Morphological characterisation of microbial aggregates by image analysis

A program, was accomplished in MATLAB, that allows the morphological characterisation of particles with special emphasis to microbial aggregates. After automatic identification and isolation of different particles in a real image, the program determines several fractal dimensions as the mass dimension, the surface dimension, the area versus perimeter dimension, and the area vs. Feret diameter. The values of many other parameters are also provided, such as: convexity, compactness, roundness, as well as the 0th, 1st, and 2nd moments, whether the 0th moment is the area or the volume of the particle. The program also displays the particle size distribution. The program is easy to operate and all the steps that need decisions from the user are displayed in menus and buttons. As an example of application, the morphological characterisation of different microbial aggregates present in anaerobic wastewater treatment systems has been performed

Higher-Derivative Two-Dimensional Massive Fermion Theories

We consider the canonical quantization of a generalized two-dimensional massive fermion theory containing higher odd-order derivatives. The requirements of Lorentz invariance, hermiticity of the Hamiltonian and absence of tachyon excitations suffice to fix the mass term, which contains a derivative coupling. We show that the basic quantum excitations of a higher-derivative theory of order 2N+1 consist of a physical usual massive fermion, quantized with positive metric, plus 2N unphysical massless fermions, quantized with opposite metrics. The positive metric Hilbert subspace, which is isomorphic to the space of states of a massive free fermion theory, is selected by a subsidiary-like condition. Employing the standard bosonization scheme, the equivalent boson theory is derived. The results obtained are used as a guideline to discuss the solution of a theory including a current-current interaction.Comment: 23 pages, Late

Aplicações de técnicas de processamento e análise de imagem em processos biotecnológicos

Neste trabalho, são apresentados quatro estudos utilizando técnicas de processamento e análise de imagem e de estatística multivariável para monitorizar processos aeróbios e anaeróbios de tratamento de águas residuais. Num primeiro caso visando a caracterização de lamas activadas de uma estação de tratamento de águas residuais (ETAR) foram examinados o conteúdo e morfologia de agregados e bactérias filamentosas. O segundo teve por objectivo a identificação dos protozoários e metazoários através da sua caracterização morfológica e tratamento dos dados por técnicas de estatística multivariável. Relativamente aos processos anaeróbios foi, num primeiro estudo, monitorizado o processo de granulação de um reactor granulado de leito expandido (EGSB), através do estudo das mudanças morfológicas dos agregados microbianos. Finalmente, foi também estudado um processo de desgranulação dos agregados microbianos anaeróbios devido a alimentação com oleato, novamente pela determinação das mudanças morfológicas dos agregados microbianos

Extended-release niacin increases anti-apolipoprotein A-I antibodies that block the antioxidant effect of high-density lipoprotein-cholesterol: the EXPLORE clinical trial.

Extended-release niacin (ERN) is the most effective agent for increasing high-density lipoprotein-cholesterol (HDL-C). Having previously identified anti-HDL antibodies, we investigated whether ERN affected the antioxidant capacity of HDL and whether ERN was associated with the production of antibodies against HDL (aHDL) and apolipoprotein A-I (aApoA-I). METHODS: Twenty-one patients older than 18 years, with HDL-C ≤40 mg dl-1 (men) or ≤50 mg dl-1 (women) were randomly assigned to receive daily ERN (n = 10) or placebo (n = 11) for two sequential 12-week periods, with 4 weeks of wash-out before cross-over. Primary outcome was change of paraoxonase-1 (PON1) activity and secondary outcomes were changes in aHDL and aApoA-I antibodies. Clinical Trial Unique Identifier: EudraCT 2006-006889-42. RESULTS: The effect of ERN on PON1 activity was nonsignificant (coefficient estimate 20.83 U l-1 , 95% confidence interval [CI] -9.88 to 51.53; P = 0.184). ERN was associated with an increase in HDL-C levels (coefficient estimate 5.21 mg dl-1 , 95% CI 1.16 to 9.25; P = 0.012) and its subclasses HDL2 (coefficient estimate 2.46 mg dl-1 , 95% CI 0.57 to 4.34; P = 0.011) and HDL3 (coefficient estimate 2.73 mg dl-1 , 95% CI 0.47 to 4.98; P = 0.018). ERN was significantly associated with the production of aApoA-I antibodies (coefficient estimate 0.25 μg ml-1 , 95% CI 0.09-0.40; P = 0.001). aApoA-I titres at baseline were correlated with decreased PON activity. CONCLUSIONS: The rise in HDL-C achieved with ERN was not matched by improved antioxidant capacity, eventually hampered by the emergence of aApoA-I antibodies. These results may explain why Niacin and other lipid lowering agents fail to reduce cardiovascular risk.info:eu-repo/semantics/publishedVersio

