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Drag reduction by polyethylene glycol in the tail arterial bed of normotensive and hypertensive rats

BESSA, K.L.; BELLETATI, J.F.; DOS SANTOS, L.; ROSSONI, L.V.; ORTIZ, J.P.
Fonte: Associação Brasileira de Divulgação Científica Publicador: Associação Brasileira de Divulgação Científica
Tipo: Artigo de Revista Científica
ENG
Relevância na Pesquisa
66.59%
This study was designed to evaluate the effect of drag reducer polymers (DRP) on arteries from normotensive (Wistar) and spontaneously hypertensive rats (SHR). Polyethylene glycol (PEG 4000 at 5000 ppm) was perfused in the tail arterial bed with (E+) and without endothelium (E-) from male, adult Wistar (N = 14) and SHR (N = 13) animals under basal conditions (constant flow at 2.5 mL/min). In these preparations, flow-pressure curves (1.5 to 10 mL/min) were constructed before and 1 h after PEG 4000 perfusion. Afterwards, the tail arterial bed was fixed and the internal diameters of the arteries were then measured by microscopy and drag reduction was assessed based on the values of wall shear stress (WSS) by computational simulation. In Wistar and SHR groups, perfusion of PEG 4000 significantly reduced pulsatile pressure (Wistar/E+: 17.5 ± 2.8; SHR/E+: 16.3 ± 2.7%), WSS (Wistar/E+: 36; SHR/E+: 40%) and the flow-pressure response. The E- reduced the effects of PEG 4000 on arteries from both groups, suggesting that endothelial damage decreased the effect of PEG 4000 as a DRP. Moreover, the effects of PEG 4000 were more pronounced in the tail arterial bed from SHR compared to Wistar rats. In conclusion, these data demonstrated for the first time that PEG 4000 was more effective in reducing the pressure-flow response as well as WSS in the tail arterial bed of hypertensive than of normotensive rats and these effects were amplified by...

Liquid-Liquid Equilibrium of Aqueous Two-Phase Systems Containing Some Synthetic Polyelectrolytes and Polyethylene Glycol

GRUENFELDER, Thomas; PESSOA FILHO, Pedro A.; MAURER, Gerd
Fonte: AMER CHEMICAL SOC Publicador: AMER CHEMICAL SOC
Tipo: Artigo de Revista Científica
ENG
Relevância na Pesquisa
56.49%
Experimental results are presented for the liquid-liquid equilibrium of aqueous two-phase systems containing a synthetic polyelectrolyte (polysodium acrylate, polysodium methacrylate, and polysodium ethylene sulfonate) and polyethylene glycol at (298.2 and 323.2) K. A total of 40 phase diagrams were obtained, comprising data both of the binodal curve (obtained through cloud-point measurements) and of equilibrium compositions. The influences of temperature, the nature of the polyelectrolyte monomer unit, and the chain length of both types of polymers are analyzed and discussed.

Effect of Polyethylene Glycol on the Thermal Stability of Green Fluorescent Protein

NOVAES, Leticia C. de Lencastre; MAZZOLA, Priscila G.; PESSOA JR., Adalberto; PENNA, Thereza C. Vessoni
Fonte: JOHN WILEY & SONS LTD Publicador: JOHN WILEY & SONS LTD
Tipo: Artigo de Revista Científica
ENG
Relevância na Pesquisa
66.59%
Green fluorescent protein (GFP) shows remarkable structural stability and high fluorescence; its stability can be directly related to its fluorescence output, among other characteristics. GFP is stable under increasing temperatures, and its thermal denaturation is highly reproducible. Some polymers, such as polyethylene glycol, are often used as modifiers of characteristics of biological macromolecules, to improve the biochemical activity and stability of proteins or drug bioavailability. The aim of this study was to evaluate the thermal stability of GFP in the presence of different PEG molar weights at several concentrations and exposed to constant temperatures, in a range of 70-95 degrees C. Thermal stability was expressed in decimal reduction time. It was observed that the D-values obtained were almost constant for temperatures of 85, 90, and 95 degrees C, despite the PEG concentration or molar weight studied. Even though PEG can stabilize proteins, only at 75 degrees C, PEG 600 and 4,000 g/mol stabilized GFP. (C) 2009 American Institute of Chemical Engineers Biotechnol. Prog., 26: 252-256, 2010; Coordination for Higher Level Graduates Improvement (Capes); National Council for Scientific and Technological Development (CNPq); State of Sao Paulo Research Foundation (Fapesp)

