## 4 Conclusions  
The effectiveness of cold plasmas in inducing a wide range of biological and therapeutic effects is demonstrated by a large and ever growing body of scientific literature. In most cases, it is generally assumed that thermal effects are negligible. This assumption is mostly based on the evaluation of the power deposition to the tissues performed through calorimetric measurements on targets of known material, typically metals. Also the existing international standards prescribe an evaluation of power transfer using copper targets of known features. The objective of the present work was to evaluate the effectiveness of the PCC plasma source at different power levels, in relation to the task of inducing non-thermal blood coagulation. Our in vitro and in vivo tests showed that the plasma, at low power and for short time treatments, is indeed able to effectively accelerate platelet aggregation and fibrin formation, thus inducing coagulation. However, at higher powers and for longer treatments, also harmful effects appear, such as red cells lysis, with destruction of collagen fibers and dehydration of muscle fibers. It is worth mentioning that, in our case, higher powers and longer treatments have been applied only for characterization purposes, while are not necessary for obtaining therapeutic effects. On the other hand, this study demonstrates the importance of controlling the plasma dose for clinical applications, in order to avoid the appearance of tissue damage. In carrying out this task, it was ascertained that the main heating mechanism is due to the electric current flowing in the sample. This leads to the conclusion that a power deposition evaluation performed on targets of given material could not be representative of what happens when the plasma is applied to actual living tissues. Indeed, the effect is expected to be remarkably different than in the case of metal targets. One might be tempted to prescribe the use of target materials which more closely resemble actual tissues in terms of resistivity, however also in this case a large uncertainty may be expected, due to the large variations of resistivity among different biological samples, especially when one includes conditions such as the presence of blood or other fluids. Furthermore, grounding of the treated sample is an issue which also affects power deposition. Overall, these findings point to the necessity of having plasma sources where input power can be varied, as is the case for the PCC, so that it can be adjusted to the substrate conditions. Furthermore, being the thermal load and not the dissipated power the relevant quantity to be adjusted, one may envision, for the next generation of devices, methods to locally measure the substrate temperature and feedback systems to adjust power levels and/or distance between source and substrate so as to keep this quantity to a desired value [40]. The identification of the best technical solutions for the development of this new generation of tools will be the task for plasma physicists and engineers working in the plasma medicine field for the years to come. Conceptualization, L.C., G.D.M., A.F., C.G., A.P. and E.M.; Data curation, L.C., A.F., C.G. and A.P. ; Formal analysis, C.G. and A.P. ; Funding acquisition, G.D.M. and C.I. ; Investigation, L.C., G.D.M., A.F., C.G., A.P. and D.D. ; Project administration, G.D.M., C.I. and E.M.; Resources, D.D., C.I. and E.M.; Software, A.P. ; Supervision, C.I. and E.M.; Validation, L.C., G.D.M., A.F., C.G., A.P., D.D. and E.M.; Visualization, L.C., A.F., C.G. and A.P. ; Writing original draft, L.C., G.D.M., A.F., C.G. and A.P. ; Writing review & editing, L.C., G.D.M., A.F., C.G., A.P., D.D. and E.M. This work was supported in part by the University of Padova--Department of Industrial Engineering, under Grant year 2017--BIRD171931 and in part by a research project named \"A novel plasma medicine tool for accelerated haemostasis\", which has received funding from the \"Fondazione Con II Sud\" within the call \"Brains2 South\".