Displaying publications 81 - 100 of 305 in total

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  1. Fulltext Direct purification of pectinase from mango (Mangifera Indica Cv. Chokanan) peel using a PEG/salt-based Aqueous Two Phase System
    Mehrnoush A, Sarker MZ, Mustafa S, Yazid AM
    Molecules, 2011 Oct 10;16(10):8419-27.
    PMID: 21986520 DOI: 10.3390/molecules16108419
    An Aqueous Two-Phase System (ATPS) was employed for the first time for the separation and purification of pectinase from mango (Mangifera Indica Cv. Chokanan) peel. The effects of different parameters such as molecular weight of the polymer (polyethylene glycol, 2,000-10,000), potassium phosphate composition (12-20%, w/w), system pH (6-9), and addition of different concentrations of neutral salts (0-8%, w/w) on partition behavior of pectinase were investigated. The partition coefficient of the enzyme was decreased by increasing the PEG molecular weight. Additionally, the phase composition showed a significant effect on purification factor and yield of the enzyme. Optimum conditions for purification of pectinase from mango peel were achieved in a 14% PEG 4000-14% potassium phosphate system using 3% (w/w) NaCl addition at pH 7.0. Based on this system, the purification factor of pectinase was increased to 13.2 with a high yield of (97.6%). Thus, this study proves that ATPS can be an inexpensive and effective method for partitioning of pectinase from mango peel.
    Matched MeSH terms: Polyethylene Glycols
  2. Different Intraorbital Implant Situations and Ocular Prosthetic Rehabilitation
    Aggarwal H, Kumar P, Eachempati P, Alvi HA
    J Prosthodont, 2016 Dec;25(8):687-693.
    PMID: 26447725 DOI: 10.1111/jopr.12369
    Enucleation is the removal of the entire globe of the eye and a portion of the optic nerve, while evisceration involves the removal of the contents of the globe leaving the sclera, extraocular muscles, and optic nerve. Following enucleation or evisceration, intraorbital implants are routinely placed to enhance the prosthetic outcome in addition to restoring the lost orbital volume. Current practice employs intraorbital implants made of nonporous silicone, hydroxyapatite, or porous polyethylene. Intraorbital implant selection and placement, being a highly demanding procedure in terms of knowledge, skill, and expertise, may be associated with a multiplicity of technical and surgical errors. Complications are usually minimal with these implants, but they do occur. The literature reveals many articles related to intraorbital implants, their benefits, and complications; however, the literature regarding the effect of various intraorbital implant situations on the subsequent prosthetic rehabilitation is markedly scarce. Moreover, the need for interdisciplinary surgical and prosthetic interventions required for successful rehabilitation in cases of compromised implant situations has been underemphasized. Hence, this review aimed to evaluate the effect of different intraorbital implant situations on ocular rehabilitation and the required interdisciplinary surgical and prosthetic treatment approach for rehabilitation of enucleated/eviscerated sockets with compromised implant situations, to provide a critical appraisal, and to present a simplified management strategy.
    Matched MeSH terms: Polyethylene
  3. Nonacog beta pegol (N9-GP) in haemophilia B: A multinational phase III safety and efficacy extension trial (paradigm™4)
    Young G, Collins PW, Colberg T, Chuansumrit A, Hanabusa H, Lentz SR, et al.
    Thromb Res, 2016 May;141:69-76.
    PMID: 26970716 DOI: 10.1016/j.thromres.2016.02.030
    INTRODUCTION: Paradigm™4 was an international extension trial investigating the safety and efficacy of nonacog beta pegol, a recombinant glycoPEGylated factor IX (FIX) with extended half-life, in haemophilia B patients (FIX activity ≤2%; aged 13-70years) who had previously participated in phase III pivotal (paradigm™2) or surgery (paradigm™3) trials.

    METHODS: Patients chose to continue treatment with nonacog beta pegol in either one of two once-weekly prophylaxis arms (10IU/kg or 40IU/kg), or an on-demand arm (40IU/kg for mild/moderate bleeds; 80IU/kg for severe bleeds). The primary objective was to evaluate immunogenicity; key secondary objectives included assessing safety and haemostatic efficacy in the treatment and prevention of bleeds.