Estudo das interações entre enzimas e polímeros: efeito do poli(etileno glicol) na atividade e na conformação estrutural de enzimas. Adsorção de enzimas sobre superfícies sólidas; Study on the interactions between enzymes and polymers: Influence of polyethylene glycol on the activity and conformation of enzymes. Adsorption of enzymes onto solid surfaces

Pancera, Sabrina Montero
Fonte: Biblioteca Digitais de Teses e Dissertações da USP Publicador: Biblioteca Digitais de Teses e Dissertações da USP
Tipo: Tese de Doutorado Formato: application/pdf
Publicado em 10/03/2006 PT
Relevância na Pesquisa
56.49%
Este trabalho visou investigar as interações entre enzimas e polímeros em solução e a adsorção das mesmas sobre superfícies sólidas e para isto foi dividido em duas partes distintas. Na primeira parte a influência do poli(etileno glicol) (PEG), polímero considerado inerte e utilizado em muitos processosbiotecnológicos, na atividade enzimática e na conformação estrutural de enzimas foi estudada através de medidas de espectrofotometria- UV, calorimetria e espalhamento de raio-X de baixo ângulo (SAXS). Foram escolhidas neste estudo as enzimas glicose-6-fosfato desidrogenase (G-6-PDH) e hexoquinase (HK), que são enzimas largamente aplicadas em análises clínicas na determinação de glicose no sangue, e também a enzima álcool desidrogenase (AD), utilizada para determinação de concentração de álcool. Foram obtidos resultados quantitativos, numa faixa de baixa concentração de enzima, que indicam uma forte influência de PEG na atividade das enzimas estudadas. Medidas de calorimetria revelaram que PEG interage não só com a enzima em estudo mas também com a coenzima NADP+. Numa faixa de concentração maior, os resultados de SAXS mostraram que PEG exerce também um efeito significativo no processo de agregação das enzimas. Acima de tudo...

Preparo de cólon para realização de colonoscopia: estudo prospectivo randomizado comparativo entre solução de polietilenoglicol baixo volume mais bisacodil versus solução de manitol mais bisacodil; Bowel preparation for performing colonoscopy: prospective randomized comparison study between low volume solution of polyethylene glycol plus bisacodyl versus bisacodyl and mannitol solution

Vieira Junior, Manoel Carlos
Fonte: Biblioteca Digitais de Teses e Dissertações da USP Publicador: Biblioteca Digitais de Teses e Dissertações da USP
Tipo: Dissertação de Mestrado Formato: application/pdf
Publicado em 31/08/2011 PT
Relevância na Pesquisa
66.59%
A colonoscopia é atualmente o padrão ouro para investigação da mucosa dos cólons, reto e íleo terminal. Para sua realização, há necessidade de uso de soluções para limpeza do cólon que, em geral, são mal toleradas pelos pacientes. Os objetivos do presente estudo foram comparar duas soluções de preparo intestinal para colonoscopia, quanto à efetividade, tolerabilidade, aceitabilidade e segurança em pacientes que se submeteriam a colonoscopia eletivamente, no Centro de Diagnóstico em Gastroenterologia do Hospital das Clínicas da Faculdade de Medicina da Universidade de São Paulo. Trata-se de estudo unicêntrico, prospectivo, com alocação aleatória dos pacientes. Cem pacientes pareados por sexo e idade foram randomizados em dois grupos. O grupo I recebeu bisacodil mais 1 litro de Polietilenoglicol (PEG) na véspera e 1 litro no dia do exame. O grupo II recebeu bisacodil na véspera e 1 litro de manitol 10% no dia do exame. A mesma dieta foi orientada nos dois grupos. A qualidade do preparo foi graduada através das escalas de Boston e Ottawa. A tolerabilidade e aceitabilidade foram aferidas por questionários previamente estudados. Quanto à segurança, foram ava liadas: variação de sinais vitais antes e após o preparo e complicações. Noventa e seis pacientes (96%) completaram o estudo. Não se observou diferença na qualidade do preparo entre os grupos(p = 0...

