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  1. The influence of sintering temperature on the porosity and strength of porous hydroxyapatite ceramics
    Rusnah M, Andanastuti M, Idris B
    Med J Malaysia, 2004 May;59 Suppl B:158-9.
    PMID: 15468866
    The present paper reports on the influence of sintering temperature on the porosity and strength of porous hydroxyapatite (HA). HA powder was first prepared by the sol-gel precipitation method using calcium hydroxide and ortho-phosporic acid. The fine HA powder, measuring <50 microm was then mixed into a slurry with the addition of binder agent, being a mixture of sago and PVA. A small amount of sodium dodecyl sulphate was also used as a foaming agent. Porous HA samples were then prepared via slip casting technique. The surface morphology of the sintered samples was observed under scanning electron microscopy at 20 kV and the compositions were determined via SEM-EDX. A universal testing machine was used to determine the compaction strength of the sintered samples.
    Matched MeSH terms: Compressive Strength
  2. Microstructure and strength of extruded porous HA ceramics
    Rusnah M, Andanastuti M, Idris B
    Med J Malaysia, 2004 May;59 Suppl B:83-4.
    PMID: 15468830
    The paper discusses the influence of sintering temperature on the microstructure and strength of hydroxyapatite ceramics prepared using the extrusion process. The average pore diameters observed were in the range of approximately 150mm to 300mm whereas the compaction strength was found to be around 120-160 MPa.
    Matched MeSH terms: Compressive Strength
  3. Fulltext Biomechanical properties of bone cement with addition of cefuroxime antibiotic
    Mohd Fuad D, Masbah O, Shahril Y, Jamari S, Norhamdan MY, Sahrim SH
    Med J Malaysia, 2006 Feb;61 Suppl A:27-9.
    PMID: 17042225
    Antibiotic-loaded bone cement has been used as prophylaxis against infection in total joint replacement surgery. Its effect on the mechanical strength of cement is a major concern as high dose of antibiotic was associated with a significant reduction in mechanical strength of bone cement. However, the cut-off antibiotic that weakens the mechanical strength of cement remains to be determined. This study was undertaken to observe the changes in the mechanical properties of bone cement with gradual increments of Cefuroxime antibiotic. Cefuroxime at different doses: 0, 1.5, 3.0 and 4.5gm were added to a packet of 40gm bone cement (Simplex P) and study samples were prepared by using third generation cementing technique. Mechanical impact, flexural and tensile strength were tested on each sample. Significant impact and tensile strength reduction were observed after addition of 4.5 gm of Cefuroxime. However, flexural strength was significantly reduced at a lower dose of 3.0 gm. The maximum dose of Cefuroxime to be safely added to 40mg Surgical Simplex P is 1.5gm when third generation cementing technique is used. Further study is needed to determine whether it is an effective dose as regards to microbiological parameters.
    Matched MeSH terms: Compressive Strength
  4. Solidification and stabilization of fly ash from mixed hazardous waste incinerator using ordinary Portland cement
    Pariatamby A, Subramaniam C, Mizutani S, Takatsuki H
    Environ Sci, 2006;13(5):289-96.
    PMID: 17096003
    Fly ash samples from a mixed hazardous waste (MHW) incinerator were subjected to solidification and stabilization (S/S) studies using ordinary Portland cement (OPC) as the binder. Additives (i.e., activated carbon and rice husk) were also homogenized with the binder and waste to determine the effectiveness of the immobilization of heavy metals. The toxicity characteristics leaching procedure (TCLP), Japanese Leaching Test (JLT-13) and the American Nuclear Test 16.1 (modified) ANS 16.1 were used to gauge the leaching of heavy metals from the solidified matrixes. Compressibility strength of the solidified matrixes was also tested using the American Standard Testing Material (ASTM) test procedure for the compressive strength of hydraulic cement mortars.
