Displaying publications 141 - 160 of 302 in total

Abstract:
Sort:
  1. Biophotonic effect of diode laser irradiance on tensile strength of diabetic rats
    Lau PS, Bidin N, Krishnan G, Nassir Z, Bahktiar H
    J Cosmet Laser Ther, 2015 Apr;17(2):86-9.
    PMID: 25260140 DOI: 10.3109/14764172.2014.968587
    Low-energy laser irradiance at certain wavelengths is able to stimulate the tissue bio-reaction and enhance the healing process. Collagen deposition is one of the important aspects in healing process because it can increase the strength of the skin. This study was designed to examine the biophotonic effect of irradiance on collagen production of diabetic wound in rat model. The tensile strength of skin was employed as a parameter to describe the wound. Diabetic rat models were induced by streptozotocin via intravenous injection. Skin-breaking strength was measured using an Instron tensile test machine. The experimental animals were treated with 808-nm diode laser at two different powers-0.1 and 0.5 W/cm(2)-and 30, 60, and 120 s for each session. The tensile strength was optimized after treated with high-power diode laser. The photostimulation effect was revealed by accelerated healing process and enhanced tensile strength of wound. Laser photostimulation on tensile strength in diabetic wound suggests that such therapy facilitates collagen production in diabetic wound healing.
    Matched MeSH terms: Tensile Strength*
  2. Fulltext Assessments of Secondary Reinforcement of Epoxy Matrix-Glass Fibre Composite Laminates through Nanosilica (SiO₂)
    Lazar PJL, Sengottuvelu R, Natarajan E
    Materials (Basel), 2018 Nov 05;11(11).
    PMID: 30400592 DOI: 10.3390/ma11112186
    The principal objective of this research work was to investigate the results of impregnating epoxy matrix-glass fibre composite laminates with nanosilica as secondary reinforcement. 0.5, 0.75, 1 and 3 wt% nanosilica was used and thereafter properties of composites were assessed through tensile, three point bending, quasi static indentation tests and dynamic mechanical analysis. Scanning electron microscope examinations were done on fracture surfaces and failure modes were analyzed. The internal failures of the composite due to quasi-static indentation were evaluated through C-Scan. Among samples of different weight fractions, 0.75 wt% nanosilica reinforced composite laminates exhibited substantial increase of 42% in tensile strength and 39.46% in flexural strength. The reduction in glass transition temperature (Tg), increase in storage modulus (E'), loss modulus (E″) and damping factor (tan δ) were also observed. Quasi-static indentation assessments revealed that energy absorption property was enhanced significantly by 53.97%. Hence nanosilica up to 0.75 wt% can be used as a potential candidate for secondary reinforcement in epoxy composite laminates.
    Matched MeSH terms: Tensile Strength
  3. Effect of substitution of normal weight coarse aggregate with oil-palm-boiler clinker on properties of concrete
    Lee JC, Payam Shafigh, Hilmi Mahmud, Muhammad Aslam
    Sains Malaysiana, 2017;46:645-653.
    Oil-palm-boiler clinker (OPBC) is an agricultural solid waste sourced from the palm oil industry in tropical regions. This study investigates the use of OPBC as coarse aggregate instead of conventional coarse aggregates to produce a greener concrete, which will help in implementing sustainable construction practices by reducing the usage of raw materials. For this purpose, normal weight coarse aggregates was substituted with dry OPBC aggregates up to 75% (by volume) in a high strength normal weight concrete. The effectiveness of this substitution on the properties of the concrete such as workability, density, compressive strength, splitting tensile strength and modulus of elasticity was studied. The slump test results showed that using OPBC in dry condition reduced the workability of the concrete and therefore can be used up to 50% of the total volume of coarse aggregate. Concrete containing 50% OPBC can be considered as semi-lightweight concrete with high strength. Using OPBC in concrete reduced the splitting tensile strength and modulus of elasticity, however, the reduction was not significant.
