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Synthesis, Characterization, and Study of PLGA Copolymer <i>in Vitro</i>Degradation

Journal of Biomaterials and Nanobiotechnology 2015年第1期6卷 8-19页

作者： Anamaria Teodora Coêlho Rios silva Barbara Camilla Oliveira Cardoso maria elisa scarpelli ribeiro e silva Roberto Fernando Souza Freitas Ricardo Geraldo Sousa Polymer Science and Technology Laboratory Chemical Engineering Department School of Engineering Federal University of Minas Gerais Belo Horizonte Brazil

The poly(lactic-co-glycolic acid), known as PLGA, is one of the main bioreabsorbable polymers used in the field of medicine today. This copolymer is widely applied in sutures, devices geared toward the controlled release of medication, and the guided regeneration of bone tissue as it presents a short degradation time. This work aimed to synthesize the 82/18 PLGA (expressed by the mass ratio of D,L-lactide and glycolide, respectively), to characterize and study the in Vitro degradation in the form of rods in phosphate buffer solution (PBS). The copolymer was synthesized by opening the cyclic dimer rings of the monomers D,L-lactide and glycolide, in the presence of the tin octanoate initiator and of the lauryl alcohol co-initiator. The characterization of the copolymer and the follow-up of its in vitro degradation were studied using: Differential Scanning Calorimetry (DSC), Thermogravimetry (TG), Infrared Molecular Absorption Spectroscopy with Fourier Transform (FTIR), Rheometry, and Scanning electron Microscopy (SeM). Through these characterization techniques, it was possible to obtain the glass transition temperature, thermal stability, chemical composition, morphology, and molar mass of both the synthesized and the degraded copolymer. The molar mass of the synthesized copolymer was, approximately, 106 g·mol-1. The degradation rate of PLGA significantly increased from the 19th to the 28th day in PBS. After 28 days in PBS, the glass transition temperature and the molar mass reduced from 45°C to 17°C and from 1.5 × 106 g·mol-1?to 7.5 × 104?g·mol-1, respectively. The pH of the medium has a significant influence on the copolymer degradation profile. When it diminishes, it accelerates the degradation process, resulting in smaller PLGA polymer chains. This pH dependent degradation can be useful for drug release systems.

关键词： Synthesis Characterization In Vitro Degradation PLGA

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Rheological and Thermal Behavior of High-Density Polyethylene (HDPe) at Different Temperatures

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Materials Sciences and Applications 2014年第13期5卷 923-931页

作者： Cynthia D’Avila Carvalho erbetta Getúlio F. Manoel Ana Paula Lelis Rodrigues Oliveira maria elisa scarpelli ribeiro e silva Roberto Fernando Souza Freitas Ricardo Geraldo Sousa Polymer Science and Technology Laboratory Chemical Engineering Department Engineering School Federal University of Minas Gerais Belo Horizonte Brazil

In the present work, rheological properties of HDPe samples were measured at temperatures of 150°C, 190°C and 230°C. It was shown, by oscillatory tests, at low frequencies, that, for temperatures of 150°C and 190°C, there was a predominance of the viscous behavior over the elastic one. At 230°C, there was a predominance of the elastic contribution, and there was an increase of the molar mass compared with the ones obtained from the tests at 150°C and 190°C. The results obtained from the temperature ramp oscillatory test showed that, up to around 248°C, the viscous behavior prevailed, the opposite being observed at higher temperatures. At 230°C the sample showed significantly lower values of strain when compared with the ones observed at 150°C and 190°C. Oxidative induction time (OIT), melting point and degree of crystallinity were determined by differential scanning calorimetry (DSC). The DSC results and the rheological measurements showed a completely different behavior for the HDPe samples at 230°C compared with the 150°C and the 190°C ones, suggesting that HDPe, at the temperature of 230°C, underwent thermo-oxidative degradation with the initial predominance of crosslinking.

关键词： HDPe Rheology Degradation DSC FTIR

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Rheological Study of Polymers Used as Viscosity Index Improvers for Automotive Lubricant Oils

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Journal of Modern Physics 2014年第12期5卷 1085-1093页

作者： Ana Paula Pena Almeida Ana Paula Lelis Rodrigues de Oliveira Cynthia D’ávila Carvalho erbetta Ricardo Geraldo de Sousa Roberto Fernando de Souza Freitas maria elisa scarpelli ribeiro e silva Polymer Science and Technology Laboratory Chemical Engineering Department Engineering School Federal University of Minas Gerais Belo Horizonte Brazil

In this work, a rheological study of automotive lubricant oils, neutral light paraffinic (NLP) and neutral medium paraffinic (NMP), additivated with two commercial viscosity index improvers-VIIs, based on hydrogenated poly (isoprene-co-styrene), at different concentrations, was carried out. The study included the determination of the kinematic viscosity of the mixtures, the calculation of the viscosity indexes and their behavior when subjected to various rheometric experiments, including stress sweep, steady state flow, creep and recovery, and temperature ramp oscillatory tests. The obtained results showed the efficacy of the additives as viscosity index improvers, enabling a significant increase in the viscosity index of the pure oils at relatively low concentrations. The determination of the storage (G’) and of the loss (G”) moduli for the mixtures oil/VII additives showed a large predominance of the viscous effect over the elastic one. except when under low shear stress, the mixtures showed a pseudoplastic behavior, with the flow curves being adjusted to fit the Ostwald-de-Waele model (Power Law), with negative flow behavior indexes.

