1,072 research outputs found
Uptake of Retrograde Tracers by Intact Optic Nerve Axons: A New Way to Label Retinal Ganglion Cells
Retrograde labelling of retinal ganglion cells with optic nerve transection often leads to degeneration of ganglion cells in prolonged experiments. Here we report that an intact optic nerve could uptake retrograde tracers applied onto the surface of the nerve, leading to high efficiency labelling of ganglion cells in the retina with long-term survival of cells. This method labelled a similar number of ganglion cells (2289 +/- 174 at 2 days) as the retrograde labeling technique from the superior colliculus (2250 +/- 94) or optic nerve stump (2279 +/- 114) after transection. This finding provides an alternative way to label retinal ganglion cells without damaging the optic tract. This will facilitate anatomical studies in identifying the morphology and connectivity of retinal ganglion cells, allowing secondary or triple labelling manipulations for long-term investigations.published_or_final_versio
Longitudinal 1H MRS of hamster superior colliculus following retinotectal deafferentation
Session: Applications of MRS to the Animal Brain - TRADpublished_or_final_versionThe 17th Scientific Meeting of the International Society for Magnetic Resonance in Medicine (ISMRM 2009), Honlolulu, HI., 18-24 April 2009. In Proceedings of ISMRM 17th Scientific Meeting & Exhibition, 200
Image processing methods to elucidate spatial characteristics of retinal microglia after optic nerve transection
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Nano hemostat solution: immediate hemostasis at the nanoscale
Hemostasis is a major problem in surgical procedures and after major trauma. There are few effective methods to stop bleeding without causing secondary damage. We used a self-assembling peptide that establishes a nanofiber barrier to achieve complete hemostasis immediately when applied directly to a wound in the brain, spinal cord, femoral artery, liver, or skin of mammals. This novel therapy stops bleeding without the use of pressure, cauterization, vasoconstriction, coagulation, or cross-linked adhesives. The self-assembling solution is nontoxic and nonimmunogenic, and the breakdown products are amino acids, which are tissue building blocks that can be used to repair the site of injury. Here we report the first use of nanotechnology to achieve complete hemostasis in less than 15 seconds, which could fundamentally change how much blood is needed during surgery of the future. © 2006.postprin
Brain resting-state functional MRI connectivity: Morphological foundation and plasticity
postprin
Forever young: How to control the elongation, differentiation, and proliferation of cells using nanotechnology
Within the emerging field of stem cells there is a need for an environment that can regulate cell activity, to slow down differentiation or proliferation, in vitro or in vivo while remaining invisible to the immune system. By creating a nanoenvironment surrounding PC12 cells, Schwann cells, and neural precursor cells (NPCs), we were able to control the proliferation, elongation, differentiation, and maturation in vitro. We extended the method, using self-assembling nanofiber scaffold (SAPNS), to living animals with implants in the brain and spinal cord. Here we show that when cells are placed in a defined system we can delay their proliferation, differentiation, and maturation depending on the density of the cell population, density of the matrix, and the local environment. A combination of SAPNS and young cells can be implanted into the central nervous system (CNS), eliminating the need for immunosuppressants. Copyright © 2009 Cognizant Comm. Corp.published_or_final_versio
Local proliferation is the main source of rod microglia after optic nerve transection
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Radial Growth of Qilian Juniper on the Northeast Tibetan Plateau and Potential Climate Associations
There is controversy regarding the limiting climatic factor for tree radial growth at the alpine treeline on the northeastern Tibetan Plateau. In this study, we collected 594 increment cores from 331 trees, grouped within four altitude belts spanning the range 3550 to 4020 m.a.s.l. on a single hillside. We have developed four equivalent ring-width chronologies and shown that there are no significant differences in their growth-climate responses during 1956 to 2011 or in their longer-term growth patterns during the period AD 1110–2011. The main climate influence on radial growth is shown to be precipitation variability. Missing ring analysis shows that tree radial growth at the uppermost treeline location is more sensitive to climate variation than that at other elevations, and poor tree radial growth is particularly linked to the occurrence of serious drought events. Hence water limitation, rather than temperature stress, plays the pivotal role in controlling the radial growth of Sabina przewalskii Kom. at the treeline in this region. This finding contradicts any generalisation that tree-ring chronologies from high-elevation treeline environments are mostly indicators of temperature changes
Use of moxibustion to treat primary dysmenorrhea at two interventional times: study protocol for a randomized controlled trial
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Understanding the nature of "superhard graphite"
Numerous experiments showed that on cold compression graphite transforms into
a new superhard and transparent allotrope. Several structures with different
topologies have been proposed for this phase. While experimental data are
consistent with these models, the only way to solve this puzzle is to find
which structure is kinetically easiest to form. Using state-of-the-art
molecular-dynamics transition path sampling simulations, we investigate kinetic
pathways of the pressure-induced transformation of graphite to various
superhard candidate structures. Unlike hitherto applied methods for elucidating
nature of superhard graphite, transition path sampling realistically models
nucleation events necessary for physically meaningful transformation kinetics.
We demonstrate that nucleation mechanism and kinetics lead to -carbon as the
final product. -carbon, initially competitor to -carbon, is ruled out by
phase growth. Bct-C structure is not expected to be produced by cold
compression due to less probable nucleation and higher barrier of formation
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