    Matched MeSH terms: Tensile Strength
  4. Fulltext Preparation and characterization of polyhydroxybutyrate/polycaprolactone nanocomposites
    Liau CP, Bin Ahmad M, Shameli K, Yunus WM, Ibrahim NA, Zainuddin N, et al.
    ScientificWorldJournal, 2014;2014:572726.
    PMID: 24600329 DOI: 10.1155/2014/572726
    Polyhydroxybutyrate (PHB)/polycaprolactone (PCL)/stearate Mg-Al layered double hydroxide (LDH) nanocomposites were prepared via solution casting intercalation method. Coprecipitation method was used to prepare the anionic clay Mg-Al LDH from nitrate salt solution. Modification of nitrate anions by stearate anions between the LDH layers via ion exchange reaction. FTIR spectra showed the presence of carboxylic acid (COOH) group which indicates that stearate anions were successfully intercalated into the Mg-Al LDH. The formation of nanocomposites only involves physical interaction as there are no new functional groups or new bonding formed. X-ray diffraction (XRD) and transmission electron microscopy (TEM) indicated that the mixtures of nanocomposites are intercalated and exfoliated types. XRD results showed increasing of basal spacing from 8.66 to 32.97 Å in modified stearate Mg-Al LDH, and TEM results revealed that the stearate Mg-Al LDH layers are homogeneously distributed in the PHB/PCL polymer blends matrix. Enhancement in 300% elongation at break and 66% tensile strength in the presence of 1.0 wt % of the stearate Mg-Al LDH as compare with PHB/PCL blends. Scanning electron microscopy (SEM) proved that clay improves compatibility between polymer matrix and the best ratio 80PHB/20PCL/1stearate Mg-Al LDH surface is well dispersed and stretched before it breaks.
    Matched MeSH terms: Tensile Strength
  5. Application of freeze-drying technology in manufacturing orally disintegrating films
    Liew KB, Odeniyi MA, Peh KK
    Pharm Dev Technol, 2016;21(3):346-53.
    PMID: 25597618 DOI: 10.3109/10837450.2014.1003657
    Freeze drying technology has not been maximized and reported in manufacturing orally disintegrating films. The aim of this study was to explore the freeze drying technology in the formulation of sildenafil orally disintegrating films and compare the physical properties with heat-dried orally disintegrating film. Central composite design was used to investigate the effects of three factors, namely concentration of carbopol, wheat starch and polyethylene glycol 400 on the tensile strength and disintegration time of the film. Heat-dried films had higher tensile strength than films prepared using freeze-dried method. For folding endurance, freeze-dried films showed improved endurance than heat-dried films. Moreover, films prepared using freeze-dried methods were thicker and had faster disintegration time. Formulations with higher amount of carbopol and starch showed higher tensile strength and thickness whereas formulations with higher PEG 400 content showed better flexibility. Scanning electron microscopy showed that the freeze-dried films had more porous structure compared to the heat-dried film as a result of the release of water molecule from the frozen structure when it was subjected to freeze drying process. The sildenafil film was palatable. The dissolution profiles of freeze-dried and heat-dried films were similar to Viagra® with f2 of 51.04 and 65.98, respectively.
    Matched MeSH terms: Tensile Strength
  6. Fulltext Characterization of oral disintegrating film containing donepezil for Alzheimer disease
    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
  7. Effect of polymer, plasticizer and filler on orally disintegrating film
    Liew KB, Tan YT, Peh KK
    Drug Dev Ind Pharm, 2014 Jan;40(1):110-9.
    PMID: 23311593 DOI: 10.3109/03639045.2012.749889
    Difficulty in swallowing tablets or capsules has been identified as one of the contributing factors to non-compliance of geriatric patients. Although orally disintegrating tablet was designed for fast disintegration in mouth, the fear of taking solid tablets and the risk of choking for certain patient populations still exist.
