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Arcanjo AP, Liborio DO, Arias S, Carvalho FR, Silva JP, Ribeiro BD, Dias ML, Castro AM, Fréty R, Barbosa CMBM, Pacheco JGA. Chemical Recycling of PET Using Catalysts from Layered Double Hydroxides: Effect of Synthesis Method and Mg-Fe Biocompatible Metals. Polymers (Basel) 2023; 15:3274. [PMID: 37571167 PMCID: PMC10422272 DOI: 10.3390/polym15153274] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2023] [Revised: 07/19/2023] [Accepted: 07/24/2023] [Indexed: 08/13/2023] Open
Abstract
The chemical recycling of poly(ethylene terephthalate) (PET) residues was performed via glycolysis with ethylene glycol (EG) over Mg-Fe and Mg-Al oxide catalysts derived from layered double hydroxides. Catalysts prepared using the high supersaturation method (h.s.c.) presented a higher surface area and larger particles, but this represented less PET conversion than those prepared by the low supersaturation method (l.s.c.). This difference was attributed to the smaller mass transfer limitations inside the (l.s.c.) catalysts. An artificial neural network model well fitted the PET conversion and bis(2-hydroxyethyl) terephthalate (BHET) yield. The influence of Fe in place of Al resulted in a higher PET conversion of the Mg-Fe-h.s.c. catalyst (~95.8%) than of Mg-Al-h.s.c. (~63%). Mg-Fe catalysts could be reused four to five times with final conversions of up to 97% with reaction conditions of EG: PET = 5:1 and catalyst: PET = 0.5%. These results confirm the Mg-Fe oxides as a biocompatible novel catalyst for the chemical recycling of PET residues to obtain non-toxic BHET for further polymerization, and use in food and beverage packaging.
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Affiliation(s)
- Ana P. Arcanjo
- Laboratory of Refining and Cleaner Technology (LabRefino-Lateclim), Department of Chemical Engineering, Institute for Petroleum and Energy Research (i-LITPEG), Federal University of Pernambuco, Recife 50740-550, PE, Brazil (S.A.)
| | - Denisson O. Liborio
- Laboratory of Refining and Cleaner Technology (LabRefino-Lateclim), Department of Chemical Engineering, Institute for Petroleum and Energy Research (i-LITPEG), Federal University of Pernambuco, Recife 50740-550, PE, Brazil (S.A.)
| | - Santiago Arias
- Laboratory of Refining and Cleaner Technology (LabRefino-Lateclim), Department of Chemical Engineering, Institute for Petroleum and Energy Research (i-LITPEG), Federal University of Pernambuco, Recife 50740-550, PE, Brazil (S.A.)
| | - Florival R. Carvalho
- Fuel Laboratory, Department of Chemical Engineering, Institute for Petroleum and Energy Research (i-LITPEG), Federal University of Pernambuco, Recife 50740-550, PE, Brazil
| | - Josivan P. Silva
- Laboratory of Refining and Cleaner Technology (LabRefino-Lateclim), Department of Chemical Engineering, Institute for Petroleum and Energy Research (i-LITPEG), Federal University of Pernambuco, Recife 50740-550, PE, Brazil (S.A.)
- Engineering and Technology Center, Uninassau University, Paulista 53401-440, PE, Brazil
| | - Bernardo D. Ribeiro
- Biochemical Engineering Department, School of Chemistry, Federal University of Rio de Janeiro, Rio de Janeiro 21941-909, RJ, Brazil
| | - Marcos L. Dias
- Macromolecules Institute, Federal University of Rio de Janeiro, Rio de Janeiro 21941-598, RJ, Brazil
| | - Aline M. Castro
- Research, Development and Innovation Center (Cenpes), Petrobras, Rio de Janeiro 21941-915, RJ, Brazil
| | - Roger Fréty
- Laboratory of Refining and Cleaner Technology (LabRefino-Lateclim), Department of Chemical Engineering, Institute for Petroleum and Energy Research (i-LITPEG), Federal University of Pernambuco, Recife 50740-550, PE, Brazil (S.A.)
| | - Celmy M. B. M. Barbosa
- Laboratory of Refining and Cleaner Technology (LabRefino-Lateclim), Department of Chemical Engineering, Institute for Petroleum and Energy Research (i-LITPEG), Federal University of Pernambuco, Recife 50740-550, PE, Brazil (S.A.)
| | - Jose Geraldo A. Pacheco
- Laboratory of Refining and Cleaner Technology (LabRefino-Lateclim), Department of Chemical Engineering, Institute for Petroleum and Energy Research (i-LITPEG), Federal University of Pernambuco, Recife 50740-550, PE, Brazil (S.A.)
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Anaya-Mancipe JM, Queiroz VM, dos Santos RF, Castro RN, Cardoso VS, Vermelho AB, Dias ML, Thiré RMSM. Electrospun Nanofibers Loaded with Plantago major L. Extract for Potential Use in Cutaneous Wound Healing. Pharmaceutics 2023; 15:1047. [PMID: 37111535 PMCID: PMC10144042 DOI: 10.3390/pharmaceutics15041047] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/17/2023] [Revised: 03/21/2023] [Accepted: 03/22/2023] [Indexed: 04/29/2023] Open
Abstract
Plantago major L. is a plant available worldwide that has been traditionally used for several medical applications due to its wound healing, anti-inflammatory, and antimicrobial properties. This work aimed to develop and evaluate a nanostructured PCL electrospun dressing with P. major extract encapsulated in nanofibers for applications in wound healing. The extract from leaves was obtained by extraction in a mixture of water:ethanol = 1:1. The freeze-dried extract presented a minimum inhibitory concentration (MIC) for Staphylococcus Aureus susceptible and resistant to methicillin of 5.3 mg/mL, a high antioxidant capacity, but a low content of total flavonoids. Electrospun mats without defects were successfully produced using two P. major extract concentrations based on the MIC value. The extract incorporation in PCL nanofibers was confirmed using FTIR and contact angle measurements. The PCL/P. major extract was evaluated using DSC and TGA demonstrating that the incorporation of the extract decreases the thermal stability of the mats as well as the degree of crystallinity of PCL-based fibers. The P. major extract incorporation on electrospun mats produced a significant swelling degree (more than 400%) and increased the capacity of adsorbing wound exudates and moisture, important characteristics for skin healing. The extract-controlled release evaluated using in vitro study in PBS (pH, 7.4) shows that the P. major extract delivery from the mats occurs in the first 24 h, demonstrating their potential capacity to be used in wound healing.
