Dissertations / Theses on the topic 'PBAC'
To see the other types of publications on this topic, follow the link: PBAC.
Create a spot-on reference in APA, MLA, Chicago, Harvard, and other styles
Consult the top 50 dissertations / theses for your research on the topic 'PBAC.'
Next to every source in the list of references, there is an 'Add to bibliography' button. Press on it, and we will generate automatically the bibliographic reference to the chosen work in the citation style you need: APA, MLA, Harvard, Chicago, Vancouver, etc.
You can also download the full text of the academic publication as pdf and read online its abstract whenever available in the metadata.
Browse dissertations / theses on a wide variety of disciplines and organise your bibliography correctly.
1
Pereira, Danilo Assis. "Adaptação e evidências de validade do teste neuropsicológico PBAC para a população brasileira." reponame:Repositório Institucional da UnB, 2014. http://repositorio.unb.br/handle/10482/17166.
Full textAbstract:
Tese (doutorado)—Universidade de Brasília, Faculdade de Ciências da Saúde, Programa de Pós-Graduação em Ciências da Saúde, 2014.Submitted by Ana Cristina Barbosa da Silva (annabds@hotmail.com) on 2014-12-01T16:57:40Z No. of bitstreams: 1 2014_DaniloAssisPereira.pdf: 4139179 bytes, checksum: e48669ba2bd83b61e0a1e8f2e52a7544 (MD5)
Approved for entry into archive by Raquel Viana(raquelviana@bce.unb.br) on 2014-12-01T18:59:28Z (GMT) No. of bitstreams: 1 2014_DaniloAssisPereira.pdf: 4139179 bytes, checksum: e48669ba2bd83b61e0a1e8f2e52a7544 (MD5)
Made available in DSpace on 2014-12-01T18:59:28Z (GMT). No. of bitstreams: 1 2014_DaniloAssisPereira.pdf: 4139179 bytes, checksum: e48669ba2bd83b61e0a1e8f2e52a7544 (MD5)
Instrumentos de rastreio cognitivos são utilizados em todo o mundo por vários profissionais de saúde para detectar indivíduos com provável comprometimento cognitivo. O teste PBAC(Philadelphia Brief Assessment of Cognition) foi proposto a partir de uma série de instrumentos neuropsicológicos bem estabelecidos na literatura para avaliar comportamento social, memória,linguagem, percepção visoespacial e funções executivas. A literatura aponta que os subtestes do PBAC são correlacionados com perda de massa encefálica em pacientes com doenças neurodegenerativas. Este estudo tem como objetivo verificar evidências de validade da adaptação brasileira do teste de rastreio cognitivo PBAC usando amostras clínicas e populacionais, comparando-o a outros testes de rastreio cognitivo e funcionais. Participaram deste estudo 325 voluntários entre 18 e 94 anos de idade (mediana de 65), com escolaridade entre 0 e 19 anos (mediana de 13). Quatro amostras distintas foram utilizadas: 103 jovens universitários, 183 idosos hígidos, 24 pacientes portadores de demências (sendo mais comum a doença de Alzheimer) e 16 Kalungas moradores da região de Cavalcante-GO, descendentes dos quilombolas. Outros instrumentos de rastreio cognitivo (MEEM, Teste do Relógio, Trilhas A e B,Stroop) e funcionais (GDS e Pfeffer) foram utilizados numa sub amostra para a validação convergente e discriminante. Análises especiais de modelagem de equação estrutural Bayesiana(BSEM) e teoria de resposta ao item multidimensionais (TRIm) e multigrupo foram utilizadas. O teste PBAC possui boa confiabilidade na amostra geral (alfa = 0,86), mas não na amostra de jovens (0,37). Quatro dimensões distintas foram encontradas: memória, linguagem, habilidade visoconstrutiva e funções executivas. O modelo BSEM mostrou para o grupo de idosos hígidos que a idade influencia negativamente a memória, mas não as demais habilidades. A escolaridade apresentou influência positiva em todos os constructos latentes. Com exceção dos itens Escrita e Trilhas, todos os demais apresentaram maior informação nas habilidades latentes dos idosos com demência, quando comparados aos hígidos nas funções de informações da TRI multigrupo.Tabelas normativas com a habilidade (teta), escore z e escala T foram calculadas para cada dimensão do teste, tendo como norma os dados dos idosos hígidos. O teste de rastreio cognitivo PBAC se mostrou tão sensível e específico quanto o MEEM para a detecção de demência do tipo Alzheimer. O teste é mais informativo em pessoas com habilidades latentes mais baixas. A retirada de alguns itens do teste pode aumentar sua acurácia para o diagnóstico de Alzheimer,no entanto mais estudos com outros grupos clínicos se tornam essenciais, uma vez que sua construção objetivou a avaliação multiclínica. ________________________________________________________________________________ ABSTRACT
Cognitive screening tests are used worldwide by many health professionals to detect individuals with probable cognitive impairment. The PBAC (Philadelphia Brief Assessment of Cognition) was proposed based on a series of well-established neuropsychological instruments to assess socialbehavior/comportment, memory, language, visuospatial perception, and executive functions. The literature indicates that the subtests of the PBAC are correlated with loss of brain tissue in patients with several neurodegenerative diseases. This study aims to find evidence of validation of the PBAC using clinical and population samples, and comparing it to other cognitive and functional screening tests. Participated in this study 325 individuals aged between 18 and 94 years-old(median 65), and schooling between 0 and 19 years (median 13). Four different samples were used: 103 university students, 183 healthy elderly, 24 patients with dementia (most common being Alzheimer's disease), and 16 afro-descendants (called Kalungas, living at Cavalcante-GO). All participants signed a consent form. Other cognitive screening instruments (MMSE, Clock Design Test, Trail Tests A and B, and Victoria Stroop Test) and functional tests (Pfeffer and GDS) were used in a subsample for the convergent and discriminant validity. Special analysis of Bayesianstructural equation modeling (BSEM), multi-group and multidimensional response theory item(mIRT) were used. The PBAC test showed good reliability in the overall sample (alpha = 0.86),but not in the youth sample (0.37). Four distinct dimensions were found: memory, language,executive functions, and visuos patial perception. The BSEM model showed that in healthy elderly people, age negatively influences memory, but not other skills. Education had a positive influence on all latent constructs. Except Writing and Oral Trails, all other items presented greaterinformation on the latent abilities for the clinical group when compared to the information functions of the healthy elderly group. Normative tables with the ability (theta), z scale, and T scores were calculated for each dimension of the test, using the healthy elderly normative data. The PBAC cognitive screening test proved to be as sensitive and specific as the MMSE for detecting cognitive disorders associated to Alzheimer’s dementia. The test is more informative on those individuals with lower latent abilities. The withdrawal of some items can increase PBAC’saccuracy for the diagnosis of Alzheimer's, however further studies with other clinical groups are essential since its construction aimed to evaluate other kind of neurodegenerative disease.
2
CALO', LUCIA. "ANALISI DEI PROBLEMI GINECOLOGICI ED OSTETRICI NELLE DONNE CON COAGULOPATIA A DIATESI EMORRAGICA ATTRAVERSO IL REGISTRO INTERNAZIONALE (WRBDD)." Doctoral thesis, Università degli Studi di Milano, 2012. http://hdl.handle.net/2434/170490.
Full textAbstract:
SUMMARY
Patients affected by bleeding disorders present a wide spectrum of clinical symptoms that vary from mild or moderate bleeding tendency to significant episodes. Women with inherited bleeding disorders are particularly disadvantaged since in addition to suffering from general bleeding symptoms they are also at risk of bleeding complications from regular haemostatic challenges during menstruation, pregnancy and childbirth. Moreover, such disorders pose important problems for affected women due to their reduced quality of life caused by limitations in activities and work, and alteration of their reproductive life. These latter problems include excessive menstrual bleeding or menorrhagia, miscarriage, bleeding complications during pregnancy and after delivery and their related complications such as acute or chronic anaemia.
Moreover, reliable information on clinical management are scarce, only a few available long term prospective studies of large cohorts provide evidence-based guideline about diagnosis and treatment.
To this end, the University of Milan has created a working group on menorrhagia and other gynecological problems in women with rare bleeding disorders (WRBD: http://www.wrbd.org/network.htm) involving worldwide renewed centers besides the Angelo Bianchi Bonomi Hemophilia and Thrombosis Centre of Milan. A prospective study recruiting women with confirmed diagnosis of von Willebrand disease (VWD), rare coagulation disorders (RBDs: rare bleeding disorders) and platelet disorders was designed. Women without evidence of coagulation disorders constituted the control group.
The aim of this project was to retrospectively and prospectively collect a large cohort of women to:
- evaluate the prevalence of gynaecological problems (menarche, ovulation bleeding, menorrhagia, bleeding during pregnancy and postpartum bleeding)
- evaluate the association between menstrual loss and clinical severity (other bleeding symptoms)
- evaluate the association between clinical severity and phenotype results
- to collect and analyse data on concomitant gynaecological abnormalities, complications of menorrhagia (anaemia), requirement of gynaecological intervention and to evaluate the occurrence of abortion, miscarriage and other pregnancy complications.
A specifically tailored questionnaire was used to collect data, along with the Bleeding Score (BS) quesstionnaire, capable of translating the hemorrhagic history of the subject in a numerical coefficient, and the pictorial blood assessment chart (PBAC), graphical tool that scores the intensity of menstrual flow, thus defining the severity of menorrhagia. The collected data have been then entered into a database specifically created to obtain a complete and extensive amount of information which will ultimately be able to extrapolate the clinical information necessary for the intended purposes.
After the first year, 231 patients were enrolled in the study: 113 (48.9%) patients were affected with VWD, 38 (16.5%) with RBDs and 80 (34%) were controls for a total of 214 pregnancies.
Our data showed that menorrhagia was a specific symptom of women with VWD, while the profuse menarche and intermittent and heavy menstrual bleeding seemed to be a symptom of women with RBDs. However, the intra-abdominal bleeding and the vaginal bleeding near ovulation seem not to be specifically related to the presence of hemorrhagic disease, confirming currently available data from the literature. Similarly, hemorrhagic complications during surgery do not seem to have a higher incidence in the presence of VWD or RBDs compared with controls, but we consider that these data needs to be further analyzed after further enlargement of the sample size in order to discriminate the population in two groups: with and without prophylaxis preopaeratoria.
The results of the study did not detect significant differences between the two groups (women with VWD and RDBs) and the general population with regard to the rate of spontaneous abortions, intrauterine deaths and the incidence of bleeding occurring during pregnancy, confirming the data of the current literature. Hemorrhage after vaginal delivery was, however, the only hemorrhagic complication showing a significantly higher incidence in the two groups of patients compared with controls. In particular secondary postpartum haemorrhage was higher in women with VWD compared to controls.
BS and PBAC in our study were also tested for their potential for predicting the phenomenon of bleeding the patient. The PBAC showed to have a predictive value on the profuse menarche in the group of women with RBDs (threshold value 606.5) and acute hemorrhagic event and bleeding near ovulation in women with VWD (threshold value 737 and 682.5, respectively). Both scoring systems were found to predict the postpartum bleeding in women with VWD: a BS higher than 11 seemed to be associated to a 3-fold increased risk of postpartum bleeding, whereas a PBAC higher than 200 to a 18-fold increased risk.
The coagulant activity level of the deficient factor was shown to be a predictive tool for hemorrhagic event at menarche and for the acute bleeding in women with VWD (24.5 and 17.5, respectively; threshold value 22) and for the acute bleeding in women with RBDs (threshold 27). It was also shown to be associated to postpartum hemorrhage in women with VWD (an activity level less than 23% was associated to a to 6-fold higher risk).
In conclusion, our results, although preliminary have considerable importance as an outcome of a collaborating data collection project, using an ad hoc database, whose final validation will happen in the course of study with the ultimate goal of providing all the necessary features to make it maximally effective and accurate. Eventually, the analysis of data collected will provide a suitable substrate for the drafting of guidelines for the universal prophylactic and therapeutic approach to obstetricians hemorrhagic gynecological problems.
3
Silva, Rafael Soares. "Termo-estabilização da blenda PLA/PBAT." Universidade Presbiteriana Mackenzie, 2016. http://tede.mackenzie.br/jspui/handle/tede/2854.
Full textAbstract:
Submitted by Rosa Assis (rosa_assis@yahoo.com.br) on 2016-09-22T13:50:32Z
No. of bitstreams: 2
license_rdf: 0 bytes, checksum: d41d8cd98f00b204e9800998ecf8427e (MD5)
Rafael Soares Silva.pdf: 2923341 bytes, checksum: a831738a4d83ca6103e1489945754a7b (MD5)Made available in DSpace on 2016-09-22T13:50:32Z (GMT). No. of bitstreams: 2 license_rdf: 0 bytes, checksum: d41d8cd98f00b204e9800998ecf8427e (MD5) Rafael Soares Silva.pdf: 2923341 bytes, checksum: a831738a4d83ca6103e1489945754a7b (MD5) Previous issue date: 2016-05-20
This study aimed to evaluate the effects of additives (primary and secondary antioxidants) in thermal stabilization process of poly (lactic acid) / poly (butylene adipate-co-terephthalate) - PLA / PBAT using a torque rheometer as a preliminary tool evaluation of the stabilization process. The additives Irganox 1010, Irganox 1076, Irganox B900, Irgafos 168, and a flavonoid were used in two concentrations, 0.3 and 0.5% w/w. The assessment of the effects of stabilizing additives was carried out by monitoring the torque during mixing molar mass measurements, infrared analysis, turbidity and Scanning Electron Microscopy of the samples after processing. It carried out the monitoring of the pure blend torque values and addition of stabilizing additives during processing up to 5 minutes in an internal mixer of the type "mixer" under rotation of 60 rpm and a temperature of 180 °C. Within a series of primary and secondary antioxidants, it was found that some of these additives failed torque values greater than or similar to the pure blend at certain concentrations (Irganox 1076, Irganox B900 and Irgafos 168). molar mass measurements showed that pure processed blend undergoes a large number of chain scission and most additives stabilizing action achieved unless the flavonoid. One important information obtained through analyzes of torque rheometry and molar mass that is higher drying time strongly prevents hydrolysis reactions. Comparing the infrared spectra of pure and pure blend blend processed, there is not the appearance of no new peak occurs due to the degradative process. By UV-Vis analysis of the polymer solutions we verified the presence of crosslinked polymer microstructures due to thermo-oxidative reactions. Images obtained by scanning Elletrônica Microscopy (SEM), one can observe the presence of two distinct phases for the pure blend processed, and the use of additives in both compositions show a much smaller difference of phases to blend pure. These results indicate the possibility of using commercial additives used for non-biodegradable polymers in systems using biodegradable polymers.