Effect of surfactants and polyethylene glycol on the activity and stability of a lipase from oilseeds of Pachira aquatica

Polizelli, Patricia Peres; Tiera, Marcio Jose; Bonilla-Rodriguez, Gustavo Orlando
Fonte: Springer Publicador: Springer
Tipo: Artigo de Revista Científica Formato: 749-753
ENG
Relevância na Pesquisa
66.59%
Lipases from oilseeds have a great potential for commercial exploration as industrial enzymes. Lipases are used mixed with surfactants in cleaning and other formulated products, and accordingly, both components must be compatible with each other. This work presents the results of the effects of anionic, cationic and nonionic surfactants, polyethylene glycol and urea on the activity and stability of a lipase extracted of oilseeds from Pachira aquatica. The enzyme was purified and the spectrophotometric assays were done using p-nitrophenyl acetate (p-NPA) as substrate pH 7.5 and 25 degrees C. The activity was significantly enhanced by the cationic surfactant CTAB. Bile salts increased the lipase activity in the tested concentration range, whereas anionic and nonionic surfactants showed an inhibitory effect. Aqueous solutions of PEG activated the lipase and maximum activation (161%) occurred in PEG 12,000. This effect on lipase that can be due to exposition of some hydrophobic residues located in the vicinity of the active site or aggregation.

Phase Diagrams of the Aqueous Two-Phase Systems of Poly(ethylene glycol)/Sodium Polyacrylate/Salts

Johansson, Hans-Olof; Feitosa, Eloi; Pessoa Junior, Adalberto
Fonte: Mdpi Ag Publicador: Mdpi Ag
Tipo: Artigo de Revista Científica Formato: 587-601
ENG
Relevância na Pesquisa
56.49%
Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP); Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq); Aqueous two-phase systems consisting of polyethylene glycol (PEG), sodium polyacrylate (NaPAA), and a salt have been studied. The effects of the polymer size, salt type (NaCl, Na2SO4, sodium adipate and sodium azelate) and salt concentrations on the position of the binodal curve were investigated. The investigated PEG molecules had a molar mass of 2,000 to 8,000 g/mol, while that of NaPAA was 8,000 g/mol. Experimental phase diagrams, and tie lines and calculated phase diagrams, based on Flory-Huggins theory of polymer solutions are presented. Due to strong enthalpic and entropic balancing forces, the hydrophobicity of the added salt has a strong influence on the position of the binodal, which could be reproduced by model calculations.

Recobrimento de tela de polipropileno com quitosana e polietileno glicol por deposição via electrospinning; Coating of polypropylene mesh with chitosan and polyethylene glycol through electrospinning deposition

Walter Anibal Rammazzina Filho
Fonte: Biblioteca Digital da Unicamp Publicador: Biblioteca Digital da Unicamp
Tipo: Dissertação de Mestrado Formato: application/pdf
Publicado em 05/09/2011 PT
Relevância na Pesquisa
66.59%
O uso de implantes em cirurgias de correção da parede abdominal é freqüentemente necessário. Telas de poli(propileno) podem ser empregadas com sucesso para essa finalidade, possuindo boa aceitação tecidual e baixo custo. O uso deste tipo de biomaterial pode, porém, ocasionar a aderência indesejada entre tecidos e/ou entre órgãos como o fígado e os intestinos e a tela, resultando em dores abdominais, obstrução intestinal e infertilidade. Neste contexto, o objetivo deste trabalho foi o de desenvolver uma estratégia de recobrimento de telas de poli(propileno) enfocando a deposição de soluções de quitosana de massa molar baixa e média e de polietilenoglicol (PEG) de massa molar igual a 1000 Da por electrospinning. Para fins de comparação, telas de poli(propileno) foram alternativamente recobertas por imersão com diferentes soluções combinando quitosana e PEG. Nos estudos de recobrimento via electrospinning, foram avaliadas as variáveis tipo de solvente para a dissolução da quitosana e do PEG, vazão de solução de recobrimento, proporção entre quitosana e PEG, diferença de potencial usada durante a deposição e distância entre a tela e o jato de injeção. As telas recobertas através da imersão em soluções de quitosana a 1% (tanto com a de baixa massa molar quanto a com massa molar média) e em soluções de quitosana misturada ao PEG também com concentração de sólidos total de 1% apresentaram-se satisfatórias para fins de barreira física em cirurgias de hérnia...

