Targeted disruption of Kv2.1-VAPA association provides neuroprotection against ischemic stroke in mice by declustering Kv2.1 channels

Kv2.1 channels mediate cell death–enabling loss of cytosolic potassium in neurons following plasma membrane insertion at somatodendritic clusters. Overexpression of the carboxyl terminus (CT) of the cognate channel Kv2.2 is neuroprotective by disrupting Kv2.1 surface clusters. Here, we define a seven–amino acid declustering domain within Kv2.2 CT (DP-2) and demonstrate its neuroprotective efficacy in a murine ischemia-reperfusion model. TAT-DP-2, a membrane-permeable derivative, induces Kv2.1 surface cluster dispersal, prevents post-injurious pro-apoptotic potassium current enhancement, and is neuroprotective in vitro by disrupting the association of Kv2.1 with VAPA. TAT-DP-2 also induces Kv2.1 cluster dispersal in vivo in mice, reducing infarct size and improving long-term neurological function following stroke. We suggest that TAT-DP-2 induces Kv2.1 declustering by disrupting Kv2.1-VAPA association and scaffolding sites required for the membrane insertion of Kv2.1 channels following injury. We present the first evidence of targeted disruption of Kv2.1-VAPA association as a neuroprotective strategy following brain ischemia.

XXII. Symposium on Atomic, Cluster and Surface Physics (SASP)

From Sunday February 2nd, 2020 until the following Friday, 75 scientists from all over the world gathered in Hotel Laudinella in St. Moritz to discuss their latest findings about surface, cluster and gas phase physics and chemistry. A program consisting of 25 invited speakers, 16 hot topic oral contributions and 27 poster presentations has been put together by the organizers from Empa.

Spin Properties of Germanium-Vacancy Centers in Bulk and Near-Surface Regions of Diamond

Germanium-vacancy (GeV) centers are now studied extensively due to perspectives of their applications in quantum information processing, nanometrology and nanoscale magnetic resonance imaging. One of the important requirements for these applications is a detailed understanding of the hyperfine interactions in such systems. Quantum chemistry simulation of the negatively charged GeV− color center in diamond is the primary goal of this paper in which we present preliminary results of computer simulation of the bulk H-terminated cluster C[Formula: see text][GeV−]H[Formula: see text], as well as of the surface cluster C[Formula: see text][GeV−]H[Formula: see text]_(100)_H[Formula: see text] having one dangling bond at (1 0 0) surface using the DFT/PW91/RI/def2-SVP level of theory.

Understanding chemical interaction between phosphonate-derivative molecules and a silver surface cluster in SERS: a combined experimental and computational approach

This joint experimental-theoretical SERS study provides new insights on the adsorption mode of phosphonate-derivative molecules on silver nanoparticles.

Influence of High-Cycle Fatigue on Crater Wear Characteristics of Cemented Carbide Tool

Recently, in order to make positively use of the effect of adhesive layer, which works as Build-up edge or Belag on the tool surface during machining operation, there have many investigations on the technique to reduce the wear of cutting tool. However, the mechanism of wear on the rake face is unknown and the reason why the adhesive layer can resist the abrasion is also unclear.This study aims to propose a new crater high-cycle fatigue wear model depending on the tool adhesion model established by the surface cluster on the interface between the Tool-Work Piece. By using this model we can elucidate the mechanism of adhesive layer. When the chip flows on the rake face, the commensurate phase occurs in the surface cluster on the interface, and the surface cluster slides in the similar form of dislocation. At the same time, the strong chemical bonding among the surface clusters becomes the repeat force which can result in the fatigue failure on the tool, and the tool crater wear happens. The energy dissipation process associates with the vibration of cluster, which increases the tool temperature rapidly. Therefore, the crater wear is a damage process on the tool with the high-temperature and high-cycle fatigue.In this study, the mechanism of crater wear when the cemented carbide cut the carbon steel was investigated using the adhesion cluster model, and the crater wear model was proposed to estimate the properties of the adhesive layer.

Comparison of sub-micro/nano structure formation on polished silicon surface irradiated by nanosecond laser beam in ambient air and distilled water

This paper compares sub-micro/nano structure formation on polished silicon surface irradiated by nanosecond laser pulses in ambient air and distilled water. Surface cluster density and optical reflectivity of silicon surface (at a typical wavelength of λ = 632 nm) were studied in terms of number of laser pulses and laser fluence. The surface density and optical reflectivity give information on clusters filling factor and clusters height respectively. The results show that the values of surface cluster density and clusters height strongly depend on laser pulse numbers and interacting ambient. Comparing to air, distilled water as an interacting ambient can affect more significantly the clusters height.