Displaying publications 241 - 260 of 307 in total

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  1. Optimization of soy protein isolate, microbial transglutaminase and glucono-δ-lactone in gluten-free rice noodles
    Ojukwu M, Ofoedu C, Seow EK, Easa AM
    J Sci Food Agric, 2021 Jul;101(9):3732-3741.
    PMID: 33301191 DOI: 10.1002/jsfa.11004
    BACKGROUND: Rice flour does not contain gluten and lacks cohesion and extensibility, which is responsible for the poor texture of rice noodles. Different technologies have been used to mitigate this challenge, including hydrothermal treatments of rice flour, direct addition of protein in noodles, use of additives such as hydrocolloids and alginates, and microbial transglutaminase (MTG). Recently, the inclusion of soy protein isolate (SPI), MTG, and glucono-δ-lactone (GDL) in the rice noodles system yielded rice noodles with improved texture and more compact microstructure, hence the need to optimize the addition of SPI, MTG, and GDL to make quality rice noodles.

    RESULTS: Numerical optimization showed that rice noodles prepared with SPI, 68.32 (g kg-1 of rice flour), MTG, 5.06 (g kg-1 of rice flour) and GDL, 5.0 (g kg-1 of rice flour) gave the best response variables; hardness (53.19 N), springiness (0.76), chewiness (20.28 J), tensile strength (60.35 kPa), and cooking time (5.15 min). The pH, sensory, and microstructure results showed that the optimized rice noodles had a more compact microstructure with fewer hollows, optimum pH for MTG action, and overall sensory panelists also showed the highest preference for the optimized formulation, compared to other samples selected from the numerical optimization and desirability tests.

    CONCLUSION: Optimization of the levels of SPI, MTG, and GDL yielded quality noodles with improved textural, mechanical, sensory, and microstructural properties. This was partly due to the favourable pH value of the optimized noodles that provided the most suitable conditions for MTG crosslinking and balanced electrostatic interaction of proteins. © 2020 Society of Chemical Industry.

    Matched MeSH terms: Tensile Strength
  2. Fulltext Development of biodegradable plastic composite blends based on sago derived starch and natural rubber
    Kiing, Sie Cheong, Balasubramaniam, Jaya-Raj, Yiu, Pang Hung, Wong, Sie Chuong, Amartalingam, Rajan
    Pertanika Journal of Science & Technology, 2010;18(2):-.
    MyJurnal
    Polyethylene is a widely used packaging material, but its non-biodegradable nature can lead to waste
    disposal problems. This increases the concern in research and development of biodegradable plastics from natural resource as alternatives to petroleum-derived plastics. In this study, biodegradable plastic composites were prepared by blending thermoplastic starch with natural rubber in the present of glycerol as plasticizer. Local sago starch was cast with 0.5 to 10% of natural rubber to prepare the bioplastic. The products were characterized by differential scanning calorimetry (DSC), Fourier transform infrared spectroscopy (FTIR), water absorption test, biodegradable test, hydrolysis test, and mechanical analysis. Meanwhile, composite with natural rubber latex was increased from 0.5 to 10% showing that the melting temperature is in the range of 120 to 150˚C, but with no significant difference. The water absorption characteristics, biodegradability, and tensile strength decreased by 11.21%, 30.18%, and 20.733 MPa, respectively. However, the elongation at break was increased from 26.67 to 503.3%. The findings of this study showed that sago starch has a great potential in bioplastic production with good miscibility and compatibility.
    Matched MeSH terms: Tensile Strength
  3. Fulltext Edible films from seaweed (kappaphycus alvarezii)
    Siah, W.M., Aminah, A., Ishak, A.
    International Food Research Journal, 2015;22(6):2230-2236.