Effect of Polyethylene Glycol on the Thermal Stability of Green Fluorescent Protein

NOVAES, Leticia C. de Lencastre; MAZZOLA, Priscila G.; PESSOA JR., Adalberto; PENNA, Thereza C. Vessoni
Fonte: JOHN WILEY & SONS LTD Publicador: JOHN WILEY & SONS LTD
Tipo: Artigo de Revista Científica
ENG
Relevância na Pesquisa
66.59%
Green fluorescent protein (GFP) shows remarkable structural stability and high fluorescence; its stability can be directly related to its fluorescence output, among other characteristics. GFP is stable under increasing temperatures, and its thermal denaturation is highly reproducible. Some polymers, such as polyethylene glycol, are often used as modifiers of characteristics of biological macromolecules, to improve the biochemical activity and stability of proteins or drug bioavailability. The aim of this study was to evaluate the thermal stability of GFP in the presence of different PEG molar weights at several concentrations and exposed to constant temperatures, in a range of 70-95 degrees C. Thermal stability was expressed in decimal reduction time. It was observed that the D-values obtained were almost constant for temperatures of 85, 90, and 95 degrees C, despite the PEG concentration or molar weight studied. Even though PEG can stabilize proteins, only at 75 degrees C, PEG 600 and 4,000 g/mol stabilized GFP. (C) 2009 American Institute of Chemical Engineers Biotechnol. Prog., 26: 252-256, 2010; Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP); Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES); Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Lysozyme and bovine serum albumin partitioning in polyethylene glycol–phenylalanine conjugate polymer/salt aqueous two-phase systems

Silvério, Sara C.; Ferreira, Luísa A.; Martins, J. A.; Marcos, João Carlos; Macedo, E. A.; Teixeira, J. A.
Fonte: Elsevier BV Publicador: Elsevier BV
Tipo: Artigo de Revista Científica
Publicado em //2012 ENG
Relevância na Pesquisa
66.59%
Polyethylene glycol (PEG) with average molecular weight of 8000 was used as a model polymer and modified by introducing an amino acid (phenylalanine) in its hydroxyl terminals. The effect of different percentages of the conjugate polymer in relation to the total polymer on binodal curve of PEG-8000–potassium phosphate buffer (KPB), pH 7.2 aqueous two-phase systems and solute partitioning was explored. The partition of lysozyme (Lyz) and bovine serum albumin (BSA) and also of the conjugated polymer was evaluated in ATPS composed of 17% (w/w) total polymer and 12.5% (w/w) KPB, pH 7.2. Lyz partition profile follows the expected trend decreasing with the increase of modified polymer concentration. However BSA shows a partition profile that is approximately symmetrical to the one observed for the partition of the conjugate polymer, which depends on PEG–phenylalanine concentration in the system. Determination of the relative hydrophobicity of the equilibrium phases and of the protein surface hydrophobicity (So) delivered information that shed some light in the mechanisms controlling the partitioning behavior. Therefore, it becomes clear that the hydrophobic character of the protein taken together with the molecular weight explain the different behavior of these two proteins with the increase of PEG–phenylalanine substitution in the systems.

