Displaying publications 141 - 160 of 249 in total

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  1. From formulation of acrylamide-based hydrogels to their optimization for drug release using response surface methodology
    Sabbagh F, Muhamad II, Nazari Z, Mobini P, Taraghdari SB
    Mater Sci Eng C Mater Biol Appl, 2018 Nov 01;92:20-25.
    PMID: 30184743 DOI: 10.1016/j.msec.2018.06.022
    This study conducted on the structure of modified acrylamide-based hydrogel by synthesizing the nano composites. The hydrogels employed in this study were provided through a combination of acrylamide monomers, sodium carboxymethyl cellulose (NaCMC) and magnesium oxide (MgO) nanoparticles by crosslinking polymerization. N,N,N',N'-tetramethylethylenediamine and ammonium persulfate as the initiator was applied in the structure of the polymer. Findings of the study considered the nano composites consisting of MgO have the highest swelling ratio compared to pure Aam hydrogels. Thus, MgO is an appropriate nanoparticle to be used in the nano composites. Response surface methodology (RSM) based on a central composite design (CCD Design) was applied to optimize the preparation variables of a hydrogel consisted of MgO, NaCMC. With the swelling ratio for acrylamide-based hydrogel as the response, the effects of two variables, i.e. MgO and NaCMC were investigated. The effects of pH, temperature, MgO, and NaCMC on the drug release were investigated using the CCD design. The predicted appropriate drug release conditions for the hydrogel at the highest rate of temperature (37.50 °C) and pH: 4.10, is at its highest value, while the lower drug release is at temperature 38 °C and pH 3.50. With the desired value of MgO (0.01 g) and amount of NaCMC (0.1 g).
    Matched MeSH terms: Polymers/chemistry
  2. 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: Polymers/chemistry
  3. Characterization of natural fiber obtained from different parts of date palm tree (Phoenix dactylifera L.)
    Alotaibi MD, Alshammari BA, Saba N, Alothman OY, Sanjay MR, Almutairi Z, et al.
    Int J Biol Macromol, 2019 Aug 15;135:69-76.
    PMID: 31116962 DOI: 10.1016/j.ijbiomac.2019.05.102
    The current study is motivated by the strict environmental regulations regarding the utilization and consumption of ecofriendly materials. In this context, the aim of this study has been to prepare and characterize different date palm tree (Phoenix dactylifera L.) fibers processed through the conventional water retting method. The chemical, elemental, crystallinity, thermal and morphological characterization of trunk (DPTRF), leaf stalk (DPLST), sheath or leaf sheath (DPLSH) and fruit bunch stalk (DPFBS) fibers was carried out. Chemical analysis revealed that the four types of date palm fibers display noteworthy differences in the content of cellulose, hemicellulose and lignin. Also, the amount of calcium is relatively high in all the date palm fibers; besides this, DPTRF exhibited 69.2% crystallinity, which is lower than that of DPLSH with 72.4% crystallinity. Moreover, DPLST and DPFBS fibers are more thermally stable (higher thermal degradation temperature) than DPTRF and DPLSH samples. Morphological analysis revealed that the fracture surface of DPFBS was relatively rougher, which would probably lead to increased bonding strength with polymers in composites. Overall, we conclude that DPFBS would be promising alternative sustainable and biomass material for the isolation of respective cellulose nanofibers and cellulose nanocrystals as potential reinforcement in polymer composites.
    Matched MeSH terms: Polymers/chemistry*
  4. Current strategies in extending half-lives of therapeutic proteins
    Zaman R, Islam RA, Ibnat N, Othman I, Zaini A, Lee CY, et al.
    J Control Release, 2019 05 10;301:176-189.