Este trabalho teve como objetivo avaliar a ação de aditivos (antioxidantes primários e secundários) no processo de estabilização térmica da blenda poli(ácido láctico)/poli(butileno adipato-co-tereftalato) - PLA/PBAT usando um reômetro de torque como ferramenta prévia de avaliação do processo de estabilização. Os aditivos Irganox 1010, Irganox 1076, Irganox B900, Irgafos 168 e o Flavonóide foram usados em duas concentrações, 0,3 e 0,5% em massa. A avaliação dos efeitos dos aditivos estabilizantes foi realizada por meio de monitoramento do torque durante mistura, medidas de massa molar, análises de infravermelho, turbidez e microscopia eletrônica de varredura das amostras após processamento. Realizou-se o monitoramento dos valores de torque da blenda pura e com adição de aditivos estabilizantes durante processamento por até 5 minutos em um misturador interno do tipo “Mixer” sob rotação de 60 rpm e temperatura de 180 oC. Dentro de uma série de antioxidantes primários e secundários, verificou-se o uso de alguns desses aditivos conseguiram valores de torque superior ou semelhante ao da blenda pura em determinadas concentrações (Irganox 1076, Irganox B900 e Irgafos 168). Medidas de massa molar mostraram que a blenda pura processada sofre um grande número de cisão de cadeias e que a maioria dos aditivos conseguiram ação estabilizante menos o flavonóide. Uma informação importante obtida por meio das análises de reometria de torque e massa molar é que um tempo maior de secagem evita fortemente as reações de hidrólise. Comparando-se os espectros de infravermelho da blenda pura e da blenda pura processada, nota-se que não aparecem nenhum novos picos relacionados ao processo degradativo. Através da análise de UV-Vis das soluções poliméricas verificou-se a presença de microestruturas poliméricas reticuladas em virtude das reações termo-oxidativas. Imagens obtidas por Microscopia Elletrônica de varredura (MEV), evidenciam a presença de duas fases distintas para a blenda pura processada, e o uso dos aditivos nas duas composições mostram uma diferenciação das fases muito menor que para blenda pura. Esses resultados indicam que existe a possibilidade do uso de aditivos comerciais usados para polímeros não-biodegradáveis em sistemas com polímeros biodegradáveis.
4
Fu, Yang. "Morphologie des mélanges ternaires PLA/PBAT/PA." Thesis, Paris Sciences et Lettres (ComUE), 2017. http://www.theses.fr/2017PSLEM068/document.
Full textAbstract:
Ce travail vise à obtenir une morphologie cœur-peau directement lors du mélangeage à l’état fondu de polymères ternaires PLA/PBAT/PA. Le but final est d'améliorer la ténacité de l'acide polylactique (PLA). La morphologie des mélanges de polymères multi-phases est contrôlée par la thermodynamique du système. La morphologie des mélanges ternaires peut être prédite à partir des valeurs relatives des trois coefficients d'étalement caractérisant le triplet de polymères. Les coefficients d'étalement sont calculés à partir des valeurs des tensions interfaciales entre les composants binaires. La détermination des tensions interfaciales entre PLA, poly (butylène adipate-co-téréphtalate) (PBAT) et un copolyamide (PA) prédit une morphologie dispersée complexe dans la matrice PLA où les sous-inclusions PA sont partiellement encapsulées dans la phase PBAT. Cette morphologie a été obtenue par mélange à l'état fondu des trois composants, comme observé par les observations en microscopie électronique à balayage. Dans une seconde étape, une compatibilisation sélective a été utilisée pour modifier l'emplacement des sous-inclusions de PA. A cette fin, deux copolymères diblocs PBAT-b-PLA, PA-b-PBAT ont été synthétisés. La présence des copolymères diblocs nous permet de modifier la tension interfaciale des couples PLA/PBAT, PA/PBAT. Cette modification de l'équilibre de tension interfaciale modifie avec succès la morphologie, passant d’une semi-encapsulation à une encapsulation complète des sous-inclusions de PA dans les gouttes de PBAT. La performance mécanique de ce mélange ternaire a été évaluéeThis work aims at achieving direct core-shell morphologies in ternary PLA/PBAT/PA polymer blends by melt mixing. The final goal is to improve the toughness of polylactic acid (PLA). The morphology of multi-phase polymer blends is controlled by the thermodynamics of the system. The morphology of ternary blends can be predicted from the relative values of the three spreading coefficients characterizing the triplet of polymers. Spreading coefficients are calculated from the values of interfacial tensions between binary components. The determination of interfacial tensions between a PLA, a poly(butylene adipate-co-terephthalate) (PBAT) and a copolyamide (PA) predicts a complex dispersed morphology in the PLA matrix where PA subinclusions are partly encapsulated in the PBAT phase. This morphology was obtained by melt mixing the three components, as observed by scanning electron microscopy. In a second step, selective compatibilization was used to modify the PA sub-inclusion location. To this end, PBAT-b-PLA and PA-b-PBAT di-block copolymers were synthesized. The presence of the di-block copolymers enabled to modify the interfacial tension in PLA/PBAT and PA/PBAT. The modification of the interfacial tension balance was shown to successfully change the morphology from semi-encapsulation to full encapsulation of PA sub-inclusions in the PBAT drops. The mechanical performance of this ternary blend was evaluated
5
Vaccioli, Kleber. "Estudo da blenda PBAT/PLA com cargas." Universidade de São Paulo, 2015. http://www.teses.usp.br/teses/disponiveis/3/3133/tde-12072016-101827/.
Full textAbstract:
Neste trabalho compósitos foram obtidos a partir da blenda comercial 100% biodegradável Ecovio® C2224 da BASF, uma blenda formada por 55% em massa de um copoliéster biodegradável, o Ecoflex® (poli[(adipato de butileno)-co-(tereftalato de butileno)]) e 45% em massa de PLA poli(ácido láctico). Como carga, utilizaram-se dois tipos de argilas comerciais do grupo das esmectitas, ambas predominantemente montmorilonitas: Cloisite Sódica® e Cloisite 30B®. Também foi utilizado como carga a sílica coloidal comercial Aerosil 200®, com área superficial de 200 m2/g e diâmetro médio de partícula 12nm. Os compósitos estudados, ambos contendo 5% e 10% em massa de cargas, foram preparados em uma extrusora de rosca dupla, acoplada a um reômetro de torque. O estudo foi dividido em três etapas: 1ª) etapa: Obtenção e caracterização dos compósitos de Ecovio®/ argila e Ecovio® / sílica; 2ª) etapa: Avaliação da fotodegradação do Ecovio® puro e dos compósitos obtidos; 3ª) etapa: Avaliação da biodegradabilidade do Ecovio® puro e dos compósitos após exposição em câmara de UV. As propriedades mecânicas dos compósitos antes e depois de serem submetidos à exposição em câmara de UV foram avaliadas por ensaios de resistência à tração e resistência ao impacto Izod. Os resultados obtidos na 1ª etapa deste trabalho indicaram aumento nos valores de módulo de elasticidade de todos os compósitos, em relação à blenda pura. Destacam-se as composições com 5% e 10% em massa de sílica coloidal, que apresentaram aumentos de até 115% nos valores de módulo de elasticidade, sem perdas significativas em resistência à tração, alongamento e resistência ao impacto, quando comparadas à fase matriz. Na 2ª etapa, a partir de 20 dias de exposição, todas as composições (blendas e compósitos) apresentam redução nas propriedades mecânicas em função do aumento do tempo de exposição à radiação UV. Na 3ª etapa, independente do tipo ou teor de carga presente na blenda, todas as composições apresentaram índices de biodegradabilidade, depois de 120 dias, de 40 a 60%, devido à prévia exposição à radiação UV.In this work, composites were prepared with 100% biodegradable commercial blend Ecovio® C2224 BASF, a polymer blend composed of 55 wt% of a biodegradable copolyester, the Ecoflex®, poly [(butylene adipate) -co- (butylene terephthalate)], and 45 wt% of PLA poly(lactic acid). Two types of commercial clays of the smectite group, predominantly montmorillonites, were used as fillers: Cloisite Na+® and Cloisite 30B®. The commercial colloidal silica Aerosil 200®, with a surface area of 200 m2/g and an average particle diameter of 12 nm, was also used as filler. The composites containing 5 and 10 wt% of filler were obtained in a twin screw extruder coupled to a torque rheometer. This study was divided in three steps: 1st) Preparation and characterization of Ecovio®/clay and Ecovio®/silica composites; 2nd) Evaluation of the photodegradation of pure Ecovio® and of the composites; 3rd) Biodegradability assessment of pure Ecovio® and composites after exposure to UV chamber. The mechanical properties of the composites before and after the exposition to UV were evaluated by tensile and Izod impact strength. The results obtained in the 1st step showed an increase in the tensile modulus of all blends, especially for the compositions with 5 and 10 wt% of colloidal silica, which presented an increase of 115% in their tensile modulus values without significant reduction in impact and tensile strength and elongation, when compared to the pure blend. In the 2nd step, from 20 UV exposure days, all compositions (blends and composites), presented a significant reduction in the mechanical properties as a function of the increase of the UV radiation exposure time. In step 3, regardless of the filler type or content, all blend compositions showed biodegradability index, after 120 days, of 40 to 60%, due to the prior UV exposure.
6
Khan, Anastassiya. "Synthesis and characterization of defective PBAs electrode material." Master's thesis, Alma Mater Studiorum - Università di Bologna, 2020. http://amslaurea.unibo.it/21015/.
Full textAbstract:
Sodium manganese hexacyanoferrate (NaMnHCF) and its derivatives have been synthesized by simple co-precipitation method with addition of the citric and ascorbic acids respectively. The correspondent crystal structure, water content, chemical formula and a deep structural investigation of prepared samples have been performed by means of the combination of the laboratory and synchrotron techniques (PXRD, FT-IR, TGA, MP-AES and XAS). Electrochemical tests have been done using three-electrode system in sodium nitrate solution at different concentration. From cyclic voltammetry curves, Fe3+/2+ redox peak has been observed, whereas Mn3+/2+ peak was not always evident. Structural stability of the cycled samples has then been tested using 2D XRF imaging and Transmission X-ray microscopy (TXM) techniques. The intercalation of NaMnHCF after 20 cycles has been found by micro-XANES analysis of the highlighted spots which have been found in the XRF images. TXM has also confirmed the appearance of the intercalated particles after 50 cycles comparing the spectra between charged and discharged materials at three different edges (Mn, Fe and N). However, by comparison with lithium samples, it seems obvious that sodium samples are more homogeneous and intercalation is at the very beginning indicating the relative structural stability of sodium manganese hexacyanoferrate electrode material.
7
Bøe, Andreas Gagnat. "Degradation and Stability of PBCA and POCA Nanoparticles." Thesis, Norges teknisk-naturvitenskapelige universitet, Institutt for fysikk, 2013. http://urn.kb.se/resolve?urn=urn:nbn:no:ntnu:diva-22417.
Full textAbstract:
Nanoparticles represent promising carriers for controlled drug delivery. In this project threedifferent intruments: Zetasizer, Nanosight and Gas Chromatography, have been used to detect and analyse degradation of monodisperse poly butylcyanoacrylate (PBCA) and polyoctylcyanoacrylate (POCA) nanoparticles with a mean size diameter of 145 and 155 nm,respectively. It was found that the Nanosight and Gas Chromatography are valuable instrumentsfor detecting and analysing degradation, whereas the Zetasizer turned out to giveunreliable results because of increasing polydispersity in the samples. PBCA and POCAparticles were tested in two different setups. One including a dialysis setup in room temperature,in which the solvent was regularly exchanged. The other consisted of reagent bottlesheld in an oven at 37C. In the dialysis method the influence of buffers with pH 4.0, pH5.5 and pH 7.4 were tested. In the reagent bottles different mediums were tested, like cellmedium, blood serum and buffer pH 7.4 with and without the enzyme esterase. From theseexperiments it became clear that PBCA particles degraded significantly faster than POCAparticles in all tested mediums. Degradation of PBCA particles were also strongly affectedby the pH. At pH 4.0 there was little (10%) or no degradation still after 30 days. The concentration of PBCA particles in pH 7.4 decayed as a 1/x -function, in which 53\% of the PBCA particles in buffer pH 7.4 have been degraded after 8.5 hours.The degradation-rate for PBCA and POCA in blood serum was approximately similar as in buffer pH 7.4, whereas in cell medium it was slightly slower.
8
SOUSA, Jokderlea Correa de. "Estudo da cinética de cristalização do compósito poli(butileno-adipato-co-tereftalato)/fibra de coco." Universidade Federal de Pernambuco, 2016. https://repositorio.ufpe.br/handle/123456789/17526.
Full textAbstract:
Submitted by Fabio Sobreira Campos da Costa (fabio.sobreira@ufpe.br) on 2016-07-22T13:49:26Z
No. of bitstreams: 2
license_rdf: 1232 bytes, checksum: 66e71c371cc565284e70f40736c94386 (MD5)
Dissertação Jokderléa - Versão digital.pdf: 2657401 bytes, checksum: aa4dfc40144fb6bdb5d19dd66aa43470 (MD5)Made available in DSpace on 2016-07-22T13:49:26Z (GMT). No. of bitstreams: 2 license_rdf: 1232 bytes, checksum: 66e71c371cc565284e70f40736c94386 (MD5) Dissertação Jokderléa - Versão digital.pdf: 2657401 bytes, checksum: aa4dfc40144fb6bdb5d19dd66aa43470 (MD5) Previous issue date: 2016-02-25
FINEP
ANP
PRH
Neste trabalho estudou-se compósitos poliméricos obtidos a partir de um poliéster biodegradável e fibra de coco (Cocus nucifera), uma fibra abundante na região Nordeste e para a qual não existem relatos na literatura de sua utilização em compósitos com o poli(butileno-adipato-co-tereftalato)(PBAT). O uso de fibra de coco nas formulações é uma alternativa para redução de custos, pois propõe uma substituição parcial do polímero a ser utilizado. Estudou-se a influência da fibra sobre as propriedades reológicas e térmicas dos compósitos. As fibras naturais foram secas e classificadas antes de sua utilização. Foi realizado um teste preliminar por Calorimetria Diferencial Exploratória (DSC) com o PBAT onde foi definida a temperatura de fusão para o processamento no reômetro. Compósitos de PBAT e fibra de coco foram preparados com formulações de 10, 20, 30, 40 e 50% em massa de fibra em um misturador interno. Foi possível quantificar a dependência do torque com a velocidade de rotação dos rotores pelo índice de pseudoplasticidade através da lei da potência. A avaliação reológica dos compósitos obtidos mostrou a dependência do torque e da temperatura com a quantidade de fibra adicionada. Foi realizado um estudo sobre a cristalização dos compósitos com 10, 20 e 30% de fibra comparando com o polímero puro, submetido as mesmas condições de preparação. A análise dos resultados obtidos pelo DSC indicou que a adição de fibras nos compósitos alterou a temperatura de cristalização para valores mais elevados, sugerindo que as fibras podem ter um efeito nucleante. Os compósitos quando submetidos a variações nas velocidades de resfriamento, mostraram que o processo de cristalização se altera, deslocando os picos de cristalização para temperaturas menores, conforme aumentava a velocidade de arrefecimento. Foi construído o modelo cinético de Pseudo-Avrami para o compósito PBAT/10% fibra de coco, pois seus parâmetros de cristalização apresentaram desvios menores ou próximos de 10% em relação ao PBAT puro. Houve boa adequação dos modelos aos dados experimentais nas três taxas de resfriamento utilizadas.
In this work, it was studied polymer composites made from a biodegradable polyester and natural coconut fibre (Cocus nucifera). Great abundance of this fibre can be found in the northeast areas of Brazil, and there are no reports in the literature of its use in polymer composites with poly (butylene-adipate-co-terephthalate). The use of coconut fiber in the formulations is an alternative for reducing costs, because it proposes a partial replacement for the polymer to be used. The study assessed the effects of the fibre on rheological and thermal properties of the biocomposites. Natural fibres were dried and classified before its utilization. Initially, the PBAT characterization was performed by differential scanning calorimetry in which were defined the melting temperature for processing in the rheometer. Composites of PBAT and coconut fibre were prepered with formulations containing 10, 20, 30, 40 and 50% in mass of fibre in the internal mixer. It was possible to quantify the dependence of torque with rotor speeds by the pseudoplasticity index through the power law. The rheological evaluation of the obtained composites showed the dependency on torque and temperature with the amount of fiber added. A study was conducted on composites crystallization of 10, 20 and 30% of fibre comparing it to the pure polymer submitted to the same conditions of preparation. Analysis of the results obtained by DSC indicated that the addition of fibres in the composite altered the crystallization temperature to higher values, suggesting that the fibres may have a nucleating effect. The composites when exposed to variations in the cooling rates, showed that the crystallization process is changed, displacing the crystallization peaks to lower temperatures as the cooling rate was increased. It was built the kinetic model of Pseudo-Avrami for the composite PBAT/10% coconut fibre, because its crystallization parameters showed lower error values or near 10% compared to pure PBAT. There was a good adjustment between models and experimental data in the three cooling rates utilized.
