From nano to the macro: tuning hierarchical aggregation of thermoresponsive PEG/PCL-based polyurethanes via molar mass/composition control

Amphiphilic hyperbranched polyurethanes (HPUs) based on PEG and PCL are promising for several biomedical applications. However, the lack of control over the molar mass and composition hinders a deep understanding of the aqueous self-assembly of HPUs. In this paper, the control over the HPU molar mass and composition was provided by dynamic urea bond-mediated polymerization (DUBMP), enabling a careful evaluation of their aqueous self-assembly by 1H NMR, DLS, and Cryo-TEM. HPUs containing a single PCL block per chain self-assemble into nanoaggregates (Rh ≈ 10 nm) in water up to its cloud-point temperature (Tcp) of 34 °C. On the other hand, HPUs with more than one PCL block per chain self-assemble into nanoaggregates and their clusters below Tcp. In this case, the solution behavior can be tuned by the HPU molar mass. Increasing Mw¯¯¯¯¯¯¯¯ from 4 to 19 kDa, HPUs of similar composition can form colloidally stable cluster suspensions (Mw¯¯¯¯¯¯¯¯ = 4 kDa) and phase separate into a denser liquid aggregate–cluster phase (Mw¯¯¯¯¯¯¯¯ = 7 kDa) or into a highly viscous aggregate-network phase (Mw¯¯¯¯¯¯¯¯ = 19 kDa). This type of control over the hierarchical aggregation of HPUs was reported for the first time and is interesting for biomedical applications

Low-Power Red and Infrared Laser Effects on Cells Deficient in DNA Repair

Introduction: Low-level lasers are successfully used to prevent and treat diseases in soft oral and bone tissues, particularly diseases in oral cavity caused by chemotherapy and radiotherapy in oncology. However, controversy exists as to whether these lasers induce molecular side effects, mainly on DNA. The aim of this work was to assess the effects of low-power lasers on mutant Escherichia coli cells in DNA repair.Methods: Escherichia coli wild type cultures as well as those lacking recombination DNA repair (recA-) and la SOS responses (lexA-) irradiated with lasers at different energy densities, powers, and emission modes for cell viability and morphology assessment were used in this study.Results: Laser irradiation: (i) did not affect cell viability of non-mutant and lexA- cells but decreased viability in recA- cultures; (ii) altered morphology of wild type and lexA, depending on the energy density, power, emission mode, and wavelength.Conclusion: Results show that low-level lasers have lethal effects on both recombination DNA repair and SOS response bacterial cells but do not induce morphological modifications in these cells

Wind turbine blade waste: a quantifying model

This thesis presents a model for the prediction of waste generated through end-of-life wind turbine blades. The methodology utilised was based on acquiring information - mainly rated power and blade weight - on 355 real wind turbine models and dividing them into categories. The resulting model, presented in equation form, was tested through a case study and then compared to similar works. The main conclusions were that the model has a higher resolution, - compared to similar models published by different authors - 15, thus more precise, proving to be a tool that can be utilised in the decision-making of organisations such as governing or environmental agencies and wind turbine manufacturers.Nesta tese apresenta-se um modelo para previsão de resíduos gerados por pás de turbinas eólicas após seu ciclo-de-vida. A metodologia utilizada foi obtenção de dados - principalmente potência instalada e peso das pás - de 355 modelos reais de aerogeradores, dividindo-os posteriormente em categorias. O modelo resultante, apresentado em forma de uma equação, foi então testado por meio de um estudo de caso e comparado com trabalhos semelhantes. A principal conclusão é de que se trata de uma ferramenta com alta resolução, - comparado com modelos similares escritos por diferentes autores - 15, logo mais preciso, que pode ser utilizada na tomada de decisões de agências governamentais e ambientais, assim como fabricantes de turbinas eólicas

Covid-19 versus H1N1: a comparative study of the impact of viruses on small and large economies on the Stock Market: The special study of Portugal

