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Publisher: Hindawi   (Total: 338 journals)

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Showing 1 - 200 of 338 Journals sorted alphabetically
Abstract and Applied Analysis     Open Access   (Followers: 3, SJR: 0.343, CiteScore: 1)
Active and Passive Electronic Components     Open Access   (Followers: 7, SJR: 0.136, CiteScore: 0)
Advances in Acoustics and Vibration     Open Access   (Followers: 37, SJR: 0.147, CiteScore: 0)
Advances in Aerospace Engineering     Open Access   (Followers: 55)
Advances in Agriculture     Open Access   (Followers: 9)
Advances in Artificial Intelligence     Open Access   (Followers: 15)
Advances in Astronomy     Open Access   (Followers: 41, SJR: 0.257, CiteScore: 1)
Advances in Bioinformatics     Open Access   (Followers: 17, SJR: 0.565, CiteScore: 2)
Advances in Biology     Open Access   (Followers: 10)
Advances in Chemistry     Open Access   (Followers: 27)
Advances in Civil Engineering     Open Access   (Followers: 43, SJR: 0.539, CiteScore: 1)
Advances in Computer Engineering     Open Access   (Followers: 4)
Advances in Condensed Matter Physics     Open Access   (Followers: 11, SJR: 0.315, CiteScore: 1)
Advances in Decision Sciences     Open Access   (Followers: 3, SJR: 0.303, CiteScore: 1)
Advances in Electrical Engineering     Open Access   (Followers: 37)
Advances in Electronics     Open Access   (Followers: 79)
Advances in Emergency Medicine     Open Access   (Followers: 12)
Advances in Endocrinology     Open Access   (Followers: 6)
Advances in Environmental Chemistry     Open Access   (Followers: 7)
Advances in Epidemiology     Open Access   (Followers: 8)
Advances in Fuzzy Systems     Open Access   (Followers: 5, SJR: 0.161, CiteScore: 1)
Advances in Geology     Open Access   (Followers: 19)
Advances in Geriatrics     Open Access   (Followers: 6)
Advances in Hematology     Open Access   (Followers: 11, SJR: 0.661, CiteScore: 2)
Advances in Hepatology     Open Access   (Followers: 2)
Advances in High Energy Physics     Open Access   (Followers: 22, SJR: 0.866, CiteScore: 2)
Advances in Human-Computer Interaction     Open Access   (Followers: 21, SJR: 0.186, CiteScore: 1)
Advances in Materials Science and Engineering     Open Access   (Followers: 30, SJR: 0.315, CiteScore: 1)
Advances in Mathematical Physics     Open Access   (Followers: 7, SJR: 0.218, CiteScore: 1)
Advances in Medicine     Open Access   (Followers: 3)
Advances in Meteorology     Open Access   (Followers: 24, SJR: 0.48, CiteScore: 1)
Advances in Multimedia     Open Access   (Followers: 2, SJR: 0.173, CiteScore: 1)
Advances in Nonlinear Optics     Open Access   (Followers: 6)
Advances in Numerical Analysis     Open Access   (Followers: 7)
Advances in Nursing     Open Access   (Followers: 33)
Advances in Operations Research     Open Access   (Followers: 12, SJR: 0.205, CiteScore: 1)
Advances in Optical Technologies     Open Access   (Followers: 4, SJR: 0.214, CiteScore: 1)
Advances in Optics     Open Access   (Followers: 5)
Advances in OptoElectronics     Open Access   (Followers: 6, SJR: 0.141, CiteScore: 0)
Advances in Orthopedics     Open Access   (Followers: 8, SJR: 0.922, CiteScore: 2)
Advances in Pharmacological Sciences     Open Access   (Followers: 8, SJR: 0.591, CiteScore: 2)
Advances in Physical Chemistry     Open Access   (Followers: 11, SJR: 0.179, CiteScore: 1)
Advances in Polymer Technology     Open Access   (Followers: 14, SJR: 0.299, CiteScore: 1)
Advances in Power Electronics     Open Access   (Followers: 33, SJR: 0.184, CiteScore: 0)
Advances in Preventive Medicine     Open Access   (Followers: 6)
Advances in Public Health     Open Access   (Followers: 24)
Advances in Regenerative Medicine     Open Access   (Followers: 3)
Advances in Software Engineering     Open Access   (Followers: 10)
Advances in Statistics     Open Access   (Followers: 4)
Advances in Toxicology     Open Access   (Followers: 2)
Advances in Tribology     Open Access   (Followers: 14, SJR: 0.265, CiteScore: 1)
Advances in Urology     Open Access   (Followers: 9, SJR: 0.51, CiteScore: 1)
Advances in Virology     Open Access   (Followers: 7, SJR: 0.838, CiteScore: 2)
AIDS Research and Treatment     Open Access   (Followers: 3, SJR: 0.758, CiteScore: 2)
Analytical Cellular Pathology     Open Access   (Followers: 3, SJR: 0.886, CiteScore: 2)
Anatomy Research Intl.     Open Access   (Followers: 3)
Anemia     Open Access   (Followers: 5, SJR: 0.669, CiteScore: 2)
Anesthesiology Research and Practice     Open Access   (Followers: 14, SJR: 0.501, CiteScore: 1)
Applied and Environmental Soil Science     Open Access   (Followers: 17, SJR: 0.451, CiteScore: 1)
Applied Bionics and Biomechanics     Open Access   (Followers: 7, SJR: 0.288, CiteScore: 1)
Applied Computational Intelligence and Soft Computing     Open Access   (Followers: 14)
Archaea     Open Access   (Followers: 3, SJR: 0.852, CiteScore: 2)
Autism Research and Treatment     Open Access   (Followers: 29)
Autoimmune Diseases     Open Access   (Followers: 3, SJR: 0.805, CiteScore: 2)
Behavioural Neurology     Open Access   (Followers: 10, SJR: 0.786, CiteScore: 2)
Biochemistry Research Intl.     Open Access   (Followers: 7, SJR: 0.437, CiteScore: 2)
Bioinorganic Chemistry and Applications     Open Access   (Followers: 11, SJR: 0.419, CiteScore: 2)
BioMed Research Intl.     Open Access   (Followers: 4, SJR: 0.935, CiteScore: 3)
Biotechnology Research Intl.     Open Access   (Followers: 1)
Bone Marrow Research     Open Access   (Followers: 2, SJR: 0.531, CiteScore: 1)
Canadian J. of Gastroenterology & Hepatology     Open Access   (Followers: 5, SJR: 0.867, CiteScore: 1)
Canadian J. of Infectious Diseases and Medical Microbiology     Open Access   (Followers: 6, SJR: 0.548, CiteScore: 1)
Canadian Respiratory J.     Open Access   (Followers: 1, SJR: 0.474, CiteScore: 1)
Cardiology Research and Practice     Open Access   (Followers: 10, SJR: 1.237, CiteScore: 4)
Cardiovascular Therapeutics     Open Access   (Followers: 1, SJR: 1.075, CiteScore: 2)
Case Reports in Anesthesiology     Open Access   (Followers: 10)
Case Reports in Cardiology     Open Access   (Followers: 7, SJR: 0.219, CiteScore: 0)
Case Reports in Critical Care     Open Access   (Followers: 10)
Case Reports in Dentistry     Open Access   (Followers: 5, SJR: 0.229, CiteScore: 0)
Case Reports in Dermatological Medicine     Open Access   (Followers: 2)
Case Reports in Emergency Medicine     Open Access   (Followers: 14)
Case Reports in Endocrinology     Open Access   (Followers: 2, SJR: 0.209, CiteScore: 1)
Case Reports in Gastrointestinal Medicine     Open Access   (Followers: 2)
Case Reports in Genetics     Open Access   (Followers: 1)
Case Reports in Hematology     Open Access   (Followers: 6)
Case Reports in Hepatology     Open Access   (Followers: 1)
Case Reports in Immunology     Open Access   (Followers: 4)
Case Reports in Infectious Diseases     Open Access   (Followers: 5)
Case Reports in Medicine     Open Access   (Followers: 2)
Case Reports in Nephrology     Open Access   (Followers: 5)
Case Reports in Neurological Medicine     Open Access   (Followers: 1)
Case Reports in Obstetrics and Gynecology     Open Access   (Followers: 10)
Case Reports in Oncological Medicine     Open Access   (Followers: 2, SJR: 0.204, CiteScore: 1)
Case Reports in Ophthalmological Medicine     Open Access   (Followers: 3)
Case Reports in Orthopedics     Open Access   (Followers: 6)
Case Reports in Otolaryngology     Open Access   (Followers: 6)
Case Reports in Pathology     Open Access   (Followers: 5)
Case Reports in Pediatrics     Open Access   (Followers: 7)
Case Reports in Psychiatry     Open Access   (Followers: 14)
Case Reports in Pulmonology     Open Access   (Followers: 3)
Case Reports in Radiology     Open Access   (Followers: 10)
Case Reports in Rheumatology     Open Access   (Followers: 8)
