51 research outputs found
Mid-infrared interferometry of massive young stellar objects
The very inner structure of massive young stellar objects (YSOs) is difficult
to trace. With conventional observational methods we identify structures still
several hundreds of AU in size. However, the (proto-)stellar growth takes place
at the innermost regions (<100 AU) where the actual mass transfer onto the
forming high-mass star occurs. We present results from our programme toward
massive YSOs at the VLTI, utilising the two-element interferometer MIDI. To
date, we observed 10 well-known massive YSOs down to scales of 20 mas
(typically corresponding to 20 - 40 AU for our targets) in the 8-13 micron
region. We clearly resolve these objects which results in low visibilities and
sizes in the order of 30-50 mas. For two objects, we show results of our
modelling. We demonstrate that the MIDI data can reveal decisive structure
information for massive YSOs. They are often pivotal in order to resolve
ambiguities still immanent in model parameters derived from sole SED fitting.Comment: 6 pages, 5 figures, necessary style files iopams.sty, jpconf11.clo,
and jpconf.cls included; contribution for the conference "The Universe under
the Microscope" (AHAR 2008), held in Bad Honnef (Germany) in April 2008, to
be published in Journal of Physics: Conference Series by Institute of Physics
Publishing, R. Schoedel, A. Eckart, S. Pfalzner, and E. Ros (eds.
Concept and optical design of the cross-disperser module for CRIRES
This is the peer reviewed version of the following article: Oliva, Ernesto, A. Tozzi, D. Ferruzzi, L. Origlia, A. Hatzes, R. Follert, T. Loewinger et al. "Concept and optical design of the cross-disperser module for CRIRES+." In SPIE Astronomical Telescopes+ Instrumentation, pp. 91477R-91477R. International Society for Optics and Photonics, 2014, which has been published in final form at 10.1117/12.2054381
MiR-200 family controls late steps of postnatal forebrain neurogenesis via Zeb2 inhibition
During neurogenesis, generation, migration and integration of the correct numbers of each neuron sub-Type depends on complex molecular interactions in space and time. MicroRNAs represent a key control level allowing the flexibility and stability needed f
Two-dimensional wave patterns of spreading depolarization: retracting, re-entrant, and stationary waves
We present spatio-temporal characteristics of spreading depolarizations (SD)
in two experimental systems: retracting SD wave segments observed with
intrinsic optical signals in chicken retina, and spontaneously occurring
re-entrant SD waves that repeatedly spread across gyrencephalic feline cortex
observed by laser speckle flowmetry. A mathematical framework of
reaction-diffusion systems with augmented transmission capabilities is
developed to explain the emergence and transitions between these patterns. Our
prediction is that the observed patterns are reaction-diffusion patterns
controlled and modulated by weak nonlocal coupling. The described
spatio-temporal characteristics of SD are of important clinical relevance under
conditions of migraine and stroke. In stroke, the emergence of re-entrant SD
waves is believed to worsen outcome. In migraine, retracting SD wave segments
cause neurological symptoms and transitions to stationary SD wave patterns may
cause persistent symptoms without evidence from noninvasive imaging of
infarction
Atypical miRNA expression in temporal cortex associated with dysregulation of immune, cell cycle, and other pathways in autism spectrum disorders
BACKGROUND: Autism spectrum disorders (ASDs) likely involve dysregulation of multiple genes related to brain function and development. Abnormalities in individual regulatory small non-coding RNA (sncRNA), including microRNA (miRNA), could have profound effects upon multiple functional pathways. We assessed whether a brain region associated with core social impairments in ASD, the superior temporal sulcus (STS), would evidence greater transcriptional dysregulation of sncRNA than adjacent, yet functionally distinct, primary auditory cortex (PAC). METHODS: We measured sncRNA expression levels in 34 samples of postmortem brain from STS and PAC to find differentially expressed sncRNA in ASD compared with control cases. For differentially expressed miRNA, we further analyzed their predicted mRNA targets and carried out functional over-representation analysis of KEGG pathways to examine their functional significance and to compare our findings to reported alterations in ASD gene expression. RESULTS: Two mature miRNAs (miR-4753-5p and miR-1) were differentially expressed in ASD relative to control in STS and four (miR-664-3p, miR-4709-3p, miR-4742-3p, and miR-297) in PAC. In both regions, miRNA were functionally related to various nervous system, cell cycle, and canonical signaling pathways, including PI3K-Akt signaling, previously implicated in ASD. Immune pathways were only disrupted in STS. snoRNA and pre-miRNA were also differentially expressed in ASD brain. CONCLUSIONS: Alterations in sncRNA may underlie dysregulation of molecular pathways implicated in autism. sncRNA transcriptional abnormalities in ASD were apparent in STS and in PAC, a brain region not directly associated with core behavioral impairments. Disruption of miRNA in immune pathways, frequently implicated in ASD, was unique to STS. ELECTRONIC SUPPLEMENTARY MATERIAL: The online version of this article (doi:10.1186/s13229-015-0029-9) contains supplementary material, which is available to authorized users
