A neural extracellular matrix-based method for in vitro hippocampal neuron culture and dopaminergic differentiation of neural stem cells

Background: The ability to recreate an optimal cellular microenvironment is critical to understand neuronal behavior and functionality in vitro. An organized neural extracellular matrix (nECM) promotes neural cell adhesion, proliferation and differentiation. Here, we expanded previous observations on the ability of nECM to support in vitro neuronal differentiation, with the following goals: (i) to recreate complex neuronal networks of embryonic rat hippocampal cells, and (ii) to achieve improved levels of dopaminergic differentiation of subventricular zone (SVZ) neural progenitor cells. Methods: Hippocampal cells from E18 rat embryos were seeded on PLL- and nECM-coated substrates. Neurosphere cultures were prepared from the SVZ of P4-P7 rat pups, and differentiation of neurospheres assayed on PLL- and nECM-coated substrates. Results: When seeded on nECM-coated substrates, both hippocampal cells and SVZ progenitor cells showed neural expression patterns that were similar to their poly-L-lysine-seeded counterparts. However, nECM-based cultures of both hippocampal neurons and SVZ progenitor cells could be maintained for longer times as compared to poly-L-lysine-based cultures. As a result, nECM-based cultures gave rise to a more branched neurite arborization of hippocampal neurons. Interestingly, the prolonged differentiation time of SVZ progenitor cells in nECM allowed us to obtain a purer population of dopaminergic neurons. Conclusions: We conclude that nECM-based coating is an efficient substrate to culture neural cells at different stages of differentiation. In addition, neural ECM-coated substrates increased neuronal survival and neuronal differentiation efficiency as compared to cationic polymers such as poly-L-lysine.

Plasma brain-derived neurotrophic factor levels, learning capacity and cognition in patients with first episode psychosis

Background: Cognitive impairments are seen in first psychotic episode (FEP) patients. The neurobiological underpinnings that might underlie these changes remain unknown. The aim of this study is to investigate whether Brain Derived Neurotrophic Factor (BDNF) levels are associated with cognitive impairment in FEP patients compared with healthy controls. Methods: 45 FEP patients and 45 healthy controls matched by age, gender and educational level were selected from the Basque Country area of Spain. Plasma BDNF levels were assessed in healthy controls and in patients. A battery of cognitive tests was applied to both groups, with the patients being assessed at 6 months after the acute episode and only in those with a clinical response to treatment. Results: Plasma BDNF levels were altered in patients compared with the control group. In FEP patients, we observed a positive association between BDNF levels at six months and five cognitive domains (learning ability,immediate and delayed memory, abstract thinking and processing speed) which persisted after controlling for medications prescribed, drug use, intelligence quotient (IQ) and negative symptoms. In the healthy control group, BDNF levels were not associated with cognitive test scores. Conclusion: Our results suggest that BDNF is associated with the cognitive impairment seen after a FEP. Further investigations of the role of this neurotrophin in the symptoms associated with psychosis onset are warranted.

Rarefied gas dynamics: fundamentals, simulations and micro flows

Abundance and distribution patters of Hawaiian odontocetes: focus on O'ahu

This dissertation is an assessment of the status of odontocetes in Hawaiian waters focussing on O´ahu. The work builds on available literature, and on data collected by the author and by others in Hawaiian waters. Abundance and distribution patterns of odontocetes were derived from stranding and aerial survey data. A stranding network operated by the National Marine Fisheries Service, Pacific Area Office collected 187 stranding reports throughout the main Hawaiian Islands between 1937 and 2002. These reports included 16 odontocete species. Number of stranding reports increased over time and was highest on O´ahu. Strandings occurred throughout the year. The difference in number of strandings per month was not significant. Fifteen of the 16 species reported in the stranding record for the main Hawaiian Islands were also reported by aerial survey studies of the area between 1993 and 1998. Only 7 of the species reported were detected during aerial transects around O′ahu between 1998 and 2000. Based on the stranding record, Kogia sp., melon-headed whales, striped dolphins and dwarf killer whale appear to be more common than suggested by aerial surveys. Conversely, pilot whales and bottlenose dolphins were more common, according to aerial surveys, than predicted by the stranding data. Aerial surveys of waters between 0 and 500m around the Island of O′ahu showed that the most abundant species by frequency of occurrence was the pilot whale (30% of sightings), followed by the spinner (16%) and bottlenose dolphin (14%). Because of small sample size, abundance estimates for odontocetes have a high level of uncertainty. The unavailability of a correction factor for g(0)<1, and the reduced visibility below the aircraft further reduced accuracy and increased the inherent underestimation in the data. The most abundant species according to distance sampling estimates were spotted dolphins, pilot whales, false killer whales and spinner dolphins. A natural factor shaping the ecology of odontocete populations is predation pressure both by other odontocetes and, more frequently, by sharks. An account of predation by a tiger shark on a spotted dolphin near Penguin Banks is used as an example of the potential mechanisms of predation by sharks on odontocetes.