Case Reports in Surgery     Open Access   (Followers: 12)
Case Reports in Transplantation     Open Access  
Case Reports in Urology     Open Access   (Followers: 10)
Case Reports in Vascular Medicine     Open Access  
Case Reports in Veterinary Medicine     Open Access   (Followers: 5)
Child Development Research     Open Access   (Followers: 18, SJR: 0.144, CiteScore: 0)
Chinese J. of Engineering     Open Access   (Followers: 2, SJR: 0.114, CiteScore: 0)
Chinese J. of Mathematics     Open Access  
Chromatography Research Intl.     Open Access   (Followers: 5)
Complexity     Hybrid Journal   (Followers: 6, SJR: 0.531, CiteScore: 2)
Computational and Mathematical Methods in Medicine     Open Access   (Followers: 2, SJR: 0.403, CiteScore: 1)
Computational Intelligence and Neuroscience     Open Access   (Followers: 12, SJR: 0.326, CiteScore: 1)
Contrast Media & Molecular Imaging     Open Access   (Followers: 3, SJR: 0.842, CiteScore: 3)
Critical Care Research and Practice     Open Access   (Followers: 12, SJR: 0.499, CiteScore: 1)
Current Gerontology and Geriatrics Research     Open Access   (Followers: 9, SJR: 0.512, CiteScore: 2)
Depression Research and Treatment     Open Access   (Followers: 15, SJR: 0.816, CiteScore: 2)
Dermatology Research and Practice     Open Access   (Followers: 3, SJR: 0.806, CiteScore: 2)
Diagnostic and Therapeutic Endoscopy     Open Access   (SJR: 0.201, CiteScore: 1)
Discrete Dynamics in Nature and Society     Open Access   (Followers: 5, SJR: 0.279, CiteScore: 1)
Disease Markers     Open Access   (Followers: 1, SJR: 0.9, CiteScore: 2)
Economics Research Intl.     Open Access   (Followers: 1)
Education Research Intl.     Open Access   (Followers: 19)
Emergency Medicine Intl.     Open Access   (Followers: 9, SJR: 0.298, CiteScore: 1)
Enzyme Research     Open Access   (Followers: 5, SJR: 0.653, CiteScore: 3)
Evidence-based Complementary and Alternative Medicine     Open Access   (Followers: 23, SJR: 0.683, CiteScore: 2)
Game Theory     Open Access   (Followers: 1)
Gastroenterology Research and Practice     Open Access   (Followers: 2, SJR: 0.768, CiteScore: 2)
Genetics Research Intl.     Open Access   (Followers: 1, SJR: 0.61, CiteScore: 2)
Geofluids     Open Access   (Followers: 5, SJR: 0.952, CiteScore: 2)
Hepatitis Research and Treatment     Open Access   (Followers: 6, SJR: 0.389, CiteScore: 2)
Heteroatom Chemistry     Open Access   (Followers: 3, SJR: 0.333, CiteScore: 1)
HPB Surgery     Open Access   (Followers: 7, SJR: 0.824, CiteScore: 2)
Infectious Diseases in Obstetrics and Gynecology     Open Access   (Followers: 5, SJR: 1.27, CiteScore: 2)
Interdisciplinary Perspectives on Infectious Diseases     Open Access   (Followers: 1, SJR: 0.627, CiteScore: 2)
Intl. J. of Aerospace Engineering     Open Access   (Followers: 74, SJR: 0.232, CiteScore: 1)
Intl. J. of Agronomy     Open Access   (Followers: 6, SJR: 0.311, CiteScore: 1)
Intl. J. of Alzheimer's Disease     Open Access   (Followers: 11, SJR: 0.787, CiteScore: 3)
Intl. J. of Analytical Chemistry     Open Access   (Followers: 22, SJR: 0.285, CiteScore: 1)
Intl. J. of Antennas and Propagation     Open Access   (Followers: 11, SJR: 0.233, CiteScore: 1)
Intl. J. of Atmospheric Sciences     Open Access   (Followers: 21)
Intl. J. of Biodiversity     Open Access   (Followers: 4)
Intl. J. of Biomaterials     Open Access   (Followers: 4, SJR: 0.511, CiteScore: 2)
Intl. J. of Biomedical Imaging     Open Access   (Followers: 3, SJR: 0.501, CiteScore: 2)
Intl. J. of Breast Cancer     Open Access   (Followers: 14, SJR: 1.025, CiteScore: 2)
Intl. J. of Cell Biology     Open Access   (Followers: 4, SJR: 1.887, CiteScore: 4)
Intl. J. of Chemical Engineering     Open Access   (Followers: 8, SJR: 0.327, CiteScore: 1)
Intl. J. of Chronic Diseases     Open Access   (Followers: 1)
Intl. J. of Combinatorics     Open Access   (Followers: 1)
Intl. J. of Computer Games Technology     Open Access   (Followers: 10, SJR: 0.287, CiteScore: 2)
Intl. J. of Corrosion     Open Access   (Followers: 10, SJR: 0.194, CiteScore: 1)
Intl. J. of Dentistry     Open Access   (Followers: 6, SJR: 0.649, CiteScore: 2)
Intl. J. of Differential Equations     Open Access   (Followers: 8, SJR: 0.191, CiteScore: 0)
Intl. J. of Digital Multimedia Broadcasting     Open Access   (Followers: 5, SJR: 0.296, CiteScore: 2)
Intl. J. of Electrochemistry     Open Access   (Followers: 8)
Intl. J. of Endocrinology     Open Access   (Followers: 4, SJR: 1.012, CiteScore: 3)
Intl. J. of Engineering Mathematics     Open Access   (Followers: 6)
Intl. J. of Food Science     Open Access   (Followers: 5, SJR: 0.44, CiteScore: 2)
Intl. J. of Forestry Research     Open Access   (Followers: 3, SJR: 0.373, CiteScore: 1)
Intl. J. of Genomics     Open Access   (Followers: 2, SJR: 0.868, CiteScore: 3)
Intl. J. of Geophysics     Open Access   (Followers: 5, SJR: 0.182, CiteScore: 1)
Intl. J. of Hepatology     Open Access   (Followers: 5, SJR: 0.874, CiteScore: 2)
Intl. J. of Hypertension     Open Access   (Followers: 7, SJR: 0.578, CiteScore: 1)
Intl. J. of Inflammation     Open Access   (SJR: 1.264, CiteScore: 3)
Intl. J. of Inorganic Chemistry     Open Access   (Followers: 3)
Intl. J. of Manufacturing Engineering     Open Access   (Followers: 2)
Intl. J. of Mathematics and Mathematical Sciences     Open Access   (Followers: 3, SJR: 0.177, CiteScore: 0)
Intl. J. of Medicinal Chemistry     Open Access   (Followers: 6, SJR: 0.31, CiteScore: 1)
Intl. J. of Metals     Open Access   (Followers: 5)
Intl. J. of Microbiology     Open Access   (Followers: 6, SJR: 0.662, CiteScore: 2)
Intl. J. of Microwave Science and Technology     Open Access   (Followers: 3, SJR: 0.136, CiteScore: 1)
Intl. J. of Navigation and Observation     Open Access   (Followers: 20, SJR: 0.267, CiteScore: 2)
Intl. J. of Nephrology     Open Access   (Followers: 1, SJR: 0.697, CiteScore: 1)
Intl. J. of Oceanography     Open Access   (Followers: 7)
Intl. J. of Optics     Open Access   (Followers: 7, SJR: 0.231, CiteScore: 1)
Intl. J. of Otolaryngology     Open Access   (Followers: 3)
Intl. J. of Partial Differential Equations     Open Access   (Followers: 2)
Intl. J. of Pediatrics     Open Access   (Followers: 6)
Intl. J. of Peptides     Open Access   (Followers: 4, SJR: 0.46, CiteScore: 1)
Intl. J. of Photoenergy     Open Access   (Followers: 3, SJR: 0.341, CiteScore: 1)
Intl. J. of Plant Genomics     Open Access   (Followers: 4, SJR: 0.583, CiteScore: 1)
Intl. J. of Polymer Science     Open Access   (Followers: 24, SJR: 0.298, CiteScore: 1)
Intl. J. of Population Research     Open Access   (Followers: 3)
Intl. J. of Quality, Statistics, and Reliability     Open Access   (Followers: 16)
Intl. J. of Reconfigurable Computing     Open Access   (SJR: 0.123, CiteScore: 1)
Intl. J. of Reproductive Medicine     Open Access   (Followers: 4)
Intl. J. of Rheumatology     Open Access   (Followers: 4, SJR: 0.645, CiteScore: 2)
Intl. J. of Rotating Machinery     Open Access   (Followers: 2, SJR: 0.193, CiteScore: 1)
Intl. J. of Spectroscopy     Open Access   (Followers: 8)
Intl. J. of Stochastic Analysis     Open Access   (Followers: 3, SJR: 0.279, CiteScore: 1)
Intl. J. of Surgical Oncology     Open Access   (Followers: 1, SJR: 0.573, CiteScore: 2)
Intl. J. of Telemedicine and Applications     Open Access   (Followers: 5, SJR: 0.403, CiteScore: 2)
Intl. J. of Vascular Medicine     Open Access   (SJR: 0.782, CiteScore: 2)
Intl. J. of Zoology     Open Access   (Followers: 2, SJR: 0.209, CiteScore: 1)
Intl. Scholarly Research Notices     Open Access   (Followers: 206)
ISRN Astronomy and Astrophysics     Open Access   (Followers: 7)
J. of Addiction     Open Access   (Followers: 14)
J. of Advanced Transportation     Hybrid Journal   (Followers: 13, SJR: 0.581, CiteScore: 1)
J. of Aerodynamics     Open Access   (Followers: 12)