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Affiliation(s)
- Javier M. Anaya-Mancipe
- COPPE/Program of Metallurgical and Materials Engineering—PEMM, Universidade Federal de Rio de Janeiro—UFRJ, Rio de Janeiro 21941-599, RJ, Brazil; (J.M.A.-M.)
- Institute of Macromolecules Professor Eloisa Mano—IMA, Universidade Federal do Rio de Janeiro—UFRJ, Rio de Janeiro 21941-598, RJ, Brazil
| | - Vanessa M. Queiroz
- COPPE/Program of Metallurgical and Materials Engineering—PEMM, Universidade Federal de Rio de Janeiro—UFRJ, Rio de Janeiro 21941-599, RJ, Brazil; (J.M.A.-M.)
| | - Rafael F. dos Santos
- Chemistry Institute, Universidade Federal Rural do Rio de Janeiro—UFRRJ, Seropédica 23890-000, RJ, Brazil
| | - Rosane N. Castro
- Chemistry Institute, Universidade Federal Rural do Rio de Janeiro—UFRRJ, Seropédica 23890-000, RJ, Brazil
| | - Verônica S. Cardoso
- Bioinovar—Instituto de Microbiologia Paulo de Góes, Universidade Federal do Rio de Janeiro—UFRJ, Rio de Janeiro 21941-902, RJ, Brazil
| | - Alane B. Vermelho
- Bioinovar—Instituto de Microbiologia Paulo de Góes, Universidade Federal do Rio de Janeiro—UFRJ, Rio de Janeiro 21941-902, RJ, Brazil
| | - Marcos L. Dias
- Institute of Macromolecules Professor Eloisa Mano—IMA, Universidade Federal do Rio de Janeiro—UFRJ, Rio de Janeiro 21941-598, RJ, Brazil
| | - Rossana M. S. M. Thiré
- COPPE/Program of Metallurgical and Materials Engineering—PEMM, Universidade Federal de Rio de Janeiro—UFRJ, Rio de Janeiro 21941-599, RJ, Brazil; (J.M.A.-M.)
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O'Connor KM, Ashoori M, Dias ML, Dempsey EM, O'Halloran KD, McDonald FB. Influence of innate immune activation on endocrine and metabolic pathways in infancy. Am J Physiol Endocrinol Metab 2021; 321:E24-E46. [PMID: 33900849 DOI: 10.1152/ajpendo.00542.2020] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
Prematurity is the leading cause of neonatal morbidity and mortality worldwide. Premature infants often require extended hospital stays, with increased risk of developing infection compared with term infants. A picture is emerging of wide-ranging deleterious consequences resulting from innate immune system activation in the newborn infant. Those who survive infection have been exposed to a stimulus that can impose long-lasting alterations into later life. In this review, we discuss sepsis-driven alterations in integrated neuroendocrine and metabolic pathways and highlight current knowledge gaps in respect of neonatal sepsis. We review established biomarkers for sepsis and extend the discussion to examine emerging findings from human and animal models of neonatal sepsis that propose novel biomarkers for early identification of sepsis. Future research in this area is required to establish a greater understanding of the distinct neonatal signature of early and late-stage infection, to improve diagnosis, curtail inappropriate antibiotic use, and promote precision medicine through a biomarker-guided empirical and adjunctive treatment approach for neonatal sepsis. There is an unmet clinical need to decrease sepsis-induced morbidity in neonates, to limit and prevent adverse consequences in later life and decrease mortality.