Robust speed control for a variable speed wind turbine

Modern wind turbines are designed in order to work in variable speed opera-tions. To perform this task, these turbines are provided with adjustable speed generators, like the double feed induction generator (DFIG). One of the main advantages of adjustable speed generators is improving the system efficiency compared with _xed speed generators, because turbine speed can be adjusted as a function of wind speed in order to maximize the output power. However, this system requires a suitable speed controller in order to track the optimal reference speed of the wind turbine. In this work, a sliding mode control for variable speed wind turbines is proposed. The proposed design also uses the vector oriented control theory in order to simplify the DFIG dynamical equations. The stability analysis of the proposed controller has been carried out under wind variations and pa-rameter uncertainties using the Lyapunov stability theory. Finally, the simulated results show on the one hand that the proposed controller provides a high-performance dynamic behavior, and on the other hand that this scheme is robust with respect to parameter uncertainties and wind speed variations, which usually appear in real systems.

Aerodynamic characteristics research on wide-speed range waverider configuration

Waverider generated from a given flow field has a high lift-to-drag ratio because of attached bow shock on leading edge. However, leading edge blunt and off-design condition can make bow shock off leading edge and have unfavorable influence on aerodynamic characteristics. So these two problems have always been concerned as important engineering science issues by aeronautical engineering scientists. In this paper, through respectively using low speed and high speed waverider design principles, a wide-speed rang vehicle is designed, which can level takeoff and accelerate to hypersonic speed for cruise. In addition, sharp leading edge is blunted to alleviated aeroheating. Theoretical study and wind tunnel test show that this vehicle has good aerodynamic performance in wide-speed range of subsonic, transonic, supersonic and hypersonic speeds.

Estimation of the abundance of yellowfin tuna, Thunnus albacares, by age groups and regions within the Eastern Pacific Ocean

ENGLISH: Monthly estimates of the abundance of yellowfin tuna by age groups and regions within the eastern Pacific Ocean during 1970-1988 are made, using purse-seine catch rates, length-frequency samples, and results from cohort analysis. The numbers of individuals caught of each age group in each logged purse-seine set are estimated, using the tonnage from that set and length-frequency distribution from the "nearest" length-frequency sample(s). Nearest refers to the closest length frequency sample(s) to the purse-seine set in time, distance, and set type (dolphin associated, floating object associated, skipjack associated, none of these, and some combinations). Catch rates are initially calculated as the estimated number of individuals of the age group caught per hour of searching. Then, to remove the effects of set type and vessel speed, they are standardized, using separate weiznted generalized linear models for each age group. The standardized catch rates at the center of each 2.5 0 quadrangle-month are estimated, using locally-weighted least-squares regressions on latitude, longitude and date, and then combined into larger regions. Catch rates within these regions are converted to numbers of yellowfin, using the mean age composition from cohort analysis. The variances of the abundance estimates within regions are large for 0-, 1-, and 5-year-olds, but small for 1.5- to 4-year-olds, except during periods of low fishing activity. Mean annual catch rate estimates for the entire eastern Pacific Ocean are significantly positively correlated with mean abundance estimates from cohort analysis for age groups ranging from 1.5 to 4 years old. Catch-rate indices of abundance by age are expected to be useful in conjunction with data on reproductive biology to estimate total egg production within regions. The estimates may also be useful in understanding geographic and temporal variations in age-specific availability to purse seiners, as well as age-specific movements. SPANISH: Se calculan estimaciones mensuales de la abundancia del atún aleta amarilla por grupos de edad y regiones en el Océano Pacífico oriental durante 1970-1988, usando tasas de captura cerquera, muestras de frecuencia de talla, y los resultados del análisis de cohortes. Se estima el número de individuos capturados de cada grupo de edad en cada lance cerquero registrado, usando el tonelaje del lance en cuestión y la distribución de frecuencia de talla de la(s) muestra(s) de frecuencia de talla "más cercana/s)," "Más cercana" significa la(s) muestra(s) de frecuencia de talla más parecida(s) al lance cerquero en cuanto a fecha, distancia, y tipo de lance (asociado con delfines, con objeto flotante, con barrilete, con ninguno de éstos, y algunas combinaciones). Se calculan inicialmente las tasas de captura como el número estimado de individuos del grupo de edad capturado por hora de búsqueda. A continuación, para eliminar los efectos del tipo de lance y la velocidad del barco, se estandardizan dichas tasas, usando un modelo lineal generalizado ponderado, para cada grupo por separado. Se estima la tasa de captura estandardizada al centro de cada cuadrángulo de 2.5°-mes, usando regresiones de mínimos cuadrados ponderados localmente por latitud, longitud, y fecha, y entonces combinándolas en regiones mayores. Se convierten las tasas de captura dentro de estas regiones en números de aletas amarillas individuales, usando el número promedio por edad proveniente del análisis de cohortes. Las varianzas de las estimaciones de la abundancia dentro de las regiones son grandes para los peces de O, 1, Y5 años de edad, pero pequeñas para aquellos de entre 1.5 Y4 años de edad, excepto durante períodos de poca actividad pesquera. Las estimaciones de la tasa de captura media anual para todo el Océano Pacífico oriental están correlacionadas positivamente de forma significativa con las estimaciones de la abundancia media del análisis de las cohortes para los grupos de edad de entre 1.5 y 4 años. Se espera que los índices de abundancia por edad basados en las tasas de captura sean útiles, en conjunto con datos de la biología reproductiva, para estimar la producción total de huevos por regiones. Las estimaciones podrían asimismo ser útiles para la comprensión de las variaciones geográficas y temporales de la disponibilidad específica por edad a los barcos cerqueros, y también las migraciones específicas por edad. (PDF contains 35 pages.)