9
Abass, Abdul-Kariem. "Electrical and optical studies of lead phthalocynanine (PbPc) thin films." Thesis, Lancaster University, 1993. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.239800.
Full text
10
Reis, Pedro Rodrigo de Sousa. "Obtenção e caracterização de compósitos de blendas poliméricas biodegradáveis reforçadas com bio-hidroxiapatita." Universidade de São Paulo, 2018. http://www.teses.usp.br/teses/disponiveis/85/85134/tde-01112018-151923/.
Full textAbstract:
Este trabalho apresenta a preparação e caracterização de materiais compósitos baseados na mistura (blenda) de poli (ácido lático) PLA e poli (adipato co-tereftalato de butileno) PBAT reforçados com bio-hidroxiapatita \"HAp\", obtida a partir de cascas de ovos brancos de galinha. A obtenção de HAp foi realizada por via úmida, reação ácido-base. Primeiramente, foi obtido o bio-carbonato de cálcio a partir das cascas de ovos brancos de galinha, seguido de um ciclo térmico de aquecimento a 800 °C para a conversão em óxido de cálcio, o qual posteriormente foi sinterizado a 900 °C para a obtenção da HAp. Os materiais compósitos de PLA/PBAT reforçados com 1, 3 e 5 %, em massa, de HAp em pó, com tamanho de partículas iguais ou menor que 10 μm, foram preparadas pelo processo de extrusão utilizando-se uma extrusora de dupla-rosca. Após o processo de extrusão, os materiais foram alimentados ao funil de alimentação de uma injetora de laboratório para a obtenção dos corpos de prova para os ensaios de caracterização. Parte dos corpos de prova foram submetidos à esterilização por radiação gama (radioesterilização), utilizando-se feixe de elétrons de alta energia, gerados em um acelerador de elétrons industrial, de 1,5 MeV, à temperatura ambiente e na presença de ar, com dose de radiação de 25 kGy. As amostras de HAp foram caracterizadas por meio dos ensaios de difração de raios X (DRX), espectroscopia vibracional de absorção no infravermelho com transformada de Fourier (FTIR), termogravimetria (TG) e microscopia eletrônica de varredura com fonte de emissão de campo (MEV-FEG). O PLA/PBAT puro e seus compósitos não irradiados e irradiados foram caracterizados por meio dos ensaios de DRX, TG, MEV-FEG, calorimetria exploratória diferencial (DSC), temperatura de distorção térmica (HDT), ponto de amolecimento Vicat, resistência à tração, à flexão e ao impacto Izod, validação do processo de esterilização (teste de carga microbiana (Biocarga ou Bioburden) e ensaios de esterilidade) e citotoxicidade \"in vitro\" pelo método de incorporação do vermelho neutro para avaliação da biocompatibilidade das amostras. As análises de DRX da HAp mostraram os picos característicos presentes na fase amorfa da HAp; os picos e bandas largas pertencentes aos grupos moleculares da HAp foram identificados por meio da análise por FTIR; a estabilidade térmica da HAp obtida foi confirmada por termogravimetria, a qual mostrou uma pequena perda de massa com o aumento da temperatura, devido à queima do solvente, evaporação de água e queima de materiais orgânicos presentes na amostra de HAp, as imagens obtidas por MEV-FEG mostraram estruturas irregulares características da HAp. A incorporação de HAp na blenda de PLA/PBAT promoveu ganhos superiores a 10 % na temperatura de distorção térmica e no ponto de amolecimento Vicat original da blenda, aumento superior a 15 % nas propriedades mecânicas de resistência à tração e à flexão, e aumento superior a 10 % a resistência ao impacto Izod, melhorando suas propriedades de forma significativa quando comparado a blenda de PLA/PBAT. Os testes de carga microbiana e esterilidade mostraram que a dose de radiação de 25 kGy aplicada foi eficaz para a esterilização das amostras dos materiais. Todas as amostras apresentaram-se biocompatíveis em ambiente celular pelo teste de citotoxicidade \"in vitro\", apresentando potencial para estudo \"in vivo\".This work presents the preparation and characterization of composites based on blends of poly (lactic acid) - PLA and poly (adipate co-terephthalate of butylene) - PBAT reinforced with bio-hydroxyapatite \"HAp\", obtained from avian eggshells waste of white color. The HAp was obtained by the wet chemical method from the acid-base reaction. Firstly, the bio-calcium carbonate (bio-CaCO3) was obtained from the avian eggshells waste. The bio-CaCO3 was submitted to a heating cycle at 800 °C in order to convert bio-CaCO3 in the bio-calcium oxide, which was then sintered at 900 °C and the bio-HAp was obtained. PLA/PBAT reinforced with 1, 3 and 5 % in weight of HAp, particle size ≤ 10 μm, were prepared by the extrusion process using a twin-screw extruder. After the extrusion process, the PLA/PBAT blend and its composites were fed into a laboratory injection molding machine and the specimens test were obtained for the characterization tests. Part of the specimens was submitted to sterilization by gamma radiation (radio-sterilization) with electron-beam using an industrial electron accelerator of 1.5 MeV, at the radiation dose of 25 kGy, room temperature and in the presence of air. HAp was characterized by X ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), thermogravimetry (TG) and scanning electron microscopy with field emission source (FE-SEM) analysis. The blends and composites (non-irradiated and irradiated samples) were characterized by XRD; TG; FE-SEM and differential scanning calorimetry (DSC) analysis. The thermal distortion temperature (HDT), Vicat softening temperature, tensile, flexural, and impact Izod tests were also carried out. The validation of materials sterilization process (Bioburden tests) and cytotoxicity test \"in vitro\" to evaluating the biocompatibility of the material composites were also made. XRD analyzes results showed a characteristic peak in the amorphous phase of HAp. FTIR analysis identified broad peaks and bands belonging to the molecular groups of HAp. The thermal stability of the HAp was confirmed by the TG analysis, which showed a small loss of mass with the increase of temperature due to the burning of solvents, water evaporation and burning of organic materials present in the sample of HAp. The FE-SEM images showed irregular structures characteristic of HAp. Regarding the PLA/PBAT/HAP composites, it can be observed increases up to 10 % in thermal distortion temperature and Vicat softening temperature, higher than 15 % in the tensile and flexural strength, and higher than 10 % in the Izod impact when compared with neat PLA/PBAT blend. The bioburden tests showed that radiation dose of 25 kGy was effective for sterilization of the materials. The results of the cytotoxicity test \"in vitro\" showed that all samples are biocompatible in the cellular environment, and therefore, presents a potential for \"in vivo\" study.
11
Schmidmaier, Ralf. "Beeinflussung der Regulatorfunktion mononukleärer Zellen des peripheren Blutes (PBMC) in vitro." [S.l.] : [s.n.], 2002. http://deposit.ddb.de/cgi-bin/dokserv?idn=964406845.
Full text
12
Cabello, Hernández Pablo Jesús. "Single nanoparticle devices: Trapping and characterizaton." Tesis, Universidad de Chile, 2017. http://repositorio.uchile.cl/handle/2250/150605.
Full textAbstract:
Magíster en Ciencias, Mención FísicaLa fabricación y posicionamiento de nanopartículas de tamaño y composición ajustable resulta interesante debido a las propiedades que surgen producto del confinamiento en bajas dimensiones. Para acceder a ellas es necesario reemplazar los dispositivos electrónicos macroscópicos típicos por equivalentes nanométricos. En este campo, uno de los mayores retos es elaborar un esquema de medición que permita estudiar el transporte de cargas a través de una nanopartícula individual. Con tal de contactar las nanopartículas a los electrodos en este nuevo esquema, es necesario conocer tanto las propiedades de ambos como sus interacciones. Dado el tamaño reducido de las nanopartículas, resulta fundamental el poder fabricar electrodos nano-espaciados. En esta tesis se realizaron caracterizaciones eléctricas de dos tipos de nanopartículas: análogas al azul Prusiano (PBA por su sigla en ingles) y a base de hierro. Dichas nanopartículas fueron depositadas sobre muestras de electrodos nano-espaciados fabricados mediante la técnica de enmascaramiento con óxido de cromo. Se concluyó que estos dispositivos son una plataforma confiable para un amplio rango de temperaturas ($4$-$300$ K). Más aún, se pudo establecer que son compatibles tanto con técnicas actualmente disponibles como drop-casting, como con nuevas técnicas como la deposición directa de clústeres generados por pulverización catódica con magnetrón. La caracterización eléctrica de las nanopartículas de \ce{CoFe} PBA depositadas por \textit{drop-casting}, permitió demostrar que es posible atraparlas y estudiar sus curvas corriente-voltaje usando los dispositivos fabricados. Sin embargo, los datos obtenidos a bajas temperaturas no permitieron esclarecer el mecanismo involucrado en el transporte eléctrico. En este sentido es importante mencionar que se observaron dos comportamientos: Un primer grupo de dispositivos que no mostró evidencia de ser afectado por el láser ($640$ nm) y que presentó un \textit{Coulomb gap}, sugiriendo transporte individual de electrones; y un segundo grupo en el que si se evidenció un efecto tras la irradiación, que no se presenta \textit{Coulomb gap}, y cuya dependencia en temperatura de la resistencia se desvió fuertemente de la ecuación de Arrhenius ($\log(R) \propto T^{-1}$). En el caso de las nanopartículas a base de hierro, se consideró un nuevo esquema de fabricación y depósito de éstas, utilizando pulverización catódica. Mediciones a temperatura ambiente indicaron que las nanopartículas habían sido atrapadas entre los electrodos tras depositarlas. Las mediciones a baja temperatura mostraron una disminución en la resistencia medida y la aparición de un \textit{Coulomb gap}, lo que sugiere transporte individual de electrones. Usando teoría ortodoxa, y la aproximación de condensador de placas paralelas, fue posible estimar que el tamaño del punto de contacto entre la nanopartícula y los electrodos estaba en el rango de $1$ a $2$ nm, lo cual tiene sentido dado el tamaño de las primeras.
Este trabajo ha sido financiado a través de los Proyectos Fondecyt 1140770 y DAFNEOX
13
Megliorini, Leonardo de Souza. "Produção de filmes de PBAT/PLA por eletrofiação para liberação de nitrofurazona." Universidade Estadual do Oeste do Paraná, 2018. http://tede.unioeste.br/handle/tede/4082.
Full textAbstract:
Submitted by Marilene Donadel (marilene.donadel@unioeste.br) on 2019-02-06T18:22:36Z
No. of bitstreams: 1
Leonardo_Megliorini_2018.pdf: 2265228 bytes, checksum: 5bec59af67778babe3b2590c1a6bf0f2 (MD5)Made available in DSpace on 2019-02-06T18:22:36Z (GMT). No. of bitstreams: 1 Leonardo_Megliorini_2018.pdf: 2265228 bytes, checksum: 5bec59af67778babe3b2590c1a6bf0f2 (MD5) Previous issue date: 2018-07-27
Nitrofurazone is a drug used to treat burns and skin transplants. The drug product is salled in cream and solution form. The ecovio® polymer is composed of poly(lactic acid) / poly(butylene adipate co-teraphtalate) and is biocompatible. In this work a film with the combination of ecovio® and nitrofurazone was produced by the electrospinning technique forming nanofibers. Two films were produced. The first was produced with dimethylformamide / tetrahydrofuran (15:85 v / v) and was capable of releasing 100% of the nitrofurazone reproducibly in the dissolution profile test evaluated for 300 minutes. The second film was produced with dimethylformamide/chloroform (15:85 v/v) and released about 90% of the nitrofurazone. But did not show reproducible results in the same range. Physicalchemical analyzes lead to the conclusion that the interaction of nitrofurazone with the polymer occurs mainly among the more polar groups. The dissolution test was performed following pharmacopoeial parameters. The quantitation of the released nitrofurazone was performed by UV-Vis spectrophotometry at 375 nm. The method used was validated and proved to be adequate, showing linearity in range 0.25 - 12.50 mg.L-1 with correlation coefficient 0.9999, high precision with relative standard deviation ≤ 1.6%, accuracy 98.9 - 100.4%, selectivity and limit of quantification 0.4 mg.L-1.
A nitrofurazona é um fármaco utilizado no tratamento de queimaduras e em transplantes de pele. O medicamento é comercializado na forma de pomada e solução. O polímero ecovio® é composto de poli(ácido lático)/poli(butileno adipato coteraftalato) e é biocompatível. Neste trabalho foi produzido um filme com a combinação de ecovio® e nitrofurazona pela técnica de eletrofiação formando nanofibras. Dois filmes foram produzidos. O primeiro foi produzido com dimetilformamida/tetrahidrofurano (15:85 v/v) e foi capaz de liberar 100% da nitrofurazona de forma reprodutível no teste de perfil de dissolução avaliado por 300 minutos. O segundo filme foi produzido com dimetilformamida/clorofórmio (15:85 v/v) e liberou cerca de 90% da nitrofurazona, mas não apresentou resultados reprodutíveis no mesmo intervalo. Análises físico-químicas levam à conclusão de que a interação da nitrofurazona com o polímero ocorre principalmente entre os grupamentos mais polares. O teste de dissolução foi realizado seguindo parâmetros farmacopeicos. A quantificação da nitrofurazona liberada foi realizada por espectrofotometria na região do UV-Vis em 375 nm. O método utilizado foi validado e comprovou-se estatisticamente que é adequado, apresentando linearidade no intervalo de 0,25 a 12,50 mg.L-1 com coeficiente de correlação de 0,9999, precisão elevada com desvio padrão relativo ≤ 1,6%, exatidão de 98,9 a 100,4%, seletividade e limite de quantificação de 0,4 mg.L-1.
14
Silva, Misael Leonardo. "Interação do adenovírus humano, sorotipo 41, com células origem hematopoiética: análise da permissividade celular e da expressão gênica viral." Universidade de São Paulo, 2008. http://www.teses.usp.br/teses/disponiveis/42/42132/tde-03062008-190643/.
Full textAbstract:
Para verificar a permissividade de células de origem hematopoiéticas à infecção por HAdV-41, foram infectados PBMC e IEL de voluntários. Os ensaios foram comparados com células HEK-293 infectadas. Foram analisadas as expressões dos genes virais E1A, E1B (55K), E3 (14K), VARNA, hexon e fibra curta (FC) e do gene celular GAPDH. O mRNA foi detectado por RT-PCR em tempo real e a produção de proteínas foi visualizada por IFI. Em HEK-293, a transcrição dos genes E1A, E1B e E3 iniciou-se às 11h p.i, hexon,às 13h pi.,VARNA e FC às 14h p.i. Em PBMC a transcrição de E1A, E1B e VARNA iniciou-se 17h p.i e a expressão dos genes hexon e fibra curta foi detectada 18h p.i e 20 h p.i. respectivamente. O nível de expressão dos genes virais em HEK-293 foi quase 200 vezes maior em relação à PBMC. Os IELs também mostraram-se permissivos à infecção pelo HAdV-41 como mostrado pela expressão dos genes virais. Essa é a primeira evidência de que este vírus possa infectar tais células. Os resultados obtidos ajudam a elucidar os mecanismos de interação do vírus com a célula-hospedeira.In order to verify the permissiveness of hematopoietic cells to HAdV-41 infection, PBMC and IEL from volunteers were infected. The infection assays were compared with infected HEK -293 cells. We analysed the E1A, E1B (55K), E3 (14K), VARNA, hexon and short fiber (SF) viral gene expression and GAPDH cellular gene expression. The mRNA were detected by real time PCR and the viral protein synthesis were detected by IIF. In HEK-293 cells E1A, E1B and E3 gene expression were detected 11h p.i Hexon gene expression was detected at 13h p.i, while VARNA and SF were detected 14h p.i In PBMC, E1A, E1B and VARNA gene expression were detected 17h p.i and the hexon and SF were detected 18h p.i and 20h p.i, respectively. The viral gene expression level in infected HEK-293 cells was 200 fold higher than infected PBMC. The IEL also were permissive to HAdV-41 infection showed by viral gene expressions. This is the first evidence that HAdV-41 is able to infect these cells types. These results helps to understand the virus-cell interaction mechanisms.