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Affiliation(s)
- K M O'Connor
- Department of Physiology, School of Medicine, College of Medicine and Health, University College Cork, Cork, Ireland
| | - M Ashoori
- Department of Physiology, School of Medicine, College of Medicine and Health, University College Cork, Cork, Ireland
- Irish Centre for Maternal and Child Health Research (INFANT), University College Cork, Cork, Ireland
| | - M L Dias
- Department of Physiology, School of Medicine, College of Medicine and Health, University College Cork, Cork, Ireland
| | - E M Dempsey
- Irish Centre for Maternal and Child Health Research (INFANT), University College Cork, Cork, Ireland
- Department of Paediatrics and Child Health, School of Medicine, College of Medicine and Health, Cork University Hospital, Wilton, Cork, Ireland
| | - K D O'Halloran
- Department of Physiology, School of Medicine, College of Medicine and Health, University College Cork, Cork, Ireland
- Irish Centre for Maternal and Child Health Research (INFANT), University College Cork, Cork, Ireland
| | - F B McDonald
- Department of Physiology, School of Medicine, College of Medicine and Health, University College Cork, Cork, Ireland
- Irish Centre for Maternal and Child Health Research (INFANT), University College Cork, Cork, Ireland
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Cunha RH, Nele M, Dias ML. Reaction and thermal behavior of vitrimer‐like polyhydroxy esters based on polyethylene glycol diglycidyl ether. J Appl Polym Sci 2020. [DOI: 10.1002/app.49329] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Affiliation(s)
- Rodrigo H. Cunha
- Universidade Federal do Rio de Janeiro, Instituto de Macromoléculas Professora Eloisa Mano Rio de Janeiro Brazil
| | - Marcio Nele
- Escola de Química, Av. Athos da Silveira RamosUniversidade Federal do Rio de Janeiro Rio de Janeiro Brazil
| | - Marcos L. Dias
- Universidade Federal do Rio de Janeiro, Instituto de Macromoléculas Professora Eloisa Mano Rio de Janeiro Brazil
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Dias ML, Schoene FAP, Ramirez C, Graciano IA, Sirelli L, Gonçalves RP. Thermal and crystallization behaviour of epoxidized high cis-polybutadiene rubber. J RUBBER RES 2019. [DOI: 10.1007/s42464-019-00028-5] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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Braghirolli DI, Caberlon B, Gamba D, Petry J, Dias ML, Pranke P. Poly(trimethylene carbonate-co-L-lactide) electrospun scaffolds for use as vascular grafts. ACTA ACUST UNITED AC 2019; 52:e8318. [PMID: 31411247 PMCID: PMC6694404 DOI: 10.1590/1414-431x20198318] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/16/2019] [Accepted: 05/31/2019] [Indexed: 11/22/2022]
Abstract
Currently, there is great clinical need for suitable synthetic grafts that can be used in vascular diseases. Synthetic grafts have been successfully used in medium and large arteries, however, their use in small diameter vessels is limited and presents a high failure rate. In this context, the aim of this study was to develop tissue engineering scaffolds, using poly(trimethylene carbonate-co-L-lactide) (PTMCLLA), for application as small diameter vascular grafts. For this, copolymers with varying trimethylene carbonate/lactide ratios - 20/80, 30/70, and 40/60 - were submitted to electrospinning and the resulting scaffolds were evaluated in terms of their physicochemical and biological properties. The scaffolds produced with PTMCLLA 20/80, 30/70, and 40/60 showed smooth fibers with an average diameter of 771±273, 606±242, and 697±232 nm, respectively. When the degradation ratio was evaluated, the three scaffold groups had a similar molecular weight (Mw) on the final day of analysis. PTMCLLA 30/70 and 40/60 scaffolds exhibited greater flexibility than the PTMCLLA 20/80. However, the PTMCLLA 40/60 scaffolds showed a large wrinkling and their biological properties were not evaluated. The PTMCLLA 30/70 scaffolds supported the adhesion and growth of mesenchymal stem cells (MSCs), endothelial progenitor cells, and smooth muscle cells (SMCs). In addition, they provided a spreading of MSCs and SMCs. Given the results, the electrospun scaffolds produced with PTMCLLA 30/70 copolymer can be considered promising candidates for future applications in vascular tissue engineering.
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Affiliation(s)
- D I Braghirolli
- Laboratório de Hematologia e Células-tronco, Faculdade de Farmácia, Universidade Federal do Rio Grande do Sul, Porto Alegre, RS, Brasil.,Programa de Pós-Graduação em Fisiologia, Universidade Federal do Rio Grande do Sul, Porto Alegre, RS, Brasil
| | - B Caberlon
- Laboratório de Hematologia e Células-tronco, Faculdade de Farmácia, Universidade Federal do Rio Grande do Sul, Porto Alegre, RS, Brasil
| | - D Gamba
- Instituto de Química, Universidade Federal do Rio Grande do Sul, Porto Alegre, RS, Brasil
| | - Jftc Petry
- Instituto de Química, Universidade Federal do Rio Grande do Sul, Porto Alegre, RS, Brasil
| | - M L Dias
- Instituto de Macromoléculas Professora Eloisa Mano (IMA), Universidade Federal do Rio de Janeiro, Rio de Janeiro, RJ, Brasil
| | - P Pranke
- Laboratório de Hematologia e Células-tronco, Faculdade de Farmácia, Universidade Federal do Rio Grande do Sul, Porto Alegre, RS, Brasil.,Programa de Pós-Graduação em Fisiologia, Universidade Federal do Rio Grande do Sul, Porto Alegre, RS, Brasil.,Instituto de Pesquisa com Células-tronco, Porto Alegre, RS, Brasil
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Affiliation(s)
- Joana S. von der Weid
- Universidade Federal do Rio de Janeiro (UFRJ), Instituto de Macromoléculas Professora Eloisa Mano (IMA); Av. Horácio Macedo, 2030 21941-598 Rio de Janeiro RJ Brazil
| | - Luis P. Icart
- Universidade Federal do Rio de Janeiro (UFRJ), Faculdade de Farmácia, Centro de Ciências da Saúde; Av. Carlos Chagas Filho, 373 21941-599 Rio de Janeiro RJ Brazil
| | - Marcos L. Dias
- Universidade Federal do Rio de Janeiro (UFRJ), Instituto de Macromoléculas Professora Eloisa Mano (IMA); Av. Horácio Macedo, 2030 21941-598 Rio de Janeiro RJ Brazil
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Agüero L, Zaldivar-Silva D, Peña L, Dias ML. Alginate microparticles as oral colon drug delivery device: A review. Carbohydr Polym 2017; 168:32-43. [DOI: 10.1016/j.carbpol.2017.03.033] [Citation(s) in RCA: 230] [Impact Index Per Article: 32.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/20/2016] [Revised: 02/18/2017] [Accepted: 03/09/2017] [Indexed: 01/13/2023]
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Dias ML, Dip RMM, Souza DHS, Nascimento JP, Santos AP, Furtado CA. Electrospun Nanofibers of Poly(lactic acid)/Graphene Nanocomposites . J Nanosci Nanotechnol 2017; 17:2531-2540. [PMID: 29652121 DOI: 10.1166/jnn.2017.12679] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/08/2023]
Abstract
Multi-layer graphene (MLG) sheets were obtained by exfoliation of natural graphite flakes in chloroform. Dispersions with concentration up to 19 mg/mL were prepared. Statistical measurements of MLG sheet sizes by transmission electron microscopy showed average width and length of ~340 nm and 860 nm, respectively. MLG/chloroform dispersions were used to prepare poly(lactic acid) (PLA)/MLG composite fibrillar membranes by electrospinning. A homogeneous distribution of MLG into the fibers was observed by optical and scanning electron microscopies. The presence of MLG leads to the decrease in the diameter distribution of the fibers, which presented average diameter values below 500 nm. Isothermal kinetic crystallization of PLA showed to be influenced by the electrospinning process and the content of MLG sheets, which acts as nucleating agents.