Bowel preparation for performing a colonoscopy: prospective randomized comparison study between a low-volume solution of polyethylene glycol and bisacodyl versus bisacodyl and a mannitol solution

Vieira,Manoel Carlos; Hashimoto,Claudio Lyoiti; Carrilho,Flair José
Fonte: Instituto Brasileiro de Estudos e Pesquisas de Gastroenterologia - IBEPEGE ; Colégio Brasileiro de Cirurgia Digestiva - CBCD ; Sociedade Brasileira de Motilidade Digestiva - SBMD ; Federação Brasileira de Gastroenterologia - FBG; Sociedade Brasileira de Hepatologia - SBH; Sociedade Brasileira de Endoscopia Digestiva - SOBED Publicador: Instituto Brasileiro de Estudos e Pesquisas de Gastroenterologia - IBEPEGE ; Colégio Brasileiro de Cirurgia Digestiva - CBCD ; Sociedade Brasileira de Motilidade Digestiva - SBMD ; Federação Brasileira de Gastroenterologia - FBG; Sociedade Brasileira de Hepatologia - SBH; Sociedade Brasileira de Endoscopia Digestiva - SOBED
Tipo: Artigo de Revista Científica Formato: text/html
Publicado em 01/06/2012 EN
Relevância na Pesquisa
66.93%
CONTEXT: Colonoscopy is currently the gold standard method to examine the colon, the rectum and the terminal ileum. In order to perform the colonoscopy, it is necessary to clean the bowel and use medications that are generally poorly tolerated by the patients. OBJECTIVE: Compare the tolerability, acceptability, safety and efficacy of two solutions used for intestinal preparation for a colonoscopy. METHODS: One hundred patients matched for sex and age were prospective randomized into two groups. Polyethylene glycol group received bisacodyl 10 mg plus 1 L of polyethylene glycol the night before and 1 L on the day of the exam. Mannitol group received bisacodyl 20 mg the day before and 1 L of a 10% mannitol solution on the day of the exam. The diet was the same for both groups. Tolerability and acceptability were measured using previously validated questionnaires. In terms of safety, variations in vital signs before and after the preparation were recorded, in addition to any complications. The quality of the preparation was graded based on the Boston and Ottawa scales. RESULTS: Ninety-six percent (96%) completed the study. As for tolerability, the mannitol preparation group exhibited a significantly higher frequency of nausea, vomiting...

Enhanced photocatalytic activity of TiO2 films by modification with polyethylene glycol

Ramírez-Santos,Álvaro A.; Acevedo-Peña,Próspero; Córdoba,Elcy M.
Fonte: Sociedade Brasileira de Química Publicador: Sociedade Brasileira de Química
Tipo: Artigo de Revista Científica Formato: text/html
Publicado em 01/01/2012 EN
Relevância na Pesquisa
66.59%
Titanium dioxide porous thin films on the Anatase phase were deposited onto glass slides by the sol-gel method assisted with polyethylene glycol (PEG). The dip-coated films were characterized using scanning electron microscopy (SEM), thermogravimetric analysis (TGA and DTG), UV-visible spectroscopy and X-ray diffraction (XRD). The photocatalytic activity of the films was determined by means of methyl-orange oxidation tests. The resultant PEG-modified films were crack-free and developed a porous structure after calcination at 500 °C. Photo-oxidation tests showed the dependency of catalytic activity of the films on the number of layers (thickness) and porosity, i.e. of the interfacial area.

Drag reduction by polyethylene glycol in the tail arterial bed of normotensive and hypertensive rats