关键词： Viscosity Index Improvers Automotive Lubricants Rheology Viscosity Index Polymer Additives

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Feasibility of performing the 3-minute step test with remote supervision in children and adolescents with cystic fibrosis: A comparative study

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Pediatric Investigation 2024年第2期8卷 83-90页

作者： Fernanda maria Vendrusculo Gisele Apolinario da Costa maria Amelia Bagatini Brenda maria Henrique Maia Lemes Carolina Aguiar Faria Larissa Carvalhaes de Oliveira evanirso da silva Aquino Marcio Vinicius Fagundes Donadio Laboratory of Pediatric Physical Activity Infant CenterPontificia Universidade Catolica do Rio Grande do Sul(PUCRS)Porto AlegreBrazil Hospital Infantil Joao Paulo II-Fundacao Hospitalar do estado de Minas Gerais(FHeMIG) Belo HorizonteBrazil Departament of Physiotherapy Pontificia Universidade Catolica de Minas Gerais(PUCMG)-Campus BetimBetimBrazil Department of Physiotherapy Faculty of Medicine and Health SciencesUniversitat Internacional de Catalunya(UIC)BarcelonaSpain

Importance:The 3-min step test is a simple option to monitor submaximal exercise capacity,although its use via remote video monitoring has not been investigated in children with cystic fibrosis(CF).Objective:This study aimed to assess the feasibility and reproducibility of performing the 3-min step test with remote ***:A cross-sectional study including CF patients(6-18 years)from two CF services were ***,anthropometric,clinical,and lung function data were collected and two 3-min step tests were performed:(i)in-person supervision,and(ii)remotely supervised by video *** and after the tests,heart rate(HR),oxygen saturation(SpO2),and the Borg score for dyspnea and lower limb fatigue were ***:Twenty-three patients(10.7±3.7 years)with a mean FeV1 of 89.5%±23.2%were *** were no significant differences between tests,with mean differences(95%confidence intervals)in final HR of-3.3(-8.9,2.4),change in HR of-1.9(-6.1,2.1),final SpO2 of 0.3(-0.4,1.0),and final dyspnea of 0.1(-0.8,0.9).The intraclass correlation coefficient was 0.852(final HR),0.762(final SpO2),and 0.775(final lower limb fatigue).Significant and moderate correlations were found between tests for final HR(r=0.75),change in HR(r=0.61),and final SpO2(r=0.61).The Bland-Altman analysis showed a mean difference in final SpO2 between tests of 0.3%(limit of agreement-3.0%,3.5%).Interpretation:Physiological responses between tests were similar,indicating it was feasible to perform the 3-min step test with remote supervision in CF children.

关键词： Children Cystic fibrosis exercise test Telehealth

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Motivations for and barriers to innovation in non-profit organizations: The case of nursing homes in Northern Portugal

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International Journal of Innovation Studies 2024年第1期8卷 25-44页

作者： Ana Rita Gonçalves Lopes Aldina Isabel de Azevedo Correia Alexandra maria da silva Braga Center for Research and Innovation in Business Sciences and Information Systems School of Management and TechnologyPolitecnico do PortoRua do Curral-Margaride4610-156 FelgueirasPortugal

To contribute to the empirical literature on innovation in non-profit organizations,this study examines innovation in Private Social Solidarity Institutions with social responses for the elderly in Northern *** enriches the literature by clarifying the concept of innovation applied to non-profit organizations,which represents a perspective different from the business ***,it is important to support the innovation decisionmaking process in similar non-profit *** this study,the population was surveyed through questionnaires based on the PUBLIN research project,which has already been applied in different countries,and the targets were employees of organizations with social responses for the *** sample is small,with 28 respondent institutions and 51 employees,but it is representative,as it includes institutions from all districts in Northern *** study employed a quantitative approach,particularly factor analysis,multiple linear regression,and correlation analyses,using scales already applied in other dimensions of the social sector,to understand the effect of each innovation dimension/determinant on creativity and innovation in nonprofit *** results show that in these organizations with social responses for the elderly,learning orientation,risk-taking,and job satisfaction have a positive impact on innovation.