    PMID: 30849445 DOI: 10.1016/j.jconrel.2019.02.016
    Macromolecular protein and peptide therapeutics have been proven to be effective in treating critical human diseases precisely. Thanks to biotechnological advancement, a huge number of proteins and peptide therapeutics were made their way to pharmaceutical market in past few decades. However, one of the biggest challenges to be addressed for protein therapeutics during clinical application is their fast degradation in serum and quick elimination owing to enzymatic degradation, renal clearance, liver metabolism and immunogenicity, attributing to the short half-lives. Size and hydrophobicity of protein molecules make them prone to kidney filtration and liver metabolism. On the other hand, proteasomes responsible for protein destruction possess the capability of specifically recognizing almost all kinds of foreign proteins while avoiding any unwanted destruction of cellular components. At present almost all protein-based drug formulations available in market are administered intravenously (IV) or subcutaneously (SC) with high dosing at frequent interval, eventually creating dose-fluctuation-related complications and reducing patient compliance vastly. Therefore, artificially increasing the therapeutic half-life of a protein by attaching to it a molecule that increases the overall size (eg, PEG) or helps with receptor mediated recycling (eg, albumin), or manipulating amino acid chain in a way that makes it more prone towards aggregate formation, are some of the revolutionary approaches to avoid the fast degradation in vivo. Half-life extension technologies that are capable of dramatically enhancing half-lives of proteins in circulation (2-100 folds) and thus improving their overall pharmacokinetic (PK) parameters have been successfully applied on a wide range of protein therapeutics from hormones and enzymes, growth factor, clotting factor to interferon. The focus of the review is to assess the technological advancements made so far in enhancing circulatory half-lives and improving therapeutic potency of proteins.
    Matched MeSH terms: Polymers/chemistry
  5. Targeting respiratory diseases using miRNA inhibitor based nanotherapeutics: Current status and future perspectives
    Mehta M, Satija S, Paudel KR, Malyla V, Kannaujiya VK, Chellappan DK, et al.
    Nanomedicine, 2021 01;31:102303.
    PMID: 32980549 DOI: 10.1016/j.nano.2020.102303
    MicroRNAs (miRNAs) play a fundamental role in the developmental and physiological processes that occur in both animals and plants. AntagomiRs are synthetic antagonists of miRNA, which prevent the target mRNA from suppression. Therapeutic approaches that modulate miRNAs have immense potential in the treatment of chronic respiratory disorders. However, the successful delivery of miRNAs/antagomiRs to the lungs remains a major challenge in clinical applications. A range of materials, namely, polymer nanoparticles, lipid nanocapsules and inorganic nanoparticles, has shown promising results for intracellular delivery of miRNA in chronic respiratory disorders. This review discusses the current understanding of miRNA biology, the biological roles of antagomiRs in chronic respiratory disease and the recent advances in the therapeutic utilization of antagomiRs as disease biomarkers. Furthermore our review provides a common platform to debate on the nature of antagomiRs and also addresses the viewpoint on the new generation of delivery systems that target antagomiRs in respiratory diseases.
    Matched MeSH terms: Polymers/chemistry
  6. The relevance of polymeric synthetic membranes in topical formulation assessment and drug diffusion study
    Ng SF, Rouse JJ, Sanderson FD, Eccleston GM
    Arch Pharm Res, 2012 Mar;35(4):579-93.
    PMID: 22553050 DOI: 10.1007/s12272-012-0401-7
    Synthetic membranes are composed of thin sheets of polymeric macromolecules that can control the passage of components through them. Generally, synthetic membranes used in drug diffusion studies have one of two functions: skin simulation or quality control. Synthetic membranes for skin simulation, such as the silicone-based membranes polydimethylsiloxane and Carbosil, are generally hydrophobic and rate limiting, imitating the stratum corneum. In contrast, synthetic membranes for quality control, such as cellulose esters and polysulfone, are required to act as a support rather than a barrier. These synthetic membranes also often contain pores; hence, they are called porous membranes. The significance of Franz diffusion studies and synthetic membranes in quality control studies involves an understanding of the fundamentals of synthetic membranes. This article provides a general overview of synthetic membranes, including a brief background of the history and the common applications of synthetic membranes. This review then explores the types of synthetic membranes, the transport mechanisms across them, and their relevance in choosing a synthetic membrane in Franz diffusion cell studies for formulation assessment purposes.