    RESULTS: Seventy-one patients received prophylaxis or on-demand treatment. No patient developed an inhibitor and no safety concerns were identified. The success rate for the treatment of reported bleeds was 94.6%; most (87.9%) resolved with one injection. The median annualised bleeding rate for patients on prophylaxis was 1.36 (interquartile range [IQR] 0.00-2.23) and 1.00 (IQR 0.00-2.03) for the 10 and 40IU/kg treatment arms, respectively. The mean FIX activity trough achieved for 10 and 40IU once weekly was 9.8% and 21.3%, respectively. Fourteen patients on prophylaxis underwent 23 minor surgical procedures; haemostatic perioperative outcomes for all of those evaluated were 'excellent' or 'good'.

    CONCLUSIONS: Nonacog beta pegol showed a favourable tolerability profile (with no safety issues identified) with good prophylactic protection and control of bleeding in previously treated adult and adolescent haemophilia B patients.

    Matched MeSH terms: Polyethylene Glycols/administration & dosage; Polyethylene Glycols/adverse effects; Polyethylene Glycols/therapeutic use*
  4. Fulltext Ligninolytic fungus Polyporus sp. S133 mediated metabolic degradation of fluorene
    Lazim ZM, Hadibarata T
    Braz J Microbiol, 2016 Jul-Sep;47(3):610-6.
    PMID: 27287336 DOI: 10.1016/j.bjm.2016.04.015
    This study aimed to investigate the impact of nonionic surfactants on the efficacy of fluorine degradation by Polyporus sp. S133 in a liquid culture. Fluorene was observed to be degraded in its entirety by Polyporus sp. S133 subsequent to a 23-day incubation period. The fastest cell growth rate was observed in the initial 7 days in the culture that was supplemented with Tween 80. The degradation process was primarily modulated by the activity of two ligninolytic enzymes, laccase and MnP. The highest laccase activity was stimulated by the addition of Tween 80 (2443U/L) followed by mixed surfactant (1766U/L) and Brij 35 (1655U/L). UV-vis spectroscopy, TLC analysis and mass spectrum analysis of samples subsequent to the degradation process in the culture medium confirmed the biotransformation of fluorene. Two metabolites, 9-fluorenol (λmax 270, tR 8.0min and m/z 254) and protocatechuic acid (λmax 260, tR 11.3min and m/z 370), were identified in the treated medium.
    Matched MeSH terms: Polyethylene Glycols
  5. Fulltext Data of continuous harvest of stem cells via partial detachment from thermoresponsive nanobrush surfaces
    Yeh CC, Muduli S, Peng IC, Lu YT, Ling QD, Alarfaj AA, et al.
    Data Brief, 2016 Mar;6:603-8.
    PMID: 26909373 DOI: 10.1016/j.dib.2015.12.056
    This data article contains two figures and one table supporting the research article entitled: "Continuous harvest of stem cells via partial detachment from thermoresponsive nanobrush surface" [1]. The table shows coating conditions of three copolymers, poly(styrene-co-acrylic acid) grafted with oligovitronectin, poly(styrene-co-N-isopropylacrylamide) and poly(styrene-co-polyethylene glycol methacrylate) to prepare thermoresponsive surface. XPS spectra show the nitrogen peak of the polystyrene surface coated with poly(styrene-co-acrylic acid) grafted with oligovitronectin. The surface coating density analyzed from sorption of poly(styrene-co-acrylic acid) grafted with oligovitronectin by UV-vis spectroscopy is also presented.
    Matched MeSH terms: Polyethylene Glycols
  6. Direct recovery of cyclodextringlycosyltransferase from Bacillus cereus using aqueous two-phase flotation
    Lin YK, Show PL, Yap YJ, Tan CP, Ng EP, Ariff AB, et al.
    J Biosci Bioeng, 2015 Dec;120(6):684-9.
    PMID: 26111602 DOI: 10.1016/j.jbiosc.2015.04.013
    Purification of cyclodextrin glycosyl transferase (CGTase) from Bacillus cereus using polyethylene glycol (PEG)-potassium phosphates aqueous two-phase flotation (ATPF) system was studied in this paper. The effects of varying PEG molecular weight, tie-line length (TLL) value, volume ratio (VR), pH value, crude concentration and gas nitrogen flotation time were investigated. The optimal condition for purification of CGTase was attained at 18.0% (w/w) PEG 8000, 7.0% (w/w) potassium phosphates, VR of 3.0, 20% (w/w) crude load at pH 7, and 80 min nitrogen flotation time at a flow rate of 5 L/min. With this optimal condition, purification factor (PFT) of 21.8 and a yield (YT) of 97.1% were attained. CGTase was successfully purified in a single downstream processing step using the ATPF.