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Similar Journals
Journal Cover
International Journal of Polymer Science
Journal Prestige (SJR): 0.298
Citation Impact (citeScore): 1
Number of Followers: 24  

  This is an Open Access Journal Open Access journal
ISSN (Print) 1687-9422 - ISSN (Online) 1687-9430
Published by Hindawi Homepage  [338 journals]
  • Exploiting the Potential of Moringa oleifera Oil/Polyvinyl Chloride
           Polymeric Bionanocomposite Film Enriched with Silver Nanoparticles for
           Antimicrobial Activity

    • Abstract: The present study focused on the prospect of fabricating a polymeric naturally extracted Moringa oleifera oil bionanocomposite film enriched with silver nanoparticles for antimicrobial activity. In this study, a standard concentration of Moringa oleifera oil (5-10 wt%) was used to fabricate a polymeric bionanocomposite film using polyvinyl chloride (PVC) enriched with silver nanoparticles. The active constituents of the extracted Moringa oleifera oil were verified using gas chromatography-mass spectrometry. Spectroscopic and microscopic techniques, including scanning electron microscopy, X-ray diffraction, and energy-dispersive X-ray analysis, were employed to characterize and study the surface morphology of the fabricated bionanocomposite film. The antimicrobial activity of the fabricated bionanocomposite film was investigated using different strains of bacteria and fungus. The results revealed well-oriented and excellently dispersed silver nanoparticles in the PVC-Moringa oleifera oil matrix. The bionanocomposite was able to inhibit the growth of Staphylococcus aureus, Escherichia coli, Klebsiella pneumoniae, Salmonella typhi, Pseudomonas aeruginosa, Shigella flexneri, and Candida albicans. The combination of nanoparticles with polymers is opening new routes for engineering fixable composites, which showed antimicrobial properties.
      PubDate: Mon, 17 Jun 2019 10:05:16 +000
       
  • Effect of Porous Chitosan Microspheres Loaded with Platelet-Rich Plasma
           and Bone Marrow-Derived Mesenchymal Stem Cells on Regeneration of Tibia
           Defect