    Matched MeSH terms: Polymers/chemistry*
  7. 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: Polymers/chemistry*
  8. Depth of composite polymerization within simulated root canals using light-transmitting posts
    Lui JL
    Oper Dent, 1994 Sep-Oct;19(5):165-8.
    PMID: 8700755
    In this study, the depth of cure of composite resins cured within simulated root canals by means of light-transmitting plastic posts was compared to that achieved by the conventional light-curing method. Six sizes of posts with diameters of 1.05 mm, 1.20 mm, 1.35 mm, 1.50 mm, 1.65 mm, and 1.80 mm were investigated. In general, the larger the post diameter, the greater was the depth of cure. There were significant differences in the depth of cure between the control and all sizes of posts investigated. There were also significant differences between the various post diameters except for the 1.35 mm and 1.50 mm diameter posts. It was possible to achieve a depth of cure exceeding 11 mm using these light-transmitting posts.
    Matched MeSH terms: Polymers/chemistry
  9. Poly(lactic acid)/poly(butylene succinate) dual-layer membranes with cellulose nanowhisker for heavy metal ion separation
    Kian LK, Jawaid M, Nasef MM, Fouad H, Karim Z
    Int J Biol Macromol, 2021 Dec 01;192:654-664.
    PMID: 34655581 DOI: 10.1016/j.ijbiomac.2021.10.042
    In this study, poly(lactic acid) (PLA)/poly(butylene succinate) (PBS) dual-layer membranes filled with 0-3 wt% cellulose nanowhisker (CNWs) were fabricated with aim to remove metal ions from wastewater. An integrated method was employed in the membrane fabrication process by combining water vapor-induced and crystallization-induced phase inversions. The membrane thickness was measured in between 11 and 13 μm, which did not pose significant flux deviation during filtration process. The 3% CNW filled membrane showed prominent and well-laminated two layers structure. Meanwhile, the increase in CNWs from 0 to 3% loadings could improve the membrane porosity (43-74%) but reducing pore size (2.45-0.54 μm). The heat resistance of neat membrane enhanced by 1% CNW but decreased with loadings of 2-3% CNWs due to flaming behavior of sulphated nanocellulose. Membrane with 3% CNW displayed the tensile strength (23.5 MPa), elongation at break (7.1%), and Young's modulus (0.75 GPa) as compared to other samples. For wastewater filtration performance, the continuous operation test showed that 3% CNW filled membrane exhibited the highest removal efficiency for both cobalt and nickel metal ions reaching to 83% and 84%, respectively. We concluded that CNWs filled dual-layer membranes have potential for future development in the removal of heavy metal ions from wastewater streams.
    Matched MeSH terms: Polymers/chemistry*
  10. Fabrication and performance evaluation of polymeric membrane using blood compatible hydroxyapatite for artificial kidney application
    Zaman SU, Saif-Ur-Rehman, Zaman MKU, Rafiq S, Arshad A, Khurram MS, et al.
    Artif Organs, 2021 Nov;45(11):1377-1390.