    Matched MeSH terms: Tensile Strength
  8. Fulltext Investigation of Fibers Reinforced Engineered Cementitious Composites Properties Using Quartz Powder
    Liew MS, Aswin M, Danyaro KU, Mohammed BS, Al-Yacouby AM
    Materials (Basel), 2020 May 26;13(11).
    PMID: 32466366 DOI: 10.3390/ma13112428
    In relation to the use of retrofit materials on damaged constructions, application on earthquake-resistant buildings, and for the strengthening and rehabilitation on weakened regions, there is a need for a more superior material than concrete. Application sites include beam-column joints, corbels, link-slabs, deep beams, support regions and dapped-end areas. Fiber reinforced engineered cementitious composites (FR-ECC) can address this issue, because FR-ECC is one of the composite materials that has high strength, ductility and durability. In order to develop FR-ECC, this study was done to investigate the effect of adding quartz powder on the compressive strength capacity and properties of FR-ECC through the use of polyvinyl alcohol (PVA) and steel fibers. The volume fraction of fiber was set to 0%-2%. To support the friendly environment, FR-ECC uses by-product materials such as fly ash and silica fume, with a cement content less than 600 kg/m3. In terms of the experimental investigation on FR-ECC, this work conducted the fresh property tests showing that PVA fibers have quite an influence on ECC workability, due to their hydrophilic behavior. By adjusting the superplasticizer (SP) content, the consistency and high workability of the ECC mixes have been achieved and maintained. The test results indicated that the PVA and steel fibers-based ECC mixes can be classified as self-compacting composites and high early compressive strength composites. Significantly, addition of quartz powder into the ECC mixes increased the compressive strength ratio of the ECC samples up to 1.0747. Furthermore, the steel fiber-based ECC samples exhibited greater compressive strength than the PVA fibers-based ECC samples with the strength ratio of 1.1760. Due to effect of the pozzolanic reaction, the fibers dispersion and orientation in the fresh ECC mixes, so that the cementitious matrices provided the high strength on the FR-ECC samples. During the compression loading, the bulging effect always occurred before the failures of the fibers-based ECC samples. No spalling occurred at the time of rupture and the collapse occurred slowly. Thus, FR-ECC has provided unique characteristics, which will reduce the high cost of maintenance.
    Matched MeSH terms: Tensile Strength
  9. Effect of suturing on the mechanical properties of bovine pericardium--implications for cardiac valve bioprosthesis
    Lim KO, Cheong KC
    Med Eng Phys, 1994 Nov;16(6):526-30.
    PMID: 7858787
    In the fabrication of a bioprosthetic heart valve from bovine pericardial tissues, the tissues are subjected to suturing. The stress-strain response of sutured as well as unsutured strips of this tissue were examined. The stress-strain response was determined using a tensile-testing machine. It was found that suturing weakens the tissue in that sutured strips are more extensible, exhibit a lower stress at rupture and a lower final elastic modulus. In addition, it was also found that the bigger the suture/needle size used the greater the decrease in tissue strength. In all, tissue strength was observed to decrease by 22 to 59% in this study. The weakening of the tissue is attributed to the puncture holes created by the surgeon's needle which create regions of weakness. This response of bovine pericardial tissue to suturing should be given due consideration in the fabrication of a bioprosthetic heart valve using this tissue.
    Matched MeSH terms: Tensile Strength
  10. Fulltext Current Progress in Tendon and Ligament Tissue Engineering
    Lim WL, Liau LL, Ng MH, Chowdhury SR, Law JX
    Tissue Eng Regen Med, 2019 Dec;16(6):549-571.
    PMID: 31824819 DOI: 10.1007/s13770-019-00196-w
    BACKGROUND: Tendon and ligament injuries accounted for 30% of all musculoskeletal consultations with 4 million new incidences worldwide each year and thus imposed a significant burden to the society and the economy. Damaged tendon and ligament can severely affect the normal body movement and might lead to many complications if not treated promptly and adequately. Current conventional treatment through surgical repair and tissue graft are ineffective with a high rate of recurrence.

