Noninvasive estimation of tumour viability in a xenograft model of human neuroblastoma with proton magnetic resonance spectroscopy (1H MRS)

The aim of the study was to evaluate proton magnetic resonance spectroscopy (1H MRS) for noninvasive biological characterisation of neuroblastoma xenografts in vivo. For designing the experiments, human neuroblastoma xenografts growing subcutaneously in nude rats were analysed in vivo with 1H MRS and magnetic resonance imaging at 4.7 T. The effects of spontaneous tumour growth and antiangiogenesis treatment, respectively, on spectral characteristics were evaluated. The spectroscopic findings were compared to tumour morphology, proliferation and viable tumour tissue fraction. The results showed that signals from choline (Cho)-containing compounds and mobile lipids (MLs) dominated the spectra. The individual ML/Cho ratios for both treated and untreated tumours were positively correlated with tumour volume (P<0.05). There was an inverse correlation between the ML/Cho ratio and the viable tumour fraction (r=−0.86, P<0.001). Higher ML/Cho ratios concomitant with pronounced histological changes were seen in spectra from tumours treated with the antiangiogenic drug TNP-470, compared to untreated control tumours (P<0.05). In conclusion, the ML/Cho ratio obtained in vivo by 1H MRS enabled accurate assessment of the viable tumour fraction in a human neuroblastoma xenograft model. 1H MRS also revealed early metabolic effects of antiangiogenesis treatment. 1H MRS could prove useful as a tool to monitor experimental therapy in preclinical models of neuroblastoma, and possibly also in children

Using lumber grade and by-products’ yield predictions for standing scots pine trees in stand level optimization

The purpose of this study was to develop models for estimating yields of lumber grades and by-products of individual Scots pine (Pinus sylvestris L.) stems using stem and crown dimensions as explanatory variables. The next stage will be combining models to simulation-optimization framework to optimize forest management at the stand level using climate change mitigation effect as an objective function when also material and energy substitution benefits of wood products are taken into account. Two separate data sets were used as a material for analysis: 1) Simulated data set generated by the process-based growth model, PipeQual, which provides information about stem form and branch properties. The model was used to predict the 3D structure of Scots pine stems in thinning regimes of varying intensity and rotation periods and 2) detailed measured empirical data set. The stems were sawn using the WoodCim sawing simulator and the yields and grades of the individual sawn pieces, as well as by-products, were recorded. The sawn timber pieces were classified on A, B, C and Dgrades for side and center boards separately (Finnish export rules). Byproducts were pulpwood, sawmill chips, sawdust and bark. The response variables were formulated as proportions of the total volume of each stem. Multinomial logistic regression models were fitted to the both data sets. Models fitted to the real stems data set was found more accurate and the dead branch height, diameter at the breast height and the natural logarithm of the diameter at breast height was found the best combination of the explanatory variables. The models were tested in the generated data set and found to overestimate the quality in medium fertile stands. The developed approach integrates forest management, its implications to the quality of raw wood and sawn wood conversion chain. The models can be used in stand management optimization for comparing different management options e.g. on the value-added basis from the sawmill’s point of view or climatic benefits of wood products

Mechanical subsystems integration and structural analysis for the autonomous underwater explorer

The aim of this study is to analyse the modular mechanical design and integration of all three low-level modules in UX-1 (pendulum, ballast system and propulsion unit). The components of the perception and navigation systems have position and orientation requirements that dictate the shape of the hull. A structural strength analysis using Finite Element Method (FEM) was made to study the hull strength during deep dives. The results are presented here, which indicates that the hull endures pressures related to deep dives. Also for validation, strain gauge locations were defined.acceptedVersionPeer reviewe