关键词： Determinants of innovation non-profit organizations social responses for the elderly Northern Portugal

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Dehydrated Natural Feed for Cats: Influence on Apparent Digestibility Coefficient, Feces Scores, and Serum Immune, Antioxidant, and Metabolic Biomarkers

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Food and Nutrition Sciences 2024年第7期15卷 594-611页

作者： Bruno Giorgio de Oliveira Cécere Guilherme Luiz Deolindo Bianca F. Bissacotti Priscila Marquezin Copetti maria Rosa Chitolina Schetinger Bruna Klein Matheus Delamea Baldissera Thiago Pereira ribeiro Walter Hugo Cuelho Suarez Daniel Pigatto Monteiro Aleksandro Schafer Da silva Graduate Multicenter Program in Biochemistry and Molecular Biology University of the State of Santa Catarina Lages Brazil Department of Biochemistry and Molecular Biology Universidade Federal de Santa Maria (UFSM) Santa Maria Brazil Department of Animal Science Universidade Federal de Santa Maria (UFSM) Chapec Brazil Department of Health Science Universidade Franciscana (UFN) Santa Maria Brazil Department of Animal Nutrition Tectron-Tecnologia e Inovao Toledo Brazil

The present study aimed to determine whether natural dehydrated feed (DNF) can replace dry extruded feed while preserving the required daily intake, nutrient digestibility and benefits for immunity and antioxidant response in cats. The animals were divided into two groups of seven animals each. One group received DNF, and the other consumed commercial extruded dry feed (DCF). The experiment lasted 45 days and we measured daily consumption and collected blood and feces samples. The animals in the DNF group showed greater digestibility of fiber and mineral matter than DCF. Cats in the DNF group had a higher volume of feces. DNF cats had lower leukocyte and granulocyte counts and cholesterol levels. Serum enzymatic antioxidant responses and non-enzymatic were higher in DNF cats. Cats in the DNF group showed lower serum acute phase proteins in addition to a tendency toward a higher concentration of transferrin than in the DCF group. Fecal escherichia coli and total coliform counts of cats fed DNF were higher than DCF. We conclude that the daily consumption of cats is adequate. This feed had greater digestibility of fiber and mineral matter, in addition to an improvement in antioxidant and immunological responses.

关键词： Alternative Feed Antioxidant Companion Animals Health

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Immune response to inactivated bacterial vector carrying the recombinant K39 antigen of Leishmania infantum in mice

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Asian Pacific Journal of Tropical Biomedicine 2024年第5期14卷 199-206页

作者： Lucelina S.Araújo Bruno B.silva eduarda N.F.N.Santos Arnaldo S.Bezerra Samuel S.Frota Assis R.Montenegro eridan O.P.T.Florean Maurício Fvan Tilburg maria Izabel F.Guedes Laboratory of Biotechnology and Molecular Biology Northeast Biotechnology NetworkState University of CearáFortalezaBrazil Faculty of Veterinary Medicine State University of CearáFortalezaBrazil

Objective:To evaluate the immunological response elicited by an inactivated bacterial vector carrying the K39 antigen of Leishmania infantum,and a purified ***:Mice were subjected to the following treatments:(1)Purified recombinant K39(rK39)protein at a 20μg dose with complete Freund’s adjuvant;(2)Inactivated escherichia coli(BL21 De3)carrying the K39 protein at an equivalent total protein content of 200μg;(3)Inactivated bacteria lacking the K39 protein;(4)Non-immunized control *** monitoring was *** groups were challenged by intraperitoneal injection of 10^(7) Leishmania infantum *** euthanasia,the liver and spleen were collected to analyze the levels of TNF,IFN-γ,IL-12,IL-4,and ***:Mice immunized with purified rK39 or the inactivated bacterial vector carrying the K39 antigen of Leishmania infantum showed a long-lasting immune response with high levels of polyclonal antibodies specifically recognizing the recombinant *** IgG1 subclass was the predominant immunoglobulin;however,the induction of IgG2a and the profile of cytokines produced were indicative of the induction of a mixed-type ***:The inactivated bacterial vector carrying the K39 antigen,as well as the purified antigen can induce a long-lasting immune response in immunized mice,predominantly favouring a Th2 profile response.