    METHODS: In this review, we first discussed the anatomy, physiology and pathophysiology of tendon and ligament injuries and its current treatment. Secondly, we explored the current role of tendon and ligament tissue engineering, describing its recent advances. After that, we also described stem cell and cell secreted product approaches in tendon and ligament injuries. Lastly, we examined the role of the bioreactor and mechanical loading in in vitro maturation of engineered tendon and ligament.

    RESULTS: Tissue engineering offers various alternative ways of treatment from biological tissue constructs to stem cell therapy and cell secreted products. Bioreactor with mechanical stimulation is instrumental in preparing mature engineered tendon and ligament substitutes in vitro.

    CONCLUSIONS: Tissue engineering showed great promise in replacing the damaged tendon and ligament. However, more study is needed to develop ideal engineered tendon and ligament.

    Matched MeSH terms: Tensile Strength
  11. Simplifying four-strand flexor tendon repair using double-stranded suture: a comparative ex vivo study on tensile strength and bulking
    Low TH, Ahmad TS, Ng ES
    J Hand Surg Eur Vol, 2012 Feb;37(2):101-8.
    PMID: 21636621 DOI: 10.1177/1753193411409840
    We have compared a simple four-strand flexor tendon repair, the single cross-stitch locked repair using a double-stranded suture (dsSCL) against two other four-strand repairs: the Pennington modified Kessler with double-stranded suture (dsPMK); and the cruciate cross-stitch locked repair with single-stranded suture (Modified Sandow). Thirty fresh frozen cadaveric flexor digitorum profundus tendons were transected and repaired with one of the core repair techniques using identical suture material and reinforced with identical peripheral sutures. Bulking at the repair site and tendon-suture junctions was measured. The tendons were subjected to linear load-to-failure testing. Results showed no significant difference in ultimate tensile strength between the Modified Sandow (36.8 N) and dsSCL (32.6 N) whereas the dsPMK was significantly weaker (26.8 N). There were no significant differences in 2 mm gap force, stiffness or bulk between the three repairs. We concluded that the simpler dsSCL repair is comparable to the modified Sandow repair in tensile strength, stiffness and bulking.
    Matched MeSH terms: Tensile Strength/physiology*
  12. A novel approach to evaluate the mechanical responses of elastin-like bioresorbable poly(glycolide-co-caprolactone) (PGCL) suture
    Low YJ, Kittur MI, Andriyana A, Ang BC, Zainal Abidin NI
    J Mech Behav Biomed Mater, 2023 Apr;140:105723.
    PMID: 36821908 DOI: 10.1016/j.jmbbm.2023.105723
    Poly(glycolide-co-caprolactone) (PGCL) has become a novice to the bioresorbable suture owing to the synergistic properties taken from the homo-polyglycolide (PGA) and polycaprolactone (PCL) such as excellent bioresorption and flexibility. In addition to under conventional monotonic loading, the understanding of mechanical responses of PGCL copolymers under complex loading conditions such as cyclic and stress relaxation is crucial for its application as a surgical suture. Consequently, the present work focuses on evaluating the mechanical responses of PGCL sutures under monotonic, cyclic, and stress relaxation loading conditions. Under monotonic loading, the stress-strain behavior of the PGCL suture was found to be non-linear with noticeable strain-rate dependence. Under cyclic loading, inelastic responses including stress-softening, hysteresis and permanent set were observed. During cyclic loading, both stress-softening and hysteresis were found to increase with the maximum strain. In multi-step stress relaxation, the PGCL sutures were observed to exhibit a strong viscoelastic response. In an attempt to describe the relationship between the stress-relaxation and strain-induced crystallization (SIC) occurring during the loading and relaxation processes, a schematic illustration of the conformational change of polymer chains in PGCL sutures was proposed in this work. Results showed that SIC was dependent on the strain level as well as the loading and relaxation durations. The inelastic phenomena observed in PGCL sutures can be thus correlated to the combined effect of stress relaxation and SIC.