Bessa,K.L.; Belletati,J.F.; Dos Santos,L.; Rossoni,L.V.; Ortiz,J.P.
Fonte: Associação Brasileira de Divulgação Científica Publicador: Associação Brasileira de Divulgação Científica
Tipo: Artigo de Revista Científica Formato: text/html
Publicado em 01/08/2011 EN
Relevância na Pesquisa
66.59%
This study was designed to evaluate the effect of drag reducer polymers (DRP) on arteries from normotensive (Wistar) and spontaneously hypertensive rats (SHR). Polyethylene glycol (PEG 4000 at 5000 ppm) was perfused in the tail arterial bed with (E+) and without endothelium (E-) from male, adult Wistar (N = 14) and SHR (N = 13) animals under basal conditions (constant flow at 2.5 mL/min). In these preparations, flow-pressure curves (1.5 to 10 mL/min) were constructed before and 1 h after PEG 4000 perfusion. Afterwards, the tail arterial bed was fixed and the internal diameters of the arteries were then measured by microscopy and drag reduction was assessed based on the values of wall shear stress (WSS) by computational simulation. In Wistar and SHR groups, perfusion of PEG 4000 significantly reduced pulsatile pressure (Wistar/E+: 17.5 ± 2.8; SHR/E+: 16.3 ± 2.7%), WSS (Wistar/E+: 36; SHR/E+: 40%) and the flow-pressure response. The E- reduced the effects of PEG 4000 on arteries from both groups, suggesting that endothelial damage decreased the effect of PEG 4000 as a DRP. Moreover, the effects of PEG 4000 were more pronounced in the tail arterial bed from SHR compared to Wistar rats. In conclusion, these data demonstrated for the first time that PEG 4000 was more effective in reducing the pressure-flow response as well as WSS in the tail arterial bed of hypertensive than of normotensive rats and these effects were amplified by...

Characterization of gliclazide-polyethylene glycol solid dispersion and its effect on dissolution

Patil,Moreshwar Pandharinath; Gaikwad,Naresh Janardan
Fonte: Universidade de São Paulo, Faculdade de Ciências Farmacêuticas Publicador: Universidade de São Paulo, Faculdade de Ciências Farmacêuticas
Tipo: Artigo de Revista Científica Formato: text/html
Publicado em 01/03/2011 EN
Relevância na Pesquisa
66.71%
The present study was initiated with the objective of studying the in vitro dissolution behavior of gliclazide from its solid dispersion with polyethylene glycol 6000. In this work, a solid dispersion of gliclazide with polyethylene glycol was prepared by the fusion method. In vitro dissolution study of gliclazide, its physical mixture and solid dispersion were carried out to demonstrate the effect of PEG 6000. Analytical techniques of FT-IR spectroscopy, differential scanning calorimetry and X-ray diffractometry were used to characterize the drug in the physical mixtures and solid dispersions. The dissolution studies of solid dispersion and physical mixture showed greater improvement compared to that of the pure drug. The mechanisms for increased dissolution rate may include reduction of crystallite size, a solubilization effect of the carrier, absence of aggregation of drug crystallites, improved wettability and dispersbility of the drug from the dispersion, dissolution of the drug in the hydrophilic carrier or conversion of drug to an amorphous state. The FT-IR spectra suggested that there was no interaction between gliclazide and PEG 6000 when prepared as a solid dispersion. DSC and XRD study indicated that the drug was converted in the amorphous form.

The influence of pH, polyethylene glycol and polyacrylic acid on the stability of stem bromelain

Novaes,Letícia Celia de Lencastre; Jozala,Angela Faustino; Mazzola,Priscila Gava; Júnior,Adalberto Pessoa
Fonte: Universidade de São Paulo, Faculdade de Ciências Farmacêuticas Publicador: Universidade de São Paulo, Faculdade de Ciências Farmacêuticas
Tipo: Artigo de Revista Científica Formato: text/html
Publicado em 01/06/2014 EN
Relevância na Pesquisa
66.59%
Enzyme stability is critical in biotechnology, pharmaceutical and cosmetic industries. Investigations on this subject have drawn attention because of its practical application. Bromelain is a thiol-endopeptidase, obtained from pineapple (Ananas comosus), known for its clinical and therapeutic applications, particularly to selective burn debridement and improvement of antibiotic action and anti-inflammatory activities. To date, the use of bromelain in pharmacological or industrial applications is limited, due to commercial availability, costs, and sensitivity to pH and temperature. Therefore, a better understanding of enzyme stability would be of great interest. The aim of this study was to evaluate bromelain activity and stability in several pH (2.0 to 8.0) and in polyethylene glycol and polyacrylic acid solutions. We observed that bromelain was able to maintain its stability at pH 5.0 for the temperatures studied. PEG solutions increased bromelain stability, but PAA solutions had the opposite effect.

