Scaffolds based bone tissue engineering : the role of chitosan

As life expectancy increases, malfunction or loss of tissue caused by injury or disease leads to reduced quality of life in many patients at significant socioeconomic cost. Even though major progress has been made in the field of bone tissue engineering, present therapies, such as bone grafts, still have limitations. Current research on biodegradable polymers is emerging, combining these structures with osteogenic cells, as an alternative to autologous bone grafts. Different types of biodegradable materials have been proposed for the preparation of three-dimensional porous scaffolds for bone tissue engineering. Among them, natural polymers are one of the most attractive options, mainly due to their similarities with extracellular matrix, chemical versatility, good biological performance, and inherent cellular interactions. In this review, special attention is given to chitosan as a biomaterial for bone tissue engineering applications. An extensive literature survey was performed on the preparation of chitosan scaffolds and their in vitro biological performance as well as their potential to facilitate in vivo bone regeneration. The present review also aims to offer the reader a general overview of all components needed to engineer new bone tissue. It gives a brief background on bone biology, followed by an explanation of all components in bone tissue engineering, as well as describing different tissue engineering strategies. Moreover, also discussed are the typical models used to evaluate in vitro functionality of a tissue-engineered construct and in vivo models to assess the potential to regenerate bone tissue are discussed.Fundação para a Ciência e a Tecnologia (FCT

Neural Pathways in Allergic Inflammation

Allergy is on the rise worldwide. Asthma, food allergy, dermatitis, and systemic anaphylaxis are amongst the most common allergic diseases. The association between allergy and altered behavior patterns has long been recognized. The molecular and cellular pathways in the bidirectional interactions of nervous and immune systems are now starting to be elucidated. In this paper, we outline the consequences of allergic diseases, especially food allergy and asthma, on behavior and neural activity and on the neural modulation of allergic responses

Espondilolise e espondilolistese ístmica de grau I no adolescente: Análise retrospectiva de 30 casos

Objectivo: a espondilolise e a espondilolistese ístmica grau I são causas de lombalgia nos adolescentes e associam-se a fractura de fadiga da pars interarticularis por movimentos repetidos de hiperextensão. Na literatura não existe consenso quanto aos benefícios do tratamento cirúrgico nestes doentes, muitas vezes atletas, e a controvérsia prolonga-se sobre qual a melhor técnica cirúrgica. Os autores descrevem a técnica cirúrgica que sistematicamente utilizam e analisam os resultados obtidos.Material e métodos: retrospectivamente, entre 2004 e 2013, foram avaliados 30 adolescentes, 12 com lise ístmica e 18 com espondilolistese ístmica grau I, operados pelo mesmo cirurgião. A reconstituição ístmica foi feita com autoenxerto de ilíaco e fixação pedicular posterior temporária. Avalia-se a taxa de consolidação, complicações, dor (VAS), função (ODI) e o grau de satisfaçãoResultados: a idade média foi 16.3 anos (13-18) e o seguimento 23.5 meses (14-48). Ocorreu consolidação em 100% dos casos. O VAS médio reduziu de 7.48 para 0.38 (p<0.0001) e, funcionalmente, o ODI médio melhorou de 38.55% para 1.59% (p<0.0001), de disfunção moderada para mínima. A todos os doentes foi retirado o material após 1 ano de reconstituição ístmica. No total, 63.3% dos doentes eram desportistas e todos retomaram o nível prévio. Não se verificou progressão da listese nem complicações significativas. Os doentes encontram-se satisfeitos e repetiriam o tratamento.Conclusão: as técnicas de artrodese obtêm bons resultados clínicos mas implicam perda de mobilidade segmentar e doença do nível adjacente. Comparativamente com técnicas dinâmicas, a técnica preconizada pelos autores permite não só a reconstituição ístmica eficaz como revela resultados superiores a médio prazo, o que supera a necessidade de segunda intervenção para extração do material. A reconstituição ístmica com autoenxerto e fixação pedicular posterior temporária na espondilolise ou espondilolistese ístmica grau I obteve excelentes resultados clínicos e elevada taxa de consolidação. Esta técnica é defendida pelos autores mesmo em atletas de alta competição