    Matched MeSH terms: Tensile Strength
  13. Antibacterial activity and mechanical properties of partially hydrolyzed sago starch-alginate edible film containing lemongrass oil
    Maizura M, Fazilah A, Norziah MH, Karim AA
    J Food Sci, 2007 Aug;72(6):C324-30.
    PMID: 17995673
    Edible films were prepared from a mixture of partially hydrolyzed sago starch and alginate (SA). Lemongrass oil (0.1% to 0.4%, v/w) and glycerol (0% and 20%, w/w) were incorporated in the films to act as natural antimicrobial agent and plasticizer, respectively. The films were characterized for antimicrobial activity, water vapor permeability (WVP), tensile strength (TS), percent elongation at break (%E), and water solubility (WS). Fourier transform infrared (FTIR) spectroscopy was conducted to determine functional group interactions between the matrix and lemongrass oil. The zone of inhibition was increased significantly (P < 0.05) by addition of lemongrass oil at all levels in the presence and the absence of glycerol. This indicates that the film containing lemongrass oil was effective against Escherichia coli O157:H7 at all levels. In the absence of glycerol, the tensile strength of film decreased as the oil content increased, but there was no significant (P > 0.05) difference in percent elongation. The percent elongation at break and WVP values for film with 20% glycerol was found to be increased significantly (P < 0.05) with an increase in lemongrass oil content. Addition of lemongrass oil did not have any interaction with the functional groups of films as measured by FTIR.
    Matched MeSH terms: Tensile Strength
  14. Engineered Electrospun Polyurethane Composite Patch Combined with Bi-functional Components Rendering High Strength for Cardiac Tissue Engineering
    Mani MP, Jaganathan SK, Faudzi AAM, Sunar MS
    Polymers (Basel), 2019 Apr 17;11(4).
    PMID: 30999634 DOI: 10.3390/polym11040705
    Cardiovascular application of nanomaterial's is of increasing demand and its usage is limited by its mechanical and blood compatible properties. In this work, an attempt is made to develop an electrospun novel nanocomposite loaded with basil oil and titanium dioxide (TiO2) particles. The composite material displayed increase in hydrophobic and reduced fiber diameter compared to the pristine polymer. Fourier transform infrared spectroscopy results showed the interaction of the pristine polymer with the added substances. Thermal analysis showed the increased onset degradation, whereas the mechanical testing portrayed the increased tensile strength of the composites. Finally, the composite delayed the coagulation times and also rendered safe environment for red blood cells signifying its suitability to be used in contact with blood. Strikingly, the cellular toxicity of the developed composite was lower than the pristine polymer suggesting its compatible nature with the surrounding tissues. With these promising characteristics, developed material with enhanced physicochemical properties and blood compatibility can be successfully utilized for cardiac tissue applications.
    Matched MeSH terms: Tensile Strength
  15. Mechanical, thermal and chemical resistance of epoxidized natural rubber toughened polylactic acid blends
    Mat Uzir Wahi, Azman Hassan, Akos Noel Ibrahim, Nurhayati Ahmad Zawawi, Kunasegeran K
    Sains Malaysiana, 2015;44:1615-1623.
    Polylactic acid (PLA)/Epoxidized natural rubber (ENR-50) blends were prepared by melt extrusion followed by injection
    molding to fabricate the test samples. The effect of ENR-50 loadings on the morphological, mechanical, chemical
    resistance and water absorption properties of the blends were studied using standard methods. The toughness of the
    blend improved with ENR loading up to 20 wt. % but flexural and tensile strength decreased. The balanced mechanical
    properties were obtained at 20 wt. % ENR-50 loading. SEM showed good distribution and increased ENR particle size
    as ENR content increased from 10 to 30 wt. %. The differential scanning calorimeter (DSC) showed a steady drop in
    crystallization temperature (Tc
    ) as ENR content increases while the glass transition temperature (Tg
    ) remained unchanged.
    Water absorption was observed to increase with ENR loadings. Increase in ENR content was also observed to reduce the
    chemical resistance of the blends.
