1,097 research outputs found
Measuring by marking; the multimedia annotation tool ELAN
ELAN is a multimedia annotation tool developed by the Max Planck Institute for Psycholinguistics. It is applied in a variety of research areas. This paper presents a general overview of the tool and new developments as the calculation of inter-rater reliability, a commentary framework, semi-automatic segmentation and labeling and export to Theme
Advancement in the multimedia annotation tool ELAN
ELAN is a multimedia annotation tool that is being developed by the Max Planck Institute for Psycholinguistics. It is a tool that is applied in various types of multimodal interaction research. This poster presents the most recent achievements in what by now is a long history of continuous tool development and support. New developments are assessment of inter-rater reliability, a commentary framework and export to Theme format
NGC922 – a new drop-through ring galaxy
We have found the peculiar galaxy NGC 922 to be a new drop-through ring galaxy using multiwavelength (ultraviolet–radio) imaging and spectroscopic observations. Its ‘C’-shaped morphology and tidal plume indicate a recent strong interaction with its companion which was identified with these observations. Using numerical simulations we demonstrate that the main properties of the system can be generated by a high-speed off-axis drop-through collision of a small galaxy with a larger disc system, thus making NGC 922 one of the nearest known collisional ring galaxies. While these systems are rare in the local Universe, recent deep Hubble Space Telescope images suggest they were more common in the early Universe
Avalia??o in silico e in vitro do efeito tripanocida de ?leos essenciais e desenvolvimento de sistemas nanoestruturados como alternativa terap?utica da doen?a de Chagas.
Programa de P?s-Gradua??o em Biotecnologia. N?cleo de Pesquisas em Ci?ncias Biol?gicas, Pr?-Reitoria de Pesquisa de P?s Gradua??o, Universidade Federal de Ouro Preto.A falta de uma terap?utica tripanocida eficiente, principalmente na fase cr?nica da
doen?a de Chagas e sem a presen?a de efeitos adversos intensos impulsiona a pesquisa
para o desenvolvimento de novos f?rmacos. As subst?ncias produzidas atrav?s do
metabolismo secund?rio de plantas podem apresentar diferentes efeitos biol?gicos e
serem utilizadas como princ?pios ativos no tratamento de doen?as. Dessa forma, o
objetivo desse trabalho foi caracterizar quimicamente os ?leos essenciais extra?dos das
esp?cies Cymbopogon densiflorus, Cymbopogon nardus, Melaleuca leucadendron e
Microlicia graveolens, bem como avaliar a atividade anti-Trypanosoma cruzi dos
f?rmacos livres e ap?s encapsulamento em sistemas nanoestruturados. A obten??o
desses ?leos ocorreu a partir da hidrodestila??o das partes a?reas, com rendimentos em
torno de 0,1 a 2,0% de acordo com a esp?cie. A caracteriza??o realizada atrav?s da
cromatografia gasosa acoplada ? espectrometria de massas permitiu a identifica??o de
mais de 90% dos compostos, com presen?a majorit?ria de monoterpenos oxigenados. A
partir da an?lise in silico foi poss?vel prever inicialmente que todos os ?leos em estudo
apresentariam potencial contra o parasito T. cruzi. No entanto, na avalia??o in vitro
desta atividade utilizando a cepa Tulahuen, somente o ?leo de folhas de C. densiflorus
se revelou ativo, a partir de uma CI50 sobre o parasito equivalente a 60 ?g/mL (IS= 3,8).
No ensaio de permeabilidade de membrana do parasito, concentra??es superiores a 30
?g/mL de ?leo apresentaram diferen?as em rela??o ao controle. Este resultado foi
confirmado atrav?s da microscopia eletr?nica de transmiss?o. Al?m disso, sistemas
nanoemulsionados, lipossomais e micelares carregados de ?leo essencial e/ou
benznidazol foram desenvolvidos e apresentaram tamanho em escala nanom?trica (<500
nm). A adi??o dos princ?pios ativos favoreceu a homogeneidade de distribui??o de
tamanho para todas as formula??es. Al?m disso, potencial zeta negativo e um pH ?cido
tamb?m definiram as formula??es. A estabilidade dos sistemas foi avaliada e apenas os
lipossomas contendo ambos os f?rmacos foram inst?veis. As formula??es foram
capazes de reproduzir a atividade tripanocida apresentada pelo ?leo e benznidazol a
partir de concentra??es inferiores quando comparadas aos f?rmacos livres. No entanto,
as micelas foram caracterizadas pelos maiores ?ndices de seletividade e um efeito
sin?rgico foi comprovado quando ambos os f?rmacos foram encapsulados
concomitantemente nessa forma farmac?utica. Sendo assim, os resultados desse
trabalho demonstram o ?leo essencial de folhas de C. densiflorus como candidato
potencial ao tratamento da doen?a de Chagas, o qual ? capaz de eliminar o T. cruzi in
vitro a partir de baixas concentra??es. Em adi??o, as formas micelares contendo
benznidazol podem ser uma alternativa na quimioterap?utica chag?sica tanto na sua
forma simples, bem como, em combina??o com o ?leo essencial de C. densiflorus.The absence of efficient trypanocidal therapy in the chronic phases of the Chagas
disease and without intense adverse effects supports research for development of new
drugs. Substances produced by plants secondary metabolism exhibit several biological
effects and they are used as active principles in the treatment of diseases. This work
aimed characterizing essential oils extracted from Cymbopogon densiflorus,
Cymbopogon nardus, Melaleuca leucadendron and Microlicia graveolens species, as
well as evaluating the anti-Trypanosona cruzi activity of the free drugs and after their
encapsulation in nanostructured systems. These oils were produced by hydrodistillation
from the aerial parts and the yields ranged from 0.1 to 2.0% according to the species.
