## 4 Discussion
That is, the amount of charge accumulated in the measuring cell is ambiguously dependent on the water flow rate, i.e., this dependence can be nonlinear. As discussed previously in [32], the appearance of jumps in the time dependence of the amount of the accumulated charge can be caused by the probability of the fact that the charge comes out of the injector nozzle in the presence of an electrohydrodynamic barrier occurring in the injector. The physical cause for the presence of this barrier, in its turn, can be conditioned by several factors, such as the presence of a negative charge on the polymeric surface of the injector [27], or a possible change in the viscosity of water upon its ortho-para conversion occurring in the course of operation of the peristaltic pump during the compression of the supply pipe. Negative charges are present on a polymer surface. They can hold positive charges in the liquid, thus creating a barrier during the formation of a positively charged drop [27]. This can be particularly sharply pronounced within the peristaltic pump, where the pump rollers significantly squeeze the feeding pipe, thereby significantly distorting the fluid flow near the boundary layer. Another cause of the charge jumps is connected with the ortho-para conversion of water, and leads to a shift in the equilibrium in the boundary layer under the action of the peristaltic pump--this can be explained in a way analogous to [33]. In the paper by [PERSON] et al. [33], it is noted that under the action of a pipette (and in our case, under the action of the peristaltic pump), a change in the hydration surface layer can be observed. In [33], it is stated that there is a hydration shell near the surface of proteins, which represents an ice-like structure. At this point, it is known that the ortho/para ratio of 3:1, which is valid for gases at room temperature, shifts in water towards a more than twofold increase in the amount of para-H\({}_{2}\)O isomers. Thus, water represents a nonequilibrium liquid in terms of spin temperature. In such a state, water can therefore stepwisely change this ratio towards the equilibrium one, i.e., towards the increase in the amount of para-isomers--particularly under the influence of physical factors, such as an increase in temperature near the characteristic point of water (\(\sim\)37 \({}^{\circ}\)C) upon the local pressure increase in the compression section of the peristaltic pump. Accordingly, upon passing through a peristaltic pump, a local conversion of ortho-para isomers can occur in water, what causes a corresponding jump in charge. Stepwise jumps are sometimes not reproducible--possibly due to the fact that their formation is affected by the simultaneous combination of several processes. Two of these processes we have described above; others, possibly, have not been described herein, and further investigation of these processes is required. Ortho-para conversion in water, associated with the anomalous properties of water (which has a complex heterostructure), is described in [33; 34]. Since the studied range of supply flow rates is typical not only for systems for AFM-based fishing, but also for other proteomic detection systems (chromatographic, chromato-mass-spectrometric, nanowire-based ones, etc. ), the data obtained in these studies can be used in the development of novel highly efficient systems for the detection of biomarkers in patients'blood. Another factor provoking interest to the studies on the dependence of charge generation on the flow rate in a wide range of flow rates is the fact that in the human body, the rate of blood flow through the vessels makes up from \(\sim\)0.5 m/s (aorta) down to the value of several orders of magnitude lower (0.5 mm/s in capillaries [35]). Thus, studying the dependence of charge generation on the liquid flow rate is of great interest for the development and refinement of hemodynamic models in the body.