19 research outputs found
A finite element model of cerebral vascular injury for predicting microbleeds location
Finite Element (FE) models of brain mechanics have improved our understanding of the brain response to rapid mechanical loads that produce traumatic brain injuries. However, these models have rarely incorporated vasculature, which limits their ability to predict the response of vessels to head impacts. To address this shortcoming, here we used high-resolution MRI scans to map the venous system anatomy at a submillimetre resolution. We then used this map to develop an FE model of veins and incorporated it in an anatomically detailed FE model of the brain. The model prediction of brain displacement at different locations was compared to controlled experiments on post-mortem human subject heads, yielding over 3,100 displacement curve comparisons, which showed fair to excellent correlation between them. We then used the model to predict the distribution of axial strains and strain rates in the veins of a rugby player who had small blood deposits in his white matter, known as microbleeds, after sustaining a head collision. We hypothesised that the distribution of axial strain and strain rate in veins can predict the pattern of microbleeds. We reconstructed the head collision using video footage and multi-body dynamics modelling and used the predicted head accelerations to load the FE model of vascular injury. The model predicted large axial strains in veins where microbleeds were detected. A region of interest analysis using white matter tracts showed that the tract group with microbleeds had 95th percentile peak axial strain and strain rate of 0.197 and 64.9 sâ1 respectively, which were significantly larger than those of the group of tracts without microbleeds (0.163 and 57.0 sâ1). This study does not derive a threshold for the onset of microbleeds as it investigated a single case, but it provides evidence for a link between strain and strain rate applied to veins during head impacts and structural damage and allows for future work to generate threshold values. Moreover, our results suggest that the FE model has the potential to be used to predict intracranial vascular injuries after TBI, providing a more objective tool for TBI assessment and improving protection against it
Ascorbyl-6-O-oleate: A Bioconjugate Antioxidant Lipid
Ascorbylâ6âOâoleate (AscâOL) was synthesized enzimatically and studied in the pure state and in aqueous dispersions. Smallâangle Xâray scattering (SAXS), differential scanning calorimetry (DSC), Fourier transformed infrared (FTIR) spectroscopy experiments and antioxidant tests were conducted in order to characterize the compound and to evaluate its reducing properties. AscâOL is a bioconjugate molecule, in fact it combines the main physicoâchemical features of the two parent molecules, i.âe. the redox and acidic properties of Vitamin C and the fluidâlike state of oleic acid. The appropriate tests were carried out to confirm the excellent radical scavenging activities of AscâOL, that turned out to be a promising candidate for the stabilization, transport and protection against radical attack of valuable hydrophobic active ingredients used in food and pharmaceutical formulations
Nature-Inspired Compounds: Synthesis and Antibacterial Susceptibility Testing of Eugenol Derivatives against <i>H. pylori</i> Strains
The antimicrobial properties of one of the most important secondary metabolites, Eugenol (EU), inspired us to design and synthesize three different series of derivatives enhancing its parent compoundâs anti-Helicobacter pylori activity. Thus, we prepared semisynthetic derivatives through (A) diazo aryl functionalization, (B) derivatization of the hydroxy group of EU, and (C) elongation of the allyl radical by incorporating a chalcogen atom. The antibacterial evaluation was performed on the reference NCTC 11637 strain and on three drug-resistant clinical isolates and the minimal inhibitory and bactericidal concentrations (MICs and MBCs) highlight the role of chalcogens in enhancing the antimicrobial activity (less than 4 ”g/mL for some compounds) of the EU scaffold (32â64 ”g/mL)
Erratum: New insights from the application of the FAbry STabilization indEX in a large population of Fabry cases
[This corrects the article DOI: 10.1093/ckj/sfy108.]