15
Boucher, Jérôme. "Feasibility studies of the pbar p -->pi0e+e- electromagnetic channel at PANDA." Phd thesis, Université Paris Sud - Paris XI, 2011. http://tel.archives-ouvertes.fr/tel-00662455.
Full textAbstract:
The proton is described by the electric G_E and magnetic G_M form factors which characterise its internal structure. The way to measure the proton form factors consists in measuring the angular distribution of the e-p elastic scattering accessing the so-called Space-Like region where q^2<0. Using the crossed channel pbar p<-->e+e-, one accesses another kinematical region, the so-called Time-Like region where q^2>0. However, due to the pbar p<-->e+e- threshold q^2_{th}, only the kinematical domain q^2>q^2_{th}>0 is available. To access the unphysical region, one may use the pbar p --> pi0e+e- reaction where the pi0 takes away a part of the system energy allowing q^2 to be varied between q^2_{th} and almost 0. This thesis aims to show the feasibility of such measurements with the PANDA detector which will be installed on the antiproton ring at the FAIR facility at Darmstadt. To describe the pbar p --> pi0e+e- reaction, a Lagrangian based approach is developed. The 5-fold differential cross section is determined and related to linear combinations of hadronic tensors. Under the assumption of one nucleon exchange, the hadronic tensors are expressed in terms of the 2 complex proton electromagnetic form factors. An extraction method which provides an access to the proton electromagnetic form factor ratio R=|G_E|/|G_M| and for the first time in an unpolarized experiment to the cosine of the phase difference is developed. Such measurements have never been performed in the unphysical region. Extended simulations were performed to show how the ratio R and the cosine can be extracted from the positron angular distribution. Furthermore, a model is developed for the pbar p-->pi0pi+pi- background reaction considered as the most dangerous one. The background contribution can be reduced to the percent level or even less. The corresponding signal efficiency ranges from a few % to 30%. The precision on the determination of the ratio R and of the cosine is determined using the expected counting rates via Monte Carlo method. A part of this thesis is also dedicated to more technical work with the study of the prototype of the electromagnetic calorimeter and the determination of its resolution.
16
Zehetmeyer, Gislene. "Desenvolvimento e caracterização de embalagens ativas compostas de PBAT com incorporação de nisina." reponame:Biblioteca Digital de Teses e Dissertações da UFRGS, 2016. http://hdl.handle.net/10183/143867.
Full textAbstract:
Neste trabalho foram preparados filmes biodegradáveis de poli(butileno adipato-co-tereftalato) (PBAT) com incorporação de um aditivo antimicrobiano (nisina), utilizando três diferentes metodologias. A primeira consiste na preparação dos filmes contendo nisina a partir do processamento no estado fundido utilizando uma extrusora dupla-rosca. A segunda fundamenta-se na preparação dos filmes utilizando a técnica de eletrofiação. Já a terceira, consiste na preparação de filmes bicamada como materiais de embalagens ativas. A morfologia destes filmes foi avaliada, bem como, as propriedades térmicas, estruturais, mecânicas e antimicrobianas. Além disso, a biodegradabilidade dos filmes extrudados foi investigada. As micrografias para todas as metodologias mostraram que a nisina apresentou-se bem dispersa na matriz do polímero, apresentando alguns aglomerados em amostras com maiores concentrações do aditivo. A temperatura de transição vítrea (Tg) e a temperatura de fusão (Tm) não foram afetadas pela incorporação da nisina nos filmes. A adição da nisina não causou modificação na resistência à tração dos filmes, por outro lado, a presença da bacteriocina causou uma pequena diminuição no alongamento na ruptura para as amostras mais concentradas de nisina quando comparadas àquelas do polímero puro. O módulo elástico foi alterado com a adição de nisina nos filmes, sugerindo uma leve redução na rigidez destes materiais. Os filmes ativos demonstraram inibição contra a bactéria Gram-positiva Listeria monocytogenes. A atividade antimicrobiana dos filmes foi investigada em soluções simulantes de alimentos e todas as amostras foram mais ativas em soluções contendo o surfactante Tween 20 ou ácido acético, aumentando até 48 h. A presença da nisina aumentou as propriedades de barreira ao oxigênio para os filmes de PBAT/nisina. A evolução da biodegradação pôde ser confirmada logo no decorrer de 30 dias, os filmes apresentavam indícios de biodegradação e mudança de coloração (manchas marrons) que indicam a ação de fungos. Os filmes bicamada apresentaram propriedades mecânicas elevadas em função da combinação dos filmes extrudados e eletrofiados. Por conseguinte, os filmes de PBAT/nisina apresentaram resultados promissores, indicando que estes novos materiais podem ser possivelmente empregados como materiais de embalagem ativa na indústria de alimentos visando o melhoramento da segurança alimentar e prolongando a vida de prateleira do produto embalado.In this study biodegradable films were developed composed by poly(butylene adipate-co-terephthalate) (PBAT) using an antimicrobial additive (nisin) at different concentrations through three different methodologies. In the first method, films were prepared from the melt processing technique using a twin-screw extruder. The second method was based on electrospinning technique. Finally, the third methodology consists of the preparation of active bilayer films composed by extruded and electrospun matrices. The film morphology was evaluated, as well as the structural, mechanical, thermal and antimicrobial properties. Furthermore, the biodegradability of the extruded films was investigated. The micrographs for films processed by extrusion and electrospinning showed that nisin was well dispersed in the polymer matrix, presenting some agglomerates when the nisin concentration was increased. The glass transition temperature (Tg) and melting temperature (Tm) were not affected by nisin incorporation. Besides, the addition of nisin did not change the tensile strength of the films. However, the presence of nisin in higher concentration caused a decrease in elongation at break. The Young’s modulus changed with presence of nisin, suggesting a slight reduction in stiffness of these materials. The active films demonstrated inhibition against Gram-positive bacteria Listeria monocytogenes. Antimicrobial activity of the films was investigated in food simulant solutions, all samples were more active in the surfactant solutions containing Tween 20 or acetic acid, increasing until 48 h. The presence of nisin increased oxygen barrier properties to PBAT/nisin films. The biodegradation was detected after 30 days, when the films showed changes on visual aspect, then confirming the fungi action. The bilayer films showed high mechanical properties due to the synergism of the films. Therefore, PBAT/nisin films showed promising results, indicating that these new materials may be possible used as active packaging materials in food industry aiming enhanced food safety and extending the shelf life of the packaged product.
17
Mançanares, Ana Carolina Furlanetto. "O estudo das células Tγδ na manutenção da tolerância materna em vacas gestantes." Universidade de São Paulo, 2016. http://www.teses.usp.br/teses/disponiveis/10/10132/tde-13052016-110412/.
Full textAbstract:
O sistema imunológico materno desempenha um papel importante no estabelecimento da gestação e desenvolvimento de concepto até início do parto. A hipótese deste projeto é que há um recrutamento de células Tγδ para o endométrio ao longo da gestação que expressam citocinas que favorecem o estabelecimento e manutenção da tolerância materna a antígenos fetais durante a gestação em bovinos. Experimento I Para estudar a dinâmica populacional das células do sistema imune no sangue periférico de não lactantes não prenhes (NLNP), vacas lactantes no 1º trimestre e vacas no 3º trimestre da gestação, as PBMCs foram separadas por gradiente de densidade de Ficoll, seguido por protocolo de imunocitoquímica e analisadas em citômetro de fluxo para os anticorpos CD3+, CD4+, CD8+, CD14+, CD25+ e WC1+. As células analisadas tanto na região de linfócitos quanto na região de monócitos, não apresentaram diferença significativa entre os grupos analisados. Experimento II Para análise do perfil de expressão gênica das células Tγδ, foram coletadas amostras de sangue de vacas no 1º trimestre da gestação, vacas lactantes não prenhes (LNP) e vacas não lactantes não prenhes (NLNP). As células mononucleares foram separadas por gradiente de densidade de Ficoll e células Tγδ foram analisadas quanto ao perfil de citocinas por qRT-PCR para os genes IFNG; IL10; IL15; IL17; IL18; IL1B; IL4; IL-6; ISG15; PFR; TGFB2 e TNFA. A análise de expressão gênica mostrou tendência no aumento na expressão de IL1B, IL6 e TGFB2 em células PBMC em vacas NLNP quando comparado com vacas LNP e no 1º trimestre da gestação, enquanto que os outros genes analisados não apresentaram diferença significativa. Experimento III Fragmentos de endométrio, provenientes de abatedouro, foram coletados de vacas em 1º trimestre (33 a 35 dias de gestação), 2º trimestre (143 a 182 dias de gestação) e 3º trimestre de gestação (228 a 247 dias de gestação). Cortes congelados foram imunolocalizados e quantificados para as células do sistema imune CD3+, CD4+, CD8+, CD14+, CD18+, CD25+, CD62L+ e WC1+ por imunofluorescência. Nossos estudos mostraram aumento das células CD25+ e CD62L+ no endométrio no início da gestação. No meio da gestação, há um aumento das células WC1+ e CD14+. No final da gestação, observamos o aumento de CD14+, CD25+, CD18+ e CD62L+. Em suma, nossos dados sugerem que a modulação do sistema imune materno é específica para cada estágio da gestação, sendo que no início da gestação há um envolvimento de células T ativadas (CD25+) provavelmente para o estabelecimento de uma resposta ativa para tolerância dos antígenos fetais. Já no meio da gestação, há um recrutamento massivo de células Tγδ para o endométrio gravídico provavelmente para manter um microambiente de tolerância para o desenvolvimento fetal e no final da gestação células efetoras como macrófagos são recrutadas para o endométrio para auxiliar no processo do parto e involução uterina.The maternal immune system plays an important role on the establishment and maintenance of pregnancy until the onset of parturition in mammals. Our hypothesis is that there is a recruitment of γδT-cell to the endometrium during pregnancy. These cells express a particular cytokine profile that is important to the establishment and maintenance of maternal toleranceto fetal antigens in cattle. Experiment I - To study the population dynamics of immune cells in the peripheral blood of NLNP, 1st and 3rd trimester of pregnancy, PBMCs were separated by Ficoll density gradient and the abundance of CD3+, CD4+, CD8+, CD14+, CD25+ and WC1+ was analyzed by single-color flow cytometry. There was no statistical difference of the abundance of CD3+, CD4+, CD8+ and CD25+ among groups of cows. Experiment II To analyze the gene expression profile of 1st trimester, LNP and NLNP. PBMCs were isolated by Ficoll density gradient and γδT-cells (WC1+) were enriched by magnetic cell sorting. Both PBMC and WC1+ cells gene expression was analyzed for IFNG; IL10; IL15; IL17; IL18; IL1B; IL4; IL-6; ISG15; PFR; TGFB2 and TNFA by qRT-PCR. Gene expression analysis showed increased expression of the IL1B, IL6 and TGFB2 in PBMC in NLNP compared with 1st trimester of pregnancy and LNP cows, while other genes analyzed showed no significant difference. Experiment III fragments of endometrium were collected from cows at the early (33 to 35 days of pregnancy), mid (143 to 182 days of pregnancy) and late pregnancy (228 to 247 days of pregnancy). Endometrial immune cells were quantified (CD3+, CD4+, CD8+, CD14+, CD18+, CD25+, CD62L+, and WC1+) by single-color immunofluorescence. There was an increase CD25+ and CD62L+ cells in the endometrium in early pregnancy. In the mid of pregnancy, there was an increase of WC1+ and CD14+ cells. At the end of pregnancy, there was an increase of CD14+, CD25+, CD18+ and CD62L+. In conclusion, our data suggest that the maternal immune system is modulated according to the stage of pregnancy in the cow. In early pregnancy, there is an increased number of endometrial CD25+ cells that may reflect the activation of local immune response and recruitment of putative T-reg cells to the endometrium for an active establishment of maternal tolerance to fetal antigens. While, in mid pregnancy there is a massive recruitment of γδT-cells and CD14+ to the pregnant endometrium perhaps to maintain an tolerogenic microenvironment and to promote tissue remodeling for proper fetal development and growth. Finally, in late pregnancy, there is a recruitment of effector immune cells such as CD62L+, CD18 and CD14+ cells associated with an increased expression of proinflammatory cytokines (i.e. IFNG, IL-6) to play a role on induction of parturition and uterine involution in the cow
18
Felix, Daniel André. "PBC and MEIS class genes in the planarian Schmidtea mediterranea." Thesis, University of Nottingham, 2011. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.575479.
Full textAbstract:
Planarians have outstanding regenerative capabilities which depend on the presence of a pool of somatic stem cells. In addition planarians keep perfect proportion of the body while degrowing during starvation. While the establishment and maintenance of the anteroposterior (AlP) axis has been shown to depend on Wnt and Hedgehog signalling, not much is known about the subsequent patterning events. PBC and MEIS class genes are evolutionary conserved TALE homeobox genes with important functions in patteming and cell differentiation. They are well known co-factors of the Hox genes however they also have other Hox-independent functions. The aim of this study was to identify the planarian orthologs of the PBC and MEIS class genes and to examine their putative role in anteroposterior patteming. Here one PBC class gene, Smed-pbx, and the three MEIS class genes Smed-meis I , Smed-meis2 and Smed-prep were identified and orthology established through phylogenetic analyses. Smed-prep was found to define the cephalic area in which the anterior structures are formed, most prominently the brain. In anterior regenerating Smed-prep(RNAi) worms a reduction or even complete absence of the brain and anterior markers was observed. Importantly, the differentiation of stem cells into nerve cells was shown not to be dependent on Smed-prep. In step with its function the Smed-prep gene was found to have an anteroposterior bias in expression, being highly expressed in the head. While both Smed-meis genes were found to be important for regeneration and maintenance of the eyes and for the adaptation of the body to the new size of the animal after amputation, Smed-pbx was found to have pleiotropic functions, phenocopying aspects of all three MEIS class genes upon RNAi interference, and also producing additional phenotypes. This study has found that the four planarian orthologs of PBC and MEIS class genes are important players in regeneration. Two genes, Smed-pbx and especially Smed-prep, have been found to be necessary for anteroposterior patterning. This is the first time that a homeobox transcription factor has been directly implicated in anteroposterior patterning in planarians.
19
Kronsbein, Juliane. "Einfluss einer RSV-Exposition auf das Zytokinmuster humaner T-Lymphozyten und PBMC in vitro." [S.l.] : [s.n.], 2004. http://deposit.ddb.de/cgi-bin/dokserv?idn=975113704.
