914 research outputs found
Application of bacterial and yeast biosurfactants for enhanced removal and biodegradation of motor oil from contaminated sand
Background: This study investigated the potential application of two
biosurfactants for enhanced removal capability and biodegradation of
motor oil contaminated sand under laboratory conditions. The
biosurfactants were produced by the yeast Candida sphaerica and by
the bacterium Bacillus sp. cultivated in low-cost substrates. The
ability of removing motor oil from soil by the two biosurfactants was
identified and compared with that of the synthetic surfactants Tween 80
and Triton X-100. Results: Both crude and isolated biosurfactants
showed excellent effectiveness on motor oil removal from contaminated
sand under kinetic conditions (70\u201390%), while the synthetic
surfactants removed between 55 and 80% of the oil. A contact time of
5\u201310 min under agitation seemed to be enough for oil removal with
the biosurfactants and synthetic surfactants tested. The crude and the
isolated biosurfactant from C. sphaerica were able to remove high
percentages of motor oil from packed columns (around 90%) when compared
to the biosurfactant from Bacillus sp. (40%). For the degradation
experiments conducted in motor oil contaminated sand enriched with
sugar cane molasses, however, oil degradation reached almost 100% after
90 d in the presence of Bacillus sp. cells, while the percentage of oil
degradation did not exceed 50% in the presence of C. sphaerica. The
presence of the biosurfactants increased the degradation rate in
10\u201320%, especially during the first 45 d, indicating that
biosurfactants acted as efficient enhancers for hydrocarbon
biodegradation. Conclusions: The results indicated the biosurfactants
enhancing capability on both removal and rate of motor oil
biodegradation in soil systems
Beaming into the Rat World: Enabling Real-Time Interaction between Rat and Human Each at Their Own Scale
Immersive virtual reality (IVR) typically generates the illusion in participants that they are in the displayed virtual scene where they can experience and interact in events as if they were really happening. Teleoperator (TO) systems place people at a remote physical destination embodied as a robotic device, and where typically participants have the sensation of being at the destination, with the ability to interact with entities there. In this paper, we show how to combine IVR and TO to allow a new class of application. The participant in the IVR is represented in the destination by a physical robot (TO) and simultaneously the remote place and entities within it are represented to the participant in the IVR. Hence, the IVR participant has a normal virtual reality experience, but where his or her actions and behaviour control the remote robot and can therefore have physical consequences. Here, we show how such a system can be deployed to allow a human and a rat to operate together, but the human interacting with the rat on a human scale, and the rat interacting with the human on the rat scale. The human is represented in a rat arena by a small robot that is slaved to the human’s movements, whereas the tracked rat is represented to the human in the virtual reality by a humanoid avatar. We describe the system and also a study that was designed to test whether humans can successfully play a game with the rat. The results show that the system functioned well and that the humans were able to interact with the rat to fulfil the tasks of the game. This system opens up the possibility of new applications in the life sciences involving participant observation of and interaction with animals but at human scale
Avaliação da técnica de lise mediada por complemento em pacientes chagásicos crônicos tratados com drogas tripanosomicidas
Levels of lytic antibodies were determined by complement mediated lysis (CoML) in chronic chagasic patients treated with nifurtimox orbenznidazole. Two groups of patients were studied: one who had been treated more than six years ago and another with less than six years since treatment, although serologic reactions remained positive. CoML was carried out in two samples obtained from patients on different occasions, in test groups as well as in positive controls. In view of results observed sensitivity of reaction (83.3%) and its specifity (100.0%) were calculated. It was observed that about half of the patients presented lysis up to 20% and this result may corroborate "parasitological cure". It was noted that 43.6% of patients treated more than six years ago and 20.0% of patients with less than six years since treatment presented variable results, either positive or negative, differing for each sample from the same individual. Such results were thus considered as inconclusive, since parasitological tests remain negative. A prolonged follow-up may shed light over such results.Os nÃveis de anticorpos lÃticos foram determinados em pacientes chagásicos crônicos, tratados com nifurtimox ou benzonidazol, através da Lise Mediada por Complemento (LMCo). Dois grupos de pacientes foram estudados: um grupo tratado há mais de seis anos e outro há menos de seis anos. Ambos os grupos, após o tratamento, apresentaram xenodiagnósticos negativos, embora as provas sorológicas permanecessem reagentes. Foram incluÃdos um grupo controle negativo com provas sorológicas não reagentes e um grupo controle positivo com provas sorológicas e parasitológicas positivas. Para a LMCo foram utilizadas duas amostras de cada paciente, obtidas em ocasiões diferentes, tanto dos grupos estudados quanto do grupo controle positivo. Em vista dos resultados foi calculada a sensibilidade da reaçáo (83.3%) e a especificidade (100,0%). Nos grupos estudados observou-se que cerca da metade dos pacientes apresentaram lise menor do que 20%, podendo, este resultado, corroborar a "cura parasitológica". Notou-se que 43,6% dos pacientes tratados há mais de seis anos apresentaram resultados contraditórios, ora negativos, ora positivos, dependendo da amostra. Tais resultados foram considerados inconclusivos, em virtude das provas parasitológicas permanecerem negativas. Um seguimento a longo prazo poderá esclarecer o significado desses resultados
A Novel Neural Substrate for the Transformation of Olfactory Inputs into Motor Output
Anatomical and physiological experiments in the lamprey reveal the neural circuit involved in transforming olfactory inputs into motor outputs, which was previously unknown in a vertebrate
Genetic characterization of cassava (Manihot esculenta) landraces in Brazil assessed with simple sequence repeats
Based on nine microsatellite loci, the aim of this study was to appraise the genetic diversity of 42 cassava (Manihot esculenta) landraces from selected regions in Brazil, and examine how this variety is distributed according to origin in several municipalities in the states of Minas Gerais, São Paulo, Mato Grosso do Sul, Amazonas and Mato Grosso. High diversity values were found among the five above-mentioned regions, with 3.3 alleles per locus on an average, a high percentage of polymorphic loci varying from 88.8% to 100%, an average of 0.265 for observed heterozygosity and 0.570 for gene diversity. Most genetic diversity was concentrated within the regions themselves (HS = 0.52). Cluster analysis and principal component based scatter plotting showed greater similarity among landraces from São Paulo, Mato Grosso do Sul and Amazonas, whereas those from Minas Gerais were clustered into a sub-group within this group. The plants from Mato Grosso, mostly collected in the municipality of General Carneiro, provided the highest differentiation. The migration of human populations is one among the possible reasons for this closer resemblance or greater disparity among plants from the various regions
Genomic, Pathway Network, and Immunologic Features Distinguishing Squamous Carcinomas
This integrated, multiplatform PanCancer Atlas study co-mapped and identified distinguishing
molecular features of squamous cell carcinomas (SCCs) from five sites associated with smokin
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