Somitogenesis is a hallmark of vertebrate embryonic development. For years, researchers have been studying this process in a variety of organisms using a wide range of techniques encompassing ex vivo and in vitro approaches. However, most studies still rely on the analysis of two-dimensional (2D) imaging data, which limits proper evaluation of a developmental process like axial extension and somitogenesis involving highly dynamic interactions in a complex 3D space. Here we describe techniques that allow mouse live imaging acquisition, dataset processing, visualization and analysis in 3D and 4D to study the cells (e.g., neuromesodermal progenitors) involved in these developmental processes. We also provide a step-by-step protocol for optical projection tomography and whole-mount immunofluorescence microscopy in mouse embryos (from sample preparation to image acquisition) and show a pipeline that we developed to process and visualize 3D image data. We extend the use of some of these techniques and highlight specific features of different available software (e.g., Fiji/ImageJ, Drishti, Amira and Imaris) that can be used to improve our current understanding of axial extension and somite formation (e.g., 3D reconstructions).Altogether, the techniques here described emphasize the importance of 3D data visualization and analysis in developmental biology, and might help other researchers to better address 3D and 4D image data in the context of vertebrate axial extension and segmentation. Finally, the work also employs novel tools to facilitate teaching vertebrate embryonic development.

Resumo. Na projeção de um sistema de comunicação digital descrito em um espaço hiperbólicoé muito importante o estabelecimento de um sistema construtivo de reticulados, como elemento chave para a determinação de constelações INTRODUÇÃOA busca por constelações de sinais que apresentem a menor probabilidade de erro, está diretamente relacionada ao problema de projetar sistemas de comunicações digitais eficientes em faixa e potência. Desta maneira se torna importante a fundamentação matemática dos códigos geometricamente uniformes através da utilização de estruturas topológicas como mostrado em B. Silva; M. (2005). Este aparato diferenciado de códigos e modulações através do estudo de espaços topológicos relacionados, bem como, das superfícies de Riemann envolvidas, permite um melhor entendimento do processo de geração de constelações de sinais. Em H. Lazari; R. Palazzo Jr. (2005) foi proposto pela primeira vez um sistema de comunicação hiperbólico considerando as tesselações auto-duais {p, p}, um importante subconjunto das tesselações {p, q} com p = q, onde {p, q} denota um polígono regular de p arestas, de tal forma que em cada vértice, q desses polígonos regulares se encontram tendo em comum somente as arestas.Em E.D. Carvalho (2001), forneceu-se técnicas para a geração de alfabetos de códigos corretores de erros dotados de uma estrutura algébrica, a partir das constelações de sinais geometricamente uniformes, cujos sinais sejam rotulados por elementos de um p-grupo G p m e por elementos de um grupo de Galois GF (p m )) em espaços de sinais euclidianos identificados por elementos de um anel de inteiros e em espaços de sinais no plano hiperbólico identificados por elementos de uma ordem de quatérnios. Em Rodrigo Gusmão Cavalcante (2008), foi realizada a análise de desempenho de constelações de sinais geometricamente uniformes provenientes de tesselações hiperbólicas, onde mostra-se que quanto maior for o gênero da superfície menor será o valor da probabilidade de erro associada. Por outro lado, em João de Deus Lima (2002) caracterizou-se as estruturas algébricas e geométricas associadas a canais discretos sem memória (DMC), determinando o conjunto das superfícies no qual o grafo correspondente ao DMC está mergulhado.

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Optically tunable gold nanoparticles have been widely used in research with near-infrared light as a means to enhance laser-induced thermal therapy since it capitalises on nanoparticles' plasmonic heating properties. There have been published several studies on numerical models replicating this therapy in such conditions. However, there are several limitations on some of the models which can render the model unfaithful to therapy simulations. In this paper, two techniques of simulating laser induced thermal therapy with a high absorbing localised region of interest inside a phantom are compared. To validate these models we conducted an experiment of an agar-agar phantom with an inclusion reproducing it with both models. The phantom was optically characterized by absorption and total attenuation. The first model is based on the macro perspective solution of the radiative transfer equation given by the diffusion equation, which is then coupled with the Pennes bioheat equation to obtain temperature. The second is a Monte Carlo model that considers a stochastic solution of the same equation and is also considered as input to the Pennes bioheat transfer equation which is then computed. The Monte Carlo is in good agreement with the experimental data having an average percentage difference of 4.5% and a correlation factor of 0.98, while the diffusion method comparison with experimental data is 61% and 0.95 respectively. The optical characterisation of the phantom and its inclusion were also validated indirectly since the Monte Carlo, which used those parameters, was also validated. While knowing the temperature in all points inside a body during photothermal therapy is important, one has to be mindful of the model which fit the conditions and properties. There are several reasons to justify the discrepancy of the diffusion method: low scattering conditions, absorption and reduced scattering are comparable. The error bars that are normally associated when characterizing an optical phantom can justify also a part of that uncertainty. For low size tumours in depth, one may have to increase the light dosage in photothermal therapies to have a more effective treatment.

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Radiation therapy is one of many common treatments applied to breast cancer. Most usual radiation sources applied are ionizing radiation, such as γ-rays and X-rays, and non-ionizing radiation such as ultraviolet radiation. The possibility of using near infrared light to photoactivate a drug inside an 8 cm diameter biological object is discussed in this work via Monte Carlo simulations. Two simulation setups performed in the Geant4/GAMOS framework are presented in order to study the viability of photoactivating a drug by using several near infrared light sources. The overall objective of this technique is to minimize energy concentrated at objects surface and maximize it in a predefined region of interest. Results show an increase energy absorption in the desired region of interest inside a 8 cm object, when a higher absorption particle is present. With the use of multiple sources it is possible to photoactivate the drug while causing minimal damage to the surface of the radiated object.