Full text
20
Kuchnier, Caroline Nogueira 1983. "Estudo do efeito de aditivo extensor de cadeia multifuncional em blendas de PLA/PBAT." [s.n.], 2014. http://repositorio.unicamp.br/jspui/handle/REPOSIP/266107.
Full textAbstract:
Orientador: Ana Rita MoralesDissertação (mestrado) - Universidade Estadual de Campinas, Faculdade de Engenharia Química
Made available in DSpace on 2018-08-25T08:54:32Z (GMT). No. of bitstreams: 1 Kuchnier_CarolineNogueira_M.pdf: 6599109 bytes, checksum: 59b6eb5172349da253716bfd2081593a (MD5) Previous issue date: 2014
Resumo: O poli(ácido lático), PLA, é um polímero biodegradável muito promissor para aplicações industriais e médicas. Contudo, algumas de suas características, como fragilidade à temperatura ambiente limitam sua potencial utilização e restringem sua degradação às condições de compostagem. Para promover modificações de propriedades do PLA este trabalho tem como objetivo o estudo de blendas com Poli(adipato-co-tereftalato de butileno), PBAT, outro polímero biodegradável. Buscou-se ainda, melhorar a compatibilidade entre os dois polímeros com a utilização do agente extensor de cadeia multifuncional Joncryl ADR-4368, que contém grupos epóxido reativos. Dois tipos de processamento foram adotados: em homogeneizador Drais e em reômetro de torque. Amostras dos polímeros puros e blendas em diferentes composições foram preparadas com e sem adição do extensor de cadeia. Na análise de calorimetria diferencial de varredura (DSC), a temperatura de transição vítrea (Tg) dos polímeros originais mostraram-se inalteradas nas blendas e revelou a imiscibilidade entre PLA e PBAT. O comportamento associado à fração cristalina apresentou variações em função da composição dos polímeros nas blendas e as transições térmicas não foram alteradas pelo extensor de cadeia. Análises de termogravimetria (TGA) mostraram o efeito de aumento na estabilidade térmica gerada pelo extensor de cadeia e o aumento da degradação térmica no processamento por injeção. A espectroscopia do infravermelho (FTIR) mostrou que grupos epóxido podem ter reagido com carboxilas e hidroxilas dos polímeros. A cromatografia por permeação em gel (GPC) mostrou que o extensor de cadeia promoveu aumento na massa molar do PLA, mas não apresentou o mesmo efeito no PBAT. Pela microscopia eletrônica de varredura (SEM), observou-se a presença de duas fases distintas. O extensor de cadeia promoveu a diminuição significativa no tamanho dos domínios da fase dispersa. Ensaios de resistência à tração mostraram que o PBAT aumentou a flexibilidade do PLA. Testes de resistência ao impacto mostraram aumento na resistência mecânica do PLA pela incorporação do PBAT. O extensor de cadeia reduziu a flexibilidade do PLA puro, mas aumentou a flexibilidade e a resistência mecânica nas blendas PLA/PBAT. Palavras-chave: Blendas poliméricas, plástico biodegradável, poli(ácido lático), aditivos
Abstract: Poly (latic acid) (PLA) is an attractive biodegradable polymer for industrial and medical applications. Although, some PLA properties like brittleness at room temperature restrict its potential applications and limit its full degradation only for composting conditions. The purpose of this work is to promote modifications in PLA properties by blending it with other biodegradable polymer, Poly (butylene-adipate-co-terephtalate) (PBAT). Joncryl ADR-4368, a multifunctional chain extender with epoxy functional groups was also used to increase polymers compatibility. Two processing methods were adopted: the samples in different compositions were processed in Drais homogenizer and torque reometer. Polymers and blends were processed with and without the chain extender. Differential Scanning Calorimetry (DSC) showed that the glass transition temperature (Tg) of the polymers did not change, which reveals immiscibility between PLA and PBAT. The behavior of the crystalline fraction exhibited variations depending on the composition of the blends and thermal transitions were not changed by chain extender. Thermo gravimetric analysis (TGA) showed that the chain extender caused an increase on thermal stability, and an increase of thermal degradation caused by injection molding processing. Infrared spectroscopy (FTIR) indicated that epoxy groups may be reacted with carboxyl and hydroxyl polymers functional groups. Gel permeation chromatograph (GPC) revealed that chain extender promoted molecular weight increasing in PLA but did not have the same effect on PBAT. Using Scanning electron microscopy (SEM) two phases morphology was detected. Chain extender promoted remarkable domains size reduction of the dispersed phase. Tensile strength tests demonstrated that PBAT enhanced flexibility and reduced brittleness of PLA. Impact strength tests showed an increment on PLA strength due to the presence of the PBAT. Chain extender reduced flexibility of PLA but also increased flexibility and tensile strength in PLA/PBAT blends. Keywords: polymer blends, biodegradable plastic, poly (latic acid), additives
Mestrado
Ciencia e Tecnologia de Materiais
Mestra em Engenharia Química
21
Pozza, Junior Mario Cezar. "Caracterização e aplicação de fibras obtidas por eletrofiação de PLA/PBAT com grafite incorporado." Universidade Estadual do Oeste do Paraná, 2018. http://tede.unioeste.br/handle/tede/3765.
Full textAbstract:
Submitted by Marilene Donadel (marilene.donadel@unioeste.br) on 2018-06-15T23:20:03Z
No. of bitstreams: 1
Mario_Pozza_Junior_2018.pdf: 2690359 bytes, checksum: 4ed77b14d4ddbed87c7173f8cce14179 (MD5)Made available in DSpace on 2018-06-15T23:20:03Z (GMT). No. of bitstreams: 1 Mario_Pozza_Junior_2018.pdf: 2690359 bytes, checksum: 4ed77b14d4ddbed87c7173f8cce14179 (MD5) Previous issue date: 2018-03-23
Conselho Nacional de Pesquisa e Desenvolvimento Científico e Tecnológico - CNPq
The need for new tools to detect pollutants and of importance in the subject, electrochemical sensors are shown as a great alternative, considering its low cost, good limits of detection, and speed of analysis. An electro-spinning technique is a small fiber production technique where many possibilities for a sensor construction are offered, mainly using biodegradable polymers. This work has the objective of incorporating polymeric fibers with graphite optimized by an electrochemical technique, as well as an electrochemical sensor capable of obtaining a detection limit for the 2,4,6-trichlorophenol compound. A total of 35 experiments were carried out, using five different electrophilic techniques (needle distance to the collector, flow, tension, % of polymers, and % of graphite), as fibers as morphologically characterized using optical microscopy, SEM and a test of Wettability. For physical e structural analyzes, DSC, TGA and FTIR analyzes were performed, where it was sought to know if the incorporation of graphite into the polymer is capable of altering its structure. Then, for a sensor construction, a membrane obtained by electrospinning was then subjected to a heat treatment of 500°C for 3 hours, the powder obtained was mixed with the Nujol® wetting agent, thereby forming a uniform paste which was inserted into the End of a hypodermic plastic syringe with a silver wire for electrical contact, being manually pressed. The electrode was subjected to a characterization and an evaluation where a limit of detection was established for compound 2,4,6-TCP, in addition to a test with real samples collected in water treatment station supply. The minimum diameter obtained in the fibers was 1.49μm, using where the stress and voltage flows interacted, showing the effect of the second most significant order among all. As it analyzes morphologically revealed that a graphite incorporation has given the polymer membrane new characteristics to the surface, while as thermal analyzes show what is graphite changing a structure of the fibers when incorporated as its own. The only oxidation pic viewed with the Cyclic Voltammetry analysis characterizated the sensor containing a irreversible behavior face to 2,4,6-TCP. Based on the Square Wave Voltammetry analyzes, was obtained a detection limit for the 2,4,6-TCP of 1x10-7 mol.L-1 and showed a detection of the concentration test of 6x10-7 mol.L-1, with recovery rates of water samples between 80 and 93%, both in accordance with current Brazilian legislation.
A necessidade de novas ferramentas para detecção de poluentes é de suma importância atualmente, neste quesito, sensores eletroquímicos se mostram como uma ótima alternativa, tendo em vista seu baixo custo, bons limites de detecção, e rapidez na análise. A eletrofiação é uma técnica de produção de fibras em pequenas escalas onde muitas possiblidades para a construção de sensores são ofertadas, principalmente utilizando polímeros biodegradáveis. Este trabalho tem por objetivo obter fibras poliméricas incorporadas com grafite de forma otimizada pela técnica de eletrofiação, além de desenvolver um sensor eletroquímico capaz de obter um limite de detecção para o composto 2,4,6-Triclorofenol. Foram realizados 35 ensaios utilizando cinco diferentes parâmetros para eletrofiação (Distância da agulha ao coletor, fluxo, tensão, % de polímeros, e % de grafite), as fibras foram caracterizadas morfologicamente utilizando microscópio óptico, MEV, e um teste de molhabilidade. Para as análises físicas e estruturais, foram realizadas analises de DSC, TGA e FTIR, onde buscou-se saber se a incorporação de grafite ao polímero foi capaz de alterar sua estrutura. Depois, para a construção do sensor, a membrana obtida por eletrofiação foi então submetida a um tratamento térmico de 500°C por 3 horas, e o pó obtido foi misturado ao agente umectante Nujol®, formando assim uma pasta uniforme que foi inserida no interior da extremidade de uma seringa plástica hipodérmica com um fio de prata para o contato elétrico, sendo prensada manualmente. O eletrodo foi submetido a uma avaliação onde estabeleceu-se uma caracterização e um limite de detecção para o composto 2,4,6-TCP, além de um teste com amostras reais coletadas em estação de tratamento de águas de abastecimento. O Diâmetro mínimo obtido nas fibras foi de 1.49μm onde os parâmetros fluxo e tensão interagiram apresentando o efeito de segunda ordem mais significativo entre todos. As analises morfológicas revelaram que a incorporação de grafite concedeu a membrana polimérica novas características a superfície, enquanto que as análises térmicas mostraram que o grafite alterou a estrutura das fibras quando incorporado as mesmas. Ao obter apenas um pico de oxidação com a análise de voltametria cíclica o sensor apresentou um comportamento irreversível frente ao 2,4,6-TCP. Já com base nas análises de voltametria de onda quadrada obteve-se com o sensor um limite de detecção para 2,4,6-TCP de 1x10-7 mol.L-1 e o teste com águas de abastecimento detectou a concentração de 6x10-7 mol.L-1, com taxas de recuperação das amostras de água tratada entre 80 e 93%, ambas em concordância com a legislação brasileira vigente.
22
Oliveira, Marcelo Ferreira Leão de. "Preparação, caracterização e avaliação de nanocompósitos de PBAT/amido de milho e vermiculita organofilizada." Universidade do Estado do Rio de Janeiro, 2015. http://www.bdtd.uerj.br/tde_busca/arquivo.php?codArquivo=9360.
Full textAbstract:
Coordenação de Aperfeiçoamento de Pessoal de Nível SuperiorNos últimos 20-30 anos polímeros biodegradáveis vêm sendo estudados e desenvolvidos e atualmente já são comercializados. Contudo, o custo, a processabilidade e algumas propriedades ainda dificultam a penetração desses polímeros no mercado e a competição com as chamadas commodities. Não são poucos os autores que se dedicam a desenvolver aditivos e formulações para superar essas limitações. Desta forma, esta Tese se dedicou ao desenvolvimento de compósitos de Ecobras, fabricado pela Basf e comercializado pela Corn Products, utilizando como carga mineral resíduo da extração da bauxita, no município de Santa Luzia/PB, o qual consiste em sua totalidade de vermiculita. Esta vermiculita foi quimicamente modificada com sais de alquil fosfônio para melhorar a compatibilidade com a matriz polimérica e também espaçar as camadas de aluminossilicato. De fato, a modificação com o brometo de hexadecil tributil fosfônio resultou na esfoliação da vermiculita tornando-a potencialmente apropriada para a obtenção de nanocompósitos. A preparação dos compósitos foi realizada pelo método de intercalação no estado fundido e foram comparadas a utilização da câmara interna de mistura e da mini extrusora de dupla rosca, sendo esta última mais eficaz na dispersão da vermiculita, conforme revelado pela microscopia eletrônica de varredura, difração de raios-X e reometria de placas. O grau de dispersão também foi influenciado pela estrutura química do modificador da vermiculita e pelo teor dessa carga incorporada à matriz. Teores mais elevados levaram a formação de aglomerados, enquanto a modificação da carga implicou na formação de micro e nanocompósitos. Ainda houve alterações das propriedades térmicas com aumento dos valores da temperatura de transição vítrea, de cristalização e fusão, embora o grau de cristalinidade tenha sido mantido. Nitidamente, foram obtidos materiais mais rígidos, com maior módulo e menor capacidade de deformação. Cerca de 58% de perda de massa foi observada para os micro e nanocompósitos obtidos após 17 semanas de enterro em solo simulado para avaliação da biodegradabilidade, valor bem próximo ao Ecobras puro. De modo geral, a incorporação das diferentes vermiculitas retardou nas primeiras semanas a biodegradação, provavelmente em função de modificações na estrutura cristalina, conforme sugerido pelos maiores valores de temperatura de fusão observados durante o acompanhamento do processo de biodegradação. No entanto, após 7 semanas os perfis de biodegradação dos micro e nanocompósitos se aproximaram bastante do Ecobras puro. Desta forma, foi possível nesta Tese obter um nanocompósito de Ecobras com vermiculita modificada com brometo de hexadecil fosfônio utilizando ferramentas comuns de processamento no estado fundido com biodegradabilidade próxima ao polímero de partida, porém mais rígido e menos deformável
In the last 20-30 years biodegradable polymers have been studied and developed and currently are already commercialized. However, cost, processability and some properties still avoid the penetration of such polymers on the market and the competition with the so-called commodity. There are few authors who are dedicated to developing additives and formulations to overcome these limitations. Thus, this thesis is devoted to the development of Ecobras composites, blend of PBAT and starch manufactured by BASF and commercialized by Corn Products, using as mineral filler a residue of bauxite extraction from Santa Luzia / PB, which consists entirely of vermiculite. The vermiculite was chemically modified with alkyl phosphonium salts to improve compatibility with the polymer matrix, and also to increase the space between aluminosilicate layers. In fact, its modification with hexadecyl tributyl phosphonium bromide promoted the exfoliation of vermiculite making it potentially suitable for obtaining a nanocomposite. The preparation of the composites was performed by the melt intercalation technique. Internal mixing chamber and a twin screw mini-extruder were compared as processing tool, the latter was more effective in dispersing the vermiculite, as revealed by scanning electron microscopy, X-ray diffraction and plate rheometry. The degree of dispersion was also influenced by the amount and chemical structure of the vermiculite. Higher filler levels led to formation of agglomerates, while filler modification led to formation of micro and nanocomposites. There were changes in the thermal properties with increasing temperature values of glass transition, crystallization and melting, although the degree of crystallinity has been retained. Clearly, stiffer materials were obtained, with a higher modulus and low strain capacity. About 58% of weight loss was observed for micro and nanocomposites after 17 weeks of burial in simulated soil for evaluation of biodegradability, very close to pure Ecobras value. Generally, the incorporation of different vermiculite delayed biodegradation in the first weeks, probably due to changes in crystalline structure as suggested by the higher melting temperature values observed during the monitoring of the biodegradation process. However, after seven weeks of the micro and nanocomposites biodegradation profiles approached quite to pure Ecobras. Thus, it was possible in this work obtain a Ecobras nanocomposite with hexadecyl tetrabutyl phosphonium bromide modified vermiculite prepared by melt intercalation technique using common processing tools and with biodegradability close the starting polymer, but more rigid and less deformable
23
Nossa, Tamires de Souza. "Novas composições poliméricas obtidas a partir da modificação do amido via extrusão reativa." Universidade de São Paulo, 2014. http://www.teses.usp.br/teses/disponiveis/18/18158/tde-09012015-104750/.