    MyJurnal
    A new patent pending process is proposed in this study to produce edible film directly from seaweed (Kappaphycus alvarezii). Seaweed together with other ingredients has been used to produce the film through casting technique. Physical and mechanical tests were performed on the edible films to examine the thickness, colour, transparency, solubility, tensile strength,
    elongation at break, water permeability rate, oxygen permeability rate and surface morphology. Produced film was transparent, stretchable, sealable and have basic properties as a film for food packaging. This study suggests that the edible film could be used as novel materials in food industry as sachet/pouch/bag for instant coffee, breakfast cereals drinks, seasoning powder,
    candies etc; as wrapper for seasoning cube and chocolate; as interleaf for frozen foods such as burger patties to avoid the patties from sticking together; and also as material for edible logo in bakeries products. Other than that, the edible film also could be used in pharmaceutical industry as functional strips such as oral freshener strips and drug strips. In cosmetic and toiletries industries, the edible film could be used to produce facial mask and bag for pre-portioned detergent. Compared with edible film developed earlier using alginate and carrageenan, film developed in this research used seaweed directly. The developed film reduced the need to extract the alginate and carrageenan, making material preparation easier and cheaper.
    Matched MeSH terms: Tensile Strength
  4. Fulltext Electrical resistivity, thermal stability and tensile strength of rice husk flour-plastic waste composites
    Shahril Anuar Bahari, Kamrie Kamlon, Masitah Abu Kassim
    Scientific Research Journal, 2012;9(2):0-0.
    MyJurnal
    In this study, the rice husk flour-plastic waste composites (RPC) was produced from polypropylene (PP) and high density polyethylene (HDPE) wastes with 30 and 50% rice husk flour (RHF) contents. RPC was made by melt compounding and compression moulding processes. The electrical resistivity, thermal stability and tensile strength of RPC were determined. The RPC was tested in electrical resistivity and tensile strength according to the ASTM D-257 and ASTM D-638 respectively, while thermal stability was tested using thermogravimetric analysis (TGA) method. From the results, high content of RHF reduces all properties, except for tensile modulus of elasticity (TMOE) in tensile strength test. The ability of moisture absorption and the presence of hemicelluloses, cellulose and silica in RHF reduce the electrical resistivity and thermal stability behaviour of RPC from 50% RHF. The good binding elements and filler agglomeration in RPC from 50% RHF improve only TMOE. Insufficient stress transfer and rigid interphase occurred between RHF and plastics during tensile maximum load and elongation at break (Eb) in tensile strength test. In general, RPC from HDPE indicates better thermal stability, tensile modulus of rupture and Eb (in tensile strength test) compared to PP, based on the good behaviour of thermal conductivity, low water absorption, high molecular weight and good elongation properties of HDPE. However, RPC from PP shows good electrical resistance due to the low thermal expansion coefficient of PP.
    Matched MeSH terms: Tensile Strength
  5. Fulltext Fabrication of cellulose acetate film from oil palm empty fruit bunch (OP-EFB) and cytotoxicity evaluation
    Dasmawati Mohamad, Wan Suzaini Wan Hamzah, Wan Rosli Wan Daud, Zainul Ahmad Rajion, Wan Zaripah Wan Bakar, Mazlan Ibrahim
    Pertanika Journal of Science & Technology, 2012;20(1):189-207.
    MyJurnal
    The aims of this study were to fabricate cellulose acetate (CA) film from oil palm empty fruit bunch (OP-EPB), as well as to characterize and evaluate their biocompatibility. Several processes were carried out, and these included prehydrolysis-soda method, chlorine free bleaching method, including oxygen, ozone and peroxide, to produce the cellulose pulp. Then, a liquid phase acetylation method was applied through acetic acid-acetic anhydride-sulphuric acid. Triethyl citrate (TEC) ester was used as additive at different percentages of 10, 20, 30 and 40 wt%. The film produced was characterized by FTIR to identify the functional group of the CA film and their tensile properties were further characterized. Biocompatibility of the film was evaluated using cytotoxicity test. Stem cell derived from human deciduous teeth (SHED) was used with MTS assay. The results showed at 30% of TEC, the tensile strength and elongation of CA (OP-EFB) film was at the optimum and is therefore suitable to be used in dental application. The cytotoxicity evaluated showed that the fabricated CA (OP-EFB) films were non-toxic up to the concentration tested, and are thus compatible with SHED.