Soluble Angiopoietin Receptor Tie-2 In Patients With Acute Myocardial Infarction And Its Detection By Optical Protein-Chip

The Tie-2 receptor has been shown to play a role in angiogenesis in atherosclerosis. The conventional method assaying the level of soluble Tie-2 (sTie-2) was ELISA. However, this method has some disadvantages. The aims of this research are to establish a more simple detection method, the optical protein-chip based on imaging ellipsomtry (OPC-IE) applying to Tie-2 assay. The sTie-2 biosensor surface on silicon wafer was prepared first, and then serum levels of sTie-2 in 38 patients with AMI were measured on admission (day 1), day 2, day 3 and day 7 after onset of chest pain and 41 healthy controls by ELISA and OPC-IE in parallel. Median level of sTie-2 increased significantly in the AMI patients when compared with the controls. Statistics showed there was a significant correlation in sTie-2 results between the two methods (r=0.923, P0.01). The result of this study showed that the level of sTie-2 increased in AMI, and OPC-IE assay was a fast, reliable, and convenient technique to measure sTie-2 in serum.

Non-governmental organizations and multi-sited marine conservation science: A case study

Non-governmental organizations (NGOs) are now major players in the realm of environmental conservation. While many environmental NGOs started as national organizations focused around single-species protection, governmental advocacy, and preservation of wilderness, the largest now produce applied conservation science and work with national and international stakeholders to develop conservation solutions that work in tandem with local aspirations. Marine managed areas (MMAs) are increasingly being used as a tool to manage anthropogenic stressors on marine resources and protect marine biodiversity. However, the science of MMA is far from complete. Conservation International (CI) is concluding a 5 year, $12.5 million dollar Marine Management Area Science (MMAS) initiative. There are 45 scientific projects recently completed, with four main “nodes” of research and conservation work: Panama, Fiji, Brazil, and Belize. Research projects have included MMA ecological monitoring, socioeconomic monitoring, cultural roles monitoring, economic valuation studies, and others. MMAS has the goals of conducting marine management area research, building local capacity, and using the results of the research to promote marine conservation policy outcomes at project sites. How science is translated into policy action is a major area of interest for science and technology scholars (Cash and Clark 2001; Haas 2004; Jasanoff et al. 2002). For science to move policy there must be work across “boundaries” (Jasanoff 1987). Boundaries are defined as the “socially constructed and negotiated borders between science and policy, between disciplines, across nations, and across multiple levels” (Cash et al. 2001). Working across the science-policy boundary requires boundary organizations (Guston 1999) with accountability to both sides of the boundary, among other attributes. (Guston 1999; Clark et al. 2002). This paper provides a unique case study illustrating how there are clear advantages to collaborative science. Through the MMAS initiative, CI built accountability into both sides of the science-policy boundary primarily through having scientific projects fed through strong in-country partners and being folded into the work of ongoing conservation processes. This collaborative, boundary-spanning approach led to many advantages, including cost sharing, increased local responsiveness and input, better local capacity building, and laying a foundation for future conservation outcomes. As such, MMAS can provide strong lessons for other organizations planning to get involved in multi-site conservation science. (PDF contains 3 pages)