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Icart LP, Fernandes E, Agüero L, Ramón J, Zaldivar D, Dias ML. Fluorescent microspheres of poly(ethylene glycol)-poly(lactic acid)-fluorescein copolymers synthesized by Ugi four-component condensation. J Appl Polym Sci 2015. [DOI: 10.1002/app.42994] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/16/2023]
Affiliation(s)
- Luis P. Icart
- Centro de Biomateriales; Universidad de la Habana; Havana Cuba
| | - Edson Fernandes
- Escola de Química, Centro de Tecnologia; Universidade Federal do Rio de Janeiro; Rio de Janeiro Brazil
| | - Lissette Agüero
- Centro de Biomateriales; Universidad de la Habana; Havana Cuba
| | - Jose Ramón
- Centro de Biomateriales; Universidad de la Habana; Havana Cuba
| | | | - Marcos L. Dias
- Instituto de Macromoléculas Professora Eloisa Mano; Universidade Federal do Rio de Janeiro; Rio de Janeiro Brazil
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Turley JP, Romer F, Trudeau ML, Dias ML, Smith ME, Hanna JV, Antonelli DM. Proton conductivity of naphthalene sulfonate formaldehyde resin-doped mesoporous niobium and tantalum oxide composites. ChemSusChem 2015; 8:301-309. [PMID: 25209169 DOI: 10.1002/cssc.201402546] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/13/2014] [Indexed: 06/03/2023]
Abstract
Proton conductivity in a series of mesoporous niobium and tantalum metal oxide (mX2 O5 ) composites of naphthalene sulfonic acid formaldehyde resin (NSF) that are resistant to moisture loss at temperatures greater than 50 °C is reported. The investigation focuses on the effect to proton conductivity by changing pore size and metal in the mesostructure of the mX2 O5 system and thus, a series of mX2 O5 -NSF composites were synthesized with C6 , C12 , and C18 templates. These were characterized by XRD, thermogravimetric analysis, nitrogen adsorption, and scanning TEM and then studied using impedance spectroscopy to establish proton conductivity values at various temperatures ranging from 25 to 150 °C. The most promising sample displayed a conductivity of 21.96 mS cm(-1) at 100 °C, surpassing the literature value for Nafion 117 (ca. 8 mS cm(-1) ). (1) H and (13) C solid state NMR studies the mX2 O5 -NSF composites demonstrate that the oligomeric nature of the NSF is preserved while in contact with the mX2 O5 surface, thus facilitating conductivity.
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Affiliation(s)
- Jonathan P Turley
- Sustainable Environment Research Centre, University of South Wales, Pontypridd, CF37 4BD (UK)
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Gonçalves RP, da Silva FFF, Picciani PHS, Dias ML. Morphology and Thermal Properties of Core-Shell PVA/PLA Ultrafine Fibers Produced by Coaxial Electrospinning. ACTA ACUST UNITED AC 2015. [DOI: 10.4236/msa.2015.62022] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
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Agüero L, Zaldivar D, Peña L, Solís Y, Ramón J, Dias ML. Preparation and characterization of pH-sensitive microparticles based on polyelectrolyte complexes for antibiotic delivery. POLYM ENG SCI 2014. [DOI: 10.1002/pen.23962] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Affiliation(s)
- L. Agüero
- Departamento de Química Macromolecular, Centro de Biomateriales; Universidad de La Habana, Ave. Universidad % G y Ronda; CP 10400 Ciudad de La Habana Cuba
| | - D. Zaldivar
- Departamento de Química Macromolecular, Centro de Biomateriales; Universidad de La Habana, Ave. Universidad % G y Ronda; CP 10400 Ciudad de La Habana Cuba
| | - L. Peña
- Departamento de Química Macromolecular, Centro de Biomateriales; Universidad de La Habana, Ave. Universidad % G y Ronda; CP 10400 Ciudad de La Habana Cuba
| | - Y. Solís
- Departamento de Química Macromolecular, Centro de Biomateriales; Universidad de La Habana, Ave. Universidad % G y Ronda; CP 10400 Ciudad de La Habana Cuba
| | - J.A. Ramón
- Departamento de Química Macromolecular, Centro de Biomateriales; Universidad de La Habana, Ave. Universidad % G y Ronda; CP 10400 Ciudad de La Habana Cuba
| | - Marcos L. Dias
- Universidade Federal do Rio de Janeiro; Instituto de Macromoléculas Professora Eloisa Mano, Av. Horácio Macedo; 2030-Centro de Tecnologia. Bloco J Rio de Janeiro, RJ Brazil
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Affiliation(s)
- Diego H. S. Souza
- Universidade Federal do Rio de Janeiro (UFRJ); Instituto de Macromoléculas Professora Eloisa Mano (IMA), Av. Horácio Macedo, 2.030, Centro de Tecnologia; BL J. 21941-598 Rio de Janeiro Brazil
| | - Cristina T. Andrade
- Universidade Federal do Rio de Janeiro (UFRJ); Instituto de Macromoléculas Professora Eloisa Mano (IMA), Av. Horácio Macedo, 2.030, Centro de Tecnologia; BL J. 21941-598 Rio de Janeiro Brazil
| | - Marcos L. Dias
- Universidade Federal do Rio de Janeiro (UFRJ); Instituto de Macromoléculas Professora Eloisa Mano (IMA), Av. Horácio Macedo, 2.030, Centro de Tecnologia; BL J. 21941-598 Rio de Janeiro Brazil
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Souza DHS, Andrade CT, Dias ML. Rheological behavior of poly(lactic acid)/synthetic mica nanocomposites. Mater Sci Eng C Mater Biol Appl 2013; 33:1795-9. [PMID: 23827638 DOI: 10.1016/j.msec.2012.12.091] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/07/2012] [Revised: 11/22/2012] [Accepted: 12/28/2012] [Indexed: 10/27/2022]
Abstract
Poly(lactic acid) nanocomposites were prepared with three synthetic fluoromicas in a twin-screw extruder. Sodium and two organomodified synthetic fluoromicas at different compositions were used. The effect of mica type and composition on the rheological behavior of the nanocomposites was evaluated. The sodium fluoromica did not have a significant effect on the poly(lactic acid) rheological properties, while addition of the organophilic micas to poly(lactic acid) has a strong effect on the rheology, showing a pronounced shear thinning behavior. The dynamic rheological studies revealed that the nanocomposites with organomica have a higher viscosity and more pronounced elastic properties than neat poly(lactic acid). Both storage and loss moduli increased with mica content.
