564 research outputs found
exploding clusters dynamics probed by XUV fluorescence
Clusters excited by intense laser pulses are a unique source of warm dense
matter, that has been the subject of intensive experimental studies. The
majority of those investigations concerns atomic clusters, whereas the
evolution of molecular clusters excited by intense laser pulses is less
explored. In this work we trace the dynamics of clusters
triggered by a few-cycle 1.45-m driving pulse through the detection of XUV
fluorescence induced by a delayed 800-nm ignition pulse. Striking differences
among fluorescence dynamics from different ionic species are observed
Estudo da composição genética de rebanho-núcleo da raça Canchim por meio de análise de pedigree: resultados preliminares
Microfabricated and multilayered PLGA structure for the development of co-cultured in vitro liver models
One of the main advantages of having an in vitro model is the possibility of reducing toxic effects of drugs on human body and evaluate their response to pharmacological treatments to improve the efficacy of a patient-specific therapy. The limitation of such in vitro model is the use of monolayer hepatocytes cultures that show some problems of protein secretion and hepatic functionality. In order to overcome these drawbacks, we present two innovative multilayer structures based on micro-stamped poly(lactic-co-glycolic acid) (PLGA) structures and hepatocytes and fibroblast co-cultures. In particular, the first model consisted of 1 up to 5 layers of PLGA seeded with the previously cited co-culture, while the second model consisted of various sandwich structures of PLGA functionalised (or not) with collagen and seeded with hepatocytes and/or fibroblasts. A mechanical analysis, contact angle and surface charge density measurements were carried out. After these preliminary tests, a metabolic analysis was performed evaluating glucose consumption and urea and albumin production over a culture period of 11 days. Results showed promising application of these in vitro liver models, in particular considering the field of cirrhotic liver treatment
Phase-matching effects in the generation of high-energy photons by mid-infrared few-cycle laser pulses
We report on our experimental and theoretical investigations on the generation of high-order harmonics driven by 1500 nm few-cycle laser pulses in xenon. In contrast to the common belief, we found experimental evidence suggesting that harmonic generation driven by mid-infrared laser pulses can be realized with high efficiency; in particular, an enhancement of very high harmonic orders can be achieved under suitable conditions of the laser–medium interaction. The experimental results were simulated by a 3D non-adiabatic model. The theoretical outcomes confirm the experimental findings and provide a physical explanation for the counter-intuitive results. In particular, a time-dependent phase-matching analysis threw light on the generation mechanisms at a timescale of half optical cycle of the fundamental pulse
High-order harmonic spectroscopy for molecular imaging of polyatomic molecules
High-order harmonic generation is a powerful and sensitive tool for probing
atomic and molecular structures, combining in the same measurement an
unprecedented attosecond temporal resolution with a high spatial resolution, of
the order of the angstrom. Imaging of the outermost molecular orbital by
high-order harmonic generation has been limited for a long time to very simple
molecules, like nitrogen. Recently we demonstrated a technique that overcame
several of the issues that have prevented the extension of molecular orbital
tomography to more complex species, showing that molecular imaging can be
applied to a triatomic molecule like carbon dioxide. Here we report on the
application of such technique to nitrous oxide (N2O) and acetylene (C2H2). This
result represents a first step towards the imaging of fragile compounds, a
category which includes most of the fundamental biological molecules
Contribuição dos efeitos de genearcas e de famílias sobre a probabilidade de permanência em rebanhos da raça Nelore.
Foram preditas diferenças esperadas na progênie para probabilidade de permanência no rebanho (stayability) de 4180 touros com filhas na base de dados do Programa de Melhoramento Genético da Raça Nelore, utilizando-se modelo de limiar unicaráter de touro-avô materno, sob metodologia bayesiana. Os touros foram classificados em ordem decrescente e aqueles com diferenças esperadas na progênie acima de 57,6%, considerados como TOP1%, foram analisados quanto à genealogia visando avaliar a existência de efeito de família, bem como a contribuição dos genearcas e ancestrais da raça Nelore para a característica considerada. Os principais fundadores, que juntos somaram 18,8% dos genes presentes nos touros TOP1%, foram Karvadi IMP (com 8,2% dos genes, essencialmente via seu filho Chummak), Godhavari IMP (com 6% de contribuição, via Kurupathy e Neófito), Rastã IMP e Falo da BV (2,5 e 2,1%, respectivamente, via materna, pois não apresentaram parentesco com touros ancestrais). O touro Rolex, da variedade mocha, esteve presente em 12 linhas (maternas ou paternas), via seu neto Cardeal. Dos sete ancestrais da raça Nelore com maiores contribuições genéticas (que somaram 15,3% dos genes), cinco foram da variedade mocha. Somente 28 animais aportaram 50% da variabilidade genética, evidenciando o baixo número de animais utilizados como reprodutores na raça Nelore
Triphasic scaffolds for the regeneration of the bone-ligament interface
A triphasic scaffold (TPS) for the regeneration of the bone-ligament interface was fabricated combining a 3D fiber deposited polycaprolactone structure and a polylactic co-glycolic acid electrospun. The scaffold presented a gradient of physical and mechanical properties which elicited different biological responses from human mesenchymal stem cells. Biological test were performed on the whole TPS and on scaffolds comprised of each single part of the TPS, considered as the controls. The TPS showed an increase of the metabolic activity with culturing time that seemed to be an average of the controls at each time point. The importance of differentiation media for bone and ligament regeneration was further investigated. Metabolic activity analysis on the different areas of the TPS showed a similar trend after 7 days in both differentiation media. Total alkaline phosphatase (ALP) activity analysis showed a statistically higher activity of the TPS in mineralization medium compared to the controls. A different glycosaminoglycans amount between the TPS and its controls was detected, displaying a similar trend with respect to ALP activity. Results clearly indicated that the integration of electrospinning and additive manufacturing represents a promising approach for the fabrication of scaffolds for the regeneration of tissue interfaces, such as the bone-to-ligament one, because it allows mimicking the structural environment combining different biomaterials at different scales
Estruturação de dados para avaliação genética de bubalinos em rebanhos-núcleo do Pará: resultados preliminares.
bitstream/item/42049/1/DOC-370.pdfVersão eletrônica disponível em papel
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