Dissertation presented as the partial requirement for obtaining a Master's degree in Statistics and Information Management, specialization in Risk Analysis and Management.Esta dissertação descreve e detalha, o impacto que as crises pandémicas têm na volatilidade dos mercados da bolsa de pequenas e grandes economias. Relativamente aos países estudados, escolhemos como casos de estudo os Estados Unidos da América (grande economia), a Grécia (pequena economia), e Portugal, como comparação aos dois países mencionados anteriormente, mas apenas no que se refere à consequência da pandemia provocada pela Covid-19. Em termos de metodologia, a volatilidade financeira diária é tradicional para modelar um processo GARCH (1,1). Este modelo foi utilizado no programa SAS para provar se a volatilidade podia ser ou não correlacionada. Adicionalmente, os coeficientes de correlação linear de Pearson foram realizados e analisados em várias variáveis, tais como o valor no fecho, casos e mortes confirmados com a volatilidade diária entre cada país e a volatilidade histórica diária. Finalmente, o estudo mostra como as pandemias do século XXI tiveram impacto tanto na bolsa de valores (financeiramente), como no produto interno bruto (economicamente). Esta dissertação comprova que existe, de facto, uma enorme volatilidade no mercado de bolsa no início de um fenómeno atípico. Contudo, após um determinado período de tempo, o mercado de bolsa corrige-se. Saliento, que na pandemia de Covid-19, apesar dos Estados Unidos da América terem sofrido uma repercussão no seu Produto Interno Bruto, Portugal teve implicações ainda mais fortes na economia, tal como a Grécia (países de economia pequena). Referente à parte financeira, Portugal compara-se igualmente à Grécia aquando se realizou as correlações entre as volatilidades históricas diárias. No entanto aproxima se dos Estados Unidos da América nas correlações das várias variáveis, transcritas anteriormente, tais como o valor no fecho e os casos e mortes confirmados com a volatilidade diária entre cada país. Conclui-se que as pandemias causaram impacto nos mercados de bolsa nos países estudados e mencionados supra

The Portuguese offline consumer behaviour: what drives customers buying offline in an online world?

Even though much attention has been paid to online consumer behavior, academic studies are deficient in comprehending offline consumer behavior. This study offers a survey of reflections concerning the Portuguese offline consumer behavior by observing how Portuguese adult consumers engage, embrace and act throughout the offline world, i.e., the offline media channels and the customer decision-making process at a store in regard of digital nativity, education and gender. Drawing on an online questionnaire and using a convenience sample of 471 respondents, data was analyzed using descriptive analysis and independent sample t-test analysis. The results observed indicate Portuguese consumers prefer calling or going to a store when they have an operational problem, value the credit card security at a store and that Portuguese females highly value touching and feeling the product at a store. Finally, implications for academics and marketeers are discussed

Análise de tensões em modelos biomecânicos osso-implante

Gerar modelos biomecânicos para análise do efeito de stress-shielding em função das propriedades dos materiais e da geometria do implante. Avaliar a resistência biomecânica em cada conjunto através da distribuição de tensões . Avaliar o efeito da geometria e do material na ocorrência de micro-movimentos entre o osso-implante. Simular situações de carga estáticas através de uma metodologia numérica para avaliação das tensões

Sheet metal forming by numerical simulations: 2D and 3D axisymmetric deformation of a cylindrical piece

Until few years ago, design of sheet metal forming was based on knowledge through work experience and expensive trial and error process. Nowadays the use of numerical simulations in different phases of the sheet metal forming process are performed using finite element analysis (Ranganath et al, 2012). Different codes are available for finite element analysis in metal forming such as Abaqus, Dynaform, Nike 2D, Ansys, etc. Deep drawing is the metalworking process used for stamping flat sheets into cup-shaped forms, where the metal is subjected to different types of deformations (Dieter, 1961). The aim of this work is conduct numerical simulations to verify the deep drawing process and the shape of the final stamping component of a simple profile of a sheet metal geometry. To evaluate the design of sheet metal forming, a nonlinear dynamic explicit numerical model was developed using two models: a 3D quarter and a 2D axisymmetric finite element model, due the geometry and loading conditions symmetry to reduce the computational time processing. The numerical simulations showed the shape deformation occurring after start the process and provided detailed quantitative information about expected weakness of the resulting piece.info:eu-repo/semantics/publishedVersio