    Matched MeSH terms: Tensile Strength
  6. Fulltext UV/O3 treatment as a surface modification of rice husk towards preparation of novel biocomposites
    Rajendran Royan NR, Sulong AB, Yuhana NY, Chen RS, Ab Ghani MH, Ahmad S
    PLoS One, 2018;13(5):e0197345.
    PMID: 29847568 DOI: 10.1371/journal.pone.0197345
    The use of rice husks (RH) to reinforce polymers in biocomposites are increasing tremendously. However, the incompatibility between the hydrophilic RH fibers and the hydrophobic thermoplastic matrices leads to unsatisfactory biocomposites. Surface modification of the fiber surface was carried out to improve the adhesion between fiber and matrix. In this study, the effect of surface modification of RH via alkali, acid and ultraviolet-ozonolysis (UV/O3) treatments on the properties of composites recycled high density polyethylene (rHDPE) composites was investigated. The untreated and treated RH were characterized by Fourier Transform Infrared (FTIR) and Scanning Electron Microscope (SEM). The composites containing 30 wt% of RH (treated and untreated) were then prepared via extrusion and followed by compression molding. As compared to untreated RH, all surface treated RH exhibited rougher surface and showed improved adhesion with rHDPE matrix. Tensile strength of UV/O3-treated RH composites showed an optimum result at 18.37 MPa which improved about 5% in comparison to the composites filled with untreated RH. UV/O3 treatment promotes shorter processing time and lesser raw material waste during treatment process where this is beneficial for commercialization in the future developments of wood plastic composites (WPCs). Therefore, UV/O3 treatment can be served as an alternative new method to modify RH surface in order to improve the adhesion between hydrophilic RH fibre and hydrophobic rHDPE polymer matrix.
    Matched MeSH terms: Tensile Strength
  7. Fulltext Engineering characterisation of epoxidized natural rubber-modified hot-mix asphalt
    Al-Mansob RA, Ismail A, Yusoff NI, Rahmat RA, Borhan MN, Albrka SI, et al.
    PLoS One, 2017;12(2):e0171648.
    PMID: 28182724 DOI: 10.1371/journal.pone.0171648
    Road distress results in high maintenance costs. However, increased understandings of asphalt behaviour and properties coupled with technological developments have allowed paving technologists to examine the benefits of introducing additives and modifiers. As a result, polymers have become extremely popular as modifiers to improve the performance of the asphalt mix. This study investigates the performance characteristics of epoxidized natural rubber (ENR)-modified hot-mix asphalt. Tests were conducted using ENR-asphalt mixes prepared using the wet process. Mechanical testing on the ENR-asphalt mixes showed that the resilient modulus of the mixes was greatly affected by testing temperature and frequency. On the other hand, although rutting performance decreased at high temperatures because of the increased elasticity of the ENR-asphalt mixes, fatigue performance improved at intermediate temperatures as compared to the base mix. However, durability tests indicated that the ENR-asphalt mixes were slightly susceptible to the presence of moisture. In conclusion, the performance of asphalt pavement can be enhanced by incorporating ENR as a modifier to counter major road distress.
    Matched MeSH terms: Tensile Strength
  8. Salmon skin gelatin-corn zein composite films produced via crosslinking with glutaraldehyde: Optimization using response surface methodology and characterization
    Fan HY, Duquette D, Dumont MJ, Simpson BK
    Int J Biol Macromol, 2018 Dec;120(Pt A):263-273.
    PMID: 30130612 DOI: 10.1016/j.ijbiomac.2018.08.084
    Composite films comprised of salmon (Salmo salar) skin gelatin and zein were prepared via crosslinking with glutaraldehyde. Response surface methodology (RSM) was used to optimize film composition to maximize tensile strength (TS) and elongation at break (EAB), and to minimize water solubility (WS) of the films. The significant (P strength as a function of increasing humidity.