    PMID: 34152645 DOI: 10.1111/aor.14020
    In the current study, a phase inversion scheme was employed to fabricate hydroxyapatite (HA)/polysulfone (PSF)-based asymmetric membranes using a film applicator with water as a solvent and nonsolvent exchanging medium. Fourier Transform Infrared (FTIR) and X-ray diffraction (XRD) spectroscopic studies were conducted to confirm the bonding chemistry and purity of filler. The inherent thick nature of PSF generated sponge-like shape while the instantaneous demixing process produced finger-like pore networks in HA/PSF-based asymmetric membranes as exhibited by scanning electron microscope (SEM) micrographs. The FTIR spectra confirmed noncovalent weak attractions toward the polymer surface. The leaching ratio was evaluated to observe the dispersion behavior of HA filler in membrane composition. Hydrophilicity, pore profile, pure water permeation (PWP) flux, and molecular weight cutoff (MWCO) values of all formulated membranes were also calculated. Antifouling results revealed that HA modified PSF membranes exhibited 43% less adhesion of bovine serum albumin (BSA) together with >86% recovery of flux. Membrane composition showed 74% total resistance, out of which 60% was reversible resistance. Biocompatibility evaluation revealed that the modified membranes exhibited prothrombin time (PT), and thrombin time (TT) comparable with typical blood plasma, whereas proliferation of living cells over membrane surface proved its nontoxic behavior toward biomedical application. The urea and creatinine showed effective adsorption aptitude toward HA loaded PSF membranes.
    Matched MeSH terms: Polymers/chemistry*
  11. Advances in organic-inorganic hybrid sorbents for the extraction of organic and inorganic pollutants in different types of food and environmental samples
    Ng NT, Kamaruddin AF, Wan Ibrahim WA, Sanagi MM, Abdul Keyon AS
    J Sep Sci, 2018 Jan;41(1):195-208.
    PMID: 28834218 DOI: 10.1002/jssc.201700689
    The efficiency of the extraction and removal of pollutants from food and the environment has been an important issue in analytical science. By incorporating inorganic species into an organic matrix, a new material known as an organic-inorganic hybrid material is formed. As it possesses high selectivity, permeability, and mechanical and chemical stabilities, organic-inorganic hybrid materials constitute an emerging research field and have become popular to serve as sorbents in various separaton science methods. Here, we review recent significant advances in analytical solid-phase extraction employing organic-inorganic composite/nanocomposite sorbents for the extraction of organic and inorganic pollutants from various types of food and environmental matrices. The physicochemical characteristics, extraction properties, and analytical performances of sorbents are discussed; including morphology and surface characteristics, types of functional groups, interaction mechanism, selectivity and sensitivity, accuracy, and regeneration abilities. Organic-inorganic hybrid sorbents combined with extraction techniques are highly promising for sample preparation of various food and environmental matrixes with analytes at trace levels.
    Matched MeSH terms: Polymers/chemistry
  12. Biomolecule-Responsive Hydrogels in Medicine
    Sharifzadeh G, Hosseinkhani H
    Adv Healthc Mater, 2017 Dec;6(24).
    PMID: 29057617 DOI: 10.1002/adhm.201700801
    Recent advances and applications of biomolecule-responsive hydrogels, namely, glucose-responsive hydrogels, protein-responsive hydrogels, and nucleic-acid-responsive hydrogels are highlighted. However, achieving the ultimate purpose of using biomolecule-responsive hydrogels in preclinical and clinical areas is still at the very early stage and calls for more novel designing concepts and advance ideas. On the way toward the real/clinical application of biomolecule-responsive hydrogels, plenty of factors should be extensively studied and examined under both in vitro and in vivo conditions. For example, biocompatibility, biointegration, and toxicity of biomolecule-responsive hydrogels should be carefully evaluated. From the living body's point of view, biocompatibility is seriously depended on the interactions at the tissue/polymer interface. These interactions are influenced by physical nature, chemical structure, surface properties, and degradation of the materials. In addition, the developments of advanced hydrogels with tunable biological and mechanical properties which cause no/low side effects are of great importance.
    Matched MeSH terms: Polymers/chemistry
  13. Synthesis and evaluation on pH- and temperature-responsive chitosan-p(MAA-co-NIPAM) hydrogels
    Rasib SZM, Ahmad Z, Khan A, Akil HM, Othman MBH, Hamid ZAA, et al.
    Int J Biol Macromol, 2018 Mar;108:367-375.