    Matched MeSH terms: Polyethylene Glycols
  7. Interaction of Aqueous Solutions of a Surface Active Copper(II) Complex with Several Common Surfactants
    Lim YY, Lim KH
    J Colloid Interface Sci, 1997 Dec 01;196(1):116-9.
    PMID: 9441659
    Micellar properties of binary mixed surfactants of a surface active mixed copper(II) chelate, [Cu(C12-tmed)(acac)Cl] (where C12-tmed is N,N,N'-trimethyl-N'-dodecylethylenediamine) with three common surfactants, viz. sodium dodecyl sulfate (SDS), cetyltrimethylammonium bromide (CTAB), and octaethylene glycol monododecyl ether (C12E8), were investigated by surface tensiometry, ESR, and UV-visible absorption techniques. The surface tension data were treated with Rubingh's method for mixed micelle formation and Rosen's method for mixed monolayer formation at the aqueous solution/air interface. It was found that in the mixed micelle there is strong attractive interaction between cationic copper surfactant and anonic dodecyl sulfate while there is almost ideal mixing between copper surfactant and CTAB and C12E8. From the ESR and UV-visible studies, a mixed block-type arrangement of head groups is proposed. Copyright 1997 Academic Press. Copyright 1997Academic Press
    Matched MeSH terms: Polyethylene Glycols
  8. Fulltext Effect of Addition of Polyaniline on Polyethylene Oxide and Polyvinyl Alcohol for the Fabrication of Nanorods
    Al-Hazeem NZ, Ahmed NM
    ACS Omega, 2020 Sep 08;5(35):22389-22394.
    PMID: 32923796 DOI: 10.1021/acsomega.0c02802
    For the first time, the fabrication of novel nanorods by the addition of polyaniline (PANI) to polyethylene oxide (PEO) and polyvinyl alcohol (PVA) polymers through electrospinning method is investigated. Field emission scanning electron microscopy observations reveal the formation of nanofibers and nanorods having diameters in the range of 26.87-139.90 nm and 64.11-122.40 nm, respectively, and lengths in the range of 542.10 nm to 1.32 μm. Photoluminescence (PL) analysis shows the presence of peaks which are characteristic of isotactic polymers (363-412, 529-691 nm), 412-529 nm for PVA/PEO and 363-691 nm for PVA/PEO/PANI. PL spectra also show peak bonding at a wavelength of 552 nm. Manufacture of nanorods by electrospinning method gives better options for controlling the diameter and length of nanorods.
    Matched MeSH terms: Polyethylene Glycols
  9. Functionalized fluorescent terephthalate monomers and their attempted polyester formation
    Choo YSL, Giamberini M, Antonio J, Waddell PG, Benniston AC
    Org Biomol Chem, 2020 Nov 04;18(42):8735-8745.
    PMID: 33094783 DOI: 10.1039/d0ob01533d
    The reaction of diethyl 2,5-bis(tert-butyl)phenoxy-3,6-dihydroxyterephthalate (1) with tetraethylene glycol di(p-toluenesulfonate) under high-dilution conditions afforded several isolated products. Two products were identified as macrocycles with one being the 1 + 1 crown ether derivative 3 (10% yield), and the second being the 2 + 2 crown ether compound D3 (19% yield). The X-ray structure for 3 was determined with the asymmetric unit observed to comprise half of the molecule. The small crown ether ring of 3 interacts with K+ or H+ ions in MeOH, but binding is weak and the macrocyclic cavity is too small to fully encapsulate the K+ ion. Transesterification of compounds 1, its methylated version 2 and 3 with diols such as ethylene glycol or 1,4-butandiol produced monomers (M1-M3) which were reacted with terephthaloyl chloride. Short oligomers were produced (PolyM1-PolyM3) rather than extensive polymeric materials and all displayed solid state fluorescence. The absorption and fluorescence properties of M1-M2 and their polymers can be related to subtle structural changes. The Stokes shift for M2 of 15 627 cm-1 in DCM is one of the largest observed for a simple organic chromophore in fluid solution.
    Matched MeSH terms: Polyethylene Glycols
  10. Fulltext Development of Polysulfone Membrane via Vapor-Induced Phase Separation for Oil/Water Emulsion Filtration
    Barambu NU, Bilad MR, Bustam MA, Huda N, Jaafar J, Narkkun T, et al.