Full textAbstract:
O amido termoplástico (TPS) é um material biodegradável, de baixo custo, com grande potencial para aplicação na composição de plásticos biodegradáveis. Muitos estudos têm sido realizados no sentido de melhorar algumas de suas propriedades, principalmente a sua baixa resistência mecânica, elevada hidrofilicidade, e baixa miscibilidade com polímeros comerciais, fatores que dificultam a ampliação da utilização desse material como plástico biodegradável. Uma alternativa para melhorar tais propriedades, é a produção de blendas destes materiais com outros polímeros. Contudo, quando a natureza química dos materiais a serem combinados é muito diversa, faz-se necessário compatibilizar os materiais, em geral obtida pela adição de agentes compatibilizantes ou promovendo reações durante a extrusão, processo denominado compatibilização reativa. No trabalho, diferentes alternativas foram investigadas com o intuito de aumentar o potencial de aplicação do amido, entre elas: o efeito do ácido cítrico na modificação do amido; o uso da ureia para estabilização da massa molar do amido via extrusão reativa permitindo seu reprocessamento; a modificação do amido com ácido cítrico e ou 4,4\'-difenil metano diisocianato e o uso de dois processos de extrusão reativa para produção do amido termoplástico; a produção de blendas de amido com poli(butileno adpato co-tereftalato) e poli(ácido lático); a produção do amido termoplástico com reticulação termorreversível pela incorporação de reações de Diels-Alder. Foram feitas diversas caracterizações entre elas, análise das propriedades térmicas por meio das técnicas de termogravimetria (TGA), calorimetria exploratória diferencial (DSC), análise dinâmicomecânica (DMA) ensaios mecânicos, absorção de umidade, espectroscopia de infravermelho por transformada de Fourier (FTIR), microscopia eletrônica de varredura (MEV), análises reológicas, cromatografia (HPSEC) e viscosimetria. Os resultados das investigações contribuíram para o desenvolvimento de novos polímeros termoplásticos ou termorrígidos a base de amido de milho e esclareceram questões não abordadas na literatura, sobre a modificação do amido via processo de extrusão reativa.Thermoplastic starch (TPS) is a biodegradable material, inexpensive, with high potential of usage in the biodegradable plastics composition. Many studies have been performed to improve some properties, mainly its low mechanical strength, high hydrophilicity and low miscibility with commercial polymers, factors that hinder the usage expansion such material as plastic. An alternative to improve these properties is the polymer blends of starch production with other polymers. However, when the materials chemical nature is quite variable then is necessary to make the polymers compatible. Usually, the reactive compatibility is obtained by the addition of coupling agents or promoting reactions during extrusion. In the present study, new alternatives were studied in order to increase the starch application potential including: the citric acid effect on starch modification; use of urea to stabilize the starch molecular weight by reactive extrusion allowing its reprocessing; the starch modification with citric acid and 4,4\'-diphenyl methane diisocyanate and the use of two reactive extrusion processes for thermoplastic starch producing; starch blends production with poly (butylene adipate co-terephthalate) and poly (lactic acid); the starch modification by incorporating crosslinking thermoreversible Diels-Alder adduct. Several characterizations were made including thermal analysis by means of thermogravimetry (TGA), differential scanning calorimetry (DSC), dynamical mechanical analysis (DMA) mechanical testing, moisture absorption, Fourier transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM), rheology analysis, chromatography (HPSEC) and viscometry. The research results have contributed to the development of new thermoplastic polymers or thermosetting from corn starch and helped to clarify issues not addressed in the literature about the starch modification by reactive extrusion process.
24
Lu, Daoqiang. "Synthesis and characterization of a star-like poly(p-Benzamide) (PBA)." Thesis, Georgia Institute of Technology, 1996. http://hdl.handle.net/1853/8604.
Full text
25
Schmiech, Peter [Verfasser]. "Zur Vorhersage des Kristallhabitus unter Fremdstoffeinfluss mittels PBC-Vektoren / Peter Schmiech." Aachen : Shaker, 2005. http://d-nb.info/1181614430/34.
Full text
26
Popayán, Avila Jhossep Augusto. "Contributions to ida-pbc with adaptive control for underactuated mechanical systems." Master's thesis, Pontificia Universidad Católica del Perú, 2018. http://tesis.pucp.edu.pe/repositorio/handle/123456789/12894.
Full textAbstract:
This master thesis is devoted to developing an adaptive control scheme for the well-
known Interconnection and Damping Assignment Passivity-Based Control (IDA-PBC) technique. The main
objective of this adaptive scheme is to asymptotically stabilize a class of Underactuated
Mechanical Systems (UMSs) in the presence of uncertainties (not necessarily matched). This class of
UMSs is characterized by the solvability of the Partial Differential Equation (PDE) resulting from
the IDA-PBC technique. Two propositions are stated in this work to design the adaptive IDA-PBC. One
of the main properties of these propositions is that even though the parameter estimation conver-
gence is not guaranteed, the adaptive IDA-PBC achieves asymptotic stabilization. To illustrate the
effectiveness of these propositions, this work performs simulations of the Inertia Wheel Inverted
Pendulum (IWIP) system, considering a time-dependent input disturbance, a type of physical damping,
i.e., friction (not considered in the standard
IDA-PBC methodology), and parameter uncertainties in the system (e.g., inertia).Tesis
27
Vidal, Sandoval Jesus Enrique. "Implicit IDA-PBC Design and Implementation for a Portal Crane System." Master's thesis, Pontificia Universidad Católica del Perú, 2019. http://hdl.handle.net/20.500.12404/15353.
Full textAbstract:
Interconnection and damping assignment passivity-based control (IDA-PBC) is a wellknown technique which regulates the behavior of nonlinear systems, assigning a target port-Hamiltonian (pH) structure to the closed-loop. In underactuated mechanical systems (UMSs) its application requires the satisfaction of matching conditions, which in many cases demands to solve partial differential equations (PDEs). Only recently, the IDA-PBC has been extended to UMSs modeled implicitly, where the system dynamics
in pH representation are described by a set of differential-algebraic equations (DAEs). In some system classes this implicit approach allows to circumvent the PDE problem and also to design an output-feedback law. The present thesis deals with the design and implementation of the total energy shaping
implicit IDA-PBC on a portal crane system located at the laboratory of the Control Engineering Group at TU-Ilmenau. The implicit controller is additionally compared with a simplified (explicit) IDA-PBC [1]. This algorithm shapes the total energy and avoids the PDE problem. However, this thesis reveales a significant implementation flaw in the algorithm, which then could be solved.Interconnection and damping assignment passivity-based control (IDA-PBC) ist eine wohlbekannte Methode zur Regelung von nichtlinearen Systemen, die im geschlossenen Regelkreis eine gewünschte Port-Hamiltonian-Struktur (pH) haben. Die Anwendung auf unteraktuierte mechanische Systeme (UMS) erfordert die Erfüllung von sogenannten Matching Conditions, die meistens die Lösung partieller Differentialgleichungen (PDE) benötigt. Erst kürzlich wurde die IDA-PBC auf implizit modellierte UMS erweitert, bei denen die Systemdynamik in pH-Darstellungen durch Differentialalgebraische Gleichungen (DAE) beschrieben wird. Dieser implizite Ansatz ermöglicht bei einigen Systemklassen, das PDE-Problem zu umgehen und auch eine Ausgangsrückführung zu entwerfen. Die vorliegende Masterarbeit beschäftigt sich mit dem Entwurf und der Implementierung des impliziten IDA-PBC zur Gesamtenergievorgabe auf einem Portalkransystem im Labor des Fachgebiets Regelungstechnik der TU-Ilmenau. Der implizite Regler wird mit einem vereinfachten (expliziten) IDA-PBC verglichen [1]. Dieser Algorithmus gibt ebenso die Gesamtenergie vor und vermeidet das PDE-Problem. In der Masterarbeit wird in diesem Algorithmus ein wesentlicher Implementierungsfehler offengelegt und behoben.
Tesis
28
Cron, Mélanie. "Implication of microRNAs in the pathophysiology of autoimmune Myasthenia Gravis Analysis of microRNA expression in the thymus of Myasthenia Gravis patients opens new research avenues Use of Toll-like receptor agonists to induce ectopic lymphoid structures in Myasthenia gravis Mouse Models." Thesis, Sorbonne université, 2018. http://www.theses.fr/2018SORUS395.
Full textAbstract:
La Myasthénie auto-immune (MG), caractérisée par des auto-anticorps dirigés contre le récepteur à l’acétylcholine à la jonction neuromusculaire, est une maladie rare entraînant des faiblesses musculaires. Cette étude présente l’implication de petits ARN non-codants, les microARN, dans la physiopathologie de la MG. Nous avons étudié l’expression de microARN dérégulés dans l’organe effecteur de la maladie, le thymus, via une analyse du miRnome. J’ai mis en évidence 1) que miR-7-5p participerait à la mise en place des anomalies thymiques observées chez les patients de par son action sur CCL21, 2) la sous-expression de deux clusters de microARN du chromosome X, et 3) une nouvelle une voie de signalisation inflammatoire dans la MG impliquant miR-125a-5p et WDR1. J’ai aussi étudié la sensibilité de souris miR-29a KO au modèle expérimental de la MG. En effet, miR-29a est sous-exprimé dans le thymus MG et module la signalisation de l’interféron de type 1, impliqué dans les changements thymiques. Enfin, j’ai étudié les causes et conséquences de la sur-expression sérique de miR-150-5p, caractérisé comme un biomarqueur dans la MG. Nous avons montré que l’expression de miR-150-5p est augmentée dans le thymus MG et corrélée à la présence de centres germinatifs ectopiques. De plus, miR-150-5p est sous-exprimé dans les cellules T CD4 dans le sang des patients. Une fois libéré dans le sérum, miR-150 module l’expression de gènes cibles, tels que MYB, et est impliqué dans la survie des cellules CD4 et CD8. Ces études permettent de mieux comprendre comment les microARN participent à la physiopathologie de la MG et m’ont permis d’ouvrir de nouvelles voies de recherche dans la MGAutoimmune Myasthenia Gravis (MG), characterized by autoantibodies directed against the acetylcholine receptor at the neuromuscular junction, is a rare disease causing muscular weaknesses. This study shows the involvement of small non coding RNAs, miRNAs, in the pathophysiology of MG. We investigated the expression of dysregulated miRNAs in the effector organ of the disease, the thymus, through a miRnome analysis. I showed 1) that miR-7-5p could participate in thymic abnormalities observed in patients through its action on CCL21, 2) the down-regulation of two miRNA clusters on chromosome X and, 3) a new MG inflammatory pathway involving miR-125a-5p and WDR1. I also studied the sensitivity of miR-29a KO mice to the experimental model of MG. Indeed, miR-29a is down-regulated in MG thymuses and modulates type 1 interferon pathway, involved in thymic changes. Finally, I investigated the causes and consequences of the serum overexpression of miR-150-5p, characterized as a biomarker in MG. We showed that miR-150 is overexpressed in MG thymuses and correlated to the presence of ectopic germinal centers. Moreover, miR-150 is down-regulated in CD4+T cells, in the blood of patients. Once in the serum, miR-150 modulated the expression of target genes, such as MYB, and is involved in the survival of CD4+ and CD8+ T cells. These studies allows a better understanding of how miRNAs are involved in the pathophysiology of MG and allowed us to open new research avenues in MG
29
Siddique, Manazzar T. "Interactions of caboxylated acrylic polymer latex particles with hydrating portland cement materials." Thesis, University of Bristol, 1999. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.297921.
Full text
30
Gupta, Priyanka. "Host gene expression and its regulation by microRNA in HCV and HIV/HCV co-infection." Thesis, The University of Sydney, 2014. http://hdl.handle.net/2123/11998.
Full textAbstract:
HCV infection is prevalent and long-term infection may lead to liver cirrhosis and hepatocellular carcinoma (HCC). HIV/HCV co-infection has been shown to accelerate progression of HCV associated liver disease, and HCV in exacerbating hepatotoxicity of antiretroviral therapy. Both viruses are able to manipulate the host gene expression (mRNA) and regulatory (miRNA) machinery. It remains unclear how the regulation of mRNA expression is governed in HCV-infected Peripheral Blood Mononuclear Cells (PBMC) and liver tissue (tumor and non-tumor). This may help explain the cross-talk between PBMC and liver for predicting early events guiding the development of cirrhosis and HCC. Differentially expressed (DE) genes and miRNAs in each group comparison were also validated by Polymerase Chain reaction (PCR). We identified significant interactions between the DE miRNAs and genes with Bayesian network analysis. Selected miRNA: mRNA interactions were validated with the dual luciferase reporter assay that showed negative regulatory effect on the gene targets. Overall, this study has helped to not only define the utility of PBMCs in predicting early genomic events guiding cirrhosis and HCC in liver tissue in HCV-infected patients, but also showed evidence for mono and co-infection specific genes and miRNAs, which may help develop new generation of biomarkers for prognosis.
31
AGOSTINI, L. P. "AMENDMENT Of Gene Expression In Mononuclear Cells Of Human Peripheral Blood Submitted To Exposure With Herbicide Based On Glyphosate." Universidade Federal do Espírito Santo, 2018. http://repositorio.ufes.br/handle/10/10333.
Full textAbstract:
Made available in DSpace on 2018-08-27T13:37:21Z (GMT). No. of bitstreams: 1
tese_12502_Tese - Lidiane Pignaton Agostini.pdf: 2963143 bytes, checksum: 76cc790c5543c25d309bc0feced39101 (MD5)
Previous issue date: 2018-06-27O Glifosato [N-(fosfonometil)glicina] é um herbicida pós-emergente, não seletivo e sistêmico. No processo de criação das formulações comerciais de herbicidas a base de glifosato (GBHs, do inglês glyphosate-based herbicides), como o Roundup®, são adicionados surfactantes com o intuito de aumentar a eficiência do composto base. A rota prioritária de degradação do glifosato por micro-organismos no solo resulta na formação do ácido aminometilfosfônico (AMPA). As respostas moleculares ao glifosato têm sido extensivamente estudadas em espécies de plantas e em alguns vertebrados. Em humanos, apesar dos estudos até agora realizados, não se conhece exatamente quais os riscos e mecanismos de atuação que explicariam a toxicidade ao glifosato relatada em alguns experimentos. Sendo assim, a hipótese dessa tese é de que a exposição rápida ao Roundup® e ao AMPA leva à alterações de expressão gênica em importantes processos celulares. Dessa forma, o objetivo desse trabalho é identificar genes diferencialmente expressos (DEGs, do inglês differentially expressed genes) em células mononucleares do sangue periférico (PBMCs, do inglês, peripheral blood mononuclear cells) humano submetidas à exposição rápida com herbicida à base de glifosato (Roundup®) e AMPA. O teste de MTT [3(4,5-dimetiltiazol-2-il)-2,5-difeniltetrazólio brometo], realizado em triplicatas, foi utilizado para avaliar a viabilidade celular e para a escolha das condições de tratamento utilizadas na técnica de microarray (GeneChip® Human Transcriptome Array 2.0, Affymetrix). As condições analisadas foram controle (3 chips), AMPA (10 mM; 3 chips) e Roundup® (0,05%; 2 chips), expostos durante 3 horas. Utilizando um valor de p<0,05 e fold-change de 1,5 foram identificados 5 DEGs no tratamento com o AMPA e 26 no tratamento com Roundup®. As análises de enriquecimento mostraram que os genes com expressão alterada após exposição ao Roundup® estavam associados a 33 processos celulares, principalmente relacionados à regulação destes processos. A plataforma digital Pathview foi utilizada para identificar a atuação dos DEGs após exposição ao Roundup® em diferentes vias. Os genes TNF, LTA, TAB2 e ATM foram relacionados à via de sinalização NF-kappa β; BCL2L11 e ATM à via de sinalização FoxO; SESN3 e ATM à via de sinalização p53; e TNF, BCL2L11 e ATM à apoptose. Dessa forma, os resultados sugerem que o Roundup® altera o padrão de expressão gênica de diversos genes associados com o controle do ciclo celular, regulação de processos celulares e apoptose.
