Design, manufacturing and evaluation of a ventricular assistance device : implantable centrifugal blood pump

Orientadores: Antonio Celso Fonseca de Arruda, Aron José Pazin de AndradeTese (doutorado) - Universidade Estadual de Campinas, Faculdade de Engenharia MecânicaResumo: Uma Bomba de Sangue Centrífuga Implantável (BSCI) foi projetada e construída para assistência ventricular de longa duração no tratamento de pacientes portadores de doenças cardiovasculares. A proposta do projeto foi desenvolver um Dispositivo de Assistência Ventricular (DAV) com custos reduzidos, originalidade de desenho e tecnologia nacional. A geometria do rotor da bomba, aliando um cone em espiral com aletas centrífugas, deu origem ao pedido de Patente de Invenção (PI 0706163-3). O desenvolvimento de seus sistemas propulsores se inclui no Projeto Temático FAPESP nº 2006/58773-1. A metodologia baseou-se em testes individuais dos mancais, atuador e rotor, seguidos de testes do conjunto da BSCI em bancada, com sangue humano e em animais. Foram realizadas simulações numéricas por computador que resultaram no dimensionamento da bomba e definição da sua geometria. Foi testado o atrito nos mancais e os resultados que apresentaram maior durabilidade foram do par alumina-polietileno. Testes em dinamômetro resultaram na caracterização do propulsor eletromagnético, um motor sem escovas trifásico de corrente contínua, e seu controlador eletrônico baseado na técnica de controle sem sensores. Foram realizados testes de hemólise de acordo com as Normas ASTM F1830 e ASTM F1841 para quantificar os danos causados ao sangue pela BSCI e seu índice de hemólise foi de 0,0054 mg/100L, considerado excelente. Testes prospectivos em animais para avaliação do implante resultaram na possibilidade de posicionamento da bomba no tórax ou abdome. Após os testes realizados, a BSCI projetada e construída foi considerada uma opção segura para o tratamento das doenças cardiovasculares. Como trabalhos futuros, serão realizados mais testes em animais para avaliação do funcionamento da BSCI antes dos testes em pacientesAbstract: An Implantable Centrifugal Blood Pump was developed for long-term ventricular assistance in cardiac patients. In vitro tests were performed, as wear evaluation, performance tests and hemolysis tests in human blood. Preliminary tests were performed with a non-implantable pump in order to properly locate the inlet port. Numerical computational simulations were performed in order to predict its best geometry. Wear evaluations helped to select the best materials for double pivot bearing system proposed to achieve longer durability. Performance tests pointed the best impeller geometry. The Implantable Centrifugal Blood Pump was compared with other two blood pumps. One is a centrifugal blood pump for cardiopulmonary bypass and the other is a similar implantable device called Gyro - Nedo Pump. The proposed implantable centrifugal blood pump showed the best performance. But, its results showed a strong descendant curve in high flow. Other prototype was manufactured with a different inlet port angle to overcome this problem. According to ASTM, the normalized index of hemolysis (NIH) tests were performed "In Vitro" with human blood in closed circuit (mock loop) in normalized conditions, as flow of 5 L/min and total pressure ahead of 100 mm Hg. After six hours, NIH measured 0.0054 mg/100L that can be considered excellent since it is close to the minimum found in literature (between 0.004 g/ 100L e 0.02 g/ 100L). Prior to evaluate performance during "In Vivo" animal studies, anatomical studies were necessary to achieve best configuration and cannulation for Left Ventricular Assistance. Results were considered satisfactory and "In Vivo" tests will be performed looking forward to implant it in patientsDoutoradoMateriais e Processos de FabricaçãoDoutor em Engenharia Mecânic

Laser-Treated Surfaces for VADs: From Inert Titanium to Potential Biofunctional Materials

Laser-treated surfaces for ventricular assist devices. Impact Statement. This work has scientific impact since it proposes a biofunctional surface created with laser processing in bioinert titanium. Introduction. Cardiovascular diseases are the world’s leading cause of death. An especially debilitating heart disease is congestive heart failure. Among the possible therapies, heart transplantation and mechanical circulatory assistance are the main treatments for its severe form at a more advanced stage. The development of biomaterials for ventricular assist devices is still being carried out. Although polished titanium is currently employed in several devices, its performance could be improved by enhancing the bioactivity of its surface. Methods. Aiming to improve the titanium without using coatings that can be detached, this work presents the formation of laser-induced periodic surface structures with a topology suitable for cell adhesion and neointimal tissue formation. The surface was modified by femtosecond laser ablation and cell adhesion was evaluated in vitro by using fibroblast cells. Results. The results indicate the formation of the desired topology, since the cells showed the appropriate adhesion compared to the control group. Scanning electron microscopy showed several positive characteristics in the cells shape and their surface distribution. The in vitro results obtained with different topologies point that the proposed LIPSS would provide enhanced cell adhesion and proliferation. Conclusion. The laser processes studied can create new interactions in biomaterials already known and improve the performance of biomaterials for use in ventricular assist devices