    • Abstract: Objective. Repair of bone defects represents a grave clinical challenge because of the tremendous difficulties in the recovery of bone function and regeneration of bone loss. Therefore, we investigated the effects of platelet-rich plasma-loaded (PRP) porous chitosan microspheres (PCMs) on the differentiation of bone marrow-derived mesenchymal stem cells (BMSCs) and the proliferation and differentiation potential of BMSCs loaded by PCMs in vitro. We also established the model of bone defect repair in rat tibia to further explore the effects of PCMs loaded with PRP and BMSCs on bone regeneration. Methods. MTT assay was used to detect the proliferative ability of BMSCs after hypoxia/reoxygenation (H/R) treatment and the proliferative ability of BMSCs loaded by PCMs; polymerase chain reaction (PCR) was used to detect the expression of alkaline phosphatase (ALP), type I collagen (Col I), and type II collagen (Col II) in BMSCs after hypoxia and in BMSCs induced by PRP-loaded PCMs; PCR was used to detect the expression of Runt-associated transcription factor 2 (Runx2) and osteocalcin (OC) in the newly generated bone tissue; micro-CT scanning was applied to measure the bone mineral density and bone volume of the newly generated bone tissue in rats. Results. BMSCs still have the normal potential of proliferation and differentiation after H/R treatment. PCMs can provide a larger surface for the attachment of BMSCs, facilitating cell proliferation. Loaded by PCMs, PRP can be slowly released, effectively stimulating the differentiation of BMSCs. PCM/PRP/BMSC composites increased the expression levels of Runx2 and OC in the newly generated bone in rat tibia defect and the bone mineral density. Moreover, the composites improved the rate of regenerated bone volume. Conclusion. The application of PCM/PRP/BMSC composites is promising in the repair of tibia defects.
      PubDate: Thu, 13 Jun 2019 07:05:12 +000
       
  • Temperature Driven Transformation in Dextran-Graft-PNIPAM/Embedded Silver
           Nanoparticle Hybrid System

    • Abstract: During the last decade, stimuli-responsible polymers based on poly(N-isopropylacrylamide) having conformational transition in the range of physiological temperature have been discussed as novel drug delivery nanosystems. A star-like copolymer with a dextran core and grafted poly(N-isopropylacrylamide) arms (D-g-PNIPAM) was synthesized, characterized, and used as a matrix for silver sol preparation. The comparative study of the behavior of individual D-g-PNIPAM and the nanohybrid system D-g-PNIPAM/silver nanoparticles has been done in the temperature range near the lower critical solution temperature (LCST). The methods of Dynamic Light Scattering, small angle X-ray scattering, and UV-VIS absorption spectroscopy have been used. The existence of single nanoparticles and aggregated nanoparticles located in a limited polymer macromolecular volume was established. The increase of the temperature leads to slight aggregation of the silver nanoparticles at the LCST transition. Single nanoparticles do not aggregate with the temperature increase. The thermally induced collapse of end-grafted poly(N-isopropylacrylamide) chains above the LCST do not affect significantly the size characteristics of silver nanoparticles incorporated into the polymer matrix.
      PubDate: Wed, 12 Jun 2019 00:05:18 +000
       
  • Investigation of the Effects of Different Hydrophilic and Hydrophobic
           Comonomers on the Volume Phase Transition Temperatures and Thermal
           Properties of N-Isopropylacrylamide-Based Hydrogels

    • Abstract: In this work, a series of thermally responsive terpolymers of N-isopropylacrylamide (NIPA) with three different comonomer contents was synthesized, and their swelling behaviour was studied as a function of composition and temperature. Temperature-sensitive, random cross-linked terpolymers of NIPA were prepared from methyl methacrylate (MMA), N-tert-butylacrylamide (NTBA), and acrylic acid (AA) using a free radical polymerization method. In the synthesis of terpolymer hydrogels, N,N-methylene bisacrylamide (BIS) was used as cross-linkers and ammonium persulfate (APS) as initiator. The NIPA content of the monomer feed varied from 80 to 50 mol %, and other comonomer feed varied from 40 to 5 mol %. The swelling equilibrium of these hydrogels was studied as a function of temperature and hydrophobic and hydrophilic comonomer contents. The swelling properties of the polymers were investigated in pure water at temperatures from 10 to 80°C. All of the synthesized gels were found to be sensitive to temperature. Glass transition temperature analyses and thermal analyses of the synthesized hydrogels were studied. The volume phase transition temperature and the swelling equilibrium () values of NIPA-based hydrogels synthesized in different feed ratios and in varying monomer contents were found in the range of 17–52°C and 14–51 g H2O/g polymer, respectively. The glass temperature () of the NIPA/AA/(MMA or NTBA) hydrogels synthesized with feed ratios of 50/40/10 was found to be 133 or 142°C, respectively. The initial and the end degradation that were determined for hydrogels at high temperatures indicated the quite good thermal stability of hydrogels. When the mass loss of the synthesized hydrogels was 50%, the temperatures were measured between 247 and 258°C.
      PubDate: Mon, 10 Jun 2019 13:05:17 +000
       
  • Thermal Stability of Shear-Induced Precursors and Their Effect on the
           Crystalline Structure of β-Nucleated Isotactic Polypropylene

    • Abstract: The thermal stability and lifetime of shear-induced precursors under various annealing temperatures, as well as the influence of their relaxation on the crystalline modification in β-nucleated isotactic polypropylene (iPP), are investigated using an ARES rheometer. The wide-angle X-ray diffraction results show that the β-crystal content of sheared β-nucleated iPP samples gradually increases with thermal treatments. The relaxation of shear-induced precursors during annealing which caused the decrease of shear nuclei may restrain the counteraction effect between the shear flow and β-nucleation agent as well as result in the increase of β-crystal content. At the early stage of relaxation, the relaxation degree is closely related to the increase of β-crystals, for which the deeper relaxed shear-induced precursors result in the more restoration of β-crystals. However, when the relaxation degree exceeded a certain limitation, where the β-crystals reached the maximum, the relaxation of shear-induced precursors will no longer influence the crystal structure of β-nucleated iPP.
      PubDate: Tue, 04 Jun 2019 13:05:05 +000
       
  • High-Efficiency DNA Extraction Using Poly(4,4-Cyclohexylidene Bisphenol
           Oxalate)-Modified Microcrystalline Cellulose-Magnetite Composite

    • Abstract: In this study, we studied the DNA extraction capability of poly(4,4-cyclohexylidene bisphenol oxalate) following the surface modification and composite formation with that of microcrystalline cellulose (MCC) and magnetic iron oxide nanoparticles (NPs). The physical characterization techniques like scanning electron microscopy (SEM), Fourier-transform infrared (FTIR) spectroscopy, energy-dispersive X-ray analysis (EDX), and thermogravimetric analysis (TGA) were employed for the poly(bisphenol Z oxalate)-MCC-magnetite composite during different stages of its formation. The results confirmed the successful modification of the polymer surface. On testing in the presence of three types of binding buffers, a high value of 72.4% (out of 10,000 ng/μL) efficiency with a total yield of DNA at ng and absorbance ratio of A260/A280 (1.980) was observed for the 2 M GuHCl/EtOH binding buffer. These results were compared against the other two buffers of phosphate-buffered saline (PBS) and NaCl. The lowest value of DNA extraction efficiency at 8125 ng/μL of 58.845% with absorbance ratios of A260/A280 (1.818) for PBS was also observed. The study has concluded an enhancement in the DNA extraction efficiency when the polymer is in the composite stage along with cellulose and magnetite particles as compared against the bare polymer.
      PubDate: Tue, 04 Jun 2019 12:05:07 +000
       