    Matched MeSH terms: Tensile Strength
  9. Effect of cogon grass fibre on the thermal, mechanical and biodegradation properties of thermoplastic cassava starch biocomposite
    Jumaidin R, Khiruddin MAA, Asyul Sutan Saidi Z, Salit MS, Ilyas RA
    Int J Biol Macromol, 2020 Mar 01;146:746-755.
    PMID: 31730973 DOI: 10.1016/j.ijbiomac.2019.11.011
    Thermoplastic cassava starch (TPCS) is a promising alternative material to replace the non-biodegradable petroleum based polymer due to its good environmental-friendly aspect i.e. abundant, sustainable, recyclable and biodegradable in nature. However, TPCS have some limitation such as poor mechanical properties. Therefore, in the present study, cogon grass fibre (CGF) were incorporated into TPCS using compression molding. Then the fundamental properties of CFG/TPCS biopolymer composites were carried out in order to evaluate their potential as a biodegradable reinforcement. From the study it was found that, the incorporation of CFG has improved the tensile and flexural properties of the TPCS composites, while the impact strength and elongation were reduced. The thermal properties of the biocomposite were reduced as the cogon grass fibres increase from 0 to 5%. In term of morphological, SEM shows good fibre adhesion between CGF and TPCS. Soil burial test shows that incorporation of CGF into TPCS has slow down the biodegradation process of the composites. Thus, CGF/TPCS biopolymer composites can be classified as composites with great potential as environmental-friendly material that biodegradable and renewable.
    Matched MeSH terms: Tensile Strength
  10. Mechanical and microstructural properties of high calcium fly ash one-part geopolymer cement made with granular activator
    Mohammed BS, Haruna S, Wahab MMA, Liew MS, Haruna A
    Heliyon, 2019 Sep;5(9):e02255.
    PMID: 31687531 DOI: 10.1016/j.heliyon.2019.e02255
    In this present experimental study, geopolymer cement is developed using high calcium fly ash and used in the production of one-part alkali-activated binders. At 8-16 percent of the total precursor materials, the HCFA was activated with anhydrous sodium metasilicate powder and cured in ambient condition. Five mixtures of one-part geopolymer paste were intended at a steady w/b proportion. Density, flowability, setting time, compressive strength, splitting tensile strength and molar ratio impact were envisaged. It was observed that the setting time of the designed one-part geopolymer paste decreases with higher activator content. The experimental findings showed that the resistance of one-part geopolymer cement paste increases with comparatively greater activator content. However, raising the granular activator beyond 12 percent by fly ash weight decreases the strength and workability of the established one-part geopolymer cement. The optimum mix by weight of the fly ash was discovered to be 12 percent (i.e. 6 percent Na2O). At 28 days of curing, one-part alkali-activated paste recorded the greatest compressive strength of almost 50 MPa. The density of the one-part geopolymer paste is nearly the same regardless of the mixes. Microstructural assessment by FESEM, FTIR and XRD has shown that the established geopolymer paste includes quartz, pyrrhotite, aluminosilicate sodium and hydrate gels of calcium aluminosilicate. Based on the experimental information acquired, it can be deduced that the strength growth of one-part geopolymer cement is similar to that of Portland cement.
    Matched MeSH terms: Tensile Strength
  11. Novel riboflavin/VE-TPGS modified universal dentine adhesive with superior dentine bond strength and self-crosslinking potential
    Daood U, Sauro S, Pichika MR, Omar H, Liang Lin S, Fawzy AS
    Dent Mater, 2020 01;36(1):145-156.
    PMID: 31818524 DOI: 10.1016/j.dental.2019.11.003
    OBJECTIVE: To modify a universal dentine adhesive with different concentrations of riboflavin and D-Alpha 1000 Succinate polyethylene (VE-TPGS) as a chemical enhancer and to assess the micro-tensile bond strength (24h/12 months), determine resin penetration, measurement of intermolecular interactions and cytotoxicity.