Studies of the effects from extracts from two local plants (Tephrosia vogelii and Parkia clappertoniana) on Clarias gariepinus (Tengels)

Studies were carried out using 96hr static toxicity bioassay to determine the effect of lethal concentrations of extracts from two local plants Tephrosia vogelii and Parkia clappertoniana which are known fish poison, on a species of mud fish. Clarias gariepinus Phytochemical analysis of the plant extracts was done and the extract from T. vogelii was found to contain alkaloids, tannins and flavonoids, while the extract from P. clappertoniana was formed to contain alkaloids tannins and saponins. Experimental fish were exposed to test water separately polluted by varying concentrations of extraction of both plant species ranging from 0.50mgl super(-1), 1.50mgl super(-1), 2.50mgl super(-1), 3.0mgl super(-1), 5.00mgl super(-1), 10.00mgl super(-1) in the case of T. vogelii and 5.00mgl super(-1), 7.50mgl super(-1), 10.00mgl super(-1), 15.00mgl super(-1), 20.00mgl super(-1) and 30.00mgl super(-1) in the case of P. clappertaniana. Behavioural hispathological and heamatological examinations were made. Both plant extracts were found to have lethal effects at the higher concentrations, affecting the gills and the central nervous system as well as having a depressive effect on the total count and increasing platelet and white blood cell count. Symptoms of toxicosis observed include, initial inactivation agitated swimming, tumbling movement air gulping, increased opercular beat and period of quiescence/knockdown before death. Marked differences were also observed in the hematological and histopathological analysis of poisoned fish. Lower concentrations of the extracts had sub lethal effects on the fish, which manifested as zigzag movement air gulping increased opercular movement etc. None of these effects were observed in the control experiment

Dieta hiperlipídica com ou sem adição de sal modula diferentemente a produção de peptídeo natriurético atrial e a expressão de renina em camundongos

Estudo dos efeitos de uma dieta rica em sal e / ou gordura saturada em grânulos de peptídeo natriurético atrial (ANP), hipertensão, expressão da renina e ultraestrutura cardíaca em camundongos C57Bl / 6. Camundongos machos adultos jovens foram separados em quatro grupos (n = 12) e alimentados com uma das seguintes dietas por 9 semanas: dieta padrão para roedores (Grupo P), dieta hiperlipídica (Grupo HL), dieta hipersódica (Grupo HS) e dieta hiperlipídica e hipersódica simultaneamente (HL-HS). Foram examinados: alterações no ANP sérico, ultra-estrutura dos cardiomiócitos produtores de ANP, estrutura do ventrículo esquerdo, pressão arterial sanguínea, expressão da renina no rim, taxa de filtração glomerular (TFG), eficiência alimentar, parâmetros lipídicos e glicídicos. Os animais alimentados com dieta hiperlipídica mostraram um pequeno aumento na produção de ANP, discreta hipertrofia ventricular esquerda, aumento da eficiência alimentar, dislipidemia e hiperglicemia. Animais alimentados com dieta hipersódica tiveram um grande aumento na produção de grânulos de ANP e correspondente elevação do seu nível sérico, hipertrofia ventricular esquerda, hipertensão arterial, diminuição dos níveis de renina e aumento da TFG. A combinação das duas dietas (HL-HS) teve um efeito aditivo. A ingestão de uma dieta com alto teor de sal e lipídeos induz alterações ultraestruturais dos cardiomiócitos, aumento da produção de ANP e elevação de seu nível sérico e reduz a quantidade de renina no rim.