    PMID: 29222015 DOI: 10.1016/j.ijbiomac.2017.12.021
    In this study, chitosan-poly(methacrylic acid-co-N-isopropylacrylamide) [chitosan-p(MAA-co-NIPAM)] hydrogels were synthesized by emulsion polymerization. In order to be used as a carrier for drug delivery systems, the hydrogels had to be biocompatible, biodegradable and multi-responsive. The polymerization was performed by copolymerize MAA and NIPAM with chitosan polymer to produce a chitosan-based hydrogel. Due to instability during synthesis and complexity of components to produce the hydrogel, further study at different times of reaction is important to observe the synthesis process, the effect of end product on swelling behaviour and the most important is to find the best way to control the hydrogel synthesis in order to have an optimal swelling behaviour for drug release application. Studied by using Fourier transform infra-red (FTIR) spectroscopy found that, the synthesized was successfully produced stable chitosan-based hydrogel with PNIPAM continuously covered the outer surface of hydrogel which influenced much on the stability during synthesis. The chitosan and PMAA increased the zeta potential of the hydrogel and the chitosan capable to control shrinkage above human body temperature. The chitosan-p(MAA-co-NIPAM) hydrogels also responses to pH and temperature thus improved the ability to performance as a drug carrier.
    Matched MeSH terms: Polymers/chemistry
  14. Synthesis and characterization of cotton fiber-based nanocellulose
    Theivasanthi T, Anne Christma FL, Toyin AJ, Gopinath SCB, Ravichandran R
    Int J Biol Macromol, 2018 Apr 01;109:832-836.
    PMID: 29133091 DOI: 10.1016/j.ijbiomac.2017.11.054
    Nanocellulose prepared from the natural material has a promising wide range of opportunities to obtain the superior material properties towards various end-products. In this research, commercially available natural cotton was treated with aqueous sodium hydroxide solution to eliminate the hemicellulose and lignin, then cellulose was collected. The collected cellulose was subjected to acid hydrolysis using sulfuric acid to obtain nanocellulose. The prepared nanocellulose was further characterized with the aid of Fourier transform infrared spectroscopy, X-ray diffraction and Scanning Electron Microscopy to elucidate the chemical structure, crystallinity and the morphology.
    Matched MeSH terms: Polymers/chemistry
  15. Immobilisation of hydroxyapatite-collagen on polydopamine grafted stainless steel 316L: Coating adhesion and in vitro cells evaluation
    Tapsir Z, Jamaludin FH, Pingguan-Murphy B, Saidin S
    J Biomater Appl, 2018 02;32(7):987-995.
    PMID: 29187035 DOI: 10.1177/0885328217744081
    The utilisation of hydroxyapatite and collagen as bioactive coating materials could enhance cells attachment, proliferation and osseointegration. However, most methods to form crystal hydroxyapatite coating do not allow the incorporation of polymer/organic compound due to production phase of high sintering temperature. In this study, a polydopamine film was used as an intermediate layer to immobilise hydroxyapatite-collagen without the introduction of high sintering temperature. The surface roughness, coating adhesion, bioactivity and osteoblast attachment on the hydroxyapatite-collagen coating were assessed as these properties remains unknown on the polydopamine grafted film. The coating was developed by grafting stainless steel 316L disks with a polydopamine film. Collagen type I fibres were then immobilised on the grafted film, followed by the biomineralisation of hydroxyapatite. The surface roughness and coating adhesion analyses were later performed by using AFM instrument. An Alamar Blue assay was used to determine the cytotoxicity of the coating, while an alkaline phosphatase activity test was conducted to evaluate the osteogenic differentiation of human fetal osteoblasts on the coating. Finally, the morphology of cells attachment on the coating was visualised under FESEM. The highest RMS roughness and coating adhesion were observed on the hydroxyapatite-collagen coating (hydroxyapatite-coll-dopa). The hydroxyapatite-coll-dopa coating was non-toxic to the osteoblast cells with greater cells proliferation, greater level of alkaline phosphate production and more cells attachment. These results indicate that the immobilisation of hydroxyapatite and collagen using an intermediate polydopamine is identical to enhance coating adhesion, osteoblast cells attachment, proliferation and differentiation, and thus could be implemented as a coating material on orthopaedic and dental implants.
