Long-term potentiation through calcium-mediated N-Cadherin interaction is tightly controlled by the three-dimensional architecture of the synapse

Poster presentation: Twenty Second Annual Computational Neuroscience Meeting: CNS*2013. Paris, France. 13-18 July 2013. The synaptic cleft is an extracellular domain that is capable of relaying a presynaptically received electrical signal by diffusive neurotransmitters to the postsynaptic membrane. The cleft is trans-synaptically bridged by ring-like shaped clusters of pre- and postsynaptically localized calcium-dependent adhesion proteins of the N-Cadherin type and is possibly the smallest intercircuit in nervous systems [1]. The strength of association between the pre- and postsynaptic membranes can account for synaptic plasticity such as long-term potentiation [2]. Through neuronal activity the intra- and extracellular calcium levels are modulated through calcium exchangers embedded in the pre- and postsynaptic membrane. Variations of the concentration of cleft calcium induces changes in the N-Cadherin-zipper, that in synaptic resting states is rigid and tightly connects the pre- and postsynaptic domain. During synaptic activity calcium concentrations are hypothesized to drop below critical thresholds which leads to loosening of the N-Cadherin connections and subsequently "unzips" the Cadherin-mediated connection. These processes may result in changes in synaptic strength [2]. In order to investigate the calcium-mediated N-Cadherin dynamics at the synaptic cleft, we developed a three-dimensional model including the cleft morphology and all prominent calcium exchangers and corresponding density distributions [3-6]. The necessity for a fully three-dimensional model becomes apparent, when investigating the effects of the spatial architecture of the synapse [7], [8]. Our data show, that the localization of calcium channels with respect to the N-Cadherin ring has substantial effects on the time-scales on which the Cadherin-zipper switches between states, ranging from seconds to minutes. This will have significant effects on synaptic signaling. Furthermore we see, that high-frequency action potential firing can only be relayed to the Calcium/N-Cadherin-system at a synapse under precise spatial synaptic reorganization

Interstitial compounds as fuel cell catalysts - Their preparative techniques and electrochemical testing

Preparation and electrochemical testing methods for fuel cell catalysts using interstitial compound

Development of an improved oxygen electrode for use in alkaline H2-O2 fuel cells Quarterly report, Oct. 1 - Dec. 31, 1966

Interstitial compounds of transition elements prepared for improving oxygen electrode in alkaline hydrox fuel cel

Signature of odd-frequency pairing correlations induced by a magnetic interface

We investigate the mutual proximity effect in a normal metal contacted to a superconductor through a magnetic interface. Analytical and self-consistent numerical results are presented, and we consider both the diffusive and ballistic regimes. We focus on the density of states in both the normal and superconducting region, and find that the presence of spin-dependent phase-shifts occurring at the interface qualitatively modifies the density of states. In particular, we find that the proximity-induced pairing amplitudes in the normal metal region undergo a conversion at the Fermi level from pure even-frequency to odd-frequency. Above a critical value of the interface spin-polarization (or, equivalently, for fixed interface spin-polarization, above a critical interface resistance), only odd frequency correlations remain. This is accompanied by the replacement of the familiar proximity minigap or pseudogap in the normal layer by an enhancement of the density of states above its normal state value for energies near the chemical potential. The robustness of this effect towards inelastic scattering, impurity scattering, and the depletion of the superconducting order parameter close to the interface is investigated. We also study the inverse proximity effect in the diffusive limit. We find that the above-mentioned conversion persists also for thin superconducting layers comparable in size to the superconducting coherence length $\xi_\text{S}$, as long as the inverse proximity effect is relatively weak. Concomitantly, we find a shift in the critical interface resistance where the pairing conversion occurs. Our findings suggest a robust and simple method for producing purely odd-frequency superconducting correlations, that can be tested experimentally.Comment: 14 pages, 12 figures. Submitted to Physical Review. Chosen as Editors' Suggestio

Native Vegetation Handbook for the Shire of Mingenew

This booklet is one of a series covering the agricultural region of Western Australia and provides agricultural land managers with information relating to the natural resources of the Shire of Mingenew including the existing vegetation, drainage systems and soils. Some of the problems relating to the management of natural vegetation resources in the Shire of Mingenew and where possible, solutions to these problems are also discussed. By providing this information it is hoped this booklet will contribute to the long term viability of the agricultural landscape and the conservation of native vegetation within the Shire

What do Retinal Vessels Reveal about Systemic Disease? Retinal Vessels and Systemic Disease – Basic Findings

A number of systemic disorders are attended by distinct changes in blood vessels. The retinal vessels can easily be inspected with an ophthalmoscope. Some changes in retinal vessels allow us to draw direct conclusions about the status of blood vessels in the entire body. Major systemic diseases, such as diabetes or hypertension, can lead to typical changes in the retinal vessels with the resulting retinal pathology. Changes in the retinal vessels can also be an indicator for some specific ocular diseases. Early diagnosis and treatment of such diseases often prevent long-term damage or even blindness. Therefore, the evaluation of retinal arteries and veins should be a crucial part of an eye examination. In the following some basic principles of retinal findings and their correlation with systemic disease shall be discussed

Native Vegetation Handbook for the Shire of West Arthur

This booklet provides land managers with information relating to the natural resources of the Shire of West Arthur including the existing vegetation, drainage systems and soils. Some of the problems relating to the management of natural vegetation resources in the Shire of West Arthur and possible solutions to these problems are also discussed. By providing this information it is hoped this booklet will contribute to the long term viability of the agricultural landscape and the conservation of native vegetation within the Shire