Incidence and Risk Factors for Cardiovascular Collapse After Unplanned Extubations in the Pediatric ICU

BACKGROUND: Cardiovascular collapse is a life-threatening event after unplanned extubations (UEs) in the pediatric ICU (PICU). However, there is a paucity of pediatric studies assessing this complication. We sought to assess the incidence, risk factors, and outcome of cardiovascular collapse after UEs in PICU patients. METHODS: All children who had been mechanically ventilated for >= 12 h were prospectively tracked for UEs over an 8-y period. Subjects were included in the study if they were between ages 1 month and 16 y and had experienced UE. They were analyzed in 2 groups: those with cardiovascular collapse (defined as the need for cardiopulmonary resuscitation or circulatory dysfunction immediately after UE) and those with no cardiovascular collapse. RESULTS: Of the 847 subjects, 109 UEs occurred in 14,293 intubation days (0.76 UEs/100 intubation days), with 21 subjects (19.2%) experiencing cardiovascular collapse, of which 10 required cardiopulmonary resuscitation. Compared with subjects without cardiovascular collapse after UE, children with cardiovascular collapse were younger(<6 months old), with respiratory failure from lower respiratory tract diseases, lower P-aO2/F-IO2 (218 vs 282 mm Hg), and higher oxygenation indices (5.5 vs 3.5) before UE events. Logistic regression revealed that only an age <6 months old was strongly associated with cardiovascular collapse (odds ratio 3.4, P = .03). There were no differences between cardiovascular collapse and non-cardiovascular collapse subjects regarding the length of hospital stay, ventilator-associated pneumonia rate, and mortality. CONCLUSIONS: Cardiovascular collapse is a frequent complication of UEs, particularly in the youngest children. Specific bundles to prevent UEs may reduce morbidity related to these events.Hosp Servidor Publ Municipal, Dept Pediat, Pediat Intens Care Unit, Rua Castro Alves 60, BR-01532900 Sao Paulo, BrazilFed Univ Sao Paulo UNIFESP, Hlth Technol Assessment Unit, Sao Paulo, BrazilFed Univ Sao Paulo UNIFESP, Hlth Technol Assessment Unit, Sao Paulo, BrazilWeb of Scienc

Perinatal Stroke: 11 Cases

Introdução: Os acidentes vasculares cerebrais (AVC) são causa de epilepsia e perturbações do neurodesenvolvimento. Têm tido uma incidencia crescente atribuível em parte à melhoria das tecnicas de imagens cerebrais. Alguns diagnósticos são efectuados retrospectivamente após o periodo neonatal. O objectivo da presente serie de casos clínicos foi identificar factores comuns que possam facilitar o diagnóstico no período neonatal. Material e métodos: Estudo retrospectivo efectuado com base na consulta dos processos clinicos dos recém-nascidos, com diagnóstico de AVC entre um de Janeiro de 2003 e 31 de Dezembro de 2013. Resultados: Foram identificados onze casos de AVC perinatal, num total 28382 nados-vivos. Dois casos foram diagnosticados no periodo fetal e nove no periodo neonatal. As convulsões foram a manifestação clinica mais frequente (8 em 11 casos). A mediana da idade de diagnóstico foi um dia e variou entre um e nove dias. A ecografia transfontanelar mostrou alterações em sete casos. A ressonancia magnetica nuclear cranio-encefalica mostrou alterações em todos os casos. Cinco AVC foram arteriais isquemicos, quatro hemorragicos e dois tromboses dos seios venosos. Em seis casos foram identificadas possiveis causas. Foram observadas complicações e sequelas em quatro dos casos. Discussão: As convulsões foram a manifestação clinica mais frequentemente encontrada.Em recém-nascidos de termo com convulsões sem historia de asfixia intraparto o AVC perinatal deverá ser diagnóstico de exclusão, mesmo na ausencia de alterações na ecografia transfontanelar