  • Piroxicam-Collagen-Based Sponges for Medical Applications

    • Abstract: Depending on the concentration of the drug and/or the method of administration, drugs could be used in various ways. To take full advantage of the drug beneficial properties in oral medical interventions but also in other types of surgery, like plastic surgery, general surgery, or gynecological surgery, the drug concentration as well as the administration method itself will depend on the wound, type of surgery, and severity of the postoperative pain which can be very different. Generally, the local administration methods are recommended. Piroxicam, a nonsteroidal anti-inflammatory drug (NSAID) of the oxicam class, is generally used to relieve the symptoms of pain and inflammation. Starting from the idea of the special benefit of the interference between collagen-based materials and drug beneficial properties, our work was focused on the synthesis and characterization of new collagen-piroxicam materials. These new collagen-based materials present a good water absorption, and the piroxicam release suggests a biphasic drug release profile whereas the obtained values for the release exponent revealed a complex release mechanism including swelling, diffusion, and erosion.
      PubDate: Wed, 29 May 2019 11:05:25 +000
       
  • The Amphoteric Ion Exchange Membrane Based on CS/CMC for Tobacco-Protein
           Adsorption and Separation from Tobacco Extract

    • Abstract: A macroporous amphoteric ion exchange membrane was prepared by blending chitosan (CS) and carboxymethylcellulose (CMC) in aqueous solution, with glutaraldehyde as a crosslinking agent and silica particles as porogens. The good compatibility between CS and CMC was confirmed by attenuated total reflectance Fourier-transform infrared spectroscopy (FTIR-ATR). A scanning electron microscope was used to observe the morphology of CS/CMC blend membranes, in which a three-dimensional opening structure was formed, and no phase separation was discovered. Tobacco extract was used as a separation model to get tobacco protein. And the effects of the pH value, adsorption time, CS/CMC content, initial protein concentration, and CS/CMC composition on tobacco protein adsorption were investigated by coomassie blue staining during the adsorption process. The results showed that the maximum adsorption capacity of 271.78 mg/g can be achieved under the condition of pH 6.15, adsorption time of 8 h, initial protein concentration of 1.52 mg/mL, and CS/CMC weight of 0.05 g with a mass ratio of 80 : 20. Tobacco proteins were successfully separated from tobacco extract by adjusting the pH of the feed and the desorption solutions to change their electrostatic force. It was found that the high desorption capacity and protein desorption efficiency can be achieved at pH 9.40. The blend membranes also demonstrated good reusability after 3 adsorption-desorption cycles.
      PubDate: Tue, 28 May 2019 10:05:54 +000
       
  • The Viscosity Effect of Masticated Natural vs. Synthetic Isoprene Rubber
           on Toughening of Polylactic Acid

    • Abstract: This study investigated the different viscosity effects of natural isoprene rubber (NR) compared to the synthetic one (IR) on toughening of polylactic acid (PLA). Here, 15 wt% rubber was melt blended with PLA in an internal mixer at 180°C and 50 rpm. It was found that the addition of these rubbers led to a significant increase in the tensile toughness and impact strength. These rubbers were masticated at 50°C and at 200 rpm for various mastication times to reduce their molecular weights. A too-long mastication time was found to adversely affect the impact strength and tensile toughness due to the fast agglomeration of rubber particles. At a comparable viscosity, it was remarkable that the impact strength of PLA/NR was higher than that of PLA/IR regardless of the similar chemical structures probably because the presence of nonrubber components including proteins and lipids could enhance the interfacial interaction between NR and the PLA matrix.
      PubDate: Mon, 27 May 2019 16:05:10 +000
       
  • Effect of an Anhydride Excess on the Curing Kinetics and Dynamic
           Mechanical Properties of Synthetic and Biogenic Epoxy Resins

    • Abstract: This work analyzes the effect of the anhydride excess on the nonisothermal curing kinetics and on the final properties of synthetic and biobased epoxy resins. Diglycidyl ether of bisphenol A (DGEBA) and epoxidized soybean oil (ESO) were crosslinked using methyltetrahydrophthalic anhydride (MTHPA) as a curing agent and 1-methylimidazole (1MI) as an initiator. It was shown that the ESO/MTHPA/1MI system reacts slower than the DGEBA/MTHPA/1MI system, giving place to a more significant evaporation of the curing agent during the reaction. As a result, an excess of anhydride improves the final thermal properties of the ESO/MTHPA/1MI network, contrary to the behavior observed for DGEBA/MTHPA/1MI. The knowledge of the kinetics of the curing process and the optimal amount of the curing agent for each system is of critical importance for a more efficient processing of these materials.
      PubDate: Sun, 26 May 2019 13:05:09 +000
       
  • Investigation of the Specific Retention Volume of the Probe Volume and the
           Effects on the Polymer-Probe System by Inverse Gas Chromatography

    • Abstract: In this study, the effects of probe quantities on retention volume and the physical and thermodynamic results of polymer-probe systems were investigated. For this purpose, by using inverse gas chromatographic method. Alcohols and alkanes with different chemical and physical properties were injected as probes on homopolymer (2-cyclohexylidene-1,3-dioxolane-4-yl-methyl methacrylate) (CHMMA). Probe quantities of 0.3, 0.6, and 0.9 μl were selected, and an injection was made at every 10°C between 40 and 150°C. In addition, 3 μl volume probes were tried but reproducible results were not obtained in these volumes and the detector was observed to be out of order after several injections. It has been observed that the specific retention volume of alcohols and alkanes partially increased by increasing the injection amount. A linear relationship was observed between probe quantities and specific retention volume. This linear relationship is apparent from the specific retention volume values, where the probes are independent of the physical and chemical structures. It was observed that the results obtained in all three injections were close to each other and within acceptable limits. The glass transition temperature of the polymer was determined to be a of 60°C. The thermodynamic data calculated for the injection of different amounts of probes were close to each other.
      PubDate: Tue, 21 May 2019 16:05:07 +000
       
  • Preparation and Characterization of Rigid Polyurethane Foams with
           Different Loadings of Lignin-Derived Polycarboxylic Acids

    • Abstract: Lignin was modified by oxidation to prepare lignin-derived polycarboxylic acids (LPCAs). LPCAs can be introduced into rigid polyurethane foams (RPUFs) via 1,4-dioxane. The expansion ratio and compressive strength of RPUFs were observed. When the loading of LPCAs was 0.67 wt% (based on polyol), the compressive strength of RPUF was the highest and was about 59.2% higher than that of the blank RPUF. The reinforcing mechanism of LPCAs was supposed that the interactions between LPCAs and RPUFs increased the strength of the cell walls. When the loading of LPCAs was less than 0.33 wt%, the expansion ratio of RPUFs increased slightly. The water resistance of RPUFs was not affected by LPCAs, suggesting that RPUFs with LPCAs could be used in a humid environment. Besides, the application of the oxidative modification products of lignin was broadened.
      PubDate: Sun, 19 May 2019 00:05:12 +000
       
  • Comparison Study between Batch and Continuous Processes to Obtain
           Chitosan-Based High Porous Biomaterial for Biological Applications