    Polymers (Basel), 2020 Oct 29;12(11).
    PMID: 33137888 DOI: 10.3390/polym12112519
    The discharge of improperly treated oil/water emulsion by industries imposes detrimental effects on human health and the environment. The membrane process is a promising technology for oil/water emulsion treatment. However, it faces the challenge of being maintaining due to membrane fouling. It occurs as a result of the strong interaction between the hydrophobic oil droplets and the hydrophobic membrane surface. This issue has attracted research interest in developing the membrane material that possesses high hydraulic and fouling resistance performances. This research explores the vapor-induced phase separation (VIPS) method for the fabrication of a hydrophilic polysulfone (PSF) membrane with the presence of polyethylene glycol (PEG) as the additive for the treatment of oil/water emulsion. Results show that the slow nonsolvent intake in VIPS greatly influences the resulting membrane structure that allows the higher retention of the additive within the membrane matrix. By extending the exposure time of the cast film under humid air, both surface chemistry and morphology of the resulting membrane can be enhanced. By extending the exposure time from 0 to 60 s, the water contact angle decreases from 70.28 ± 0.61° to 57.72 ± 0.61°, and the clean water permeability increases from 328.70 ± 8.27 to 501.89 ± 8.92 (L·m-2·h-1·bar-1). Moreover, the oil rejection also improves from 85.06 ± 1.6 to 98.48 ± 1.2%. The membrane structure was transformed from a porous top layer with a finger-like macrovoid sub-structure to a relatively thick top layer with a sponge-like macrovoid-free sub-structure. Overall results demonstrate the potential of the VIPS process to enhance both surface chemistry and morphology of the PSF membrane.
    Matched MeSH terms: Polyethylene Glycols
  11. Fulltext Inclusion of graphene on LDPE properties
    Sabet M, Soleimani H
    Heliyon, 2019 Jul;5(7):e02053.
    PMID: 31334378 DOI: 10.1016/j.heliyon.2019.e02053
    The spread of graphene in low-density polyethylene (LDPE) improves LDPE/graphene nanocompounds' thermal/mechanical/electrical characteristics. The images of scanning electron microscopy (SEM) verify full graphene exfoliation at 1000 °C. Inclusion graphene develops crystallinity; increases the local order of lattice and thermal stability of LDPE/graphene nanocompounds. The consistent distributions and further inclusion of graphene caused the great heat breakdown strength, increasing heat breakdown activation energy and a superior melting point (Tm) for LDPE nanocompounds. Percolation occurs with the graphene incorporation of 0.5 wt%. The complex viscosity test showed Newtonian behavior for LDPE at a very low frequency. But, graphene inclusion to LDPE changed the viscosity performance from liquid-like to solid-like which caused a decrease in the melt flow rate (MFR) values for all LDPE/graphene nanocompounds.
    Matched MeSH terms: Polyethylene
  12. Effect of mixing process parameters and suitability of backbone polymer for aluminum powder injection molding feedstock
    Abdullahi A, Choudhury I, Azuddin M, Nahar N
    Sains Malaysiana, 2017;46:477-483.
    A suitable and cost-effective microfabrication technique for processing aluminum micropart is required, as the choice
    of aluminum microparts for aerospace, electronics and automobile components is preferred over other metals due to its
    excellent properties. Meanwhile, powder injection molding (PIM) is identified as an economical manufacturing technique
    for processing ceramic and micro-metal powders into microparts and or components. Therefore, this study investigates
    formulation and processing of aluminum PIM feedstock using a custom-made machine. The investigation is focused on
    the effect of mixing process parameters (powder loading, rotor speed and mixing temperature) and the suitability of
    the backbone polymer. The formulated PIM feedstock constituents are paraffin wax (PW), stearic acid (SA), high-density
    polyethylene (HDPE)/ medium-density polyethylene (MDPE) alternatively and aluminum micro-metal powder. Taguchi
    method is used for the design of experiments (DOEs) and analysis. In addition, response surface methodology (RSM) is
    employed to develop empirical viscosity models. The optimum powder-binder mixing ratio of 58:42 vol. % with rotor
    speed of 43 rpm were determined for preparing aluminum PIM feedstock using mini-lab mixer developed. The empirical
    model developed for aluminum PIM feedstock viscosity shows a good fit with R2
    values of 0.84 using HDPE and 0.96 for
    MDPE binder system. This investigation demonstrates preparation and suitability of aluminum PIM feedstock using waxbased
    binder system.