    Matched MeSH terms: Polymers/chemistry*
  16. Influence of Solvent on the Drug-Loading Process of Amphiphilic Nanogel Star Polymers
    Carr AC, Piunova VA, Maarof H, Rice JE, Swope WC
    J Phys Chem B, 2018 05 31;122(21):5356-5367.
    PMID: 29385796 DOI: 10.1021/acs.jpcb.7b10539
    We present an all-atom molecular dynamics study of the effect of a range of organic solvents (dichloromethane, diethyl ether, toluene, methanol, dimethyl sulfoxide, and tetrahydrofuran) on the conformations of a nanogel star polymeric nanoparticle with solvophobic and solvophilic structural elements. These nanoparticles are of particular interest for drug delivery applications. As drug loading generally takes place in an organic solvent, this work serves to provide insight into the factors controlling the early steps of that process. Our work suggests that nanoparticle conformational structure is highly sensitive to the choice of solvent, providing avenues for further study as well as predictions for both computational and experimental explorations of the drug-loading process. Our findings suggest that when used in the drug-loading process, dichloromethane, tetrahydrofuran, and toluene allow for a more extensive and increased drug-loading into the interior of nanogel star polymers of the composition studied here. In contrast, methanol is more likely to support shallow or surface loading and, consequently, faster drug release rates. Finally, diethyl ether should not work in a formulation process since none of the regions of the nanogel star polymer appear to be sufficiently solvated by it.
    Matched MeSH terms: Polymers/chemistry*
  17. Cyclodextrin based polymer sorbents for micro-solid phase extraction followed by liquid chromatography tandem mass spectrometry in determination of endogenous steroids
    Manaf NA, Saad B, Mohamed MH, Wilson LD, Latiff AA
    J Chromatogr A, 2018 Mar 30;1543:23-33.
    PMID: 29478831 DOI: 10.1016/j.chroma.2018.02.032
    Sorbents were prepared by cross-linking β-cyclodextrin (β-CD) using two different types of cross-linker units at variable reactant mole ratios. The resulting polymers containing β-CD were evaluated as sorbents in micro-solid phase extraction (μ-SPE) format for the extraction of the endogenous steroids testosterone (T), epitestosterone (E), androsterone (A), etiocholanolone (Etio), 5α-androstane-3α,17β-diol (5αAdiol) and 5β-androstane-3α,17β-diol (5βAdiol). The best sorbent (C1; cyclodextrin polymer) showed superior extraction characteristics compared with commercial sorbents (C18 and Bond Elut Plexa). Parameters influencing the extraction efficiency of the C1 sorbent such as extraction and desorption times, desorption solvent and volume of sample were investigated. The extracts were separated using a Hypersil Gold column (50 × 2.1 mm, 1.9 μm) under gradient elution coupled to a LC-MS/MS. The compounds were successfully separated within 8 min. The method offers good repeatability (RSD  0.995) were within the range of 1-200 ng mL-1 for T and E, 250-4000 ng mL-1 for A and Etio and 25-500 ng mL-1 for 5αAdiol and 5βAdiol, respectively. The method was applied for the determination of steroid profile of urine from volunteers.
    Matched MeSH terms: Polymers/chemistry
  18. Size-selective purification of hepatitis B virus-like particle in flow-through chromatography: Types of ion exchange adsorbent and grafted polymer architecture
    Ng HW, Lee MFX, Chua GK, Gan BK, Tan WS, Ooi CW, et al.
    J Sep Sci, 2018 May;41(10):2119-2129.