    Matched MeSH terms: Compressive Strength
  5. Fulltext Effect of slurries density on the properties of ceramic foam produced via polymer replication method
    Mohd Al Amin Muhamad Nor, Lee, Chain Hong, Hazizan Md. Akil, Zainal Arifin Ahmad
    Journal of Nuclear and Related Technologies, 2007;2005(1):35-41.
    MyJurnal
    Ceramic foams are a class of high porosity materials that are used or being considered for a wide range of technological applications. Ceramic foam was produce by polymer replication method. In this process, commercial polymeric sponge was use as template, dipping with ceramic particles slurry, drying and then sintered to yield a replica of the original foams. The study was focus on the fabrication of different density of ceramic foams by varying the density of ceramic slurries (1.1876, 1.2687, 1.3653 and 1.5295 g/cm3). Properties of ceramic foam produced such as density was characterized accordingly to ASTM C 271-94 and porosity were characterized using Archimedes methods. Compressive and bending strength was performed accordingly to ASTM C1161-94 and C773-88 (1999), respectively. The morphological study was performed using Scanning Electron Microscopy (SEM) and EDX. Density of ceramic foams produced was about 0.5588 and 1.1852 g/cm3, where as porosity was around 26.28 and 70.59 %. Compressive and bending strength was increase from strength also increases from 2.60 to 23.07 MPa and 1.20 to 11.10 MPa, respectively, with increasing of slurries density from 1.1876 to 1.3653 g/cm3. The SEM micrographs show that the cells structure become denser as the slurries density increased. EDX proved that the ceramic used is porcelain. As a conclusion, increasing in slurries density produced ceramic foams with good mechanical properties such as compressive and bending strength and denser body.
    Matched MeSH terms: Compressive Strength
  6. Surface properties of Indonesian-made narrow dynamic compression plates
    Dewo P, Sharma PK, van der Tas HF, van der Houwen EB, Timmer M, Magetsari R, et al.
    Med J Malaysia, 2008 Jul;63 Suppl A:21-2.
    PMID: 19024964
    The enormous need of orthopaedic (surgical) implants such as osteosynthesis plates is difficult to be fulfilled in developing countries commonly rely on imported ones. One of the alternatives is utilization of local resources, but only after they have been proven safe to use, to overcome this problem. Surface properties are some of the determining factors of safety for those implants. We have succeeded in developing prototype of osteosynthesis plate and the results indicate that Indonesian-made plates need improvement with regards to the surface quality of physical characterization.
    Matched MeSH terms: Compressive Strength
  7. Recent development on porous calcium phosphate ceramics for biomedical application
    Sopyan I
    Med J Malaysia, 2008 Jul;63 Suppl A:14-5.
    PMID: 19024961
    Porous calcium phosphate ceramics have found enormous use in biomedical applications including bone tissue regeneration, cell proliferation, and drug delivery. In bone tissue engineering it has been applied as filling material for bone defects and augmentation, artificial bone graft material, and prosthesis revision surgery. Their high surface area leads to excellent osteoconductivity and resorbability providing fast bone ingrowths. Porous calcium phosphate can be produced by a variety of methods. This paper discusses briefly fundamental aspects of porous calcium phosphate for biomedical applications as well as various techniques used to prepare porous calcium phosphate.
    Matched MeSH terms: Compressive Strength
  8. Effect of luting cements on the compressive strength of Turkom-Cera all-ceramic copings
    Al-Makramani BM, Razak AA, Abu-Hassan MI
    J Contemp Dent Pract, 2008;9(2):33-40.
    PMID: 18264523
    The objective of this study is to investigate the effect of different luting agents on the fracture strength of Turkom-Cera all-ceramic copings.
    Matched MeSH terms: Compressive Strength
  9. Fabrication of porous hydroxyapatite for bone graft substitutes via gas technique
    Mohd. Reusmaazran Yusof, Roslinda Shamsudin, Syafiq Baharuddin, Idris Besar
    Sains Malaysiana, 2008;37:233-237.