Oils characterization by gas chromatography mass spectrometry allowed identifying
more than 90% of the compounds, that were mainly classified as oxygenated
monoterpenes. In silico analysis initially predicted that all oils under study have
potential against the T. cruzi parasite. However, this activity was evaluated in vitro
using Tulahuen strain and only the essential oil from C. densiflorus leaves was active,
from IC50 on the parasite equivalent to 60 ?g/mL (SI = 3.8). In the parasite membrane
permeability assay, oil concentrations higher than 30 ?g/mL showed differences when
compared to the control. This result was confirmed by transmission electron
microscopy. In addition, nanoemulsion, liposome and micellar systems loaded with
essential oil and/or benznidazole were developed and showed a nanometric size (<500
nm). The drug addition favored the homogeneous size distribution. Moreover, negative
zeta potential and acid pH also defined these formulations. The systems stability was
evaluated and only liposomes loaded with both drugs were unstable. The formulations
were able to reproduce the oil and benznidazole trypanocidal activity at lower
concentrations than free drugs. However, micelles showed the highest selectivity index
and a synergistic effect was demonstrated when both drugs were encapsulated in that
pharmaceutical form. Thus, the results of this work indicate the essential oil from C.
densiflorus leaves as a potential candidate for the treatment of Chagas disease since it is
able to eliminate T. cruzi in vitro at low concentrations. Moreover, benznidazole-loaded
micellar forms may be an alternative in chagasic chemotherapeutics through of its
simple form or in combination with the C. densiflorus essential oil
Noncommutative Quantum Cosmology
We consider noncommutative quantum cosmology in the case of the low-energy
string effective theory. Exacts solutions are found and compared with the
commutative case.The Noncommutative quantum cosmology is considered in the case
of the low-energy string effective theory. Exacts solutions are found and
compared with the commutative case.Comment: Revtex4, 3 pages, 2 figures, to appear in Gen.Rel.Gra
Morphology of ledge patterns during step flow growth of metal surfaces vicinal to fcc(001)
The morphological development of step edge patterns in the presence of
meandering instability during step flow growth is studied by simulations and
numerical integration of a continuum model. It is demonstrated that the kink
Ehrlich-Schwoebel barrier responsible for the instability leads to an invariant
shape of the step profiles. The step morphologies change with increasing
coverage from a somewhat triangular shape to a more flat, invariant steady
state form. The average pattern shape extracted from the simulations is shown
to be in good agreement with that obtained from numerical integration of the
continuum theory.Comment: 4 pages, 4 figures, RevTeX 3, submitted to Phys. Rev.
Competing mechanisms for step meandering in unstable growth
The meander instability of a vicinal surface growing under step flow
conditions is studied within a solid-on-solid model. In the absence of edge
diffusion the selected meander wavelength agrees quantitatively with the
continuum linear stability analysis of Bales and Zangwill [Phys. Rev. B {\bf
41}, 4400 (1990)]. In the presence of edge diffusion a local instability
mechanism related to kink rounding barriers dominates, and the meander
wavelength is set by one-dimensional nucleation. The long-time behavior of the
meander amplitude differs in the two cases, and disagrees with the predictions
of a nonlinear step evolution equation [O. Pierre-Louis et al., Phys. Rev.
Lett. {\bf 80}, 4221 (1998)]. The variation of the meander wavelength with the
deposition flux and with the activation barriers for step adatom detachment and
step crossing (the Ehrlich-Schwoebel barrier) is studied in detail. The
interpretation of recent experiments on surfaces vicinal to Cu(100) [T.
Maroutian et al., Phys. Rev. B {\bf 64}, 165401 (2001)] in the light of our
results yields an estimate for the kink barrier at the close packed steps.Comment: 8 pages, 7 .eps figures. Final version. Some errors in chapter V
correcte
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