    PMID: 29427396 DOI: 10.1002/jssc.201700823
    Hepatitis B virus-like particles expressed in Escherichia coli were purified using anion exchange adsorbents grafted with polymer poly(oligo(ethylene glycol) methacrylate) in flow-through chromatography mode. The virus-like particles were selectively excluded, while the relatively smaller sized host cell proteins were absorbed. The exclusion of virus-like particles was governed by the accessibility of binding sites (the size of adsorbents and the charge of grafted dextran chains) as well as the architecture (branch-chain length) of the grafted polymer. The branch-chain length of grafted polymer was altered by changing the type of monomers used. The larger adsorbent (90 μm) had an approximately twofold increase in the flow-through recovery, as compared to the smaller adsorbent (30 μm). Generally, polymer-grafted adsorbents improved the exclusion of the virus-like particles. Overall, the middle branch-chain length polymer grafted on larger adsorbent showed optimal performance at 92% flow-through recovery with a purification factor of 1.53. A comparative study between the adsorbent with dextran grafts and the polymer-grafted adsorbent showed that a better exclusion of virus-like particles was achieved with the absorbent grafted with inert polymer. The grafted polymer was also shown to reduce strong interaction between binding sites and virus-like particles, which preserved the particles' structure.
    Matched MeSH terms: Polymers/chemistry*
  19. Accuracy of a new elastomeric impression material for complete-arch dental implant impressions
    Baig MR, Buzayan MM, Yunus N
    J Investig Clin Dent, 2018 May;9(2):e12320.
    PMID: 29349910 DOI: 10.1111/jicd.12320
    AIM: The aim of the present study was to assess the accuracy of multi-unit dental implant casts obtained from two elastomeric impression materials, vinyl polyether silicone (VPES) and polyether (PE), and to test the effect of splinting of impression copings on the accuracy of implant casts.

    METHODS: Forty direct impressions of a mandibular reference model fitted with six dental implants and multibase abutments were made using VPES and PE, and implant casts were poured (N = 20). The VPES and PE groups were split into four subgroups of five each, based on splinting type: (a) no splinting; (b) bite registration polyether; (c) bite registration addition silicone; and (d) autopolymerizing acrylic resin. The accuracy of implant-abutment replica positions was calculated on the experimental casts, in terms of interimplant distances in the x, y, and z-axes, using a coordinate measuring machine; values were compared with those measured on the reference model. Data were analyzed using non-parametrical Kruskal-Wallis and Mann-Whitney tests at α = .05.

    RESULTS: The differences between the two impression materials, VPES and PE, regardless of splinting type, were not statistically significant (P>.05). Non-splinting and splinting groups were also not significantly different for both PE and VPES (P>.05).

    CONCLUSIONS: The accuracy of VPES impression material seemed comparable with PE for multi-implant abutment-level impressions. Splinting had no effect on the accuracy of implant impressions.

    Matched MeSH terms: Polymers/chemistry*
  20. Preparation and characterization of polysulfone/zeolite mixed matrix membranes for removal of low-concentration ammonia from aquaculture wastewater
    Moradihamedani P, Abdullah AH
    Water Sci Technol, 2018 Jan;77(1-2):346-354.
    PMID: 29377819 DOI: 10.2166/wst.2017.545
    Removal of low-concentration ammonia (1-10 ppm) from aquaculture wastewater was investigated via polysulfone (PSf)/zeolite mixed matrix membrane. PSf/zeolite mixed matrix membranes with different weight ratios (90/10, 80/20, 70/30 and 60/40 wt.%) were prepared and characterized. Results indicate that PSf/zeolite (80/20) was the most efficient membrane for removal of low-concentration ammonia. The ammonia elimination by PSf/zeolite (80/20) from aqueous solution for 10, 7, 5, 3 and 1 ppm of ammonia was 100%, 99%, 98.8%, 96% and 95% respectively. The recorded results revealed that pure water flux declined in higher loading of zeolite in the membrane matrix due to surface pore blockage caused by zeolite particles. On the other hand, ammonia elimination from water was decreased in higher contents of zeolite because of formation of cavities and macrovoids in the membrane substructure.
    Matched MeSH terms: Polymers/chemistry*
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