32
Deng, Yixin. "Optimising properties of poly(lactic acid) blends through co-continuous phase morphology." Thesis, Loughborough University, 2017. https://dspace.lboro.ac.uk/2134/33338.
Full textAbstract:
This PhD project investigated the effects of a co-continuous phase structure on the ductility of poly(lactic acid) (PLA) blends. An empirical model was used to predict the phase inversion point of the blends. The co-continuous phase morphology was first observed in polybutylene succinate(PBS)/PLA blends. With as little as 10 wt% of PBS, PBS/PLA blends achieved a dramatic improvement in ductility, over 250% elongation-to-break. Clay additives were incorporated in PBS/PLA blends. Clay was found out to affect the compatibility and co-continuous phase morphology of PBS/PLA blends. The clay dispersion was found to have an intercalated and exfoliated structure at a PBS/PLA composition ratio of 20/80. The clay particles increased the mixing conditions between the polymers by producing a finer structure, but also destroyed the co-continuous phase morphology, resulting in a substantial decrease in elongation-at-break. PLA was then blended with Poly(butylene adipate-co-terephthalate) (PBAT) to examine whether the co-continuous phase model could also be applied to other PLA-polymer blends. From the melt viscosity ratio of PLA and PBAT in the processing regime used in the study, the predicted phase inversion value was 19 wt% of PBAT. This value was verified by the results of mechanical properties, where results for elongation-to-break show a dramatic rise from around 10% up to 300% in the composition range between 10 and 20wt% of PBAT. Polyhydroxyalkanoate (PHA) was also blended with PLA and this project investigated how co-continuous phase morphology affects the blends of two brittle polymers. It was found that when PHA content ranged from 10 to 20wt%, the brittle-brittle polymer blends showed ductile behaviour due to a plane stress effect.
33
Uhl, Juli D. "Hox Specificity: Constrained vs. Flexible Requirements for the PBC and MEIS Cofactors." University of Cincinnati / OhioLINK, 2014. http://rave.ohiolink.edu/etdc/view?acc_num=ucin1397234792.
Full text
34
Frantz, Markus. "Dehydroepiandrosteron (DHEA): Ein Steroidhormon mit immunmodulatorischem Potential im Hinblick auf die PBMC-Funktion abdominal-chirurgischer Patienten." Diss., lmu, 2005. http://nbn-resolving.de/urn:nbn:de:bvb:19-39353.
Full text
35
Zannini, Chiara <1988>. "Studio dell'effetto immunomodulatorio in vitro di NGAL su PBMC di pazienti in trattamento emodialitico e iperimmuni." Doctoral thesis, Alma Mater Studiorum - Università di Bologna, 2018. http://amsdottorato.unibo.it/8282/1/Chiara%20Zannini_PhD%20thesis.pdf.
Full textAbstract:
Negli ultimi anni è cresciuto l’interesse verso pazienti in attesa di un trapianto di rene identificati per la presenza elevata di alloanticorpi contro antigeni HLA e non-HLA, definiti iperimmuni. Recentemente, è stato dimostrato l’aumento dell'immunotolleranza ad opera della componente linfocitaria T regolatoria (Treg) dopo l'infusione di MSCs in modelli sperimentali di trapianto d’organo. Alcuni studi hanno infatti dimostrato il contributo di Treg nella modulazione della risposta immunitaria in diversi modelli animali e nel trapianto clinico, per suggerire il loro potenziale utilizzo come marcatori di tolleranza, rigetto o previsione dell’outcome del trapianto d'organo.
Un precedente studio ha dimostrato che NGAL (Neutrophil gelatinase-associated lipocalin), un noto biomarker di danno renale, è in grado di indurre in vitro immunotolleranza aumentando l'espressione di HLA-G e l'espansione di Treg in cellule linfo-monocitarie (PBMC) di soggetti sani.
In questo studio, si è valutato l'effetto di NGAL sull'espansione di Treg e l'espressione di HLA-G in pazienti con insufficienza renale cronica sottoposti ad emodialisi e iperimmuni, e si è approfondita la capacità immunomodulatoria di cellule staminali mesenchimali adulte derivate da tessuto adiposo (ASC) nei confronti di PBMC derivati da queste categorie di pazienti.
I nostri risultati hanno dimostrato un effetto immunomodulatorio, dose dipendente, mediato da NGAL sulla popolazione linfo-monocitaria derivata da pazienti in emodialisi non iperimmuni evidenziato dall’aumento della popolazione di Treg e dall'espressione di HLA-G. Questo effetto è risultato inibito in PBMC derivati da pazienti iperimmuni. L'immunomodulazione sui PBMC in quest’ultima categoria di pazienti è stata ristabilita in vitro in seguito all’allestimento di co-colture con cellule staminali mesenchimali derivate da tessuto adiposo. Le ASC risultano una buona prospettiva futura di terapia cellulare autologa, in concomitanza e a supporto del trapianto di rene, in pazienti uno stato immunologico alterato, ampliando l'accesso ai trapianti d’organo a questi pazienti complessi che presentano un PRA sfavorevole.In recent years, an increasing number of patients waiting for a kidney transplant showed the presence of alloantibodies against HLA antigens and non-HLA. Evidence demonstrates the contribution of regulatory T lymphocyte cells (Treg) in modulating the immune response in different animal models and in clinical transplant, to suggest their potential use as markers of tolerance, rejection or prediction of organ transplant outcome. Recently, Treg has been shown to increase immunotolerance following MSCs infusion into experimental models of solid organ transplantation. We have previously provided in vitro evidence that NGAL (Neutrophil gelatinase-associated lipocalin), a known biomarker of renal injury, is able to induce immune tolerance by upregulating HLA-G expression and expansion of Treg in normal subjects. In this study, we evaluated the effect of NGAL on the expansion of Treg and HLA-G expression in haemodialysis and hyperimmunized patients; then, we investigated the immunomodulatory effect of adipose-derived mesenchymal stem cells (ASCs) on PBMCs derived from patients. We carried out isolation from peripheral blood mononuclear cells (PBMCs) and immunophenotypic in vitro characterization of Treg after NGAL treatment and after co-culture with ASCs. Our results demonstrated an immunomodulatory effect NGAL-mediated on lymphomonocyte population derived by non-hyperimmunized, as Treg population and HLA-G expression augmented, while this effect is inhibited in PBMCs derived from hyperimmunized patients. The immunomodulatory effect on PBMCs in these patients is re-established in vitro by co-culture with adipose-derived mesenchymal stem cells. ASCs could be a good future possibility for modulating immune system before or during kidney transplant in hyperimmunized patients, expanding access to transplants to these complex patients.
36
Su, Shiwei. "Effectiveness of central bank communication on financial markets in emerging economies, with a special focus on China." Thesis, Loughborough University, 2018. https://dspace.lboro.ac.uk/2134/33386.
Full textAbstract:
Central bank communication has become an important monetary policy tool. This is because it helps to improve the effectiveness of monetary policy by sharing information, which reduces uncertainty. Previous research on the topic has concentrated on central banks in developed economies, such as the Bank of England, the European Central Bank, and the Federal Reserve. This research contributes to the literature by providing insights from the perspective of emerging economies, where communications of Chinese and Indian central banks are examined. The first empirical chapter investigates the effectiveness of communication of People s Bank of China (PBOC) on Chinese financial markets: the interbank money market, the equity market, and foreign exchange markets, are analysed using time-series models. The main focus of the chapter includes an analysis of PBOC s credibility, construction of a new communication index on global economic outlook, more detailed communication indexes, and addressing how-to-communicate questions in the PBOC s communication strategies. The results indicate that the PBOC has credibility and its communication generally reduces volatility in these markets. The second empirical chapter looks at the role of the PBOC s communication in predicting policy rates, using an ordered probit model. The communication indexes constructed in the chapter cover both formal and informal communications of PBOC for 2009 to 2015 and a new communication index on money supply was also constructed. The main finding is that PBOC s communications (particularly on inflation) are useful for predicting PBOC s monetary policy stance. The money supply communication index has some, but not much predictability powers. Finally, the third empirical chapter compares central bank communications in China and India. The contribution of the chapter lies in the comparative analysis of two central banks communications of developing economies, which were overlooked in the extant literature. It shows that the communications on the countries monetary policy inclination have influence on macroeconomic variables of the countries, particularly, the short-term inflation expectations. The findings, therefore, suggest the effectiveness of communications as an unconventional monetary policy tool in emerging economies.
37
Dunn, Andrew W. "Cationic Nanoparticles for the Targeting and Delivery of Nucleic Acids to the Pulmonary Endothelium." University of Cincinnati / OhioLINK, 2018. http://rave.ohiolink.edu/etdc/view?acc_num=ucin1544098242321181.
Full text
38
Kohrs, Nicholas John. "SYNTHESIS AND CHARACTERIZATION OF BLUE LIGHT POLY(β-AMINO ESTER)S." UKnowledge, 2018. https://uknowledge.uky.edu/cbme_etds/53.
Full textAbstract:
Volumetric muscle loss (VML) is a debilitating injury which results in full or partial loss of function. Current clinical options utilize tissue grafts and bracing to restore function. Tissue graft implantation oftentimes leads to serious complications, some of which end in graft rejection and thereby necessitate further surgeries and procedures. Polymeric scaffolds show promise as scaffolding systems due to their mechanical properties and overall degradation profiles. Scaffolds need appropriate mechanical properties, 10-60 kPa modulus, and overall degradation times, five days to two weeks, to initiate tissue regeneration. Poly(β-amino ester)s (PBAE), a class of synthetic polymers, act as a safe biocompatible material with overall degradation times that are suitable for healing; however, due to harmful ultraviolet light (UV) irradiation from common crosslinking methods, these scaffold systems cannot be synthesized in vivo. This research presents the development and characterization of blue light (BL) crosslinked PBAEs. BL PBAEs showed vastly higher swelling ratios, 300-400% increase; decreased mechanical strength, an average decrease of 877 kPa in compressive modulus and 431 kPa in tensile modulus; and prolonged degradation patterns, 22% average mass retention. BL PBAEs show mechanical properties and degradation profiles that could be used as a skeletal muscle scaffolds.
39
Silva, Lorena Christine Ferreira da. "Interação de acanthamoeba polyphaga mimivirus com o sistema interferon humano em células mononucleares do sangue periférico (PBMC)." Universidade Federal de Minas Gerais, 2013. http://hdl.handle.net/1843/BUBD-9UKJ3B.
Full textAbstract:
Acanthamoeba polyphaga mimivirus (APMV) is a giant, double-stranded virus of the Mimiviridae family that was discovered in 2003. This virus presents high structural and genetic complexity. Although free-living amoebas are hosts for the APMV, recent studies have shown that this virus is able to replicate in phagocytes and it is believed that might be a human pathogen that causes pneumonia. In the present study, were investigated how some components of the interferon (IFN) system are stimulated by APMV in human peripheral blood mononuclear cells (PBMC) and how APMV replication is affected by IFN treatment. The results demonstrated that APMV is able to replicate in human total PBMC, inducing type I Interferons (IFN) in these cells but inhibiting interferon stimulated genes (ISG) induction by viroceptor and STAT dephosphorylation independent mechanisms. Were also showed that APMV is resistant to the antiviral action of interferon-alpha2 (IFNA2) but is sensitive to the antiviral action of interferon-beta (IFNB1). The results confirm those obtained in previous studies, which demonstrated the productive infection of professional phagocytes with APMV, and expands them by showing that this virus is recognized by the immune system of vertebrates and inhibits it. Thus, were provided the first data regarding APMV and the IFN system interaction and raised new and relevant evolutional questions about the relationship between APMV and vertebrate hosts.Acanthamoeba polyphaga mimivirus (APMV) é um vírus gigante de DNA, descoberto em 2003, pertencente a família Mimiviridae e que apresenta elevada complexidade estrutural e genômica. Embora amebas de vida livre sejam consideradas hospedeiros de APMV, estudos recentes têm demonstrado que o vírus é capaz de multiplicar em fagócitos e acredita-se que pode ser um agente patogênico causador de pneumonia em humanos. No presente estudo, foi investigado como alguns componentes do sistema interferon humano são estimulados por APMV em células mononucleares do sangue periférico (PBMC) e como a multiplicação do vírus é afetada pelo tratamento com IFN do tipo I. Os resultados demonstraram que APMV é capaz de se replicar em PBMC humanas totais, induzindo IFN do tipo I nestas células, mas inibindo genes estimulados por IFN (ISG) por um mecanismo independente da presença de viroceptores e desfosforilação de STAT. Foi visto também que APMV é resistente à ação antiviral do IFN alfa2 (IFNA2) mas é sensível à ação antiviral de IFN beta (IFNB1). Os resultados obtidos confirmam estudos anteriores, os quais demonstraram que há infecção produtiva de fagócitos profissionais com APMV, e mais, mostram que este vírus é reconhecido pelo sistema imunitário dos vertebrados e é capaz de inibí-lo. Assim, foram fornecidos os primeiros dados sobre interação do sistema IFN e APMV e levantadas novas questões evolutivas e relevantes sobre a relação entre APMV e hospedeiros vertebrados.
40
Mells, George Frank Gannaway. "Investigation of the genetic basis of primary biliary cirrhosis : the PBC genetics study." Thesis, University of Cambridge, 2014. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.648610.
Full text
41
Foos, Nicolas. "Etudes structurales d'un complexe HOX-PBC de drosophile. : Un exemple de régulateur transcriptionnel." Thesis, Aix-Marseille, 2013. http://www.theses.fr/2013AIXM4075.