    Porous hydroxyapatite (HAp) as a bone graft substitute was produced via gas technique with three different concentrations of hydrogen peroxide (H2O2) namely 20, 30 and 50%. Hydroxyapatite(HA) slurries with different concentration were produced by mixing between H2O2 solutions and HA powder (L/P) with different ratio i.e. 0.9 to 2.20 ml.g-1. Different L/P ratio and H2O2 concentration affected the porosity, interconnectivity and compressive strength of HAp sample. Changes in L/P ratio between 0.9 to 2.20 ml.g-1, increases the porosity around 50 - 65% at 20% H2O2 concentration. Porosity increases with the L/P values and H2O2 concentration which 76% of porosity was obtained at 50% H2O2 and 2.20 mlg-1 of L/P. The compressive strength of HAp is in the range of 0.5 to 2.15 MPa and is found decreasing with the increasing of L/P values.
    Matched MeSH terms: Compressive Strength
  10. Use of waste gypsum to replace natural gypsum as set retarders in portland cement
    Chandara C, Azizli KA, Ahmad ZA, Sakai E
    Waste Manag, 2009 May;29(5):1675-9.
    PMID: 19131236 DOI: 10.1016/j.wasman.2008.11.014
    The present study is focused on clarifying the influence of waste gypsum (WG) in replacing natural gypsum (NG) in the production of ordinary Portland cement (OPC). WG taken from slip casting moulds in a ceramic factory was formed from the hydration of plaster of paris. Clinker and 3-5wt% of WG was ground in a laboratory ball mill to produce cement waste gypsum (CMWG). The same procedure was repeated with NG to substitute WG to prepare cement natural gypsum (CMNG). The properties of NG and WG were investigated via X-ray Diffraction (XRD), X-ray fluorescence (XRF) and differential scanning calorimetry (DSC)/thermogravimetric (TG) to evaluate the properties of CMNG and CMWG. The mechanical properties of cement were tested in terms of setting time, flexural and compressive strength. The XRD result of NG revealed the presence of dihydrate while WG contained dihydrate and hemihydrate. The content of dihydrate and hemihydrates were obtained via DSC/TG, and the results showed that WG and NG contained 12.45% and 1.61% of hemihydrate, respectively. Furthermore, CMWG was found to set faster than CMNG, an average of 15.29% and 13.67% faster for the initial and final setting times, respectively. This was due to the presence of hemihydrate in WG. However, the values obtained for flexural and compressive strength were relatively the same for CMNG and CMWG. Therefore, this result provides evidence that WG can be used as an alternative material to NG in the production of OPC.
    Matched MeSH terms: Compressive Strength
  11. Minimum level of jumping exercise required to maintain exercise-induced bone gains in female rats
    Ooi FK, Singh R, Singh HJ, Umemura Y
    Osteoporos Int, 2009 Jun;20(6):963-72.
    PMID: 18839049 DOI: 10.1007/s00198-008-0760-6
    SUMMARY: This study determines the minimum level of exercise required to maintain 8 weeks of jumping exercise-induced bone gains in rats. It was found that the minimum level of exercise required for maintaining the different exercise-induced bone gains varied between 11% and 18% of the initial exercise intensity.

    INTRODUCTION: This study ascertains the minimum level of follow-up exercise required to maintain bone gains induced by an 8-week jumping exercise in rats.

    METHODS: Twelve groups of 12-week old rats (n = 10 rats per group) were given either no exercise for 8 (8S) or 32 weeks (32S), or received 8 weeks of standard training program (8STP) that consisted of 200 jumps per week, given at 40 jumps per day for 5 days per week, followed by 24 weeks of exercise at loads of either 40 or 20 or 10 jumps per day, for either 5, or 3, or 1 day/week. Bone mass, strength, and morphometric properties were measured in the right tibia. Data were analyzed using one-way analyses of variance.

    RESULTS: Bone mass, strength, mid-shaft periosteal perimeter and cortical area were significantly (p < 0.05) higher in the rats given 8STP than that in the 8S group. The minimal level of exercise required to maintain the bone gains was 31, 36, 25, and 21 jumps per week for mass, strength, periosteal perimeter and cortical area, respectively.