    Matched MeSH terms: Tensile Strength
  16. Fulltext Influence of Secondary Reinforcement on Behaviour of Corbels with Various Types of High-Performance Fiber-Reinforced Cementitious Composites
    Md Zin N, Al-Fakih A, Nikbakht E, Teo W, Anwar Gad M
    Materials (Basel), 2019 Dec 11;12(24).
    PMID: 31835775 DOI: 10.3390/ma12244159
    An experimental study is conducted to determine the influence of secondary reinforcement on the behaviour of corbels fabricated with three different types of high-performance fiber-reinforced cementitious composites, including engineered cementitious concrete (ECC); high-performance steel fiber-reinforced composite (HPSFRC); and hybrid fiber-reinforced composite (HyFRC). Two shear span-to-depth ratios (a/d = 0.75 and 1.0) are explored. The mechanical properties of the composites in terms of tensile, compressive, and flexural strengths are investigated. Next, the structural behaviour of the high-performance cementitious composite corbels in terms of ultimate load capacity, ductility, and failure modes under the three-point bending test are investigated. The secondary reinforcement is proven to significantly affect stiffness and ultimately load capacity of all three high-performance composite corbels with an aspect ratio of 0.75. However, the secondary reinforcement was more impactful for the HPSFRC corbels, with 51% increase of ultimate strength. Moreover, in terms of damage, fewer cracks occurred in ECC corbels. HPSFRC corbels displayed the highest level of ductility and deformation capacity compared to the other specimens. The results were comparatively analyzed against the predicted results using truss and plastic truss models which provided relatively reliable shear strength.
    Matched MeSH terms: Tensile Strength
  17. Fulltext Graphene/PVA buckypaper for strain sensing application
    Mehmood A, Mubarak NM, Khalid M, Jagadish P, Walvekar R, Abdullah EC
    Sci Rep, 2020 11 18;10(1):20106.
    PMID: 33208815 DOI: 10.1038/s41598-020-77139-2
    Strain sensors in the form of buckypaper (BP) infiltrated with various polymers are considered a viable option for strain sensor applications such as structural health monitoring and human motion detection. Graphene has outstanding properties in terms of strength, heat and current conduction, optics, and many more. However, graphene in the form of BP has not been considered earlier for strain sensing applications. In this work, graphene-based BP infiltrated with polyvinyl alcohol (PVA) was synthesized by vacuum filtration technique and polymer intercalation. First, Graphene oxide (GO) was prepared via treatment with sulphuric acid and nitric acid. Whereas, to obtain high-quality BP, GO was sonicated in ethanol for 20 min with sonication intensity of 60%. FTIR studies confirmed the oxygenated groups on the surface of GO while the dispersion characteristics were validated using zeta potential analysis. The nanocomposite was synthesized by varying BP and PVA concentrations. Mechanical and electrical properties were measured using a computerized tensile testing machine, two probe method, and hall effect, respectively. The electrical conducting properties of the nanocomposites decreased with increasing PVA content; likewise, electron mobility also decreased while electrical resistance increased. The optimization study reports the highest mechanical properties such as tensile strength, Young's Modulus, and elongation at break of 200.55 MPa, 6.59 GPa, and 6.79%, respectively. Finally, electrochemical testing in a strain range of ε ~ 4% also testifies superior strain sensing properties of 60 wt% graphene BP/PVA with a demonstration of repeatability, accuracy, and preciseness for five loading and unloading cycles with a gauge factor of 1.33. Thus, results prove the usefulness of the nanocomposite for commercial and industrial applications.
    Matched MeSH terms: Tensile Strength
  18. Fulltext Mechanical and morphological properties of polypropylene/nano α-Al2O3 composites
    Mirjalili F, Chuah L, Salahi E
    ScientificWorldJournal, 2014;2014:718765.