TRATAMENTO DE SEMENTES NO CONTROLE DE PRAGAS INICIAIS EM CULTIVARES DE SOJA (GLYCINE MAX (L.) MERRILL)

A soja representa, a nível mundial, o papel de principal oleaginosa produzida e consumida. Uma das estratégias de manejo dessa cultura, visando minimizar os danos e as perdas de produção, é o tratamento de sementes. O objetivo neste estudo foi avaliar a eficiência do tratamento de sementes no controle de pragas iniciais em cultivares de soja em campo. O experimento foi realizado no Município de Guaraciaba, SC, com o delineamento experimental de blocos casualizados (DBC) com três cultivares, com e sem tratamento de sementes, e cinco repetições, com arranjo fatorial de 3 x 2. O experimento teve cinco blocos, cada um com seis parcelas, as quais foram compostas por cinco linhas cada, com espaçamento entre elas de 0,47 m e com 1,5 metro de comprimento, porém, apenas foi utilizado um metro de comprimento das linhas centrais nas análises (2ª e 4ª linha). Foram utilizadas as cultivares de soja: Brasmax BMX Turbo RR (1), Syngenta 1059 RR (VTop) (2) e da marca Nidera NS 6262 RR (3), finalidade de grãos de ciclo superprecoce. O tratamento de sementes utilizado foi o CROPSTAR® (Imidacloprid + Thiodicarb). Após a emergência das plantas, foram realizadas visitas diárias para acompanhamento da cultura. Realizaram-se sete leituras a cada sete dias após a semeadura (DAE). Foi realizada a contagem das plantas que emergiram e a das pragas presentes, bem como a identificação de danos, e também foi medida a estatura de plantas. Também foram avaliados os componentes da produção: peso de grãos, peso de mil sementes, número de vagens, número de sementes por vagem e produção de grãos (kg/ha). Realizou-se a análise da variância das variáveis e as médias foram comparadas pelo teste de Tukey a 5% de significância. Foi observada diferença de respostas entre as cultivares testadas quanto ao número de vagens/planta, peso de grãos/planta, número de grãos/planta e peso de mil sementes. Não houve diferença entre as cultivares com e sem tratamento de sementes em relação às variáveis relacionadas à produção de grãos. A cultivar BMX Turbo apresentou desempenho superior para peso de grãos e peso de mil sementes e igualou-se à VTop na produção, número de grãos e número de vagens. A cultivar NS 6262 apresentou desempenho inferior nas variáveis analisadas e apresentou maior estatura aos 42 DAE. Foi verificada maior incidência de pragas e menor ocorrência de danos nas cultivares com tratamento de sementes, o que pode ser resultado da eficiência do produto. Estudos futuros devem ser realizados para comprovar ou contestar esses resultados.Palavras-chave: Pragas iniciais. Tratamento de sementes. Sistemicidade. Soja.

The infectiousness of tuberculosis patients coinfected with HIV

The current understanding of airborne tuberculosis (TB) transmission is based on classic 1950s studies in which guinea pigs were exposed to air from a tuberculosis ward. Recently we recreated this model in Lima, Peru, and in this paper we report the use of molecular fingerprinting to investigate patient infectiousness in the current era of HIV infection and multidrug-resistant (MDR) TB

Upper-Room Ultraviolet Light and Negative Air Ionization to Prevent Tuberculosis Transmission

Background Institutional tuberculosis (TB) transmission is an important public health problem highlighted by the HIV/AIDS pandemic and the emergence of multidrug- and extensively drug-resistant TB. Effective TB infection control measures are urgently needed. We evaluated the efficacy of upper-room ultraviolet (UV) lights and negative air ionization for preventing airborne TB transmission using a guinea pig air-sampling model to measure the TB infectiousness of ward air. Methods and Findings For 535 consecutive days, exhaust air from an HIV-TB ward in Lima, Perú, was passed through three guinea pig air-sampling enclosures each housing approximately 150 guinea pigs, using a 2-d cycle. On UV-off days, ward air passed in parallel through a control animal enclosure and a similar enclosure containing negative ionizers. On UV-on days, UV lights and mixing fans were turned on in the ward, and a third animal enclosure alone received ward air. TB infection in guinea pigs was defined by monthly tuberculin skin tests. All guinea pigs underwent autopsy to test for TB disease, defined by characteristic autopsy changes or by the culture of Mycobacterium tuberculosis from organs. 35% (106/304) of guinea pigs in the control group developed TB infection, and this was reduced to 14% (43/303) by ionizers, and to 9.5% (29/307) by UV lights (both p < 0.0001 compared with the control group). TB disease was confirmed in 8.6% (26/304) of control group animals, and this was reduced to 4.3% (13/303) by ionizers, and to 3.6% (11/307) by UV lights (both p < 0.03 compared with the control group). Time-to-event analysis demonstrated that TB infection was prevented by ionizers (log-rank 27; p < 0.0001) and by UV lights (log-rank 46; p < 0.0001). Time-to-event analysis also demonstrated that TB disease was prevented by ionizers (log-rank 3.7; p = 0.055) and by UV lights (log-rank 5.4; p = 0.02). An alternative analysis using an airborne infection model demonstrated that ionizers prevented 60% of TB infection and 51% of TB disease, and that UV lights prevented 70% of TB infection and 54% of TB disease. In all analysis strategies, UV lights tended to be more protective than ionizers. Conclusions Upper-room UV lights and negative air ionization each prevented most airborne TB transmission detectable by guinea pig air sampling. Provided there is adequate mixing of room air, upper-room UV light is an effective, low-cost intervention for use in TB infection control in high-risk clinical settings