    CONCLUSIONS: Eight weeks of jumping exercise-induced bone gains could be maintained for a period of 24 weeks with follow-up exercise consisting of 11% to 18% of the initial exercise load.

    Matched MeSH terms: Compressive Strength/physiology
  12. Unconfined compression properties of a porous poly(vinyl alcohol)-chitosan-based hydrogel after hydration
    Lee SY, Pereira BP, Yusof N, Selvaratnam L, Yu Z, Abbas AA, et al.
    Acta Biomater, 2009 Jul;5(6):1919-25.
    PMID: 19289306 DOI: 10.1016/j.actbio.2009.02.014
    A poly(vinyl alcohol) (PVA) hydrogel composite scaffold containing N,O-carboxymethylated chitosan (NOCC) was tested to assess its potential as a scaffold for cartilage tissue engineering in a weight-bearing environment. The mechanical properties under unconfined compression for different hydration periods were investigated. The effect of supplementing PVA with NOCC (20wt.% PVA:5vol.% NOCC) produced a porosity of 43.3% and this was compared against a non-porous PVA hydrogel (20g PVA: 100ml of water, control). Under non-hydrated conditions, the porous PVA-NOCC hydrogel behaved in a similar way to the control non-porous PVA hydrogel, with similar non-linear stress-strain response under unconfined compression (0-30% strain). After 7days' hydration, the porous hydrogel demonstrated a reduced stiffness (0.002kPa, at 25% strain), resulting in a more linear stiffness relationship over a range of 0-30% strain. Poisson's ratio for the hydrated non-porous and porous hydrogels ranged between 0.73 and 1.18, and 0.76 and 1.33, respectively, suggesting a greater fluid flow when loaded. The stress relaxation function for the porous hydrogel was affected by the hydration period (from 0 to 600s); however the percentage stress relaxation regained by about 95%, after 1200s for all hydration periods assessed. No significant differences were found between the different hydration periods between the porous hydrogels and control. The calculated aggregate modulus, H(A), for the porous hydrogel reduced drastically from 10.99kPa in its non-hydrated state to about 0.001kPa after 7days' hydration, with the calculated shear modulus reducing from 30.92 to 0.14kPa, respectively. The porous PVA-NOCC hydrogel conformed to a biphasic, viscoelastic model, which has the desired properties required for any scaffold in cartilage tissue engineering.
    Matched MeSH terms: Compressive Strength
  13. Comparison of the load at fracture of Turkom-Cera to Procera AllCeram and In-Ceram all-ceramic restorations
    AL-Makramani BM, Razak AA, Abu-Hassan MI
    J Prosthodont, 2009 Aug;18(6):484-8.
    PMID: 19694015
    PURPOSE: This study investigated the occlusal fracture resistance of Turkom-Cerafused alumina compared to Procera AllCeram and In-Ceram all-ceramic restorations.

    MATERIALS AND METHODS: Sixmaster dies were duplicated from the prepared maxillary first premolar tooth using nonprecious metal alloy (Wiron 99). Ten copings of 0.6 mm thickness were fabricated from each type of ceramic, for a total of thirty copings. Two master dies were used for each group, and each of them was used to lute five copings. All groups were cemented with resin luting cement Panavia F according to manufacturer's instructions and received a static load of 5 kg during cementation. After 24 hours of distilled water storage at 37 degrees C, the copings were vertically compressed using a universal testing machine at a crosshead speed of 1 mm/min.

    RESULTS: The results of the present study showed the following mean loads at fracture: Turkom-Cera (2184 +/- 164 N), In-Ceram (2042 +/- 200 N), and Procera AllCeram (1954 +/- 211 N). ANOVA and Scheffe's post hoc test showed that the mean load at fracture of Turkom-Cera was significantly different from Procera AllCeram (p < 0.05). Scheffe's post hoc test showed no significant difference between the mean load at fracture of Turkom-Cera and In-Ceram or between the mean load at fracture of In-Ceram and Procera AllCeram.

