In vitro and in vivo studies on biocompatibility of carbon fibres

In the present study we focused on the in vitro and in vivo evaluation of two types of carbon fibres (CFs): hydroxyapatite modified carbon fibres and porous carbon fibres. Porous CFs used as scaffold for tissues regeneration could simultaneously serve as a support for drug delivery or biologically active agents which would stimulate the tissue growth; while addition of nanohydroxyapatite to CFs precursor can modify their biological properties (such as bioactivity) without subsequent surface modifications, making the process cost and time effective. Presented results indicated that fibre modification with HAp promoted formation of apatite on the fibre surface during incubation in simulated body fluid. The materials biocompatibility was determined by culturing human osteoblast-like cells of the line MG 63 in contact with both types of CFs. Both tested materials gave good support to adhesion and growth of bone-derived cells. Materials were implanted into the skeletal rat muscle and a comparative analysis of tissue reaction to the presence of the two types of CFs was done. Activities of marker metabolic enzymes: cytochrome c oxidase (CCO) and acid phosphatase were examined to estimate the effect of implants on the metabolic state of surrounding tissues. Presented results evidence the biocompatibility of porous CFs and activity that stimulates the growth of connective tissues. In case of CFs modified with hydroxyapatite the time of inflammatory reaction was shorter than in case of traditional CFs

Influence of nuclear power unit on decreasing emissions of greenhouse gases

The paper presents a comparison of selected power technologies from the point of view of emissions of greenhouse gases. Such evaluation is most often based only on analysis of direct emissions from combustion. However, the direct analysis does not show full picture of the problem as significant emissions of GHG appear also in the process of mining and transportation of fuel. It is demonstrated in the paper that comparison of power technologies from the GHG point of view has to be done using the cumulative calculus covering the whole cycle of fuel mining, processing, transportation and end-use. From this point of view coal technologies are in comparable level as gas technologies while nuclear power units are characterised with lowest GHG emissions. Mentioned technologies are compared from the point of view of GHG emissions in full cycle. Specific GHG cumulative emission factors per unit of generated electricity are determined. These factors have been applied to simulation of the influence of introduction of nuclear power units on decrease of GHG emissions in domestic scale. Within the presented simulations the prognosis of domestic power sector development according to the Polish energy policy till 2030 has been taken into account. The profitability of introduction of nuclear power units from the point of view of decreasing GHG emissions has been proved

The influence of compositions of alternative fuels on higher heating values - a review

Ciepło spalania (Qw) jest ważnym parametrem charakteryzującym paliwa, a określane jest jako entalpia całkowitego spalania paliwa, z uwzględnieniem entalpii kondensacji skroplonej pary. Liczne korelacje empiryczne są dostępne w literaturze, na podstawie których można oszacować ciepło spalania Qw paliwa znając jego skład pierwiastkowy. W artykule, zestawiono 10 różnych wzorów empirycznych i na ich podstawie określono Qw dla wybranych paliw alternatywnych o różnym składzie. Dodatkowo obliczono średni błąd procentowy w odniesieniu do wyników eksperymentalnych. Stwierdzono, że użycie wzoru Dulonga w przypadku rozważanych paliw alternatywnych jest obarczone najmniejszym średnim błędem procentowym.Heating value of a fuel is an important parameter in selection of fuel. Higher Heating value (HHV) is the enthalpy of complete combustion of a fuel, including the condensation enthalpy of formed water. Numerous empirical correlations are available in the open literature to obtain the HHV of the fuel from its elementary composition. In the present study, these correlations are used to obtain HHV of few alternative fuels and the value of HHV for each fuel is compared with experimental values and mean absolute error % is calculated. It was found that Dulong model had the least mean error percentage for alternative fuels considered in the present study

Thermodynamic evaluation of biomass-to-biofuels production systems

Biomass is a renewable feedstock for producing modern energy carriers. However, the usage of biomass is accompanied by possible drawbacks, mainly due to limitation of land and water, and competition with food production. In this paper, the analysis concerns so-called second generation biofuels, like Fischer-Tropsch fuels or Substitute Natural Gas which are produced either from wood or from waste biomass. For these biofuels the most promising conversion case is the one which involves production of syngas from biomass gasification, followed by synthesis of biofuels. The thermodynamic efficiency of biofuels production is analyzed and compared using both the direct exergy analysis and the thermo-ecological cost. This analysis leads to the detection of exergy losses in various elements which forms the starting point to the improvement of conversion efficiency. The efficiency of biomass conversion to biofuels is also evaluated for the whole production chain, including biomass cultivation, transportation and conversion. The global effects of natural resources management are investigated using the thermo-ecological cost. The energy carriers' utilities such as electricity and heat are externally generated either from fossil fuels or from renewable biomass. In the former case the production of biofuels not always can be considered as a renewable energy source whereas in the latter case the production of biofuels leads always to the reduction of depletion of non-renewable resources. (C) 2013 Elsevier Ltd. All rights reserved

Arrhythmogenic right ventricular cardiomyopathy: clinical registry, tissue and DNA bank

A multidisciplinary collaborative European study has been designed with the aim to investigate the clinical, pathological and genetic features of arrhythmogenic right ventricular cardiomyopathy (ARVC), which is a progressive, genetically determined disorder of the right ventricular myocardium and a major risk of sudden death particularly in the young.1–3 The disease is reported familial up to 50% with autosomal dominant inheritance while an autosomal recessive form (Naxos disease) associated with cutaneous abnormalities also exists. Nine genetic loci and mutations in three genes have been discovered so far.4–7 Treatment and prevention of ventricular tachyarrhythmias and sudden death include antiarrhythmic drug therapy, catheter ablation and the implantable cardioverter-defibrillator.However, a systematic evaluation of treatment options is not yet available