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Affiliation(s)
- D H S Souza
- Universidade Federal do Rio de Janeiro (UFRJ), Instituto de Macromoléculas Professora Eloisa Mano (IMA), Av. Horácio Macedo, 2.030, Centro de Tecnologia, B. J. 21941-598 Rio de Janeiro, Brazil.
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Azuma C, Dias ML, Mano EB. Molecular weight determination of acrylonitrile polymers by gel permeation chromatography in N,N-dimethylformamide. ACTA ACUST UNITED AC 2011. [DOI: 10.1002/masy.19860020118] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
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Erdmann E, Acosta D, Pita VJRR, Monasterio FE, Carrera MC, Dias ML, Destéfanis HA. Effect of the organoclay preparation on the extent of intercalation/exfoliation and barrier properties of polyethylene/PA6/montmorillonite nanocomposites. J Appl Polym Sci 2010. [DOI: 10.1002/app.32560] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
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Nascimento CR, Azuma C, Bretas R, Farah M, Dias ML. Chain extension reaction in solid-state polymerization of recycled PET: The influence of 2,2â²-bis-2-oxazoline and pyromellitic anhydride. J Appl Polym Sci 2010. [DOI: 10.1002/app.31400] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
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Gomes EVD, Oliveira CMF, Dias ML. Blends of Poly(Hydroxybutyrate) and Oligomeric Polyester. International Journal of Polymer Analysis and Characterization 2009. [DOI: 10.1080/10236660802596573] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/21/2022]
Affiliation(s)
- Elaine V. D. Gomes
- a Instituto de Macromoléculas Professora Eloisa Mano , Universidade Federal do Rio de Janeiro , Rio de Janeiro, Brazil
| | - Clara M. F. Oliveira
- a Instituto de Macromoléculas Professora Eloisa Mano , Universidade Federal do Rio de Janeiro , Rio de Janeiro, Brazil
| | - Marcos L. Dias
- a Instituto de Macromoléculas Professora Eloisa Mano , Universidade Federal do Rio de Janeiro , Rio de Janeiro, Brazil
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Sanches NDB, Dias ML, Pacheco EB. Environmental stress cracking behavior of bottle and fiber grade poly(ethylene terephthalate) in contact with aqueous amine solutions. POLYM ENG SCI 2008. [DOI: 10.1002/pen.21173] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
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Sirelli L, Prado RMK, Tavares MIB, Nunes RCR, Dias ML. Molecular Dynamics of Poly(Ethylene Terephthalate)/Muscovite Mica Composite by Low-Field NMR. International Journal of Polymer Analysis and Characterization 2008. [DOI: 10.1080/10236660802070678] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/21/2022]
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Gomes EVD, Marize C, Oliveira F, Dias ML. Blends of Poly(hydroxybutyrate) and Poly(ethylene succinate) Prepared in the Presence of Samarium. INT J POLYM MATER PO 2008. [DOI: 10.1080/00914030801891278] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022]
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Bomfim JA, Dias ML, Filgueiras CA, Peruch F, Deffieux A. The effect of polymerization temperature on the structure and properties of poly(1-hexene) and poly(1-decene) prepared with a Ni(II)–diimine catalyst. Catal Today 2008. [DOI: 10.1016/j.cattod.2007.12.042] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
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Sirelli L, Pereira RA, Perez CA, Dias ML. Thermal Behavior of Poly(ethylene terephthalate) Crystalline and Amorphous Phases by Wide Angle X‐ray Scattering. J MACROMOL SCI B 2007. [DOI: 10.1080/00222340500523842] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/24/2022]
Affiliation(s)
- Lys Sirelli
- a Instituto de Macromoléculas Professora Eloísa Mano , Universidade Federal do Rio de Janeiro‐UFRJ, Centro de Tecnologia , Rio de Janeiro, Brazil
| | - Romeu A. Pereira
- b Faculdade de Filosofia Ciências e Letras Santa Marcelina, Pça. Annina Bisegna , Muriaé, MG, Brazil
| | - Carlos A. Perez
- c Núcleo de Catálise‐COPPE , Universidade Federal do Rio de Janeiro , Rio de Janeiro, Brazil
| | - Marcos L. Dias
- a Instituto de Macromoléculas Professora Eloísa Mano , Universidade Federal do Rio de Janeiro‐UFRJ, Centro de Tecnologia , Rio de Janeiro, Brazil
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Oliveira FC, Dias ML, Castilho LR, Freire DMG. Characterization of poly(3-hydroxybutyrate) produced by Cupriavidus necator in solid-state fermentation. Bioresour Technol 2007; 98:633-8. [PMID: 16580194 DOI: 10.1016/j.biortech.2006.02.022] [Citation(s) in RCA: 68] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/11/2005] [Revised: 01/09/2006] [Accepted: 02/03/2006] [Indexed: 05/08/2023]
Abstract
Solid-state fermentation (SSF) has recently been proposed as an alternative to submerged fermentation for the production of poly(hydroxyalkanoates). In the present work, X-ray diffraction, differential scanning calorimetry, nuclear magnetic resonance and infrared spectroscopy were employed to investigate the chemical structure, as well as the thermal properties and the crystalline morphology of poly(3-hydroxybutyrate) samples produced by SSF, using as raw material either soy cake or soy cake supplemented with 2.5% (m/m) sugarcane molasses. The results obtained showed that the biopolymer obtained by SSF presented the same properties as commercial PHB, except for the higher molar mass and the lower degree of crystallinity that were observed. Thus, the present data indicate that solid-state fermentation is an interesting alternative for the production of PHB, allowing the production of biopolymers with adequate properties from low-cost, renewable resources.