    MATERIALS AND METHODS: An experimental adhesive system based on bis-GMA, HEMA and hydrophobic monomer was doped with RF0.125 (RF - Riboflavin) or RF/VE-TPGS (0.25/0.50) and submitted to μTBS evaluation. Resin dentine slabs were prepared and examined using SEM and TEM. Adhesion force was analysed on ends of AFM cantilevers deflection. Quenched peptide assays were performed using fluorescence scanner and wavelengths set to 320nm and 405nm. Cytotoxicity was assessed using human peripheral blood mononuclear cell line. Molecular docking studies were carried out using Schrödinger small-molecule drug discovery suite 2018-2. Data from viable cell results was analyzed using one-way ANOVA. Bond strength values were analysed by two-way ANOVA. Nonparametric results were analyzed using a Kruskal-Wallis test at a 0.05 significance level.

    RESULTS: RF/VE-TPGS0.25 groups showed highest bond strength results after 24-h storage in artificial saliva (p<0.05). RF/VE-TPGS0.50 groups showed increased bond strength after 12-months of ageing. RF/VE-TPGS modified adhesives showed appreciable presence of a hybrid layer. Packing fraction indicated solid angle profiles describing well sized density and topology relations for the RF/VE-TPGS adhesives, in particular with the RF/VE-TPGS0.50 specimens. Qualitative analysis of the phenotype of macrophages was prominently CD163+ in the RF/VE-TPGS0.50. Both the compounds showed favourable negative binding energies as expressed in terms of 'XP GScore'.

    CONCLUSION: New formulations based on the incorporation of RF/VE-TPGS in universal adhesives may be of significant potential in facilitating penetration, distribution and uptake of riboflavin within the dentine surface.

    Matched MeSH terms: Tensile Strength
  12. Titanium dioxide nanotubes incorporated gellan gum bio-nanocomposite film for wound healing: Effect of TiO2 nanotubes concentration
    Razali MH, Ismail NA, Mat Amin KA
    Int J Biol Macromol, 2020 Jun 15;153:1117-1135.
    PMID: 31751725 DOI: 10.1016/j.ijbiomac.2019.10.242
    The synthesized titanium dioxide nanotubes (TiO2-NTs) were emerged as wound healing enhancer as well as exhibited significant wound healing activity on Sprague Dawley rats. In our present study, the blends of GG and TiO2-NTs bio-nanocomposite film was characterised by fourier transform infrared (FTIR), x-ray diffraction (XRD), scanning electron microscopy (SEM), thermogravimetric analysis, atomic force microscopy (AFM). The morphology of TiO2-NTs was investigated using transmission electron microscopy (TEM). The mechanical properties study shows that the GG + TiO2-NTs (20 w/w %) bio-nanocomposite film possessed the highest tensile strength and young modulus which are (4.56 ± 0.15) MPa and (68 ± 1.63) MPa, respectively. GG + TiO2-NTs (20 w/w %) also displays the highest antibacterial activity with (16 ± 0.06) mm, (16 ± 0.06) mm, (14 ± 0.06) mm, and (12 ± 0.25) mm inhibition zone were recorded against Staphylococcus aureus, Streptococcus, Escherichia coli, and Pseudomonas aeruginosa. The prepared bio-nanocomposite films have good biocompatibility against 3T3 mouse fibroblast cells and caused accelerated healing of open excision type wounds on Sprague Dawley rat model. The synergistic effects of bio-nanocomposite film like good swelling and WVTR properties, excellent hydrophilic nature, biocompatibility, wound appearance and wound closure rate through in vivo test makes it a suitable candidate for wound healing applications.
    Matched MeSH terms: Tensile Strength
  13. Enhancement of thermal, mechanical and physical properties of polyamide 12 composites via hybridization of ceramics for bone replacement
    Abdullah AM, Mohamad D, Rahim TNAT, Akil HM, Rajion ZA
    Mater Sci Eng C Mater Biol Appl, 2019 Jun;99:719-725.