    Matched MeSH terms: Polyethylene
  13. Co-encapsulation of gemcitabine and tocotrienols in nanovesicles enhanced efficacy in pancreatic cancer
    Maniam G, Mai CW, Zulkefeli M, Fu JY
    Nanomedicine (Lond), 2021 02;16(5):373-389.
    PMID: 33543651 DOI: 10.2217/nnm-2020-0374
    Aim: To synthesize niosomes co-encapsulating gemcitabine (GEM) and tocotrienols, and physicochemically characterize and evaluate the antipancreatic effects of the nanoformulation on Panc 10.05, SW 1990, AsPC-1 and BxPC-3 cells. Materials & methods: Niosomes-entrapping GEM and tocotrienols composed of Span 60, cholesterol and D-α-tocopheryl polyethylene glycol 1000 succinate were produced by Handjani-Vila and film hydration methods. Results: The film hydration produced vesicles measuring 161.9 ± 0.5 nm, approximately 50% smaller in size than Handjani-Vila method, with maximum entrapment efficiencies of 20.07 ± 0.22% for GEM and 34.52 ± 0.10% for tocotrienols. In Panc 10.05 cells, GEM's antiproliferative effect was enhanced 2.78-fold in combination with tocotrienols. Niosomes produced a significant ninefold enhancement in cytotoxicity of the combination, supported by significantly higher cellular uptake of GEM in the cells. Conclusion: This study is a proof of concept on the synthesis of dual-drug niosomes and their efficacy on pancreatic cancer cells in vitro.
    Matched MeSH terms: Polyethylene Glycols
  14. Effects of degree of substitution and irradiation doses on the properties of hydrogel prepared from carboxymethyl-sago starch and polyethylene glycol
    Zahib IR, Md Tahir P, Talib M, Mohamad R, Alias AH, Lee SH
    Carbohydr Polym, 2021 Jan 15;252:117224.
    PMID: 33183648 DOI: 10.1016/j.carbpol.2020.117224
    Carboxymethyl starch (CMS) was produced from sago starch via carboxymethylation. The CMS with different degree of substitution (DS) ranges from 0.4 to 0.8 were mixed with polyethylene glycol (PEG) of different molecular weight and distilled water and the hydrogel was cured by electron beam irradiation with doses ranging from 25 to 35 kGy. The results revealed that CMS-PEG hydrogels with DS 0.4 give the optimum gel content when radiated at 30 kGy and with PEG 600. Thermogravimetric analysis (TGA) revealed that there are two phases exist in CMS with DS 0.4 in contrast to the three steps decomposition occurs in DS 0.6 and 0.8. It shows that the CMS with DS 0.4 is more thermally stable. Surface morphology revealed crosslinking among the blends when subjected into the radiation dose. The study shows both radiation and PEG addition improved most of the properties of CMS irrespective of the DS value.
    Matched MeSH terms: Polyethylene Glycols
  15. Fulltext Recovery of a Bacteriocin-Like Inhibitory Substance from Lactobacillus bulgaricus FTDC 1211 Using Polyethylene-Glycol Impregnated Amberlite XAD-4 Resins System
    Abdul Aziz NFH, Abbasiliasi S, Ng ZJ, Abu Zarin M, Oslan SN, Tan JS, et al.
    Molecules, 2020 Nov 16;25(22).
    PMID: 33207534 DOI: 10.3390/molecules25225332
    Lactobacillus bulgaricus is a LAB strain which is capable of producing bacteriocin substances to inhibit Staphylococcus aureus. The aim of this study was to purify a bacteriocin-like inhibitory substance (BLIS) produced by L. bulgaricus FTDC 1211 using an aqueous impregnated resins system consisting of polyethylene-glycol (PEG) impregnated on Amberlite XAD4. Important parameters influencing on purification of BLIS, such as the molecular weight and concentration of PEG, the concentration and pH of sodium citrate and the concentration of sodium chloride, were optimized using a response surface methodology. Under optimum conditions of 11% (w/w) of PEG 4000 impregnated Amberlite XAD4 resins and 2% (w/w) of sodium citrate at pH 6, the maximum purification factor (3.26) and recovery yield (82.69% ± 0.06) were obtained. These results demonstrate that AIRS could be used as an alternate purification system in the primary recovery step.