Building with sugar and corn

Two alternative and highly sustainable building techniques are presented and described. The techniques are sugar reinforcement of earth based material and corncob based thermal isolation material. Some experimental results highlight the advantages and disadvantages of these two proposed techniques whose study is still beginning. The water resistance of earth based materials may be increased by adding a certain amount of sugar. On the other hand, corn cob material may have a similar thermal behavior as the common thermal insulation materials currently used in the building industry

Economia circular: Novos modelos, novos negócios

[Excerto] Este livro (e-book) contém as comunicações apresentadas nas 11as Jornadas Técnicas Internacionais de Resíduos (JTIR), que tiveram lugar em Lisboa, nos dias 14 a 18 de novembro de 2019. Este evento, promovido pela Associação Portuguesa de Engenharia Sanitária e Ambiental (APESB), teve como Tema Especial “Economia Circular: Novos modelos, novos negócios”. Para além do Tema Especial foram selecionados temas relevantes para serem discutidos em Sessões Plenárias, como é o caso do “Licenciamento de Operadores de Gestão de Resíduos”, da “Recolha Seletiva de Bioresíduos” e da “Avaliação de Modelos para a Tara Retornável”. Pela primeira vez foi considerado um espaço dedicado à Limpeza Urbana, contando com as sessões plenárias onde foi analisado “O Desafio da Limpeza Urbana: Inovação e Desenvolvimento” e a importância das “Campanhas de Comunicação em Limpeza Urbana”. Apesar de centrado nos desafios reais no nosso país, todos estes temas estiveram alinhados com os principais eixos estratégicos mundiais deste setor, contando com seis oradores internacionais de referência, como é o caso de Antonis Mavropoulos, Presidente da International Solid Waste Association (ISWA). Através de várias sessões plenária foram ainda apresentados e discutidos os desenvolvimentos técnicos, as inovações científicas e as opções tecnológicas no setor da Engenharia Sanitária e Ambiental nos seguintes temas: Valorização de Resíduos: Tecnologias, Materiais, Eficiências, Problemas e Soluções; Recolha e Tecnologias de Transporte de Resíduos: Novas Soluções; Operação de Infraestruturas e Gestão de Resíduos; Comportamentos, Comunicação e Sensibilização; Avaliação de Desempenho e Qualidade de Serviços. [...

Novel types of anti-ecloud surfaces

In high power RF devices for space, secondary electron emission appears as the main parameter governing the multipactor effect and as well as the e-cloud in large accelerators. Critical experimental activities included development of coatings with low secondary electron emission yield (SEY) for steel (large accelerators) and aluminium (space applications). Coatings with surface roughness of high aspect ratio producing the so-call secondary emission suppression effect appear as the selected strategy. In this work a detailed study of the SEY of these technological coatings and also the experimental deposition methods (PVD and electrochemical) are presented. The coating-design approach selected for new low SEY coatings include rough metals (Ag, Au, Al), rough alloys (NEG), particulated and magnetized surfaces, and also graphene like coatings. It was found that surface roughness also mitigate the SEY deterioration due to aging processes.Comment: 4 pages, contribution to the Joint INFN-CERN-EuCARD-AccNet Workshop on Electron-Cloud Effects: ECLOUD'12; 5-9 Jun 2012, La Biodola, Isola d'Elba, Italy; CERN Yellow Report CERN-2013-002, pp.153-15

Liver involvement in hereditary hemorrhagic telangiectasia

O envolvimento hepático na Telangiectasia Hemorrágica Hereditária (THH) é raro e, na maioria dos casos, é assintomático e não carece de terapêutica específica. No entanto, apresenta alterações hepáticas que fazem diagnóstico diferencial com entidades mais frequentes e clinicamente mais significativas, como a doença hepática crónica, a cirrose ou mesmo o carcinoma hepatocelular. O diagnóstico errado trará angústia ao doente, gastos desnecessários e eventual iatrogenia potencialmente fatal. O conhecimento das características clínicas e imagiológicas que caracterizam esta entidade irá permitir o diagnóstico confiante usando os mesmos exames diagnósticos envolvidos no seguimento de qualquer doença hepática. Descrevemos um caso de THH com envolvimento hepático, referenciado à nossa instituição por suspeita de doença de Caroli. Apesar dos antecedentes familiares de THH da examinada, epistaxis episódica e pequenas lesões cutâneas, o diagnóstico só foi confirmado após identificação de ectasia da artéria hepática e de ‘shunts’ artériovenosos intra-hepáticos na avaliação imagiológica