Age-dependent availability and functionality of bone marrow stem cells in an experimental model of acute and chronic myocardial infarction

The aim of this study was to investigate the effect of aging and timing of left ventricular ischemic injury on the availability and functionality of stem cells. We studied young and aged male inbred Lewis rats that were used as donors of bone marrow mononuclear cells (BM-MNCs), divided in four experimental groups: controls, sham operated, 48 h post-myocardial infarction (MI), and 28 days post-MI. In vitro studies included flow cytometry analysis, hematopoietic colony-forming capacity, and invasion assays of migration capacity. BM-MNCs from these groups were transplanted in female rats after MI induction. Late engraftment was evaluated by real-time PCR of the SRY chromosome. Percentage of CD34+/CD45+low cells was similar among different experimental groups in young rats, but was significantly higher in aged animals (p < 0.001), particularly 28 days post-MI. KDR+/CD34+ cells were increased 48 h after MI and decreased 28 days post-MI in young animals, while they were profoundly reduced in the aged group (p < 0.001). Triple staining for CD44+/CD29+/CD71+ cells was similar in different groups of aged rats, but we observed an intense increase 48 h post-MI in young animals. Colony-forming units and cytokine-induced migration were significantly attenuated 28 days after the MI. Late engraftment in infarcted transplanted female hearts was present, but considerably heterogeneous. Finally, recovery of left ventricular systolic function in transplanted female recipients was significantly influenced by donors’ BM-MNCs groups (p < 0.01). We have demonstrated that aging and timing of myocardial injury are factors that may act synergistically in determining stem cell availability and function. Such interaction should be considered when planning new cell therapy strategies for acute and chronic ischemic heart disease in the clinical arena

Detailed modelling of a large sample of Herschel sources in the Lockman Hole: identification of cold dust and of lensing candidates through their anomalous SEDs

We have studied in detail a sample of 967 SPIRE sources with 5σ detections at 350 and 500 μm and associations with Spitzer-SWIRE 24 μm galaxies in the HerMES-Lockman survey area, fitting theirmid- and far-infrared, and submillimetre, spectral energy distributions (SEDs) in an automatic search with a set of six infrared templates. For almost 300 galaxies,we havemodelled their SEDs individually to ensure the physicality of the fits. We confirm the need for the new cool and cold cirrus templates, and also of the young starburst template, introduced in earlier work. We also identify 109 lensing candidates via their anomalous SEDs and provide a set of colour–redshift constraints which allow lensing candidates to be identified from combined Herschel and Spitzer data. The picture that emerges of the submillimetre galaxy population is complex, comprising ultraluminous and hyperluminous starbursts, lower luminosity galaxies dominated by interstellar dust emission, lensed galaxies and galaxies with surprisingly cold (10–13 K) dust. 11 per cent of 500 μm selected sources are lensing candidates. 70 per cent of the unlensed sources are ultraluminous infrared galaxies and 26 per cent are hyperluminous. 34 per cent are dominated by optically thin interstellar dust (‘cirrus’) emission, but most of these are due to cooler dust than is characteristic of our Galaxy. At the highest infrared luminosities we see SEDs dominated by M82, Arp 220 and young starburst types, in roughly equal proportions

Mapeamento da revista Enseñanza de las Ciencias : uma análise de redes geradas a partir da catalogação das publicações no período de 2004 a 2015

Esta pesquisa analisou as publicações da revista Enseñanza de las Ciências no período de 2004 a 2015. Através de um estudo bibliográfico, catalogamos um total de 417 artigos, excetuandose os números especiais resultantes do Congreso Internacional sobre Investigación en Didáctica de las Ciencias. Foram mapeadas as palavras-chaves, os autores e os países das instituições de ensino com o intuito de analisar os termos mais relevantes baseados nas medidas de centralidade aplicadas. Notamos que o periódico possui uma diversidade de publicações quanto aos 22 países, 761 autores e as 1.352 palavras-chaves. Dos resultados obtidos destacam-se as expressões "educação secundária", "educação científica" e "livro didático" como temáticas bastante discutidas, assim como uma grande concentração de publicações vinculadas a instituições espanholas