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Affiliation(s)
- Fabiane C Oliveira
- Federal University of Rio de Janeiro (UFRJ), COPPE/Programa de Engenharia Química, Caixa Postal 68502, 21941-972 Rio de Janeiro, RJ, Brazil
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Santos MS, Dias ML, Altstädt V. Blends of Poly(ether imide) and Styrene Sulfonic Acid Based Polymer: Thermal, Mechanical and Ionic Conduction Behavior. INT J POLYM MATER PO 2007. [DOI: 10.1080/00914030600972758] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
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Abstract
A aplicação de estruturas tridimensionais bio-reabsorvíveis como suporte temporário na engenharia de tecidos tem crescido nos últimos anos. Neste estudo, estruturas porosas de poli(3-hidroxibutirato) (P(3HB)) foram preparadas pelo método de vazamento e lixiviação de partículas. As amostras foram obtidas pela adição de cloreto de sódio em concentrações de 50, 60, 70, 80 e 90% p/p, a uma solução de P(3HB) em clorofórmio. O tamanho das partículas de sal foi controlado nas faixas de 38-53, 53-75 e 75-150 µm. As propriedades térmicas das matrizes poliméricas foram estudadas via calorimetria diferencial de varredura (DSC) e análise termogravimétrica (TGA). A morfologia das amostras foi observada por microscopia eletrônica de varredura (MEV), onde se constatou a formação de estruturas assimétricas para concentrações de sal de 50, 60 e eventualmente 70%. Os tamanhos dos poros obtidos apresentaram dependência somente com a fração em peso inicial e com o tamanho da partícula do sal empregado. Análises de difração de raios X indicaram que o tipo de sal, a concentração e a granulometria não influenciam as características cristalinas do polímero na estrutura porosa. Pelo teste de bioatividade "in vitro" foi constatada a formação espontânea de uma camada de fosfato de cálcio sobre a superfície das estruturas porosas.
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Brandão LS, Mendes LC, Medeiros ME, Sirelli L, Dias ML. Thermal and mechanical properties of poly(ethylene terephthalate)/lamellar zirconium phosphate nanocomposites. J Appl Polym Sci 2006. [DOI: 10.1002/app.24096] [Citation(s) in RCA: 46] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
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Firme CL, Grafov AV, Dias ML. Ethylene and propylene polymerization with bis(indenyl)zirconium/Mao catalytic systems modified by sterically demanding alcohols. ACTA ACUST UNITED AC 2005. [DOI: 10.1002/pola.20839] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
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Crossetti GL, Dias ML, Queiroz BT, Silva LP, Ziglio CM, Bomfim JAS, Filgueiras CAL. Ethylene polymerization with imine and phosphine nickel complexes containing isothiocyanate. Appl Organomet Chem 2004. [DOI: 10.1002/aoc.633] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
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Dias ML, Silva APF. Transesterification reactions in triphenyl phosphite additivated-poly(ethylene terephthalate)/poly(ethylene naphthalate) blends. POLYM ENG SCI 2004. [DOI: 10.1002/pen.11309] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
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Barrera Galland G, Da Silva LP, Dias ML, Crossetti GL, Ziglio CM, Filgueiras CAL. 13C NMR determination of the microstructure of polypropylene obtained with the DADNi(NCS)2/methylaluminoxane catalyst system. ACTA ACUST UNITED AC 2004. [DOI: 10.1002/pola.20047] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
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Costa DA, Santos ALS, Sanches NB, Oliveira CMF, Dias ML. Mistura reativa de poliamida 6 e policarbonato: reatividade do copolímero formado "in situ". Polímeros 2004. [DOI: 10.1590/s0104-14282004000400004] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
As misturas físicas de poliamida 6 (PA6) e policarbonato (PC) processadas a 240 ºC, durante 10, 30 e 60 minutos formam um copolímero de PA6-PC. A alta temperatura e o longo tempo de processamento podem causar modificações nas propriedades dessas misturas e degradar o copolímero, originando grupos isocianato e subseqüentemente CO2 e grupos NH2 terminais. A quantidade de copolímero PA6-PC formado durante o processo de mistura é maior com o aumento da proporção de PC na mistura. As ligações uretânicas de polímeros termoplásticos exibem mais baixas estabilidades térmica e oxidativa, resultando no aumento da concentração de grupos terminais NH2. A reatividade dessas misturas foi investigada através do torque durante o processo de mistura, da titulação potenciométrica dos grupos NH2 terminais e por microscopia eletrônica de varredura.
