Structure and mechanical properties of tungsten-containing hydrogenated diamond like carbon coatings for space applications

AbstractTungsten-containing diamond like carbon (W-C:H) coatings were prepared by unbalanced magnetron sputtering (UBM) using tungsten carbide targets in Ar/C2H2 atmosphere. The structure and mechanical properties of these coatings with different C2H2 flow (from 40sccm to 140sccm) were studied. According to the analysis of Raman spectroscopy and the measurement of hardness and Young's modulus about the coatings, it was showed that sp3/sp2 ratio in the coatings changed and the hardness and Young's modulus decreased with increase of the C2H2 flow. Besides, the adhension and friction wear properties of the coatings were evaluated using the scratch test and dry sliding tests respectively. It was found that the coatings exhibited very good adhension and the C2H2 flow (actually the hydrogen) played a very important role in the tribological behavior of the W-C:H coatings in vacuum

tert-Butyl 2-borono-1H-pyrrole-1-carboxyl­ate

In the crystal structure of the title compound, C9H14BNO4, the boronic acid group and carbamate groups are nearly co-planar with the pyrrole ring, making dihedral angles of 0.1 (2) and 2.2 (2)°, respectively. Intra­molecular and inter­molecular O—H⋯O hydrogen bonds help to stabilize the structure, the latter interaction leading to inversion dimers.

Brain natriuretic peptide suppresses pain induced by BmK I, a sodium channel-specific modulator, in rats.

Background: A previous study found that brain natriuretic peptide (BNP) inhibited inflammatory pain via activating its receptor natriuretic peptide receptor A (NPRA) in nociceptive sensory neurons. A recent study found that functional NPRA is expressed in almost all the trigeminal ganglion (TG) neurons at membrane level suggesting a potentially important role for BNP in migraine pathophysiology. Methods: An inflammatory pain model was produced by subcutaneous injection of BmK I, a sodium channel-specific modulator from venom of Chinese scorpion Buthus martensi Karsch. Quantitative PCR, Western Blot, and immunohistochemistry were used to detect mRNA and protein expression of BNP and NPRA in dorsal root ganglion (DRG) and dorsal horn of spinal cord. Whole-cell patch clamping experiments were conducted to record large-conductance Ca2+-activated K+ (BKCa) currents of membrane excitability of DRG neurons. Spontaneous and evoked pain behaviors were examined. Results: The mRNA and protein expression of BNP and NPRA was up-regulated in DRG and dorsal horn of spinal cord after BmK I injection. The BNP and NPRA was preferentially expressed in small-sized DRG neurons among which BNP was expressed in both CGRP-positive and IB4-positive neurons while NPRA was preferentially expressed in CGRP-positive neurons. BNP increased the open probability of BKCa channels and suppressed the membrane excitability of small-sized DRG neurons. Intrathecal injection of BNP significantly inhibited BmK-induced pain behaviors including both spontaneous and evoked pain behaviors. Conclusions: These results suggested that BNP might play an important role as an endogenous pain reliever in BmK I-induced inflammatory pain condition. It is also suggested that BNP might play a similar role in other pathophysiological pain conditions including migraine

Elimination of the confrontation between theory and experiment in flexoelectric Bi2GeO5

In this paper, we have investigated the flexoelectric effect of Bi2GeO5(BGO), successfully predicted the maximum flexoelectric coefficient of BGO, and tried to explore the difference between experimental and simulated flexoelectric coefficients.Comment: 16 pages,6 figure