Avaliação da sorção de Cu (II) e Hg (II) pela Sargassum sp modificado com epicloridrina

É crescente o aumento da preocupação do homem com a contaminação de ambientes aquáticos uma vez que da subsistência dos mesmos depende o bem estar de todos. Ao mesmo tempo em que cresce a preocupação tem aumentado a quantidade de pesquisas em busca de tecnologias alternativas ao tratamento e remediação de efluentes aquosos contaminados pelas mais diversas substâncias incluindo os metais pesados. Nas últimas décadas, tem crescido o número de trabalhos avaliando a capacidade de sorção e a viabilidade da utilização de biossorventes de baixo custo na captação de íons metálicos e um desses materiais são as biomassas de algas pardas. Dentre os vários gêneros existentes no planeta o território brasileiro é rico na macroalga do gênero Sargassum. Muito embora a composição dessas biomassas varie o principal constituinte das mesmas é o ácido algínico e seus sais alcalinos na forma de um copolímero linear, homopolimérico, com unidades do ácido manurônico, (M), (1-4)-β-D- ligado e seu epímero em C-5 nos resíduos α-L-gulurônicos, (G), respectivamente, covalentemente ligados entre si em sequencias diferenciadas ou em blocos. Os monômeros podem aparecer em blocos homopoliméricos consecutivos, resíduos G (unidades G), resíduos consecutivos M (unidades M), pequenas unidades alternadas M e G (blocos MG), ou em blocos aleatoriamente organizados. A proposta dessa dissertação é realizar a modificação do copolímero existente na biomassa com epicloridrina, avaliar e comparar a captação de íons Cu (II) e Hg (II) pela biomassa da alga Sargassum sp., com a biomassa não modificada e resultados publicados na literatura

Síntese e caracterização de copolímeros à base de poli(metacrilato de metila) e divinilbenzeno com propriedades magnéticas

Nesta dissertação, foram sintetizados copolímeros à base de poli(metacrilato de metila) (PMMA), divinilbenzeno (DVB) com propriedades magnéticas pela técnica de polimerização em suspensão. O material utilizado para conferir propriedade magnética foi o ferro. Foi estudada a influência das variáveis reacionais para a formação de microesferas (ordem de adição das fases orgânica e aquosa e a dispersão do ferro antes e após a pré-polimerização), o efeito da concentração de ferro adicionado na polimerização, a influência da razão molar MMA/DVB na formação do copolímero, o efeito do tipo de agente de suspensão e a velocidade de agitação para a síntese dos copolímeros. Os copolímeros foram caracterizados quanto à morfologia, estabilidade térmica, teor de ferro incorporado, distribuição de tamanho de partículas, propriedades magnéticas, área superficial, volume e tamanho de poros. As análises de propriedades magnéticas mostraram que os materiais obtidos não apresentaram ciclos de histerese, estando assim próximos de um material com propriedades superparamagnéticas, com magnetização de saturação entre 8,0 e 13,0 emu/g. Os copolímeros sintetizados com velocidade de agitação 500 RPM, temperaturade 90 C, tempo de polimerização de 24h, monômeros MMA/DVB 50/50 (% molar); razão volumétrica fase orgânica/fase aquosa 1/3, diluente heptano, grau de diluição 100% apresentaram melhor controle morfológico, melhor magnetização de saturação, tamanho de partículas menores e maior tamanho de poros

Preparação e caracterização de bionanocompósitos à base de gelatina e magnetita reticulados com sacarose

Nesta dissertação, foram estudadas a preparação e a caracterização debionanocompósitos à base de gelatina e magnetita. Sacarose foi empregada comoagente de reticulação e gelatina tipo A e gelatina tipo B foram comparadas nautilização para a preparação das microesferas por meio de emulsão água-em-óleo.As microesferas foram caracterizadas por VSM, DSC, TGA, FTIR, testes deinchamento, espectroscopia de absorção atômica, microscopia ótica e microscopiaeletrônica de varredura. Um planejamento de experimentos variando-se aconcentração de gelatina e de sacarose, a temperatura e a velocidade de agitaçãofoi realizado a fim de encontrar quais parâmetros influenciam o diâmetro dasmicroesferas. A concentração de gelatina e velocidade de agitação foram osparâmetros diretamente associados com os tamanhos de partículas. A distribuiçãode tamanho das partículas revelou que o diâmetro das microesferas variou de 5 a 60micrômetros, com predominância na faixa de 11 a 30 micrômetros. A extensão dareticulação foi aumentada com o aumento do tempo de aquecimento na etapa depreparação das microesferas. Todos os bionanocompósitos apresentaramsuperparamagnetismo. Os resultados mostraram que não há diferença significativa entre a utilização de gelatina do tipo A e gelatina do tipo B. Além disso, o estudo de reticulação degelatina revelou que, ao contrário do que diz a literatura, a sacarose não é umagente de reticulação para as cadeias proteicas, pois não foram encontradasevidências de uma reação química entre a sacarose e gelatina