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Grafova IA, Grafov AV, Costantino U, Marmottini F, Dias ML. Layered Double Hydroxides as Supports for Norbornene Addition Polymerisation Catalysts. Zeitschrift für Naturforschung B 2003. [DOI: 10.1515/znb-2003-1106] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Abstract
Abstract Addition polymerisation of norbornene with transition metal catalysts activated by methylaluminoxane was first realised on heterogeneous catalytic systems. Advanced inorganic functional polymers possessing anion-exchange properties - layered double hydroxides of Al and Zn of hydrotalcitetype - were applied as supports. They possess high polarity and are selective towards polar molecules like organometallic compounds. The activity of immobilised nickel catalysts was found to be higher than that of the homogeneous one. A certain catalytic activity was also found for group 4 phthalocyanines. The polynorbornenes obtained were characterised by gel permeation chromatography and SEM microimaging. The support’s morphology influences the shape, density, and dimensions of the resulting polymer particles.
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Affiliation(s)
- Iryna A. Grafova
- 1Institute for Sorption and Problems of Endoecology, National Academy of Sciences, Gen. Naumova 13, Kiev , UA- 03164, Ukraine; Present address: E. Mano Institute of Macromolecules Federal University of Rio de Janeiro, C. P. 68525, 21945-970, Rio de Janeiro, Brazil
| | - Andrei V. Grafov
- 2V. I. Vernadskii Institute of General and Inorganic Chemistry, National Academy of Sciences, Prospekt Palladina 32/34, Kiev, UA-03142, Ukraine; Present Address: E. Mano Institute of Macromolecules Federal University of Rio de Janeiro, C. P. 68525, 21945-970, Rio de Janeiro, Brazil
| | - Umberto Costantino
- 3Department of Chemistry, University of Perugia, Via Elce di Sotto 8, Perugia, Italy
| | - Fabio Marmottini
- 3Department of Chemistry, University of Perugia, Via Elce di Sotto 8, Perugia, Italy
| | - Marcos L. Dias
- 4E. Mano Institute of Macromolecules, Federal University of Rio de Janeiro, C.P. 68525, 21945-970 Rio de Janeiro, RJ, Brazil
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Dias ML, Eiras JC, Machado MH, Souza GT, Pavanelli GC. The attachment of Clinostomum sp. (Digenea, Clinostomidae) to the oesophagus of the bird Ardea cocoi (Aves, Ardeidae). Parasite 2003; 10:185-7. [PMID: 12847929 DOI: 10.1051/parasite/2003102185] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
The attachment of Clinostomum sp. to the oesophagus of the bird definitive host Ardea cocoi is reported. The parasite attaches to the mucous layer of the oesophagus by the acetabulum, oral sucker, and oral collar. The mucous layer of the oesophagus engulfed by the oral sucker presents an intense liquefactive necrosis, and the engulfment is not likely to contribute significantly to the attachment of the parasite. The oral collar of the parasite, surrounding the oral sucker, is juxtaposed to the oesophagus mucous layer, showing a perfect fitting of both surfaces. It is concluded that the main attachment mechanism of the parasites to the oesophagus of the host is provided by the acetabulum and by the juxtaposition of the oral collar of the parasites to the oesophagus host surface.
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Affiliation(s)
- M L Dias
- Universidade Estadual de Maringá, Departamento de Analises Clinicas, AV. Colombo 5790, 87020-900 Maringá, PR, Brasil
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Coutinho FM, Neves MA, Dias ML. Porous crosslinked spherical resins for diversified applications: packing materials for size exclusion chromatography. ACTA ACUST UNITED AC 2002. [DOI: 10.1002/masy.200290005] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
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Neves MAFS, Coutinho FMB, Dias ML, Simão RA, Achete CA. Surface morphology evaluation of polymer beads based on divinylbenzene by atomic force microscopy. J Appl Polym Sci 2002. [DOI: 10.1002/app.10290] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
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Dias ML, Silva APF. Extensão de Cadeia em Poli(Naftalato de Etileno) pelo Fosfito de Trifenila. Polímeros 2001. [DOI: 10.1590/s0104-14282001000300008] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
O processamento reativo de poli(naftalato de etileno) (PEN) na presença de fostito de trifenila (TPP) em um misturador interno acoplado ao reômetro de torque foi investigado. O acompanhamento do torque e da temperatura durante o processamento revelou a ocorrência de reações de extensão de cadeia. A massa molecular do poliéster aumentou com o tempo de processamento, passando por um máximo, após o qual começa a decrescer como resultado de degradação molecular acelerada pela presença de subprodutos da extensão de cadeia. A intensidade das reações de extensão de cadeia aumenta com o aumento do teor de TPP, da temperatura e do cisalhamento. Tanto a extensão de cadeia quanto a degradação ocorrem mais lentamente para o PEN que para o poli(tereftalato de etileno). A presença de TPP no material provoca modificações na Tg, devido a um efeito de plastificação, e aumenta a velocidade de cristalização.