MicroRNAs in brain development and function: a matter of flexibility and stability
International audienceFine-tuning of gene expression is a fundamental requirement for development and function of cells and organs. This requirement is particularly obvious in the nervous system where originally common stem cell populations generate thousands of different neuronal and glial cell types in a temporally and quantitatively perfectly orchestrated manner. Moreover, after their generation, young neurons have to connect with pre-determined target neurons through the establishment of functional synapses, either in their immediate environment or at distance. Lastly, brain function depends not only on static circuitries, but on plastic changes at the synaptic level allowing both, learning and memory. It appears evident that these processes necessitate flexibility and stability at the same time. These two contrasting features can only be achieved by complex molecular networks, superposed levels of control and tight interactions between regulatory mechanisms. Interactions between microRNAs and their target mRNAs fulfill these requirements. Here we review recent literature dealing with the involvement of microRNAs in multiple aspects of brain development and connectivity
4D (x-y-z-t) imaging of thick biological samples by means of Two-Photon inverted Selective Plane Illumination Microscopy (2PE-iSPIM)
In the last decade light sheet fluorescence microscopy techniques, such as selective plane illumination microscopy (SPIM), has become a well established method for developmental biology. However, conventional SPIM architectures hardly permit imaging of certain tissues since the common sample mounting procedure, based on gel embedding, could interfere with the sample morphology. In this work we propose an inverted selective plane microscopy system (iSPIM), based on non-linear excitation, suitable for 3D tissue imaging. First, the iSPIM architecture provides flexibility on the sample mounting, getting rid of the gel-based mounting typical of conventional SPIM, permitting 3D imaging of hippocampal slices from mouse brain. Moreover, all the advantages brought by two photon excitation (2PE) in terms of reduction of scattering effects and contrast improvement are exploited, demonstrating an improved image quality and contrast compared to single photon excitation. The system proposed represents an optimal platform for tissue imaging and it smooths the way to the applicability of light sheet microscopy to a wider range of samples including those that have to be mounted on non-transparent surfaces
4D (x-y-z-t) imaging of thick biological samples by means of Two-Photon inverted Selective Plane Illumination Microscopy (2PE-iSPIM)
In the last decade light sheet fluorescence microscopy techniques, such as selective plane illumination microscopy (SPIM), has become a well established method for developmental biology. However, conventional SPIM architectures hardly permit imaging of certain tissues since the common sample mounting procedure, based on gel embedding, could interfere with the sample morphology. In this work we propose an inverted selective plane microscopy system (iSPIM), based on non-linear excitation, suitable for 3D tissue imaging. First, the iSPIM architecture provides flexibility on the sample mounting, getting rid of the gel-based mounting typical of conventional SPIM, permitting 3D imaging of hippocampal slices from mouse brain. Moreover, all the advantages brought by two photon excitation (2PE) in terms of reduction of scattering effects and contrast improvement are exploited, demonstrating an improved image quality and contrast compared to single photon excitation. The system proposed represents an optimal platform for tissue imaging and it smooths the way to the applicability of light sheet microscopy to a wider range of samples including those that have to be mounted on non-transparent surfaces
Sicherung der Strukturqualität in der stationären medizinischen Rehabilitation von Kindern und Jugendlichen
Corrigendum: miR-200 family controls late steps of postnatal forebrain neurogenesis via Zeb2 inhibition
International audienc
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