    Matched MeSH terms: Polyethylene Glycols
  16. Fulltext Effects on the Properties after Addition of Lithium Salt in Poly(ethylene oxide)/Poly(methyl acrylate) Blends
    Abdul Halim SI, Chan CH, Kressler J
    Polymers (Basel), 2020 Dec 11;12(12).
    PMID: 33322501 DOI: 10.3390/polym12122963
    The studies of phase behavior, dielectric relaxation, and other properties of poly(ethylene oxide) (PEO)/poly(methyl acrylate) (PMA) blends with the addition of lithium perchlorate (LiClO4) were done for different blend compositions. Samples were prepared by a solution casting technique. The binary PEO/PMA blends exhibit a single and compositional-dependent glass transition temperature (Tg), which is also true for ternary mixtures of PEO/PMA/LiClO4 when PEO was in excess with low content of salt. These may indicate miscibility of the constituents for the molten systems and amorphous domains of the systems at room temperature from the macroscopic point of view. Subsequently, the morphology of PEO/PMA blends with or without salt are correlated to the phase behavior of the systems. Phase morphology and molecular interaction of polymer chains by salt ions of the systems may rule the dielectric or electric relaxation at room temperature, which was estimated using electrochemical impedance spectroscopy (EIS). The frequency-dependent impedance spectra are of interest for the elucidation of polarization and relaxation of the charged entities for the systems. Relaxation can be noted only when a sufficient amount of salt is added into the systems.
    Matched MeSH terms: Polyethylene Glycols
  17. Comparison of Clinical Results and Pathological Examinations Between Locally Synthesized Bone-derived Hydroxyapatite and Medpor® Orbital Implants in Animal Models
    Roslinah M, Wan Hitam WH, Md Salleh MS, Abdul Hamid SS, Shatriah I
    Cureus, 2019 Jan 25;11(1):e3954.
    PMID: 30956907 DOI: 10.7759/cureus.3954
    We aimed to compare clinical and pathological reactions towards locally synthesized bovine bone derived from hydroxyapatite (bone docosahexaenoic acid (dHA)) and commercially available porous polyethylene (Medpor®, Porex Surgical Incorporation, Georgia, USA) orbital implants in animal models. An experimental study was performed on 14 New Zealand white rabbits. Group A (n=7) was implanted with bovine bone dHA and group B (n=7) was implanted with Medpor®. Clinical examinations were performed on Days 1, 7, 14, 28, and 42 post-implantation. The implanted eyes were enucleated on Day 42 and were sent for pathological evaluation. Serial clinical examinations included urine color and odor; feeding and physical activity demonstrated normal wellbeing in all the subjects. Localized minimal infection was observed in both groups during the first two weeks following implantation, and the subjects responded well to topical moxifloxacin. Both groups exhibited evidence of wound breakdown. No signs of implant migration or extrusion were observed in either group. The histopathological examination revealed no statistically significant difference in inflammatory cell reactions and fibrovascular tissue maturation between both types of implants. However, all (100%) of the bovine bone dHA implants displayed complete fibrovascular ingrowth compared to Medpor® implants (57.1%) at six weeks post-implantation (p=0.001). In conclusion, bovine bone dHA and Medpor® orbital implants were well-tolerated clinically and displayed similar inflammatory reactions and fibrovascular tissue maturation. Locally synthesized bovine bone dHA orbital implants displayed significantly greater complete fibrovascular ingrowth in comparison with Medpor® implants.
    Matched MeSH terms: Polyethylene
  18. Fulltext Highly Crosslinked Polyethylene Tibial Post Fracture in the Unafflicted Limb of a Patient with Unilateral Lower Limb Poliomyelitis: A Case Report
    Lee WC, Wee L
    Malays Orthop J, 2019 Mar;13(1):42-44.
    PMID: 31001383 DOI: 10.5704/MOJ.1903.008
    We present a unique case of tibial post fracture of a posterior-stabilised total knee arthroplasty (PS-TKA) using highly crosslinked polyethylene (HXLPE) in the unafflicted limb of a patient who had poliomyelitis. The tibial post is an upright structure perpendicular to the PE insert articular surface which articulates with the cam of the femoral component to prevent excessive posterior translation of the tibia. We explore the choice of PS polyethylene (PE) inserts in patients with neuromuscular disorders (NMD). A 74-year old gentleman presented with recurrent knee pain seven years after the index PS-TKA with HXLPE. The TKA was performed on the unafflicted left limb (contralateral to the weak side affected by poliomyelitis). The posterior drawer test was positive. During the single-stage revision surgery, the HXLPE tibial post was noted to be broken. The liner was replaced with a thicker non-HXLPE. The patient achieved an excellent outcome at one-year post-surgery. This is the first report of HXLPE tibial post fracture in the unaffected knee of a patient with NMD affecting the lower limb. The HXLPE's reduced resistance to fatigue crack propagation might not be suitable in PS-TKA where there might be focal stress points on the tibial post, which was amplified in this case as it was the limb that the patient most depended on. When managing end-stage osteoarthritis with TKA in the unafflicted knee of a patient with NMD causing lower limb weakness, the selection of polyethylene material in PS-TKA may need more consideration than previously thought.