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Nele M, Mohammed M, Xin S, Collins S, Dias ML, Pinto JC. Two-State Models for Propylene Polymerization Using Metallocene Catalysts. 2. Application to ansa-Metallocene Catalyst Systems. Macromolecules 2001. [DOI: 10.1021/ma0021186] [Citation(s) in RCA: 38] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- Marcio Nele
- Department of Chemistry, University of Waterloo, 200 University Avenue West, Waterloo, Ontario, Canada N2L 3G1
| | - Muqtar Mohammed
- Department of Chemistry, University of Waterloo, 200 University Avenue West, Waterloo, Ontario, Canada N2L 3G1
| | - Shixuan Xin
- Department of Chemistry, University of Waterloo, 200 University Avenue West, Waterloo, Ontario, Canada N2L 3G1
| | - Scott Collins
- Department of Chemistry, University of Waterloo, 200 University Avenue West, Waterloo, Ontario, Canada N2L 3G1
| | - Marcos L. Dias
- Instituto de Macromoléculas Eloísa Mano/IMA, Universidade Federal do Rio de Janeiro, Cidade Universitária - CP: 68502, Rio de Janeiro 21945−970 RJ, Brasil
| | - J. C. Pinto
- Programa de Engenharia Química/COPPE, Universidade Federal do Rio de Janeiro, Cidade Universitária - CP: 68502, Rio de Janeiro 21945−970 RJ, Brasil
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Genta PR, Dias ML, Janiszewski TA, Carvalho JP, Arai MH, Meireles LP. Streptococcus agalactiae endocarditis and giant pyomyoma simulating ovarian cancer. South Med J 2001; 94:508-11. [PMID: 11372803] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 04/16/2023]
Abstract
Group B streptococcus (Streptococcus agalactiae) is a common etiology of bacteremia among adults. Pyomyoma is a rare infectious complication of uterine leiomyomas. We report the case of a diabetic postmenopausal woman with a giant pyomyoma simulating an ovarian cancer. It was associated with S. agalactiae endocarditis and deep venous thrombosis of the right external iliac and femoral veins. Treated initially with intravenous penicillin, amikacin, and anticoagulation, the patient later had abdominal hysterectomy with an uneventful recovery. We also review the cases of pyomyoma reported since 1945. Of 14 cases described (including ours), mortality was 21%. Endocarditis was never reported in association with pyomyoma. The presence of bacteremia and a leiomyoma should raise suspicion for this disease.
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Affiliation(s)
- P R Genta
- Department of Internal Medicine, University of São Paulo School of Medicine, SP, Brazil
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Pereira BCA, Klein SI, Dias ML. Efeitos estéricos e eletrônicos de substituintes alquilas em catalisadores titanocênicos solúveis na polimerização sindioespecífica de estireno. Polímeros 1999. [DOI: 10.1590/s0104-14281999000400019] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Titanocenos são catalisadores solúveis conhecidos para a polimerisação estereoespecífica de olefinas pró-quirais como o estireno. Nesse trabalho descrevemos as relações entre as características do poliestireno e a estrutura do precursor do catalisador, de fato aqueles da família (RCp)2TiCl2 (R = H, etila, iso-propila, n-propila, sec-butila, n-butila, iso-amila e ciclohexila). Todos os catalisadores são ativos para a produção de poliestireno acima de zero graus centígrados. A sindiotaticidade dos polímeros são dependentes da cadeia lateral dos anéis aromáticos do titanoceno e da temperatura da polimerização. A relação entre os fatores estéricos e eletrônicos do precursor do catalisador e os produtos de polimerização são apresentados e discutidos.
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Guilherme AL, de Araújo SM, Falavigna DL, Pupulim AR, Dias ML, de Oliveira HS, Maroco E, Fukushigue Y. [Endoparasite prevalence in truck farmers and in the vegetables of Feira do Produtor de Maringá, Paraná]. Rev Soc Bras Med Trop 1999; 32:405-11. [PMID: 10495671 DOI: 10.1590/s0037-86821999000400012] [Citation(s) in RCA: 19] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
Few studies have assessed the contamination of vegetables at Brazilian production sites. From April 1996 to December of 1997, the sanitary conditions of raw consumed vegetables sold in the Feira do Produtor de Maringá were investigated. We based the analyses on the contamination of vegetables, of the producers (stool samples and material under the fingernails) and of the water used for irrigation. It was observed that 16.6% of 144 samples of five different types of vegetables were contaminated with intestinal parasites. Forty three of 163 individuals (26%) were infected with one or more parasites. Only three of the 49 samples of material under the fingernails analyzed were positive for intestinal parasites. Analysis of samples of the water used for vegetable irrigation showed that the water did not satisfy bacteriological standards of potability. We conclude that in the investigated area the contamination of vegetables occurred during the production phase and that a sanitary education campaign directed at the producers is needed.
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Affiliation(s)
- A L Guilherme
- Setor de Parasitologia Básica, Universidade Estadual de Maringá, PR, Brasil
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Abstract
Copolímeros de estireno-divinilbenzeno para a aplicação em cromatografia de exclusão por tamanho foram sintetizados através de polimerização em suspensão aquosa modificada pela presença de diluentes. Na síntese dos copolímeros foram variados os seguintes parâmetros reacionais: tipo de diluente, grau de diluição e teor de divinilbenzeno. Os copolímeros obtidos como partículas esféricas com tamanho médio em torno de 10 µm foram caracterizados quanto à porosidade no estado seco e às propriedades de inchamento. Os copolímeros foram utilizados como material de empacotamento de colunas para cromatografia de exclusão por tamanho (SEC). O aumento do grau de diluição na síntese do copolímero aumentou o limite de exclusão da cromatografia, porém a redução do poder solvatante do diluente teve um efeito mais pronunciado sobre esse parâmetro.
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D'Almeida AR, Dias ML. Comparative study of shear degradation of carboxymethylcellulose and poly(ethylene oxide) in aqueous solution. Polym Degrad Stab 1997. [DOI: 10.1016/s0141-3910(96)00187-5] [Citation(s) in RCA: 22] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/17/2022]
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