    CONCLUSION: Because Turkom-Cera demonstrated equal to or higher loads at fracture than currently accepted all-ceramic materials, it would seem to be acceptable for fabrication of anterior and posterior ceramic crowns.

    Matched MeSH terms: Compressive Strength*
  14. Performance appraisal of industrial waste incineration bottom ash as controlled low-strength material
    Razak HA, Naganathan S, Hamid SN
    J Hazard Mater, 2009 Dec 30;172(2-3):862-7.
    PMID: 19665294 DOI: 10.1016/j.jhazmat.2009.07.070
    Controlled low-strength material (CLSM) is slurry made by mixing sand, cement, ash, and water. It is primarily used as a replacement for soil and structural fillings. This paper presents the findings of a preliminary investigation carried out on the performance of industrial waste incineration bottom ash as CLSM. CLSM mixes were designed using industrial waste incineration bottom ash, and cement. Tests for density, setting time, bleed, and compressive strength on cubes under various curing conditions, corrosivity, and leaching of heavy metals and salts were carried out on the CLSM mixtures, and the results discussed. Compressive strength for the designed CLSM mixtures ranged from 0.1 to 1.7 MPa. It is shown that the variations in curing conditions have less influence on the compressive strength of CLSM at high values of water to cement ratio (w/c), but low values of w/c influences the strength of CLSM. The CLSM produced does not exhibit corrosive characters as evidenced by pH. Leaching of heavy metals and salts is higher in bleed than in leachate collected from hardened CLSM. Cement reduces the leaching of Boron in bleed. It is concluded that there is good potential for the use of industrial waste incineration bottom ash in CLSM.
    Matched MeSH terms: Compressive Strength
  15. In-vitro digestibility and amino acid composition of soy protein isolate cross-linked with microbial transglutaminase followed by heating with ribose
    Gan CY, Cheng LH, Azahari B, Easa AM
    Int J Food Sci Nutr, 2009;60 Suppl 7:99-108.
    PMID: 19194813 DOI: 10.1080/09637480802635090
    Cross-linked soy protein isolate (SPI) gels were produced via single-treatment of SPI with microbial transglutaminase (MTG) for 5 h or 24 h, or with ribose for 2 h, or via combined-treatments of SPI with MTG followed by heating with ribose. Assessment of gel strength and solubility concluded that measures which increased protein cross-links resulted in improved gel strength; however, in most cases the digestibility and amino acid content of the gels were reduced. The combined treated gel of SPI/MTG for 24 h/ribose was more easily digested by digestive enzymes and retained higher amounts of amino acids compared with the control Maillard gels of SPI with ribose. MTG consumed lysine and glutamine and reduced the availability of amino acids for the Maillard reaction with ribose. MTG was able to preserve the nutritional value of SPI against the destructive effect of the Maillard reaction and cross-links.
    Matched MeSH terms: Compressive Strength
  16. Fulltext Influence of CO2 flux on the properties of carbonate apatite synthesized by solid state reaction
    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: Compressive Strength
  17. Reinforcement of calcium phosphate cement with multi-walled carbon nanotubes and bovine serum albumin for injectable bone substitute applications
    Chew KK, Low KL, Sharif Zein SH, McPhail DS, Gerhardt LC, Roether JA, et al.
    J Mech Behav Biomed Mater, 2011 Apr;4(3):331-9.