Polyethylene glycol effects on somatic embryogenesis of papaya hybrid UENF/CALIMAN 01 seeds

Heringer,Angelo Schuabb; Vale,Ellen Moura; Barroso,Tatiana; Santa-Catarina,Claudete; Silveira,Vanildo
Fonte: Sociedade Brasileira de Fisiologia Vegetal Publicador: Sociedade Brasileira de Fisiologia Vegetal
Tipo: Artigo de Revista Científica Formato: text/html
Publicado em 01/01/2013 EN
Relevância na Pesquisa
66.59%
Among commercial fruits, papaya (Carica papaya L.) is notably one of the most common ones around the world. The aim of the current study was to establish a somatic embryogenesis protocol for the hybrid UENF/CALIMAN 01, elucidating the effects of sucrose and 2,4-dichlorophenoxyacetic acid (2,4-D) on the induction of embryogenic cultures and the effect of polyethylene glycol (PEG) on somatic embryo maturation. Immature zygotic embryos of C. papaya hybrid UENF/CALIMAN 01 were cultured in MS culture medium supplemented with different concentrations of sucrose (30 and 60 g L-1) and 2,4-D (0, 20, 40 and 80 μM). The combination of 30 g L-1 sucrose and 20 μM 2,4-D resulted in the highest induction rates and the largest callus diameters. Furthermore, this combination was associated with the greatest potential to form somatic embryos. To promote maturation, cultures were inoculated in MS medium and exposed to different concentrations of PEG (0, 30 and 60 g L-1). The 60 g L-1 PEG treatment group had the highest average for the number, maturation and conversion of somatic embryos that resulted in plantlets at the end of the process. The addition of PEG to MS medium led to increased protein synthesis. These results are unprecedented for C. papaya hybrid UENF/CALIMAN 01 as the current study demonstrates the development of somatic embryogenesis in this high quality hybrid.

Polyethylene glycol improves conjugation of bovine hemoglobin and human serum albumin in a controlled ratio

Zheng, C.; Bi, J.; Ma, G.; Su, Z.
Fonte: Marcel Dekker Inc Publicador: Marcel Dekker Inc
Tipo: Artigo de Revista Científica
Publicado em //2007 EN
Relevância na Pesquisa
66.71%
Direct conjugation of bovine hemoglobin (Hb) and human serum albumin (HSA) with glutaraldehyde would result in a complex mixture of dimers Hb-Hb, Hb-HSA, HSA-HSA and other oligomers. To obtain a high yield of target Hb-HSA, modulation of the reaction environment was carried out. It was found that polyethylene glycol (PEG), a hydrophilic polymer, could improve the yield of Hb-HSA conjugate. The degree of improvement depended on the molecular weight and concentration of PEG. Under optimum condition of 9% (w/v) of PEG 4000, the reaction proceeded in a controlled mode with conversion yield of starting proteins to Hb-HSA increasing from 6% to 30%. The purity was about 88% of the total conjugates. Furthermore, the impurities were mainly tetrameric molecules of two Hb-HSA conjugates. The improvement could be attributed to the “micro-compartment” created by addition of polyethylene glycol, which brings HSA and Hb close together, thus increasing the chance of conjugation between the two molecules.; http://www.informaworld.com/smpp/content~db=all?content=10.1080/10731190701586236; Chunyang Zheng, Jingxiu Bi, Guanghui Ma, Zhiguo Su

Improvement of flowability, compressibility and dissolution of aceclofenac by emulsion solvent diffusion with polyethylene glycol