    • Abstract: Foaming process can be monitored under batch or continuous flows conditions. In the batch process, foaming is time-dependent and the foaming efficiency is controlled by the operator. On the other hand, in the continuous process, the foaming efficiency is only monitored by gas and liquid flow rates. The aim of this work is to compare the two technologies to perform porous scaffold biomaterial based on chitosan (a biocompatible polysaccharide) as well as calcium (Ca2+) and silica (SiO2) (two osteogenesis compounds). Diverse recipes using chitosan (CS) solution (2% ()) in acetic acid (1% ( in distilled water)) mixed with whey protein isolate (WPI) (2% ()) as natural surfactant were studied. They were supplemented or not by hydroxyapatite powder (HAp) and tetraethyl orthosilicate (TEOS). A jacketed narrow annular gap unit (NAGU) was used to perform the continuous foaming process. For all experimentations, the mixture flow rate was maintained at 30 mL min-1. The influence of operating conditions such as gas and liquid flow rates was studied to obtain foams and final scaffold material with different densities and porosities. Some other recipes followed foaming under batch conditions. Generally, the recipes were placed in a vessel under mixing allowing the gas phase to come from the roof of the vessel. In this case, it becomes very difficult to control the density and the size distribution of bubbles in the final product. In both cases, liquid foams were analysed (density, bubble size distribution) and then freeze-dried for mechanical and porosity investigations using the dynamic mechanical analysis (DMA) system and scanning electron microscopy (SEM). It has been shown that the controlled injected gas affected the continuous phase, resulting in a lighter and higher porous structure, a more homogeneous appearance, and a more uniform distribution of osteogenesis components compared to one obtained using batch operation. The obtained porous materials exhibited good properties (porosity, interconnectivity, and good HAp and silica distribution) and potential for future bone regeneration applications.
      PubDate: Wed, 15 May 2019 12:05:14 +000
       
  • Predictable Behavior of GFRP-Reinforced Bridge Decks: Formulation of a
           Strain-Based Capacity Model

    • Abstract: This paper proposes a reliability analysis framework for glass fiber-reinforced polymer- (GFRP-) reinforced concrete systems with uncertain capacities and demands over time. Unfortunately, there has been limited discussion or research done related to the potential change of failure modes over time. Therefore, a rational approach is needed to integrate multiple failure modes in a single analysis framework, considering uncertainties of time-variant demands and capacities. To account for multiple failure modes, this study proposes the limit state function to estimate the safety margin, based on strain values of GFRP-reinforcing bars. A proposed limit state function can capture the likelihood of both shear and flexural failure modes, simultaneously. In this study, seven typical bridge deck configurations (e.g., varied deck thickness, girder spacing, and bar size) were exposed to various ambient temperatures. Simulation results show that reliability indices of 100-year exposure exhibit significant variance, ranging from 2.35 to 0.93, with exposure temperatures ranging from 13 to 33°C. Exposure temperature and time are the dominant factors influencing the reliability indices, so are the ones that need to be changed. As exposure time and/or exposure temperature increase, the flexural capacity model plays an important role to determine the reliability indices. When flexural and shear failure modes are equally dominant, reliability indices can capture risks of both failures, using the proposed strain-based approach.
      PubDate: Wed, 15 May 2019 09:05:21 +000
       
  • Effect of Codonopsis pilosula Polysaccharides on the Growth and Motility
           of Hepatocellular Carcinoma HepG2 Cells by Regulating β-Catenin/TCF4
           Pathway

    • Abstract: Objective. To study the effect of Codonopsis pilosula polysaccharide (CPP) on the growth and motility of HepG2 cells and its possible mechanism. Methods. Cells were randomly divided into Control group, CPP (5 μM) group, CPP (10 μM) group, and CPP (20 μM) group. The proliferation, invasion, migration ability, and expression of proteins involved in the epithelial-mesenchymal transition (EMT) and signaling pathway of HepG2 cells were detected by CCK8 assay, BrdU staining, Transwell, Scratch test, and Western blot, respectively. Results. Codonopsis pilosula polysaccharide inhibited the proliferation of HepG2 cells cultured in vitro along with the expression level of Ki67 and PCNA protein (), decreased the number of invasive cells (), and reduced the scratch closure rate (). It also adjusted the expression of vascular endothelial growth factor (VEGF), E-cadherin, and N-cadherin (). Other than that, downregulation of β-catenin, TCF4, and c-Myc protein expression () was observed as well. Conclusion. Codonopsis pilosula polysaccharide can inhibit the proliferation and motility of HepG2 cells cultured in vitro, and the underlying mechanism is proposed to be related to the inhibition of the β-catenin/TCF4 pathway.
      PubDate: Wed, 08 May 2019 11:05:17 +000
       
  • Investigation of Epoxidized Palm Oils as Green Processing Aids and
           Activators in Rubber Composites

    • Abstract: Epoxidized palm oil (EPO) is environmentally friendly, biodegradable, and a relatively less costly processing aid. In this study, we investigated the suitability of EPO in place of aromatic processing oils in styrene butadiene rubber. The curing properties, mechanical properties, abrasion resistance, and heat buildup properties of rubber composites with EPO were compared with those of the standard with aromatic oils. The rubber composites with EPO showed enhanced mechanical properties including modulus, tensile strength, and elongation at break. This is ascribed to the improved dispersion of fillers in the rubber matrix and interaction between the filler and the polymer. Furthermore, EPO in the rubber matrix showed remarkable abrasion resistance, rebound resilience, and heat buildup at low loadings. EPO in a rubber composite presents feasibility as a renewable raw material that can serve as an alternative to petrochemical oils in various applications.
      PubDate: Sun, 05 May 2019 09:05:15 +000
       
  • Thermal Response and Degressive Reaction Study of Oxo-Biodegradable
           Plastic Products Exposed to Various Degradation Media

    • Abstract: In this work, three plastic film products commonly used as commodity thermoplastic articles were analysed with the aim of characterizing their thermal behaviour and stability. The test specimens were subjected to a series of analytical tests to confirm their biodegradable nature. The specimens ranged between 30 and 70 μm in thickness and showed high concentrations of regulated metals, namely, lead (Pb), postchemical analysis which can lead to its migration to natural sinks. The specimens were also exposed to degressive media, namely, accelerated (UV induced) weathering and soil burial field testing. The weight loss measured exceeded 58% after soil burial indicating deterioration under natural environmental stressors. In addition, the thermal characterization campaign executed with the aim of determining the product’s thermal response followed internationally recognised experimental protocols for the determination of thermal stability. The methodology used followed the International Confederation for Thermal Analysis and Calorimetry (ICTAC) recommendation for thermal stability and the computation of kinetic parameters. The degradation reaction kinetics were also determined postexposure to degressive media. Thermogravimetric analysis coupled with differential scanning calorimetry heat flow analysis and Fourier infrared spectroscopy results was also used in studying the degradation behaviour of the specimens. Analytical kinetic estimation methods relying on model free solutions enabled the determination of the apparent activation energy () of the specimens postexposure to degradation media. A shift in the degradation mechanism was also detected after studying the kinetic parameters which showed a range of between 86.64 and 226.90 kJ mol-1 depending on the type of specimens and exposure media. It can be concluded that the oxo-biodegradable films are well suited for thermal treatment in the future as discarded plastic solid waste (PSW) articles. This work also paves the way for developing national standards and future plans for societies burdened with PSW accumulation.
      PubDate: Tue, 30 Apr 2019 12:05:49 +000
       
