Visualization of subcutaneous insulin injections by x-ray computed tomography

We report how the three-dimensional structure of subcutaneous injections of soluble insulin can be visualized by x-ray computed tomography using an iodine based contrast agent. The injections investigated are performed ex vivo in porcine adipose tissue. Full tomography scans carried out at a laboratory x-ray source with a total acquisition time of about 1 min yield CT-images with an effective pixel size of 109 × 109 μm2. The depots are segmented using a modified Chan–Vese algorithm and we are able to observe differences in the shape of the injection depot and the position of the depot in the skin among equally performed injections. To overcome the beam hardening artefacts, which affect the quantitative prediction of the volume injected, we additionally present results concerning the visualization of two injections using synchrotron radiation. The spatial concentration distribution of iodine is calculated to show the dilution of the insulin drug inside the depot. Characterisation of the shape of the depot and the spatial concentration profile of the injected fluid is important knowledge when improving the clinical formulation of an insulin drug, the performance of injection devices and when predicting the effect of the drug through biomedical simulations

Computational Methods in Supporting Spatial Decision Making - Case Studies on Vulnerability Analysis of Critical Infrastructure and Utilisation of Population Information

Hazards, disasters cause insecurity for people and society. Critical infrastructure plays an important role in supporting society and human life, and also in helping to respond to such disasters. Often, the reason for fatalities and financial loss is the inadequacy of critical infrastructure to withstand the cataclysmic effects of natural disasters and the lack of mitigation strategies and preparedness. If the vulnerable locations of the critical infrastructure can be identified and reinforced in advance, the damage and impact can be significantly reduced. Therefore, vulnerability analysis of critical infrastructure is essential. In this dissertation, we formulate four research questions and solve them with five computational methods namely spatio-temporal modelling, graph theory (centrality measures), multi-criteria decision analysis, fuzzy logic and influence diagrams from different fields of science, in order to support spatial decision-making and the vulnerability analysis of critical infrastructure. Most of the methods use population information as one of the parameters and take uncertainty into consideration in the modelling process. In this dissertation, an object oriented spatio-temporal population model was developed to estimate the number of people inside a risk area at a particular time. Graph theory and a set of centrality measures were used to model critical infrastructure´s topological importance. Multi-criteria decision analysis was used to combine various types of input variables to compute an overall vulnerability map. We further developed a fuzzy multi-criteria decision model to solve the vagueness of classification and the decision-making problems with conflict objectives. Finally, we constructed a graphical representation of spatial decision problems by using an influence diagram with fuzzy logic and spatial analysis in order to model spatial objects dependency and it was used to model tree-related electricity outages. Regarding results; a spatio-temporal population model was implemented by using programming languages. The number of people inside a particular risk area at a certain time can be calculated by using this software model. The model is flexible, because it is knowledge based model and user can update his/her knowledge frequently in order to produce more accurate results. The results of using other computational methods are represented as vulnerability maps and vulnerable locations of critical infrastructure in the case of disaster can easily be identified. The biggest benefit of using multi-criteria decision analysis to combine all the attributes, is to save resources in preparedness planning of possible future disasters

An X-ray diffraction study of direct-bonded silicon interfaces:A model semiconductor grain boundary

Semiconductor wafer bonding techniques have been used to create a giant twist grain boundary from two Si(0 0 1) wafers. We show, using X-ray diffraction measurements that after annealing the interface forms a highly ordered superstructure with relaxations extending to many layers into the crystals on either side of the interface

Injection of high dose botulinum-toxin A leads to impaired skeletal muscle function and damage of the fibrilar and non-fibrilar structures

Botulinum-toxin A (BoNT/A) is used for a wide range of conditions. Intramuscular administration of BoNT/A inhibits the release of acetylcholine at the neuromuscular junction from presynaptic motor neurons causing muscle-paralysis. The aim of the present study was to investigate the effect of high dose intramuscular BoNT/A injections (6 UI = 60 pg) on muscle tissue. The gait pattern of the rats was significantly affected 3 weeks after BoNT/A injection. The ankle joint rotated externally, the rats became flat footed, and the stride length decreased after BoNT/A injection. Additionally, there was clear evidence of microstructural changes on the tissue level by as evidenced by 3D imaging of the muscles by Synchrotron Radiation X-ray Tomographic Microscopy (SRXTM). Both the fibrillar and the non-fibrillar tissues were affected. The volume fraction of fibrillary tissue was reduced significantly and the non-fibrillar tissue increased. This was accompanied by a loss of the linear structure of the muscle tissue. Furthermore, gene expression analysis showed a significant upregulation of COL1A1, MMP-2, TGF-b1, IL-6, MHCIIA and MHCIIx in the BoNT/A injected leg, while MHVIIB was significantly downregulated. In conclusion: The present study reveals that high dose intramuscular BoNT/A injections cause microstructural damage of the muscle tissue, which contributes to impaired gait