    PMID: 21316621 DOI: 10.1016/j.jmbbm.2010.10.013
    This paper presents the development of novel alternative injectable calcium phosphate cement (CPC) composites for orthopaedic applications. The new CPC composites comprise β-tri-calcium phosphate (β-TCP) and di-calcium phosphate anhydrous (DCPA) mixed with bovine serum albumin (BSA) and incorporated with multi-walled carbon nanotubes (MWCNTs) or functionalized MWCNTs (MWCNTs-OH and MWCNTs-COOH). Scanning electron microscopy (SEM), compressive strength tests, injectability tests, Fourier transform infrared spectroscopy and X-ray diffraction were used to evaluate the properties of the final products. Compressive strength tests and SEM observations demonstrated particularly that the concomitant admixture of BSA and MWCNT improved the mechanical properties, resulting in stronger CPC composites. The presence of MWCNTs and BSA influenced the morphology of the hydroxyapatite (HA) crystals in the CPC matrix. BSA was found to act as a promoter of HA growth when bounded to the surface of CPC grains. MWCNT-OH-containing composites exhibited the highest compressive strengths (16.3 MPa), being in the range of values for trabecular bone (2-12 MPa).
    Matched MeSH terms: Compressive Strength
  18. Ageing modifies the fibre angle and biomechanical function of the lumbar extensor muscles
    Singh DK, Bailey M, Lee RY
    Clin Biomech (Bristol, Avon), 2011 Jul;26(6):543-7.
    PMID: 21392870 DOI: 10.1016/j.clinbiomech.2011.02.002
    Ageing is associated with geometrical changes in muscle fascicles that may lead to deteriorations in physical functions. The purpose of this study was to study the effects of ageing on fibre orientation and strength of the lumbar extensor muscles.
    Matched MeSH terms: Compressive Strength
  19. Design and validation of a bi-axial loading bioreactor for mechanical stimulation of engineered cartilage
    Yusoff N, Abu Osman NA, Pingguan-Murphy B
    Med Eng Phys, 2011 Jul;33(6):782-8.
    PMID: 21356602 DOI: 10.1016/j.medengphy.2011.01.013
    A mechanical-conditioning bioreactor has been developed to provide bi-axial loading to three-dimensional (3D) tissue constructs within a highly controlled environment. The computer-controlled bioreactor is capable of applying axial compressive and shear deformations, individually or simultaneously at various regimes of strain and frequency. The reliability and reproducibility of the system were verified through validation of the spatial and temporal accuracy of platen movement, which was maintained over the operating length of the system. In the presence of actual specimens, the system was verified to be able to deliver precise bi-axial load to the specimens, in which the deformation of every specimen was observed to be relatively homogeneous. The primary use of the bioreactor is in the culture of chondrocytes seeded within an agarose hydrogel while subjected to physiological compressive and shear deformation. The system has been designed specifically to permit the repeatable quantification and characterisation of the biosynthetic activity of cells in response to a wide range of short and long term multi-dimensional loading regimes.
    Matched MeSH terms: Compressive Strength
  20. Mechanical and microarchitectural analyses of cancellous bone through experiment and computer simulation
    Syahrom A, Abdul Kadir MR, Abdullah J, Öchsner A
    Med Biol Eng Comput, 2011 Dec;49(12):1393-403.
    PMID: 21947767 DOI: 10.1007/s11517-011-0833-0
    The relationship between microarchitecture to the failure mechanism and mechanical properties can be assessed through experimental and computational methods. In this study, both methods were utilised using bovine cadavers. Twenty four samples of cancellous bone were extracted from fresh bovine and the samples were cleaned from excessive marrow. Uniaxial compression testing was performed with displacement control. After mechanical testing, each specimen was ashed in a furnace. Four of the samples were exemplarily scanned using micro-computed tomography (μCT) and three dimensional models of the cancellous bones were reconstructed for finite element simulation. The mechanical properties and the failure modes obtained from numerical simulations were then compared to the experiments. Correlations between microarchitectural parameters to the mechanical properties and failure modes were then made. The Young's modulus correlates well with the bone volume fraction with R² = 0.615 and P value 0.013. Three different types of failure modes of cancellous bone were observed: oblique fracture (21.7%), perpendicular global fracture (47.8%), and scattered localised fracture (30.4%). However, no correlations were found between the failure modes to the morphological parameters. The percentage of error between computer predictions and the actual experimental test was from 6 to 12%. These mechanical properties and information on failure modes can be used for the development of synthetic cancellous bone.
    Matched MeSH terms: Compressive Strength/physiology
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