Superelasticity of Carbon Nanocoils from Atomistic Quantum Simulations

A structural model of carbon nanocoils (CNCs) on the basis of carbon nanotubes (CNTs) was proposed. The Young’s moduli and spring constants of CNCs were computed and compared with those of CNTs. Upon elongation and compression, CNCs exhibit superelastic properties that are manifested by the nearly invariant average bond lengths and the large maximum elastic strain limit. Analysis of bond angle distributions shows that the three-dimensional spiral structures of CNCs mainly account for their unique superelasticity

Significance of vascular endothelial growth factor in growth and peritoneal dissemination of ovarian cancer

Vascular endothelial growth factor (VEGF) is a key regulator of angiogenesis which drives endothelial cell survival, proliferation, and migration while increasing vascular permeability. Playing an important role in the physiology of normal ovaries, VEGF has also been implicated in the pathogenesis of ovarian cancer. Essentially by promoting tumor angiogenesis and enhancing vascular permeability, VEGF contributes to the development of peritoneal carcinomatosis associated with malignant ascites formation, the characteristic feature of advanced ovarian cancer at diagnosis. In both experimental and clinical studies, VEGF levels have been inversely correlated with survival. Moreover, VEGF inhibition has been shown to inhibit tumor growth and ascites production and to suppress tumor invasion and metastasis. These findings have laid the basis for the clinical evaluation of agents targeting VEGF signaling pathway in patients with ovarian cancer. In this review, we will focus on VEGF involvement in the pathophysiology of ovarian cancer and its contribution to the disease progression and dissemination

The molecular logic of endocannabinoid signalling

The endocannabinoids are a family of lipid messengers that engage the cell surface receptors that are targeted by Δ9-tetrahydrocannabinol, the active principle in marijuana (Cannabis). They are made on demand through cleavage of membrane precursors and are involved in various short-range signalling processes. In the brain, they combine with CB1 cannabinoid receptors on axon terminals to regulate ion channel activity and neurotransmitter release. Their ability to modulate synaptic efficacy has a wide range of functional consequences and provides unique therapeutic possibilities. © 2003, Nature Publishing Group. All rights reserved

Flame spray pyrolysis generated transition metal oxide nanoparticles as catalysts for the growth of carbon nanotubes

Herein, we investigate the growth of multi-walled carbon nanotubes (CNT) using three transition metal oxide nanoparticles; namely hematite (Fe 2O3), cobalt oxide (Co3O4) and nickel oxide (NiO). The nanoparticles were synthesised using flame spray pyrolysis (FSP). As the nanoparticle and CNT syntheses are identical for all materials, a direct comparison between the products is possible and a link between catalyst and morphology of the resultant nanostructures can be elucidated. Conventional CNT were grown on Fe2O3 nanoparticles, no discernible nanotubes were observed on the Co 3O4 catalysts whilst a mixture of conventional and coiled CNT (CCNT) were synthesised on the NiO nanoparticles. We investigated the effect of temperature, time and acetylene/hydrogen gas mixtures on the morphology, yield and purity of the CNT produced. By regulating the acetylene pyrolysis temperature for NiO, the CCNT yield can be increased to approximately 70% of the CNT yield. © The Royal Society of Chemistry 2013

Investigating the Structural, Electronic, and Chemical Evolution of B-Doped Multi-walled Carbon Nanotubes as a Result of Joule Heating

The evolution of B-doped multiwalled carbon nanotubes in the presence of a passing current has been investigated using the in situ TEM/STM Nanofactory holder. The Joule heating results in the dopant being partially removed as the internal structure of the nanotube is altered, and significant changes in its electrical properties were observed. This is of great importance for electrical applications where doping is used to tune the Fermi level of carbon nanotubes. © 2011 American Chemical Society

Synthesis of carbon nanocoil forests on BaSrTiO3 substrates with the aid of a Sn catalyst

A simple route for the Sn-assisted synthesis of carbon nanocoils (CNCs) by chemical vapor deposition of acetylene on polycrystalline BaSrTiO3 (BST) substrates is reported. In this study, high-quality CNC forests have been synthesized on BST substrates with the presence of Sn. The morphologies and qualities of the CNCs were characterized by scanning electron microscopy, transmission electron microscopy, and Raman spectroscopy, while the structures and compositions of catalysts were investigated by transmission electron microscopy and energy-dispersive X-ray spectroscopy. Structural control over the CNCs was achieved by simply altering the Sn concentration or acetylene flow rates. This study demonstrates that Sn can act as an efficient catalyst for CNC synthesis in conjunction with either perovskite oxides (BST) or transition metals (Fe)