    PMID: 30889745 DOI: 10.1016/j.msec.2019.02.007
    This study reports the influence of ZrO2/β-TCP hybridization on the thermal, mechanical, and physical properties of polyamide 12 composites to be suited for bone replacement. Amount of 15 wt% of nano-ZrO2 along with 5,10,15,20 and 25 wt% of micro-β-TCP was compounded with polyamide 12 via a twin-screw extruder. The hybrid ZrO2/β-TCP filled polyamide 12 exhibited higher thermal, mechanical and physical properties in comparison to unfilled polyamide 12 at certain filler loading; which is attributed to the homogenous dispersion of ZrO2/β-TCP fillers particle in polyamide 12 matrix. The hybrid ZrO2/β-TCP filled PA 12 demonstrated an increment of tensile strength by up to 1%, tensile modulus of 38%, flexural strength of 15%, flexural modulus of 45%, and surface roughness value of 93%, as compared to unfilled PA 12. With enhanced thermal, mechanical and physical properties, the newly developed hybrid ZrO2/β-TCP filled PA 12 could be potentially utilized for bone replacement.
    Matched MeSH terms: Tensile Strength
  14. Degradation of methyl orange and congo red by using chitosan/polyvinyl alcohol/TiO2 electrospun nanofibrous membrane
    Habiba U, Lee JJL, Joo TC, Ang BC, Afifi AM
    Int J Biol Macromol, 2019 Jun 15;131:821-827.
    PMID: 30904531 DOI: 10.1016/j.ijbiomac.2019.03.132
    In this study, chitosan/polyvinyl alcohol/TiO2 nanofiber was fabricated via electrospinning at a pump rate of 1.5 mL/h and voltage 6 kV. Field-emission scanning electron microscopic images showed bead free finer nanofiber. Fourier transform infrared spectra proved the formation of strong bond among chitosan, polyvinyl alcohol and TiO2. X-ray powder diffraction showed that TiO2 became amorphous in the composite nanofiber. Toughness and thermal stability of the chitosan/PVA nanofibrous membrane was increased with addition TiO2. The chitosan/PVA/TiO2 nanofibrous membrane was stable at basic medium. But degraded in acidic and water medium after 93 and 162 h, respectively. The adsorption mechanism of congo red obeyed the Langmuir isotherm model. On the other hand, adsorption characteristic of methyl orange fitted well with both Langmuir and Freundlich isotherm models. The maximum adsorption capacity of the resulting membrane for congo red and methyl orange is 131 and 314 mg/g, respectively. However, a high dose of adsorbent was required for congo red.
    Matched MeSH terms: Tensile Strength
  15. Fulltext The Role of Two-Step Blending in the Properties of Starch/Chitin/Polylactic Acid Biodegradable Composites for Biomedical Applications
    Olaiya NG, Nuryawan A, Oke PK, Khalil HPSA, Rizal S, Mogaji PB, et al.
    Polymers (Basel), 2020 Mar 05;12(3).
    PMID: 32151004 DOI: 10.3390/polym12030592
    The current research trend for excellent miscibility in polymer mixing is the use of plasticizers. The use of most plasticizers usually has some negative effects on the mechanical properties of the resulting composite and can sometimes make it toxic, which makes such polymers unsuitable for biomedical applications. This research focuses on the improvement of the miscibility of polymer composites using two-step mixing with a rheomixer and a mix extruder. Polylactic acid (PLA), chitin, and starch were produced after two-step mixing, using a compression molding method with decreasing composition variation (between 8% to 2%) of chitin and increasing starch content. A dynamic mechanical analysis (DMA) was used to study the mechanical behavior of the composite at various temperatures. The tensile strength, yield, elastic modulus, impact, morphology, and compatibility properties were also studied. The DMA results showed a glass transition temperature range of 50 °C to 100 °C for all samples, with a distinct peak value for the loss modulus and factor. The single distinct peak value meant the polymer blend was compatible. The storage and loss modulus increased with an increase in blending, while the loss factor decreased, indicating excellent compatibility and miscibility of the composite components. The mechanical properties of the samples improved compared to neat PLA. Small voids and immiscibility were noticed in the scanning electron microscopy images, and this was corroborated by X-ray diffraction graphs that showed an improvement in the crystalline nature of PLA with starch. Bioabsorption and toxicity tests showed compatibility with the rat system, which is similar to the human system.