Full textAbstract:
Les protéines Hox sont des protéines à homéodomaine. Elles sont très conservées et impliquées dans l'identité cellulaire selon les axes antéropostérieur, dorsoventral et proximodistal. Elles reconnaissent l'ADN pour réguler l’expression des gènes. La coopérativité avec des partenaires de la famille PBC est un modèle pour l'amélioration de la spécificité. Cette étude utilise Ubx (Hox) et Exd (PBC) de D. melanogaster comme modèles. Deux modes d'interaction entre Ubx et Exd : un par le motif « hexapeptide » d'Ubx et un autre par le motif UbdA objet de ce travail. UbdA se situe en C-terminal de l'hélice de reconnaissance de l'ADN d'Ubx. Nous avons résolu différentes structures de complexes Ubx-Exd-ADN avec deux types de séquences d'ADN. Ces structures montrent que le motif UbdA peut adopter différentes conformations permettant différents rôles : surface d'interaction avec Exd ou charnière entre l'HD et les domaines C-terminaux. En plus des motifs d'Ubx important pour la fonction de régulation, Ubx et Exd comportent des motifs intrinsèquement désordonnés appelés linker et bras N-terminal de l'homéodomaine, respectivement. Ces motifs interagissent avec l'ADN au niveau du sillon mineur et ont la capacité d'explorer l’environnement. Nous avons étudié l'extrémité en C-terminale d'Exd. Ce motif forme une quatrième hélice dont le repliement peut influer sur les contacts établis avec Ubx et avec l'ADN. L'ensemble de ces observations nous a permis d'apporter des éléments supplémentaires pour la compréhension de la spécificité de fonctions et de contribuer à alimenter les modèles de scannage de l'ADN de type monkey bar et d'« interface glissante »Hox proteins are homeodomain proteins belonging to the Transcription Factors superfamilly. These proteins are necessary for the determination of the cellular identity along the anteroposterior, dorsoventral and proximodistal axes. It's essential to recognize DNA targets with high specificity. One possible mechanism to acquire specificity implies the cooperativity between Hox and their PBC partners. Ubx (Hox) and Exd (PBC) proteins from D. melanogaster are the object of this work. One mechanisme of coopertivity involves the “hexapeptide” motif in Ubx and another one that involves its UbdA motif. The UbdA motif is located C-terminal to the recognition helix. We have solved seven different structures of Ubx-Exd-DNA complexes. Thanks to these structures, we show that UbdA can have a multipurpose role : it can provide an interaction surface to contact Exd and it can also act like a hinge between the C-terminal regions of Ubx and its homeodomain. UbdA and HX motifs from Ubx are not the only regions involved in the control of these proteins functions. Ubx and Exd also contain intrinsically disordered regions which are the linker region and the homeodomain N-terminal arm, for Ubx and Exd respectively. They interact with the DNA in the minor groove and can explore the space around. We studied the Exd 's C-terminal motif and determined that it has a flexible, helical fold. The folding of this fourth helix could modify the contacts established with Ubx and with the DNA. All these observations allow us to add supplementary information for the understanding of functional specificity and provide new arguments for the monkey-bar and for the « gliding interface » DNA- scanning models
42
Escudero, Astudillo Paulino Alberto. "Diseño de un silo dosificador para pasta de baterías." Tesis, Universidad de Chile, 2016. http://repositorio.uchile.cl/handle/2250/143614.
Full textAbstract:
Ingeniero Civil MecánicoEl trabajo muestra el diseño de un silo para el acopio y dosificación de pasta de baterías (PBat), para la línea productiva de una planta industrial y fundición; que se dedica al reciclaje de baterías de plomo-ácido para la obtención de plomo refinado. El objetivo del trabajo es el diseño de un silo para el acopio y dosificación de PBat integrado en una línea de manejo y dosificación de materiales. Los objetivos específicos son: i) Revisar el es-tado del arte sobre silos para acopio y dosificación de pastas, ii) Caracterizar la PBat y determinar las condiciones de operación del silo inserto en la línea de producción, iii) Diseñar los mecanismos de extracción de la PBat, iv) Seleccionar y diseñar detalladamente una motorización ad hoc para el silo, y v) Diseñar una lógica de control que permita integrar el silo de PBat con la tecnología Weightfeeders de la línea de manejo y dosificación de materiales. Para desarrollar los objetivos específicos se emplea una metodología que integra revisión biblio-gráfica del estado del arte de silos y dosificación de pasta para obtener el marco teórico para el diseño de los componentes principales; revisión de normas internacionales ASTM para diseñar y validar técnicamente los ensayos de caracterización de la PBat. Para el diseño detallado se em-plean los resultados de los ensayos y los requerimientos de operación a partir de los que se realiza el dimensionamiento y la configuración de los mecanismos de descarga y dosificación junto con la motorización de ellos. Para abordar el sistema de control se define la filosofía de control, los sensores y los lazos de control. Los principales resultados del trabajo muestran que: i. La tecnología para silos de pasta se centra en los sistemas de descarga. Los sistemas más im-portantes en la actualidad son descarga mecánica por: movimiento alternativo, ejes encontra-dos, descargador de tornillo y descargador rotatorio. ii. La pasta de baterías es un material reologicamente complejo con facilidad para formar bóvedas con un ángulo de reposo alto, una granulometría heterogénea y un esfuerzo de cizalle rela-tivamente alto de 0,6 kg/cm2. iii. El silo, un estanque cilíndrico-cónico de 4,5 m3 en AISI 316L, contempla dos sistemas de des-carga complementarios: un descargador rotatorio que arrastra la pasta por el fondo del silo sin compactarla descargando el material por una lumbrera y un sistema de arrastre vertical; que destruye las bóvedas al forzar el avance de la pasta hacia el fondo del silo. iv. La lógica de control integra los distintos equipos que forman la línea de manejo de materiales plomados. En particular la integración con los weightfeeder está diseñada lograr la dosificación precisa de los materiales involucrados en la línea de proceso.
43
Kam, Siu-kei Christy. "The role of TGF-[beta] signaling in the initiation of TNF-[beta] expression in human PBMC derived macrophages." Click to view the E-thesis via HKUTO, 2006. http://sunzi.lib.hku.hk/hkuto/record/B38746049.
Full text
44
Kam, Siu-kei Christy, and 甘笑琪. "The role of TGF-{221} signaling in the initiation of TNF-α expression in human PBMC derived macrophages." Thesis, The University of Hong Kong (Pokfulam, Hong Kong), 2006. http://hub.hku.hk/bib/B38746049.
Full text
45
Chuck, Lisa. "A PREDICTIVE MODEL FOR BENCHMARKING ACADEMIC PROGRAMS (PBAP)USING U.S. NEWS RANKING DATA FOR ENGINEERING COLLEGES OFFERING GRADU." Doctoral diss., University of Central Florida, 2005. http://digital.library.ucf.edu/cdm/ref/collection/ETD/id/2397.
Full textAbstract:
Improving national ranking is an increasingly important issue for university administrators. While research has been conducted on performance measures in higher education, research designs have lacked a predictive quality. Studies on the U.S. News college rankings have provided insight into the methodology; however, none of them have provided a model to predict what change in variable values would likely cause an institution to improve its standing in the rankings. The purpose of this study was to develop a predictive model for benchmarking academic programs (pBAP) for engineering colleges. The 2005 U.S. News ranking data for graduate engineering programs were used to create a four-tier predictive model (pBAP). The pBAP model correctly classified 81.9% of the cases in their respective tier. To test the predictive accuracy of the pBAP model, the 2005 U.S .News data were entered into the pBAP variate developed using the 2004 U.S. News data. The model predicted that 88.9% of the institutions would remain in the same ranking tier in the 2005 U.S. News rankings (compared with 87.7% in the actual data), and 11.1% of the institutions would demonstrate tier movement (compared with an actual 12.3% movement in the actual data). The likelihood of improving an institution's standing in the rankings was greater when increasing the values of 3 of the 11 variables in the U.S. News model: peer assessment score, recruiter assessment score, and research expenditures.Ed.D.
Department of Educational Research, Technology and Leadership
Education
Educational Leadership
46
ABANS, Mariângela de Oliveira. "Parametrização de redes neurais artificiais em problemas de séries temporais não lineares empregando PBCA (Plackett-burman correlation analysis)." reponame:Repositório Institucional da UNIFEI, 2018. http://repositorio.unifei.edu.br/xmlui/handle/123456789/1429.
Full textAbstract:
Submitted by repositorio repositorio (repositorio@unifei.edu.br) on 2018-06-29T17:53:27Z
No. of bitstreams: 1
tese_2018016.pdf: 7348957 bytes, checksum: 39237c89c95bdb2055e4b91fe2b855c3 (MD5)Made available in DSpace on 2018-06-29T17:53:27Z (GMT). No. of bitstreams: 1 tese_2018016.pdf: 7348957 bytes, checksum: 39237c89c95bdb2055e4b91fe2b855c3 (MD5) Previous issue date: 2018-04-20
Séries temporais são encontradas em fenômenos naturais, mercadológicos e financeiros, e em processos de manufatura, entre outros, o que as torna importantes objetos de pesquisa. Quando não são lineares, sua modelagem é complexa devido ao grande número de parâmetros, à existência de fatores exógenos, à alta volatilidade e à presença de sazonalidade. Tem sido demonstrado que, nesses casos, RNAs apresentam bom desempenho tanto na apreensão do comportamento dos dados como na sua previsão dentro dos limites de exatidão requeridos. Apesar do grande número de parâmetros de uma RNA, delineamentos têm sido usados com sucesso, porém a alta demanda de recursos humanos, computacionais, financeiros e de tempo são obstáculos para sua total exploração. Neste trabalho, implantou-se uma nova metodologia denominada Análise de Correlação em Plackett_Burman (Plackett_Burman Correlation Analysis ̶ PBCA) na parametrização de Redes Neurais Artificiais ̶ RNAs, com o propósito de modelar e prever Séries Temporais Univariadas Não Lineares. Esta é uma metodologia de seleção de variáveis significativas baseada no Delineamento de Experimentos (DOE) de Plackett_Burman com rebatimento e que propõe a análise de correlação entre as séries de resíduos, consideradas como sinais. Sua vantagem é requerer um número de experimentos menor que o Delineamento Fatorial Completo e ser capaz de identificar as significativas interações de segunda ordem entre todas as variáveis. Nesta tese, implementou-se esta nova metodologia PBCA na construção de RNAs previsoras para auxiliar os profissionais responsáveis por decisões tático-estratégicas baseadas em séries temporais. A metodologia foi aplicada a dois casos: (i) número de horas disponíveis para pesquisa em um observatório astronômico profissional de classe mundial e (ii) distribuição de carga elétrica fornecida a uma empresa brasileira, com o objetivo de fornecer previsões de curtíssimo e curto prazos para a tomada de decisões sobre o melhor uso das infraestruturas envolvidas. Ambas as séries foram primeiramente estudadas através da aplicação de técnicas e modelos ditos “clássicos” a fim de estabelecer benchmarking para comparação. Os resultados deste trabalho sugerem a adequação apenas parcial da metodologia para estes fins. Não é possível aplicar a PBCA totalmente devido (i) à maneira de definir as RNAs, (ii) ao fato do processo não ser modelável, afinal e (iii) à impossibilidade de uso das interações de ordem dois entre as variáveis significativas no software Statistica®. São também apresentados possíveis desdobramentos da pesquisa e aplicações em outras áreas do conhecimento.
47
Hammack, Lindsay Jo. "Identification of the Pba1 and Pba2 Binding Sites on 20S Core Particle Intermediates." 2013. http://hdl.handle.net/1805/3362.
Full textAbstract:
Indiana University-Purdue University Indianapolis (IUPUI)The proteasome is responsible for breaking down the majority of the proteins in the cell. However, a complete understanding of how this large multi-subunit protease is assembled is currently lacking. Proper and timely assembly of the proteasome is critical for the functioning of the ubiquitin-proteasome pathway, defects in which have been associated with several different cancers. A recently discovered heterodimeric proteasome assembly chaperone, Pba1p-Pba2p, has been suggested to prevent the assembly process from straying off path. Pba1p-Pba2p associates with proteasomal assembly intermediates via C-terminal HbYX motifs. The HbYX motif is a tri-peptide sequence containing a hydrophobic residue (Hb) followed by a tyrosine (Y), then any amino acid (X). This motif was originally identified in proteasomal activators, and shown to mediate the association of activators with the proteasome by inserting into intersubunit pockets on either end of the proteasome. There are seven unique intersubunit binding pockets, located between neighboring α subunits on the proteasome, to which a HbYX-containing protein can bind; which of these pockets Pba1p-Pba2p binds to remains elusive. I attempted to identify where Pba1p and Pba2p bind via a crosslinking approach. Specific residues were mutagenized to cysteines on Pba1p, Pba2p, and the individual α subunits in order to generate crosslinkable species. By exposing yeast cells expressing these crosslinkable proteins to mild oxidizing conditions, I attempted to trap the Pba1p and Pba2p α intersubunit pocket interactions. In order to optimize crosslinking conditions, the assay was modified several ways. Additionally, measures were taken to increase detection of the crosslinked species via immunoblotting. Despite the efforts to improve the crosslinking and detection, I was unable to successfully detect a crosslinked species. However, crosslinking is a reasonable method to identify the Pba1p and Pba2p proteasomal binding sites, having been successfully used to identify binding sites for other HbYX-motif-containing proteins; further assay optimization should yield Pba1p and Pba2p proteasomal crosslinks.
48
Liao, Hsiang-Chou, and 廖翔舟. "PBAT/MA crosslink films physical and to confer PBAT biodegradable conditions." Thesis, 2008. http://ndltd.ncl.edu.tw/handle/30349848572644601507.
Full textAbstract:
碩士國立臺灣科技大學
高分子系
96
First part of this dissertation is to study the crosslink reaction between PBAT and MA in order to apply to the study of the biodegradable membrane by analyzing the physical property, chemical property and biolysis of the membrane after adding different MA proportion o PBAT. Second part is to study the life cycle of Alcaligens faecalis and resolving condition of PBAT membrane by resolving the PBAT membrane (Poly (butylene adipate-co-terephthalate) by Alcaligens faecalis. Under NB medium environment, the amount of Alcaligens faecalis reaches the maximum germs after 11 hours of culture. And Under the mineral medium (MM) environment, 2.6% (the percentage of loss of weight) of PBAT is resolved in two weeks. As of the PBAT membrane after crosslink reaction with MA, -OH peak disappears (observed by IR); both stress and Yang's modulus increase (by tension test); the roughness is reduced (observed by AFM); the heat stability property of the material increase while Tm does not to rise (by TGA and DSC); the original crystallization structure of PBAT is invariant after the crosslink reaction of PBAT/MA (by SAXS). In general, after PBAT/MA crosslink reaction, the mechanical property of PBAT membrane is improved so that expand the application in the biodegradable environmental protection membrane.
49
Ke, Li Yuan, and 柯力元. "Measuring Magnetoresistance of PbAu Alloy at Low Temperatures." Thesis, 2016. http://ndltd.ncl.edu.tw/handle/qn2y9d.
Full textAbstract:
碩士國立清華大學
物理系
105
Binary surface alloy made of heavy elements, Pb and Au, has exhibited strong Rashba effect in its band structure. To investigate its corresponding performance in electric transport, we first grew such a PbAu-alloy thin film, composed of the Pb film with PbAu alloy layer on the top, in the UHV chamber. After the sample of PbAu-alloy film was made, we took the sample out of UHV chamber and fabricate it into a Hall-bar device via lithography for low-temperature magneto-resistance measurement with the applied magnetic field parallel to the sample surface. Based on the experimental result, we could find that once the temperature dropped below transition temperature. ~ 6 K, of Pb, the spin-polarized charge current appeared in the transverse direction causing the observed abrupt increase of the voltage. Furthermore, we also observed that the oscillation of voltage as a function of applied magnetic field in the weak limits from 0.2 Tesla to 3.6 Tesla and the non-ohmic behavior in terms of the I-V relation. One can realize the appearance of spin-polarized charge current by considering the influence from Rashba effect, leading to spin Hall or anomalous Hall effect. Such spin -polarized charge current is closely related to superconductivity of Pb thin films; when the temperature goes below the transition temperature, the transport currents would concentrate on the Pb film so as to increase the probability of scattering to top PbAu alloy layer that has giant Rashba effect. Such strong spin-orbital interaction would not just lead to the diffusion of spin-polarized current in transverse direction but very likely breaking time-resolved symmetry via the change of superconducting state under Rashba interaction. When the temperature goes above transition temperature, spin polarized charge current is small, so the behavior becomes more Ohmic. Finally, the measured oscillation of voltage under the weak magnetic field could be realized by considering spin-magnetic moment of electrons in the spin-polarized charged currents exposed to the external magnetic field resulting in precession of spin magnetic moment.
50
Liu, Tien Sheng, and 劉天聲. "Characterization of PBAT/PEgMA Blends and Blend-based Nanocomposites." Thesis, 2015. http://ndltd.ncl.edu.tw/handle/88937833257857119515.
Full text