Patil, S.V.; Pati, N.; Sahoo, S.K.
Fonte: Universidad de Granada, Facultad de Farmacia Publicador: Universidad de Granada, Facultad de Farmacia
Tipo: Artigo de Revista Científica
ENG
Relevância na Pesquisa
66.59%
Aim: The objective behind this study is to improve the compressibility, flowability, packability and dissolution rate of aceclofenac by preparing spherical crystals using quasi emulsion solvent diffusion method. Materials and Method: Spherical agglomerates of aceclofenac were effectively prepared using acetone, dichloromethane and 0.1 N HCl as good solvent, bridging liquid and poor solvent respectively with different concentrations of polyethylene glycol 6000 in poor solvent. Results: Prepared agglomerates were spherical with enhanced fragmentation and less elastic recovery. Particle size, flowability, compactibility, packability, solubility and dissolution rate of agglomerates were preferably improved for direct compression compared with raw crystal of aceclofenac. X-ray powder diffraction and differential scanning calorimetry study indicated slight amorphization of drug during recrystallization but not associated with any chemical transition indicated by Fourier transforms infrared spectra. Conclusion: The present research improved tableting properties and dissolution characteristics of aceclofenac.; Objetivo: El objetivo detr??s de este estudio es mejorar la tasa de compresi??n, la fluidez, packability y la disoluci??n de aceclofenaco mediante la preparaci??n de cristales esf??ricos utilizando el m??todo cuasi emulsi??n de disolvente de difusi??n. Material y M??todo: Aglomerados esf??ricos de aceclofenac se prepararon con acetona...

Characterization of gliclazide-polyethylene glycol solid dispersion and its effect on dissolution

Patil, Moreshwar Pandharinath; Gaikwad, Naresh Janardan
Fonte: Universidade de São Paulo. Faculdade de Ciências Farmacêuticas Publicador: Universidade de São Paulo. Faculdade de Ciências Farmacêuticas
Tipo: info:eu-repo/semantics/article; info:eu-repo/semantics/publishedVersion; ; ; ; ; ; Formato: application/pdf
Publicado em 01/03/2011 ENG
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O presente trabalho foi realizado com o objetivo de estudar o comportamento in vitro da dissolução da gliclazida a partir da sua dispersão sólida com polietileno glicol 6000. Neste trabalho, as dispersões sólidas de gliclazida com polietileno glicol foram preparadas pelo método de fusão. Os estudo de dissolução in vitro da gliclazida, na mistura física e nas dispersões sólidas foram realizados para demonstrar o efeito de PEG 6000. Técnicas analíticas como espectroscopia FT-IR, calorimetria diferencial de varredura e difração de raios-X foram empregadas para caracterizar o fármaco nas misturas físicas e nas dispersoes sólidas. Os estudos de dissolução demonstraram maior melhoria. Os mecanismos para aumentar a velocidade de dissolução podem incluir a redução do tamanho dos cristais, a solubilização do carreador, a ausência de agregação dos cristais do fármaco, a melhoria da molhabilidade e dispersibilidade do fármaco a partir da dispersão, a dissolução do fármaco no carreador hidrofílico ou conversão da forma cristalina do fármaco para estado amorfo. Os espectros de FT-IR sugeriram que não houve interação entre gliclazide PEG 6000 e na sua combinação. Os estudos de DSC e DRX indicaram que o fármaco foi convertido para a forma amorfa.; The present study was initiated with the objective of studying the in vitro dissolution behavior of gliclazide from its solid dispersion with polyethylene glycol 6000. In this work...

Use of polyethylene glycol as organic additive in Copper electrodeposition over stainless steel cathodes

Schrebler Arratia,R.; Aros Meneses,H.; Schrebler Guzman,R.; Carlesi Jara,C.
Fonte: Latin American applied research Publicador: Latin American applied research
Tipo: Artigo de Revista Científica Formato: text/html
Publicado em 01/10/2012 EN
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This study comprise a comparative analysis of the effects of polyethylene glycol (PEG) and other additives used in copper electrodeposition processes over 316 L stainless steel permanent cathodes. Both cyclic voltammetry and potentiostatic pulse techniques showed analogous results with regard to the increase in the use of the real organic additive and the persistence of a more constant roughness level at higher electrodeposition times when PEG baths are used instead of baths containing glue. The mechanism taking place in the presence of PEG corresponds to two-dimensional nucleation together with three-dimensional diffusion grain growth. Furthermore, the contribution of the hydrogen evolution reaction (HER) was observed at t > 15 seconds when additives of PEG + thiourea were used, while the same contribution was observed from the beginning of the reaction in the case of solutions without PEG.