Morphological analysis of Yarrowia lipolytica under stress conditions through image processing

Yarrowia lipolytica is an aerobic microrganism capable to produce important metabolites, has an intense secretory activity which drives efforts to be employed in industry (as a biocatalyst), in molecular biology and genetics studies. Dimorphism is refeered to fungi ability to growth in two distinct forms, usually as single oval cells os as a filament and to be reversible between each one. The cell shape is controlled by environmental factors and has been seeked by some authors [1,2,3]. Y. lipolytica has been considered an adequate model for dimorphism studies in yeasts since it has an efficient system for transformation and is easy to distinct between its morphological forms, on opposite to S. cerevisiae that do not produce true filaments and exhibits pseudohyphae growth under nitrogen limited conditions. Y. lipolytica has an hyphae diameter corresponding 60 to 100% of its single cell stage [4,5]. It is believed that Y. lipolytica dimorphism is related to defense mechanism from adverse conditions. The aim of this work resides on investigate morphological changes in Y. lipolytica under thermal and oxidative stress conditions. Yarrowia lipolytica (IMUFRJ 50682) was cultivated in YPD medium (glucose 2%, peptone 0.64%, yeast extract 1%) at 29oC and 160 rpm. Thermal stress experiments were carried employing a temperature shift (37oC / 1 h.). For oxidative ones, an addition of H2O2 was used to reach final concentration of 10mM. Both stress conditions were applied at exponential growth phase. Morphology was observed in a optic microscope (Axiolab, Zeiss) and cell characteristics were determined employing image processing analysis (Matlab v. 6.1, The Mathworks Inc.) and comparisons were carried on to a control system. A net increase around 22% on hyphae formation was detected as well as a significant increment in its length in relation to control system, when both thermal and oxidative stress was applied. The results herein obtained drives to consider a possible relationship between dimorphism and a cell response mechanism to stress conditions.Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq); Fundação para a Ciência e a Tecnologia (FCT); CAPES

Aplicações de técnicas de análise de imagem em microbiologia ambiental

São evidenciadas algumas aplicações da análise de imagem em microbiologia ambiental, nomeadamente: o reconhecimento e identificação automática de algumas espécies de protozoários presentes em estações de tratamento de águas residuais; o estudo da influência de três tóxicos na mobilidade do protozoário ciliado Tetrahymena pyriformis em meio líquido; a correlação entre actividade metanogénica, velocidade de sedimentação e parâmetros morfológicos de agregados microbianos em digestores anaeróbios; e finalmente o estudo da correlação entre as actividades metanogénicas acetoclástica e hidrogenofílica e a fluorescência de um consórcio de microrganismos de um digestor anaeróbio. Procura-se assim demonstrar a utilidade das técnicas de análise de imagem na monitorização quer de processos de tratamento de águas resíduais quer da própria qualidade ambiental.Ministério da Ciência e Tecnologia. Instituto de Cooperação Científica e Tecnológica Internacional (ICCTI).Embaixada de França em Portugal

Tailoring Ca3Co4O9 microstructure and performances using a transient liquid phase sintering additive

et al.A flexible, adaptable, economical and easily scalable processing route, allowing microstructural control, is presented. It involves classical solid state sintering method and addition of liquid promoting compound. Controlled porosity and high thermoelectric performance have been attained in CaCoO by KCO additions, drastically improving the sintering procedure. KCO behaves as transient liquid phase, providing microstructural benefits, vanishing during sintering. Electrical resistivity was improved by enhanced grains connectivity and growth. Significant increase in Seebeck coefficient at high temperatures has been produced while lattice thermal conductivity was unaffected. The best ZT value, estimated at 800°C, assuming the thermal conductivity value at 140°C, is 0.35 for 5wt.% KCO samples. These values are significantly higher than that obtained in highly-dense textured materials at the same temperature. The results suggest that this approach is very effective for preparing highly-performing CaCoO-based thermoelectric materials with relatively high porosity to control thermal conductivity.The authors wish to thank the MINECO-FEDER (MAT2013-46505-C3-1-R) and Gobierno de Aragón-Fondo Social Europeo (Research Groups T12 and T87) for financial support. This research was also partially supported by FCT, Portugal (IF/00302/2012 and PEst-C), project RECI/CTM-CER/0336/2012 co-financed by FEDER, QREN reference COMPETE: FCOMP-01-0124-FEDER-027465, and the projects financed by national funds through the FCT/MEC: UID/CTM/50025/2013, UID/CTM/50011/2013.Peer Reviewe

Desempenho reprodutivo de novilhas de corte expostas a diferentes métodos de bioestimulação.

Nota breve