关键词： Visceral leishmaniasis K39 Inactivated bacterial vector Vaccine Immune response Th1 Th2 Leishmania infantum

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Comparison between Care Strategies for Patients with Osteoarthritis of the Hands Based on the Use of Joint Protection, Assistive Technology and exercises

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Open Journal of Orthopedics 2024年第7期14卷 295-311页

作者： Daniele dos Santos Scarcella Talita Dias da silva Victoria Yanara Hernandes da silva maria Cândida de Miranda Luzo Selma Lancman Marcia Uchoa de Rezende Carlos Bandeira de Mello Monteiro Instituto de Ortopedia e Traumatologia Hospital das Clnicas HCFMUSP Faculdade de Medicina Universidade de So Paulo So Paulo Brazil Programa de Ps-Graduao em Cincias da Reabilitao Faculdade de Medicina Universidade de So Paulo So Paulo Brazil escola de Artes Cincias e Humanidades Universidade de So Paulo So Paulo Brazil

Background: Osteoarthritis (OA) is a disabling disease that can affect 6% to 12% of the adult population and more than a third of people over 65 years of age. Purpose: To assess whether a group of people with hand osteoarthritis (hOA) who received different types of treatment improved their function after two years of follow-up. Method: The entire sample (n = 97) underwent three follow-up assessments regarding anthropometric parameters of the upper limbs and ability to perform functional activities. Subsequently, the sample was divided into two groups for the intervention periods, called the First Period (n = 73) and the Second Period (n = 24);the First Period kept the same protocol with orientations, and the Second Period went to an intervention with orientation strength exercises and use of orthosis. Findings: In the separate analysis of the three questions of the DASH pain module, no differences were found between the assessment moments for groups of guidelines, treatment, or symptoms. Significant effects were observed for F(2, 162) = 3.5, p = 0.033, η2 = 0.04, and interaction for moments and intervention F(2, 162) = 4.3, p = 0.016, η2 = 0.05. Implications: It can be concluded that only guidance treatment does not benefit patients with hand osteoarthritis. In contrast, guidance, exercise, and orthosis treatment can significantly improve the disease.

关键词： Hand Osteoarthritis Hand Deformities Occupational Therapy

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Challenges in Implementing DVI Best Practice Guidelines Due to the Brumadinho Disaster

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Forensic Medicine and Anatomy Research 2024年第1期12卷 1-12页

作者： Reinaldo Moreira silva Bruno Diniz Sander Morais Carlos Danilo Ruas silva elza Cristina Lopes de Oliveira Fernando Pereira Macedo Giovanni Vitral Pinto Guadalupe Dell’Arret Coutinho Higgor Gonçalves Dornelas João Luiz silva Moreira Laila evangelista de Almeida Fernandes Marcia Lobão Iannini Patrícia Siqueira Valéria Rosalina Dias e Santos Sordaini maria Caligiorne Instituto de Criminalística Polícia Civil de Minas Gerais Belo Horizonte Brazil

The broke of a tailings dam from Vale S.A. destroyed a gigantic area killing 270 persons in Brumadinho/Brazil. Organizing activities after a mass disaster is a complex process that requires the involvement of many people and resources in the laboratory. To DNA identification of the victims, a daunting work had to be made by DNA laboratory staff in a collaborative effort with many partners. efforts to implement good practice guidelines in Disaster Victim Identification (DVI) have revealed several important aspects that need to change in the forensic DNA laboratory. This article highlights the challenges of implementing DVI best practice guidelines in resource-poor settings, but with professionals from different sectors engaged in the same goal of briefly identifying victims and helping families and society.

关键词： Disaster Victim Identification DNA Brumadinho

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Adsorption of yttrium(Y^(3+)) and concentration of rare earth elements from phosphogypsum using chitin and chitin aerogel

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Journal of Rare earths 2024年第4期42卷 775-782页

作者： Glaydson S.dos Reis Diana Pinto Sabrina F.Lütke eder C.Lima Luis F.O.silva Irineu A.S.De Brum Guilherme L.Dotto Department of Forest Biomaterials and Technology Biomass Technology Centre Swedish University of Agricultural SciencesUmeaE13Swedn Universidad De La Costa Calle 58#55-66080002BarranquillaAtlanticoColombia Research Group on Adsorptive and Catalytic Process engineering(eNGePAC) Federal University of Santa MariaAv.Roraima100079705900Santa MariaRSBrazil Institute of Chemistry Federal University of Rio Grande do Sul90040060Porto AlegreBrazil

Chitin powder and chitin-aerogel were prepared from shrimp wastes and used to uptake Y^(3+)from aqueous solutions and concentrate this rare earth element from phosphogypsum(PG).Chitin aerogel displays a specific surface area of 945 m^(2)/g,while chitin powder is 3.6 m^(2)/g,which largely influences its adsorption *** the adsorption in synthetic solutions,the effect of pH on Y^(3+)removal is strong for chitin powder *** contrast,no big pH influence was detected for chitin *** interactions and chelation can highlight the proposed mechanism of Y^(3+)on chitin adsorbents for the powder and ***,in addition to these interactions,pore filling/pore diffusion is the main mechanism of Y^(3+)removal in the chitin *** aerogel is efficient in concentrating 8 times the Y^(3+)from PG,a very complex *** complex chitin aerogel-Y^(3+)can be a secondary source of rare earth elements for other applications.

关键词： Rare earths Sustainable material Chitin powder Chitin porous aerogel Yttrium adsorption and recovery

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