Hair loss is a feared side effect of chemotherapy treatment. It may be prevented by cooling the scalp during administration of cytostatics. The supposed mechanism is that by cooling the scalp, both temperature and perfusion are diminished, affecting drug supply and drug uptake in the hair follicle. However, the effect of scalp cooling varies strongly. To gain more insight into the effect of cooling, a computer model has been developed that describes heat transfer in the human head during scalp cooling. Of main interest in this study are the mutual influences of scalp temperature and perfusion during cooling. Results of the standard head model show that the temperature of the scalp skin is reduced from 34.4 • C to 18.3 • C, reducing tissue blood flow to 25%. Based upon variations in both thermal properties and head anatomies found in the literature, a parameter study was performed. The results of this parameter study show that the most important parameters affecting both temperature and perfusion are the perfusion coefficient Q 10 and the thermal resistances of both the fat and the hair layer. The variations in the parameter study led to skin temperature ranging from 10.1 • C to 21.8 • C, which in turn reduced relative perfusion to 13% and 33%, respectively.

Cooling the scalp during administration of chemotherapy can prevent hair loss. It reduces both skin blood flow and hair follicle temperature, thus affecting drug supply and drug effect in the hair follicle. The extent to which these mechanisms contribute to the hair preservative effect of scalp cooling remains unknown. The purpose of this study was to establish a relationship between local scalp skin temperature and cutaneous blood flow during scalp cooling. We measured skin temperature and cutaneous perfusion during a cooling and re-warming experiment. Experiments on a single subject showed that the measurements were reproducible and that the response was identical for the two positions that were measured. Inter-subject variability was investigated on nine subjects. We found that for the first 10• C of cooling, perfusion of the scalp skin decreases to below 40%. Perfusion can be further reduced to below 30% by a few degrees more cooling, but a plateau is reached after that. We found that a generally accepted relation in thermal physiology between temperature and perfusion (i.e. Q 10 relation) does not describe the data well, but we found an alternative relation that describes the average behavior significantly better.

Cancer chemotherapy treatment often leads to hair loss, which may be prevented by cooling the scalp during drug administration. The current hypothesis for the hair preservative effect of scalp cooling is that cooling of the scalp skin reduces blood flow (perfusion) and chemical reaction rates. Reduced perfusion leads to less drugs available for uptake, whereas the reduced temperature decreases uptake of and damage by chemotherapy. Altogether, less damage is exerted to the hair cells, and the hair is preserved. However, the two mechanisms in the hypothesis have not been quantified yet. To quantify the effect of reduced drug damage caused by falling temperatures, we investigated the effect of local drug concentration and local tissue temperature on hair cell damage using in vitro experiments on keratinocytes. Cells were exposed for 4 h to a wide range of doxorubicin concentrations. During exposure, cells were kept at different temperatures. Cell viability was determined after 3 d using a viability test. Control samples were used to establish a concentrationviability curve. Results show that cell survival is significantly higher in cooled cells (T<22°C) than in non-cooled cells (T=37°C), but no significant differences are visible between T=10°C and T=22°C. Based on this result and previous work, we can conclude that there is an optimal temperature in scalp cooling. Further cooling will only result in unnecessary discomfort for the patient and should therefore be avoided.

People interested in the research are advised to contact the author for the final version of the publication, or visit the DOI to the publisher's website.• The final author version and the galley proof are versions of the publication after peer review.• The final published version features the final layout of the paper including the volume, issue and page numbers. Link to publication General rightsCopyright and moral rights for the publications made accessible in the public portal are retained by the authors and/or other copyright owners and it is a condition of accessing publications that users recognise and abide by the legal requirements associated with these rights.• Users may download and print one copy of any publication from the public portal for the purpose of private study or research. • You may not further distribute the material or use it for any profit-making activity or commercial gain • You may freely distribute the URL identifying the publication in the public portal.If the publication is distributed under the terms of Article 25fa of the Dutch Copyright Act, indicated by the "Taverne" license above, please follow below link for the End User Agreement:

The production of energy from fossil fuels gives rise to the emission of CO2, NO x and SO2. The amounts of these compounds formed during the production of energy from renewables such as wind, sun and biomass are less than those in case of fossil fuels. Therefore, research and development is carried out for the application of renewables now and in the near future. This chapter focuses on the application of biomass, and more specific on the use of catalysts for the conversion technologies of biomass. Promising technologies, which are in a demonstration phase, are pyrolysis, gasification and hydrothermal upgrading. The products from these types of conversion technologies are: gas, fuel oil or bio-oil transport fuels and chemicals for the food and chemical industry. The production of hydrocarbons is a major objective of most bio-oil upgrading research. Flash and fast pyrolysis are techniques combining high heating rates and short reaction times. Rapid quenching preserves valuable products. Most of the technologies are studied on lab-scale or pilot-scale. For a number of conversion routes catalysts are applied. Char formation and coke deposition are major problems in upgrading of pyrolysis oils. Coke deposition deactivates the catalyst and has to be avoided or minimised. Pyrolysis oils are highly oxygenated, viscous, corrosive, relatively unstable and very complex. However, catalytic upgrading may produce a high valuable chemical feedstock. Oxygen in the oxygenated compounds is, therefore, converted to CO and CO2 rather than H2O to preserve hydrogen for hydrocarbon reactions. This paper discusses the use of catalysts in the field of thermal conversion of biomass.