  • Modeling of the Penultimate Unit Effect in Chain-Growth Copolymerizations

    • Abstract: The present work addresses the modeling and simulation of the addition of copolymerizations of styrene and methyl methacrylate in batch mode, and the formation of tailored vinyl acetate/acrylic acid copolymers is evaluated through stochastic optimization procedures based on the Monte Carlo method. A kinetic model of the free-radical reaction was proposed in order to predict the behavior of the reaction system taking into consideration the presence of the penultimate unit effect. The profiles of conversion and copolymer composition were also evaluated considering the effect of the medium viscosity (kinetic phenomena related to gel and glass effects) on the reaction performance. It was shown that the proposed model for chain-growth copolymerization is able to describe strong nonlinear behaviors such as autoacceleration of the polymerization and drift of copolymer composition. It was also shown that copolymers with homogeneous composition can be successfully synthesized through manipulation of the monomer feed flow rate based on a stochastic optimization procedure.
      PubDate: Sun, 28 Apr 2019 00:00:00 +000
       
  • Synthesis and Ring-Opening Metathesis Polymerization of a New Norbornene
           Dicarboximide with a Pendant Carbazole Moiety

    • Abstract: A new norbornene dicarboximide presenting a pendant carbazole moiety linked by a p-methylene benzyl spacer is synthesized. This carbazole-functionalized monomer is polymerized via ring-opening metathesis polymerization using Grubbs third-generation catalyst. Microstructural analysis of resulting polymers performed by Nuclear Magnetic Resonance (NMR) shows that they are stereoirregular. Wide-angle X-ray diffraction (WAXD) and thermal (DSC) analysis indicate that polymers are also amorphous. With respect to the fluorescence analysis, both solution and film polymer samples exhibit only “normal structured” carbazole fluorescence, while excimer formation by overlap of carbazole groups is not detected.
      PubDate: Wed, 24 Apr 2019 19:05:18 +000
       
  • Greener Synthesis, Characterization, and Antimicrobiological Effects of
           Helba Silver Nanoparticle-PMMA Nanocomposite

    • Abstract: Nanocomposites are characterized as a multiphase material where one of the phases has a dimension in the nanoscale. There has been huge enthusiasm for the commercialization of nanocomposites for an assortment of uses including medicinal, electronic, and basic. The general motivation behind this study was on the development of silver nanoparticles, due to the present enthusiasm encompassing these metals due to their exceptional properties which are not quite the same as the relating bulk material. A novel, simple, cost-effective, nontoxic, and environmentally friendly technique was developed for synthesizing silver nanoparticle- (AgNP-) poly(methyl methacrylate) (PMMA) nanocomposite using Trigonella foenum-graecum (Helba) aqueous extract. UV-visible spectroscopic analysis was carried out to assess the formulation of AgNPs. The particle size distribution of AgNPs was determined by dynamic light scattering (DLS). The average size of green AgNPs was about 83 nm. Images of spherical green nanoparticles were characterized using transmission electron microscopy (TEM). The resultant green AgNPs were added slowly to polymer (PMMA) solution. The AgNPs encapsulated within the polymer chains were characterized by X-ray diffraction (XRD) and Fourier transform infrared spectroscopy (FTIR). Modification of thermal stabilities of AgNP/PMMA nanocomposites was confirmed using thermogravimetric analysis (TGA). The green AgNP/PMMA nanocomposites showed improved thermal stabilities. The green AgNP/PMMA nanocomposite film proved antimicrobial in water microbiological testing. Thus, the key findings of the work include the use of a safe and simple nanocomposite, which had marked antibacterial activity and potential application in water filtration.
      PubDate: Sun, 21 Apr 2019 13:30:13 +000
       
  • Frost-Resistant Epoxy-Urethane Binders Containing Diglycidyl Urethane

    • Abstract: A novel method for developing frost-resistant epoxy-urethane binders is proposed that is based on mixtures of epoxy-urethane oligomers and diglycidyl urethane formed during synthesis. The microheterogeneous elastic materials obtained by curing these mixtures by the cycloaliphatic amines have a low glass transition temperature and high mechanical properties.
      PubDate: Sun, 21 Apr 2019 10:05:13 +000
       
  • Understanding Collaborative Effects between the Polymer Gel Structure and
           the Applied Electrical Field in Gel Electrophoresis Separation

    • Abstract: The collaborative effects between an applied orthogonal electrical field and the internal structure of polymer gels in gel electrophoresis is studied by using microscopic-based electrophoretic transport models that then are upscaled via the format of electro kinetics-hydrodynamics (EKHD). The interplay of the electrical field and internal gel morphology could impact the separation of biomolecules that, because of similar chemical properties, are usually difficult to separate. In this study, we focus on an irregular pore geometry of the polymer-gel structure by using an axially varying pore (i.e., an axially divergent section) and an orthogonal (to the main flow of solutes) applied electrical field. The microscopic-based conservation of species equation is formulated for the standard case of electrophoresis of charged particles within a geometrical domain, i.e., a pore, and upscaled to obtain macroscopic-based diffusion and mobility coefficients. These coefficients are then used in the calculation of the optimal time of separation to study the effect of the varying parameters of the pore structure under different values of the electrical field. The results are qualitatively consistent with those reported, in the literature, by using computational-based approaches as well as with experiments also reported in the literature, previously. The study shows the important collaborative effects between the applied electrical field and the internal geometry of the polymer gels that could lead to improving biomolecule separation in gel electrophoresis.
      PubDate: Wed, 17 Apr 2019 11:05:14 +000
       
  • Characterization of Rice Husk Fiber-Reinforced Polyvinyl Chloride
           Composites under Accelerated Simulated Soil Conditions

    • Abstract: To study the effect of accelerated simulated soil aging on the physical, mechanical, and thermal behavior of rice husk fiber-reinforced polyvinyl chloride composites. The worst soil aging condition was determined using the orthogonal design method, and the physical, mechanical, and thermal properties of the composites were analyzed over 21 d. The results indicate that the worst soil-accelerated aging condition was as follows: soil temperature of 65°C, soil pH of 2.5, soil moisture content of 45%, and soil porosity (ratio of thick to thin) of 3 : 7. An extended aging time tends to cause poor interfacial bonding quality, and the presence of many microcracks reduced thermal stability and flexural and impact strength. Many fibers were exposed, which resulted in increasing 24 h water absorption and thermal expansion coefficient. The hardness, tensile strength, flexural strength, impact strength, and pyrolysis temperature of the composites (after 21 d of aging) decreased from 50 HRR, 17.42 MPa, 35.2 MPa, 3.19 kJ/m2, and 258.5°C to 26 HRR, 11.5 MPa, 16.8 MPa, 1.16 kJ/m2, and 251.3°C, respectively. The mass loss rate, 24 h water absorption, discoloration, and line thermal expansion coefficient of the composites increased from 0%, 4.19%, 0, and 28.43 to 2.9%, 7.92%, 29.03, and 29.98, respectively.
      PubDate: Wed, 17 Apr 2019 06:05:09 +000
       
  • Improving the Color Stability of Naturally Colored Silk by Cross-Linking
           the Sericin with Phytic Acid

    • Abstract: The color of naturally colored silk (NCS) fades easily during home washing due to the loss of pigment accompanied by dissolution of the sericin. In this study, phytic acid was used to cross-link the sericin of NCS and reduce its solubility, aiming at improving the color fastness of NCS to repeated washing. It was found that the sericin-fixing effect increased as the concentration of phytic acid to 1.0 wt% and the cross-linking time to 5 h increased and then reached a constant level. Cross-linking at pH 7.0-8.5 and temperature 30-40°C could obtain relatively good sericin-fixing effects. The cross-linked NCS showed low sericin loss during the degumming and had much better color fastness to repeated washing as compared with the samples before cross-linking. The cross-linking method proposed in this study may be not only a kind of solution for improving the color fastness of NCS with high practicality but also an alternative for cross-linking sericin-based materials in the biomedical field.
      PubDate: Mon, 15 Apr 2019 09:05:35 +000
       
