPE); and (6) onlay with pulp chamber extension (OPE).
    RESULTS: In each case, tensile stresses were found to be concentrated subjacent to the occlusal fossa. Peak tensile stress and peak shear stress values along the tooth/restoration interface for IPC, O IPCPE and OPE cavity designs were found to be associated with the axiogingival line angle. Overall, the order of the various forms of restoration investigated in terms of the maximum principal stress (from greatest to lowest) was as follows: IPE > IPCPE > OPE > I > IPC > O.
    Matched MeSH terms: Tensile Strength
  14. Kouhi M, Jayarama Reddy V, Ramakrishna S
    Appl Biochem Biotechnol, 2019 Jun;188(2):357-368.
    PMID: 30456599 DOI: 10.1007/s12010-018-2922-0
    Bioceramic nanoparticles with high specific surface area often tend to agglomerate in the polymer matrix, which results in undesirable mechanical properties of the composites and poor cell spreading and attachment. In the present work, bredigite (BR) nanoparticles were modified with an organosilane coupling agent, 3-glycidoxypropyltrimethoxysilane (GPTMS), to enhance its dispersibility in the polymer matrix. The polyhydroxybutyrate-co-hydroxyvaletare (PHBV) nanofibrous scaffolds containing either bredigite or GPTMS-modified bredigite (G-BR) nanoparticles were fabricated using electrospinning technique and characterized using scanning electron microscopy, transmission electron microscopy, and tensile strength. Results demonstrated that modification of bredigite was effective in enhancing nanoparticle dispersion in the PHBV matrix. PHBV/G-BR scaffold showed improved mechanical properties compared to PHBV and PHBV/BR, especially at the higher concentration of nanoparticles. In vitro bioactivity assay performed in the simulated body fluid (SBF) indicated that composite PHBV scaffolds were able to induce the formation of apatite deposits after incubation in SBF. From the results of in vitro biological assay, it is concluded that the synergetic effect of BR and GPTMS provided an enhanced hFob cells attachment and proliferation. The developed PHBV/G-BR nanofibrous scaffolds may be considered for application in bone tissue engineering.
    Matched MeSH terms: Tensile Strength
  15. Aznan MI, Khan OH, Unar AO, Tuan Sharif SE, Khan AH, Syed Abd Aziz SH, et al.
    BMC Complement Altern Med, 2016 Jan 23;16:28.
    PMID: 26803744 DOI: 10.1186/s12906-016-1003-6
    BACKGROUND: Honey has long been used for the treatment of number of ailments and diseases including surgical wounds. Current study evaluates the effectiveness of Tualang honey (TH) for large bowel anastomotic healing in Wistar rats.

    METHODS: Thirty male Wistar rats were given a 3 centimeter infra-umbilical laparotomy wound, in`flicted on their abdomen. The colonic transection was performed at 5 cm distal to caecum, with end to end anastomosis of colon segment. They were divided into two groups. Group I was fed with standard rat chow and water. Meanwhile, Group II apart from standard feed, was also given TH 1.0 g/kg every morning until day seven post operatively. Afterwards, anastomotic bursting pressures were measured and histopathological examination on the anastomosis line was performed with light microscopes. The data from two groups were analyzed by Independent paired t test for continuous variables.

    RESULTS: It was found that the tensile strength of colon anastomosis (95 % CI; p = <0.001) and the histopathological study including fibroblast count (p = <0.001) and inflammatory cells (p = 0.002) showed statistically significant difference in the favor of TH-treated group. Meanwhile, neovascularization formation was not statistically significant (p = 0.807); however, the overall count in the TH group was high.

    CONCLUSION: Oral treatment with TH enhances anastomotic wound healing by increasing the number of fibroblasts and by decreasing inflammatory cells leading towards increased wound strength.