TiO2 bioactive implant surfaces doped with specific amount of Sr modulate mineralization

One of the main problems that remain in the implant industry is poor osseointegration due to bioinertness of implants. In order to promote bioactivity, calcium (Ca), phosphorus (P) and strontium (Sr) were incorporated into a TiO2 porous layer produced by micro-arc oxidation. Ca and P as bioactive elements are already well reported in the literature, however, the knowledge of the effect of Sr is still limited. In the present work, the effect of various amounts of Sr was evaluated and the morphology, chemical composition and crystal structure of the oxide layer were investigated. Furthermore, in vitro studies were carried out using human osteoblast-like cells. The oxide layer formed showed a triplex structure, where higher incorporation of Sr increased Ca/P ratio, amount of rutile and promoted the formation of SrTiO3 compound. Biological tests revealed that lower concentrations of Sr did not compromise initial cell adhesion neither viability and interestingly improved mineralization. However, higher concentration of Sr (and consequent higher amount of rutile) showed to induce collagen secretion but with compromised mineralization, possibly due to a delayed mineralization process or induced precipitation of deficient hydroxyapatite. Ca-P-TiO2 porous layer with less concentration of Sr seems to be an ideal candidate for bone implants.This work was supported by FCT with the reference projects UID/EEA/04436/2019, M-ERA-NET/0001/2015 and FCT/CAPES Procs.. 4.4.1.00. Also the support of FAPESP is acknowledged (Proc. 2017/24300-4). A.I. Costa is very grateful for the PhD grant through NORTE-08-5369-FSE-000051 project. The authors would like to thank the LABNANO/CBPF and Centro Nacional de Biologia Estrutural e Bioimagem (Cenabio) in Rio de Janeiro for technical support during electron microscopy work

Cartilage tissue engineering using electrospun PCL nanofiber meshes and MSCs

Mesenchymal stem cells (MSCs) have been recognized for their ability to differentiate into cells of different tissues such as bone, cartilage, or adipose tissue, and therefore are of great interest for potential therapeutic strategies. Adherent, colony-forming, fibroblastic cells were isolated from human bone marrow aspirates, from patients undergoing knee arthroplasties, and the MSCs phenotype characterized by flow cytometry. Afterward, cells were seeded onto electrospun polycaprolactone nanofiber meshes and cultured in a multichamber flow perfusion bioreactor to determine their ability to produce cartilagineous extracellular matrix. Results indicate that the flow perfusion bioreactor increased the chondrogenic differentiation of hBM-MSCs, as confirmed either by morphological and RT-PCR analysis. Cartilage-related genes such as aggrecan, collagen type II, and Sox9 were expressed. ECM deposition was also detected by histological procedures. Collagen type II was present in the samples, as well as collagen type I. Despite no statistically significant values being obtained for gene expression, the other results support the choice of the bioreactor for this type of culture.M. Alves da Silva would like to acknowledge the Portuguese Foundation for Science and Technology (FCT) for her grant (SFRH/BD/28708/2006). The authors would like to acknowledge the patients of Hospital de S. Marcos, Braga, Portugal, for the donation of the biological samples, as well to its medical staff. The authors would also like to thank the Institute for Health and Life Sciences (ICVS), University of Minho, Braga, Portugal, for allowing the use of their research facilities. Authors would like specially to acknowledge Luis Martins for his valuable help with the histological procedures and Goreti Pinto for the aid in the microscopy. We thank Ana M. Frias for the important help with the FACS procedure. Finally, we would like to acknowledge the European NoE EXPERTISSUES (NMP3-CT-2004-500283). This work was partially supported by the European FP7 Project Find and Bind (NMP4-SL-2009-229292)