    PMID: 24688421 DOI: 10.1155/2014/718765
    A nanocomposite containing polypropylene (PP) and nano α-Al2O3 particles was prepared using a Haake internal mixer. Mechanical tests, such as tensile and flexural tests, showed that mechanical properties of the composite were enhanced by addition of nano α-Al2O3 particles and dispersant agent to the polymer. Tensile strength was approximately ∼ 16% higher than pure PP by increasing the nano α-Al2O3 loading from 1 to 4 wt% into the PP matrix. The results of flexural analysis indicated that the maximum values of flexural strength and flexural modulus for nanocomposite without dispersant were 50.5 and 1954 MPa and for nanocomposite with dispersant were 55.88 MPa and 2818 MPa, respectively. However, higher concentration of nano α-Al2O3 loading resulted in reduction of those mechanical properties that could be due to agglomeration of nano α-Al2O3 particles. Transmission and scanning electron microscopic observations of the nanocomposites also showed that fracture surface became rougher by increasing the content of filler loading from 1 to 4% wt.
    Matched MeSH terms: Tensile Strength
  19. The effects of alpha-tocopherol supplementation on fracture healing in a postmenopausal osteoporotic rat model
    Mohamad S, Shuid AN, Mohamed N, Fadzilah FM, Mokhtar SA, Abdullah S, et al.
    Clinics (Sao Paulo), 2012 Sep;67(9):1077-85.
    PMID: 23018307
    OBJECTIVE: Osteoporosis increases the risk of bone fractures and may impair fracture healing. The aim of this study was to investigate whether alpha-tocopherol can improve the late-phase fracture healing of osteoporotic bones in ovariectomized rats.

    METHOD: In total, 24 female Sprague-Dawley rats were divided into three groups. The first group was sham-operated, and the other two groups were ovariectomized. After two months, the right femora of the rats were fractured under anesthesia and internally repaired with K-wires. The sham-operated and ovariectomized control rat groups were administered olive oil (a vehicle), whereas 60 mg/kg of alpha-tocopherol was administered via oral gavage to the alpha-tocopherol group for six days per week over the course of 8 weeks. The rats were sacrificed, and the femora were dissected out. Computed tomography scans and X-rays were performed to assess fracture healing and callus staging, followed by the assessment of callus strengths through the biomechanical testing of the bones.

    RESULTS: Significantly higher callus volume and callus staging were observed in the ovariectomized control group compared with the sham-operated and alpha-tocopherol groups. The ovariectomized control group also had significantly lower fracture healing scores than the sham-operated group. There were no differences between the alpha-tocopherol and sham-operated groups with respect to the above parameters. The healed femora of the ovariectomized control group demonstrated significantly lower load and strain parameters than the healed femora of the sham-operated group. Alpha-tocopherol supplementation was not able to restore these biomechanical properties.

    CONCLUSION: Alpha-tocopherol supplementation appeared to promote bone fracture healing in osteoporotic rats but failed to restore the strength of the fractured bone.

    Matched MeSH terms: Tensile Strength
  20. Effect of powder to liquid ratio on tensile strength and glass transition temperature of alumina filled poly methyl methacrylate (PMMA) denture base material
    Mohamed SH, Arifin A, Mohd Ishak ZA, Nizam A, Samsudin AR
    Med J Malaysia, 2004 May;59 Suppl B:147-8.
    PMID: 15468861
    The aim of this study was to evaluate the mechanical properties and glass transition temperature (Tg) of a denture base material prepared from high molecular weight poly methyl methacrylate (PMMA) and alumina (Al2O3). The glass transition temperature was studied by using differential scanning calorimetry (DSC). The effect of powder-to-liquid ratio was investigated. The result showed that the tensile properties and the Tg were slightly effected by the powder-to-liquid ratio. The ratio of 2.2:1 by weight of powder to liquid was found to be the best ratio for mixing the material to give the best result in this formulation.
    Matched MeSH terms: Tensile Strength
Related Terms
Filters
Contact Us

Please provide feedback to Administrator (afdal@afpm.org.my)

External Links