    Matched MeSH terms: Tensile Strength/drug effects
  16. Wan Abas WA
    Biomed Mater Eng, 1995;5(2):59-63.
    PMID: 7655319
    The response of human skin to "stress relaxation" tests at low loads in vitro was investigated. A number of behaviours, other than those already well established and documented, were observed. The significant behaviours are pure recovery and relaxation-recovery. Other behaviours observed are temporary stress recovery during the relaxation process, and momentary sudden non-linear drop in stress value followed by a second relaxation. The pure recovery and relaxation-recovery responses are repeatable. The latter represents the transitional response between the well-known behaviour of stress relaxation and the behaviour of stress recovery.
    Matched MeSH terms: Tensile Strength
  17. Wan Abas WA
    Biomed Mater Eng, 1994;4(7):473-86.
    PMID: 7881331
    The response of human skin to biaxial stretch tests in vivo was investigated and compared to the response to uniaxial tension. The results obtained illustrate the nonlinear, anisotropic, and viscoelastic (time-dependent) properties of skin under biaxial stretch. Preconditioning in the load-extension response was found not to be prominent. The results also suggest that the response of skin to a biaxial stretch in vivo is qualitatively similar to that in vitro. Values of the terminal stiffness and limit strain of skin under a biaxial stretch are found.
    Matched MeSH terms: Tensile Strength
  18. Wan Abas WA, Asseli MR
    Biomed Mater Eng, 1994;4(7):463-71.
    PMID: 7881330
    Local strains acting across an area of skin loaded uniaxially in vivo are converted to stresses using the standard elastic formulae. The stress values are compared to those obtained using the classical Bossinesq and Michell stress functions. The results indicate that these functions are capable of describing the response of the skin, both in the low load and the high load regions.
    Matched MeSH terms: Tensile Strength
  19. Baharuddin MY, Salleh ShH, Hamedi M, Zulkifly AH, Lee MH, Mohd Noor A, et al.
    Biomed Res Int, 2014;2014:478248.
    PMID: 24800230 DOI: 10.1155/2014/478248
    Stress shielding and micromotion are two major issues which determine the success of newly designed cementless femoral stems. The correlation of experimental validation with finite element analysis (FEA) is commonly used to evaluate the stress distribution and fixation stability of the stem within the femoral canal. This paper focused on the applications of feature extraction and pattern recognition using support vector machine (SVM) to determine the primary stability of the implant. We measured strain with triaxial rosette at the metaphyseal region and micromotion with linear variable direct transducer proximally and distally using composite femora. The root mean squares technique is used to feed the classifier which provides maximum likelihood estimation of amplitude, and radial basis function is used as the kernel parameter which mapped the datasets into separable hyperplanes. The results showed 100% pattern recognition accuracy using SVM for both strain and micromotion. This indicates that DSP could be applied in determining the femoral stem primary stability with high pattern recognition accuracy in biomechanical testing.
    Matched MeSH terms: Tensile Strength
  20. Feng Z, Ishiguro Y, Fujita K, Kosawada T, Nakamura T, Sato D, et al.
    Biomaterials, 2015 Oct;67:365-81.
    PMID: 26247391 DOI: 10.1016/j.biomaterials.2015.07.038
    In this paper, we present a general, fibril-based structural constitutive theory which accounts for three material aspects of crosslinked filamentous materials: the single fibrillar force response, the fibrillar network model, and the effects of alterations to the fibrillar network. In the case of the single fibrillar response, we develop a formula that covers the entropic and enthalpic deformation regions, and introduce the relaxation phase to explain the observed force decay after crosslink breakage. For the filamentous network model, we characterize the constituent element of the fibrillar network in terms its end-to-end distance vector and its contour length, then decompose the vector orientation into an isotropic random term and a specific alignment, paving the way for an expanded formalism from principal deformation to general 3D deformation; and, more important, we define a critical core quantity over which macroscale mechanical characteristics can be integrated: the ratio of the initial end-to-end distance to the contour length (and its probability function). For network alterations, we quantitatively treat changes in constituent elements and relate these changes to the alteration of network characteristics. Singular in its physical rigor and clarity, this constitutive theory can reproduce and predict a wide range of nonlinear mechanical behavior in materials composed of a crosslinked filamentous network, including: stress relaxation (with dual relaxation coefficients as typically observed in soft tissues); hysteresis with decreasing maximum stress under serial cyclic loading; strain-stiffening under uniaxial tension; the rupture point of the structure as a whole; various effects of biaxial tensile loading; strain-stiffening under simple shearing; the so-called "negative normal stress" phenomenon; and enthalpic elastic behaviors of the constituent element. Applied to compacted collagen gels, the theory demonstrates that collagen fibrils behave as enthalpic elasticas with linear elasticity within the gels, and that the macroscale nonlinearity of the gels originates from the curved fibrillar network. Meanwhile, the underlying factors that determine the mechanical properties of the gels are clarified. Finally, the implications of this study on the enhancement of the mechanical properties of compacted collagen gels and on the cellular mechanics with this model tissue are discussed.
    Matched MeSH terms: Tensile Strength/drug effects
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