    Matched MeSH terms: Polyethylene
  19. Fulltext Effects of different tube potentials and iodine concentrations on image enhancement, contrast-to-noise ratio and noise in micro-CT images: a phantom study
    Abdul Razak HR, Shaffiq Said Rahmat SM, Md Saad WM
    Quant Imaging Med Surg, 2013 Oct;3(5):256-61.
    PMID: 24273743 DOI: 10.3978/j.issn.2223-4292.2013.10.04
    The study aimed to investigate the effects of different tube potentials and concentrations of iodinated contrast media (CM) on the image enhancement, contrast-to-noise ratio (CNR) and noise in micro-computed tomography (µCT) images. A phantom containing of five polyethylene tube was filled with 2 mL of deionized water and iodinated CM (Omnipaque 300 mgI/mL) at four different concentrations: 5, 10, 15, and 20 mol/L, respectively. The phantom was scanned with a µCT machine (SkyScan 1176) using various tube potentials: 40, 50, 60, 70, 80, and 90 kVp, a fixed tube current; 100 µA, and filtration of 0.2 mm aluminum (Al). The percentage difference of image enhancement, CNR and noise of all images, acquired at different kVps and concentrations, were calculated. The image enhancement, CNR and noise curves with respect to tube potential and concentration were plotted and analysed. The highest image enhancement was found at the lowest tube potential of 40 kVp. At this kVp setting, the percentage difference of image enhancement [Hounsfield Unit (HU) of 20 mol/L iodine concentration over HU of deionized water] was 43%. By increasing the tube potential, it resulted with the reduction of HU, where only 17.5% different were noticed for 90 kVp. Across all iodine concentrations (5-20 M), CNR peaked at 80 kVp and then these values showed a slight decreasing pattern, which might be due insufficient tube current compensation. The percentage difference of image noise obtained at 40 and 90 kVp was 72.4%. Lower tube potential setting results in higher image enhancement (HU) in conjunction with increasing concentration of iodinated CM. Overall, the tube potential increment will substantially improve CNR and reduce image noise.
    Matched MeSH terms: Polyethylene
  20. Fulltext Pseudo-Ductility, Morphology and Fractography Resulting from the Synergistic Effect of CaCO3 and Bentonite in HDPE Polymer Nano Composite
    Ahmed T, Ya HH, Khan R, Hidayat Syah Lubis AM, Mahadzir S
    Materials (Basel), 2020 Jul 27;13(15).
    PMID: 32726965 DOI: 10.3390/ma13153333
    Polymeric materials such as High density polyethylene(HDPE) are ductile in nature, having very low strength. In order to improve strength by non-treated rigid fillers, polymeric materials become extremely brittle. Therefore, this work focuses on achieving pseudo-ductility (high strength and ductility) by using a combination of rigid filler particles (CaCO3 and bentonite) instead of a single non-treated rigid filler particle. The results of all tensile-tested (D638 type i) samples signify that the microstructural features and surface properties of rigid nano fillers can render the required pseudo-ductility. The maximum value of tensile strength achieved is 120% of the virgin HDPE, and the value of elongation is retained by 100%. Furthermore, the morphological and fractographic analysis revealed that surfactants are not always going to obtain polymer-filler bonding, but the synergistic effect of filler particles can carry out sufficient bonding for stress transfer. Moreover, pseudo-ductility was achieved by a combination of rigid fillers (bentonite and CaCO3) when the content of bentonite dominated as compared to CaCO3. Thus, the achievement of pseudo-ductility by the synergistic effect of rigid particles is the significance of this study. Secondly, this combination of filler particles acted as an alternative for the application of surfactant and compatibilizer so that adverse effect on mechanical properties can be avoided.
    Matched MeSH terms: Polyethylene
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