  • Studies of Formation Mechanism, Structure, and Properties of Network
           Copolymers Obtained by Cocuring of Rolivsan Thermosetting Resins with
           Aromatic Diamines

    • Abstract: Rolivsan thermosetting resins (ROLs) demonstrate high glass-transition temperatures and excellent processability. In our work, high-temperature properties of ROLs were significantly improved using a novel technique for structural and chemical modification of microheterogeneous network polymers. This technique involves, among other procedures, cocuring of rolivsan resins with aromatic diamines (ADA). The most noticeable increase in storage moduli and glass transition temperatures () of these copolymers was achieved when ROLs were modified with 10-15 wt.% of ADA and the resulting blends were subjected to thermal treatment in air in the temperature range 180 to 320°C for several hours. FTIR, 13С NMR spectroscopy, and dynamic mechanical and thermal analyses were used for studying the structure and properties of the obtained products. It was demonstrated that the mechanism of formation of ROL-ADA copolymers includes the following high-temperature reactions: (i) three-dimensional radical copolymerization of unsaturated ROL components and (ii) cleavage of heat-sensitive methacrylate crosslinking units inside the polymer network. The second process is accompanied by formation of pending units of methacrylic acid and methacrylic anhydride, which participate in condensation reactions with ADA.
      PubDate: Tue, 09 Apr 2019 09:05:16 +000
       
  • Polysaccharides for Biomedical Applications

    • PubDate: Tue, 09 Apr 2019 07:05:10 +000
       
  • Alphastatin-Loaded Chitosan Nanoparticle Preparation and Its
           Antiangiogenic Effect on Lung Carcinoma

    • Abstract: Alphastatin is a 24-amino acid peptide and can suppress tumor angiogenesis by inhibiting both the migration and tubule formation of vascular endothelial cells. However, the anticancer effect of Alphastatin is limited due to the short half-life and degradation in the body. In this study, Alphastatin-loaded chitosan nanoparticles (AsCs NPs) were prepared with an initial concentration of 2 mg/ml for chitosan and 1 mg/ml for Alphastatin. AsCs NPs presented the encapsulation efficiency of 32.4%, the mean particle size of 387.4 nm, the polydispersity index of 0.223, and the zeta potential of +28.1 mV. AsCs NPs have a sustained release for 6 days and were stable in serum for at least 24 hours. And the NPs could preserve the integrity of encapsulated Alphastatin and released Alphastatin for 24 hours. In a subcutaneous LA975 lung carcinoma xenograft T739 mouse model, AsCs NPs significantly inhibited the tumor growth, tumor volume, and microvessel density (MVD), and the antitumor effect was even stronger than that of Alphastatin. In addition, the VEGF-induced tube formation of HUVEC could be inhibited by AsCs NPs in vitro and the serum containing AsCs NPs, and the protein level of SphK1 in HUVEC was also decreased by AsCs NPs, suggesting an inhibitory effect of AsCs NPs on the SphK1-S1P signaling pathway. Furthermore, hemolysis assay showed a safety on blood compatibility of AsCs NPs. Our study indicated that AsCs NPs inhibited the SphK1-S1P signaling pathway and enhanced the antiangiogenic effect of Alphastatin both in vitro and in vivo.
      PubDate: Sun, 07 Apr 2019 13:30:02 +000
       
  • Hybrid and Nonhybrid Laminate Composites of Sugar Palm and Glass
           Fibre-Reinforced Polypropylene: Effect of Alkali and Sodium Bicarbonate
           Treatments

    • Abstract: In recent years, the hybrid composites of cellulosic and synthetic fibres are tailored to yield materials with reduced cost and weight. Prior to the fabrication of the hybrid composite, in most case, the cellulosic fibre needs surface modification for proper bonding. Therefore, this study investigates the effect of sodium bicarbonate treatment on the physical and mechanical properties of the hybrid and nonhybrid laminate composites of sugar palm and glass fibre-reinforced polypropylene. The findings will be compared with the conventional alkali treatment. The laminate composites were fabricated using the film stacking technique and hot compression process. Prior to the fabrication process, the sugar palm fibre in it which is naturally woven mat was treated with 4 wt% and 10 wt% alkali and sodium bicarbonate, respectively. All the laminate composites were investigated by tensile, flexural, and impact test, water absorption, and morphological examination. The tensile strength increased with both alkaline and sodium bicarbonate treatments for the hybrid and nonhybrid composites. The increase was more pronounced with the alkaline-treated SPF composite (L03) which displayed the highest value of 61.75 MPa, while that of the sodium bicarbonate-treated SPF composite (L04) recorded 58.76 MPa against 53.01 MPa for the untreated SPF composite (L02). The same trend was observed for the flexural strength. In overall, the alkaline treatment yielded better performance in comparison with sodium bicarbonate treatment.
      PubDate: Thu, 04 Apr 2019 13:05:13 +000
       
  • Chitosan-Based Nanogel Enhances Chemotherapeutic Efficacy of
           10-Hydroxycamptothecin against Human Breast Cancer Cells

    • Abstract: Chitosan (CS), the second most abundant polysaccharide in nature, has been widely developed as a nanoscopic drug delivery vehicle due to its intriguing characteristics. In this work, a positively charged CS-based nanogel was designed and synthesized to inhibit the proliferation of breast cancer cell lines. The model drug of 10-hydroxycamptothecin (HCPT) was entrapped into the core via a facile diffusion to form CS/HCPT. The characteristics of CS/HCPT were evaluated by assessing particle size, drug loading content, and drug loading efficiency. Furthermore, cell internalization, cytotoxicity, and apoptosis of CS/HCPT were also investigated in vitro. The present investigation indicated that the positively charged CS-based nanogel could be potentially used as a promising drug delivery system.
      PubDate: Thu, 04 Apr 2019 09:05:24 +000
       
  • Synthesis and Characterization of an Iron-Containing Fatty Acid-Based
           Ionomer

    • Abstract: One of the desirable research goals today is to convert agro-based raw materials into low-cost functional polymers. Among the readily available natural raw materials are the fatty acids that can be obtained from the hydrolysis of plant oils or from the paper industry as byproducts. In this work, a novel iron-containing ionomer has been prepared through the reaction of fatty acids with steel dust or iron powder in the presence of carbon dioxide and water. Characterization has been achieved via 1H and 13C NMR, FT-IR, and size exclusion chromatography. The product has been shown to have an ionomeric structure, consisting of oligomers of fatty acid carboxylates (derived from Diels-Alder reaction) coupled with iron(II) and iron(III) ions (from the oxidation of iron). Because the fatty acid oligomers have low molecular weights, the ionomer easily dissolves in a solvent and can be made into different physical forms, such as liquid, solid, film, or foam.
      PubDate: Thu, 04 Apr 2019 07:05:15 +000
       
 
 
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