30 research outputs found
Elastic modulus of multi-walled carbon nanotubes produced by catalytic chemical vapour deposition
Carbon nanotubes (CNTs) are ideal structures for use as reinforcement fibres in composite materials, due to their extraordinary mechanical properties, in particular high Young's modulus (E∼1TPa). Usually the high value of E is taken as granted for all types of carbon CNTs. Here we demonstrate that multi-walled carbon nanotubes (MWCNTs) produced by catalytic chemical vapour deposition (CCVD) have low moduli (E<100GPa) independently of their growth conditions. We attribute this to the presence of structural defects. Additional high-temperature annealing failed to improve the mechanical properties. This study urges a better control of the growth process in order to obtain high strength CCVD grown MWCNTs suitable for reinforcement in large-scale industrial application
Elastic modulus of multi-walled carbon nanotubes produced by catalytic chemical vapour deposition
Cerebral kynurenic acid levels are increased by asphyxia but not by its putative neuroprotectant analogue SZR72 in a piglet model of hypoxic-ischemic encephalopathy
Targeted UHPLC-MS/HRMS raw data files.THIS DATASET IS ARCHIVED AT DANS/EASY, BUT NOT ACCESSIBLE HERE. TO VIEW A LIST OF FILES AND ACCESS THE FILES IN THIS DATASET CLICK ON THE DOI-LINK ABOV
Arthropod molting hormones (ecdysteroids) are present in the blood of insectivorous bats
In this study, blood samples of eight insectivorous bat species were analyzed for the presence of ecdysteroids with highly sensitive targeted ultra-high-performance liquid chromatography coupled to high-resolution quadrupole-orbitrap mass spectrometry method (SIM). Nine ecdysteroids were detected in bat blood
Enantioseparation of Aromatic β³-Amino acid by Precolumn Derivatization with o-Phthaldialdehyde and N-Isobutyryl-l-cysteine
Elastic-Modulus of Multi-Walled Carbon Nanotubes produced by catalyctic chemical-Vapor-Deposition
Elastic modulus of multi-walled carbon nanotubes produced by catalytic chemical vapour deposition
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20-Hydroxyecdysone and several of its oxidized derivatives exert cytoprotective effect in mammals including humans. Inspired by this bioactivity of ecdysteroids, in the current study it was our aim to prepare a set of sidechain-modified derivatives and to evaluate their potential to protect the blood-brain barrier (BBB) from oxidative stress. Six novel ecdysteroids, including an oxime and five oxime ethers, were obtained through regioselective synthesis from a sidechain-cleaved calonysterone derivative 2 and fully characterized by comprehensive NMR techniques revealing their complete 1H and 13C signal assignments. Surprisingly, several compounds sensitized hCMEC/D3 brain microvascular endothelial cells to tert-butyl hydroperoxide (tBHP)-induced oxidative damage as recorded by impedance measurements. Compound 8, containing a benzyloxime ether moiety in its sidechain, was the only one that exerted a protective effect at a higher, 10 μM concentration, while at lower (10 nM– 1 μM) concentrations it promoted tBHP-induced cellular damage. Brain endothelial cells were protected from tBHP-induced barrier integrity decrease by treatment with 10 μM of compound 8, which also mitigated the intracellular reactive oxygen species production elevated by tBHP. Based on our results, 17-oxime ethers of oxidized ecdysteroids modulate oxidative stress of the BBB in a way that may point towards unexpected toxicity. Further studies are needed to evaluate any possible risk connected to dietary ecdysteroid consumption and CNS pathologies in which BBB damage plays an important role.</div