    Matched MeSH terms: Tensile Strength
  16. Diclofenac release from eudragit-containing matrices and effects of thermal treatment
    Billa N, Yuen KH, Peh KK
    Drug Dev Ind Pharm, 1998 Jan;24(1):45-50.
    PMID: 15605596
    Ethyl acrylate-methyl methacrylate copolymer (Eudragit NE40D) was evaluated as matrix material for preparing controlled-release tablets of diclofenac sodium. Drug release could be modified in a predictable manner by varying the Eudragit NE40D content, but was pH dependent, being markedly reduced at lower pH. This could be attributed to the low solubility of the drug at these pH values. Thermal treatment of the tablets at 60 degrees C was also found to affect the rate of drug release, which was found to decrease with an increase in the treatment duration, but could be stabilized after 96 hr of treatment. This was also associated with a corresponding increase in the tablet tensile strength. However, treatment of the granules for 5 hr prior to compaction into tablets could shorten the stabilizing time of the drug release to 48 hr and that of the tensile strength to 24 hr. The effect of thermal treatment may be ascribed to better coalescence of the Eudragit particles to form a fine network, resulting in matrix of higher tortuosity and lower porosity.
    Matched MeSH terms: Tensile Strength
  17. Comparison studies on the percolation thresholds of binary mixture tablets containing excipients of plastic/brittle and plastic/plastic deformation properties
    Amin MC, Fell JT
    Drug Dev Ind Pharm, 2004;30(9):937-45.
    PMID: 15554218
    Percolation theory has been used with great interest in understanding the design and characterization of dosage forms. In this study, work has been carried out to investigate the behavior of binary mixture tablets containing excipients of similar and different deformation properties. The binary mixture tablets were prepared by direct compression using lactose, polyvinyl chloride (PVC), Eudragit RS 100, and microcrystalline cellulose (MCC). The application of percolation theory on the relationships between compactibility, Pmax, or compression susceptibility (compressibility), gamma, and mixture compositions reveals the presence of percolation thresholds even for mixtures of similar deformation properties. The results showed that all mixture compositions exhibited at least one discreet change in the slope, which was referred to as the percolation threshold. The PVC/Eudragit RS100 mixture compositions showed significant percolation threshold at 80% (w/w) PVC loading. Two percolation thresholds were observed from a series of binary mixtures containing similar plastic deformation materials (PVC/MCC). The percolation thresholds were determined at 20% (w/w) and 80% (w/w) PVC loading. These are areas where one of the components percolates throughout the system and the properties of the tablets are expected to experience a sudden change. Experimental results, however, showed that total disruption of the tablet physical properties at the specified percolation thresholds can be observed for PVC/lactose mixtures at 20-30% (w/w) loading while only minor changes in the tablets' strength for PVC/MCC or PVC/Eudragit RS 100 mixtures were observed.
    Matched MeSH terms: Tensile Strength
  18. Thermoplastic starch/beeswax blend: Characterization on thermal mechanical and moisture absorption properties
    Diyana ZN, Jumaidin R, Selamat MZ, Suan MSM
    Int J Biol Macromol, 2021 Nov 01;190:224-232.
    PMID: 34481857 DOI: 10.1016/j.ijbiomac.2021.08.201
    Cassava starch has acquired many attentions owing to its ability to be developed as thermoplastic cassava starch (TPCS) where it can be obtained in low cost, making it to be one of alternatives to substitute petroleum-based plastic. An attempt was made to investigate the thermal, mechanical and moisture absorption properties of thermoplastic cassava starch blending with beeswax (TPCS-BW) fabricated using hot moulding compression method in the range of beeswax loading from 0, 2.5, 5 to 10 wt%. Addition of beeswax has significantly reduced tensile strength, elongation and flexural strength while improving tensile modulus and flexural modulus until 5 wt% beeswax. Incorporation of 10 wt% beeswax has successfully produced the lowest value of moisture absorption and water solubility among the bio-composite which might be attributed to the beeswax's hydrophobic properties in improving water barrier of the TPCS-BW bio-composite. Furthermore, the addition of beeswax resulted in the appearance of irregular and rough fractured surface. Meanwhile, fourier transform infrared (FT-IR) spectroscopy presented that incorporation of beeswax in the mixture has considerably improve hydrogen bonding of blends indicating good interaction between starch and beeswax. Hence, beeswax with an appropriate loading value able to improve the functional properties of TPCS-BW bio-composite.
