265 research outputs found

    Small-Scale Fluidized Bed Bioreactor for Long-Term Dynamic Culture of 3D Cell Constructs and in vitro Testing

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    With the increasing interest in three-dimensional (3D) cell constructs that better represent native tissues, comes the need to also invest in devices, i.e., bioreactors, that provide a controlled dynamic environment similar to the perfusion mechanism observed in vivo. Here a laboratory-scale fluidized bed bioreactor (sFBB) was designed for hydrogel (i.e., alginate) encapsulated cells to generate a dynamic culture system that produced a homogenous milieu and host substantial biomass for long-term evolution of tissue-like structures and “per cell” performance analysis. The bioreactor design, conceptualized through scale-down empirical similarity rules, was initially validated through computational fluid dynamics analysis for the distributor capacity of homogenously dispersing the flow with an average fluid velocity of 4.596 × 10–4 m/s. Experimental tests then demonstrated a consistent fluidization of hydrogel spheres, while maintaining shape and integrity (606.9 ± 99.3 μm diameter and 0.96 shape factor). It also induced mass transfer in and out of the hydrogel at a faster rate than static conditions. Finally, the sFBB sustained culture of alginate encapsulated hepatoblastoma cells for 12 days promoting proliferation into highly viable (>97%) cell spheroids at a high final density of 27.3 ± 0.78 million cells/mL beads. This was reproducible across multiple units set up in parallel and operating simultaneously. The sFBB prototype constitutes a simple and robust tool to generate 3D cell constructs, expandable into a multi-unit setup for simultaneous observations and for future development and biological evaluation of in vitro tissue models and their responses to different agents, increasing the complexity and speed of R&D processes

    High connectivity of the Crocodile Shark between the Atlantic and Southwest Indian Oceans: highlights for conservation

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    Among the various shark species that are captured as bycatch in commercial fishing operations, the group of pelagic sharks is still one of the least studied and known. Within those, the crocodile shark, Pseudocarcharias kamoharai, a small-sized lamnid shark, is occasionally caught by longline vessels in certain regions of the tropical oceans worldwide. However, the population dynamics of this species, as well as the impact of fishing mortality on its stocks, are still unknown, with the crocodile shark currently one of the least studied of all pelagic sharks. Given this, the present study aimed to assess the population structure of P. kamoharai in several regions of the Atlantic and Indian Oceans using genetic molecular markers. The nucleotide composition of the mitochondrial DNA control region of 255 individuals was analyzed, and 31 haplotypes were found, with an estimated diversity Hd = 0.627, and a nucleotide diversity pi = 0.00167. An analysis of molecular variance (AMOVA) revealed a fixation index phi(ST) = -0.01118, representing an absence of population structure among the sampled regions of the Atlantic Ocean, and between the Atlantic and Indian Oceans. These results show a high degree of gene flow between the studied areas, with a single genetic stock and reduced population variability. In panmictic populations, conservation efforts can be concentrated in more restricted areas, being these representative of the total biodiversity of the species. When necessary, this strategy could be applied to the genetic maintenance of P. kamoharai.Foundation for Research Support of the Sao Paulo State - FAPESP [2011/23787-0, 2010/51903-2]; Portuguese Foundation for Science and Technology (FCT) [SFRH/BPD/93936/2013]; Foundation for Research Support of the Sao Paulo State - FAPESP [2011/23787-0, 2010/51903-2]; Portuguese Foundation for Science and Technology (FCT) [SFRH/BPD/93936/2013]info:eu-repo/semantics/publishedVersio

    Zoneamento das áreas suscetíveis à desertificação do estado de Pernambuco.

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    Desertificação - conceitos adotados; Combate à desertificação como medida de adaptação às mudanças climáticas; Desertificação e os Objetivos de Desenvolvimento Sustentável Gênero e desertificação; Aspectos metodológicos; Do mapeamento das variáveis biofísicas; Da realização dos Diálogos Municipais e Workshops Regionais; Desertificação no estado de Pernambuco; Um panorama da suscetibilidade à desertificação em Pernambuco em dois recortes temporais; Suscetibilidade à Desertificação nas Regiões de Desenvolvimento Situadas no Semiárido; Região de Desenvolvimento Agreste Setentrional; Região de Desenvolvimento Agreste Central; Região de Desenvolvimento Agreste Meridional; Região de Desenvolvimento Sertão do Pajeú; Região de Desenvolvimento Sertão do Moxotó; Região de Desenvolvimento Sertão de Itaparica; Região de Desenvolvimento Sertão Central Região de Desenvolvimento Sertão do Araripe; Semiárido, desertificação e zoneamento na percepção dos atores locais; Semiárido, desertificação e zoneamento na percepção dos atores locais das RDs do Agreste; Semiárido, desertificação e zoneamento na percepção dos atores locais das RDs do Sertão; Refletir o agora e olhar para o futuro.bitstream/item/222045/1/Zoneamento-PE.-2020.pd

    Depth cues and perceived audiovisual synchrony of biological motion

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    Due to their different propagation times, visual and auditory signals from external events arrive at the human sensory receptors with a disparate delay. This delay consistently varies with distance, but, despite such variability, most events are perceived as synchronic. There is, however, contradictory data and claims regarding the existence of compensatory mechanisms for distance in simultaneity judgments. Principal Findings: In this paper we have used familiar audiovisual events – a visual walker and footstep sounds – and manipulated the number of depth cues. In a simultaneity judgment task we presented a large range of stimulus onset asynchronies corresponding to distances of up to 35 meters. We found an effect of distance over the simultaneity estimates, with greater distances requiring larger stimulus onset asynchronies, and vision always leading. This effect was stronger when both visual and auditory cues were present but was interestingly not found when depth cues were impoverished. Significance: These findings reveal that there should be an internal mechanism to compensate for audiovisual delays, which critically depends on the depth information available.FEDERFundação para a Ciência e a Tecnologia (FCT

    Evaluation of 3-(3-chloro-phenyl)-5-(4-pyridyl)-4,5-dihydroisoxazole as a Novel Anti-Inflammatory Drug Candidate

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    BACKGROUND: 3-(3-chloro-phenyl)-5-(4-pyridyl)-4,5-dihydroisoxazole (DIC) is a five-membered heterocyclic compound containing a N-O bond. The anti-inflammatory effects of this compound were studied both in vitro and in vivo. PRINCIPAL FINDINGS: DIC effectively decreased TNF-α and IL-6 release from LPS-stimulated macrophages in a dose dependent manner. DIC diminished the levels of COX-2 with subsequent inhibition of PGE(2) production. DIC also compromised HMGB1 translocation from the nucleus to the cytoplasm. Moreover, DIC prevented the nuclear translocation of NF-κB and inhibited the MAPK pathway. In vivo, DIC inhibited migration of neutrophils to the peritoneal cavity of mice. CONCLUSIONS: This study presents the potential utilization of a synthetic compound, as a lead for the development of novel anti-inflammatory drugs
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