    Matched MeSH terms: Tensile Strength
  19. Force delivery of NiTi orthodontic arch wire at different magnitude of deflections and temperatures: A finite element study
    Razali MF, Mahmud AS, Mokhtar N
    J Mech Behav Biomed Mater, 2018 Jan;77:234-241.
    PMID: 28954242 DOI: 10.1016/j.jmbbm.2017.09.021
    NiTi arch wires are used widely in orthodontic treatment due to its superelastic and biocompatibility properties. In brackets configuration, the force released from the arch wire is influenced by the sliding resistances developed on the arch wire-bracket contact. This study investigated the evolution of the forces released by a rectangular NiTi arch wire towards possible intraoral temperature and deflection changes. A three dimensional finite element model was developed to measure the force-deflection behavior of superelastic arch wire. Finite element analysis was used to distinguish the martensite fraction and phase state of arch wire microstructure in relation to the magnitude of wire deflection. The predicted tensile and bending results from the numerical model showed a good agreement with the experimental results. As contact developed between the wire and bracket, binding influenced the force-deflection curve by changing the martensitic transformation plateau into a slope. The arch wire recovered from greater magnitude of deflection released lower force than one recovered from smaller deflection. In contrast, it was observed that the plateau slope increased from 0.66N/mm to 1.1N/mm when the temperature was increased from 26°C to 46°C.
    Matched MeSH terms: Tensile Strength
  20. Cryopreservation versus fresh frozen meniscal allograft: A biomechanical comparative analysis
    Ahmad S, Singh VA, Hussein SI
    J Orthop Surg (Hong Kong), 2017 8 29;25(3):2309499017727946.
    PMID: 28844199 DOI: 10.1177/2309499017727946
    Meniscal allograft transplantation may be a better alternative for the treatment of irreparable meniscal injury compared to other forms of treatment. However, it remains to be seen whether the use fresh frozen allograft is better than cryopreserved allograft in treating this type of injury. We hypothesized that cryopreserved meniscal allograft would work better in maintaining the original biomechanical properties compared to fresh frozen ones, due to the lower amount of damage it incurs during the storage process. We examined young and healthy human menisci obtained from orthopedic oncology patients who underwent resection surgeries around the knee. The menisci obtained were preserved via cryopreservation and deep-freezing process. Traction tests were carried out on the menisci after 6 weeks of preservation. Twelve pairs ( N = 24) of menisci were divided equally into two groups, cryopreservation and deep frozen. There were six males and six female menisci donors for this study. The age range was between 15 and 35 years old (24.9 ± 8.6 years). Cryopreserved specimens had a higher ultimate tensile strength (UTS; 8.2 ± 1.3 Mpa vs. 13.3 ± 1.7 Mpa: p < 0.05) and elastic modulus (61.7 ± 27.6 Mpa vs. 87.0 ± 44.10 Mpa: p < 0.05) compared to the fresh frozen specimens. There was a significant difference in UTS ( p < 0.05) between the two groups but no significant difference in their elastic modulus ( p > 0.05). The elastic modulus of the preserved meniscus was similar to fresh normal menisci taken from other studies (60-120 Mpa; cryopreserved (87.0 ± 44.1) and fresh frozen (61.7 ± 27.5)). Cryopreserved menisci had a higher elastic modulus and point of rupture (UTS) compared to fresh frozen menisci. Cryopreservation proved to be a significantly better method of preservation, among the two methods of preservation in this study.
    Matched MeSH terms: Tensile Strength
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