A functional shunt in the umbilical cord: the role of coiling in solute and heat transfer

The Python notebook ‘angle_estimation_tool.ipynb’ contains the semi-automated Python tool used to extract the outline of the umbilical cord and each vessel.The file ‘Interpolated_outlines.zip’ contains all the interpolated outlines of cords and vessels used in the paper, provided as .txt files. Other extracted parameters, such as the characteristic angles, can be found in the file ‘cross-section_data.xlsx’.The datasets used to create each figure are included in ‘Figures-data.xlsx’.The COMSOL simulation file ‘2D_flux-repository.mph’ is used to solve the two-dimensional diffusion problem. To produce the fluxes shown in Figs 2-4, refer to the corresponding captions to set the geometric and model parameters for each figure and use the following settings:Fig. 2(a): define the parameter ‘omega’ using pitch ‘P’ and run the parameter sweep ‘Sweep P-helicity’. This is saved as a solution.Fig. 2(b): run the parameter sweep ‘Sweep d’Fig. 2(c): run the parameter sweep ‘Sweep eta’Fig. 3(a,b): run the parameter sweeps ‘Sweep theta1’ and ‘Sweep dtheta’ togetherFig. 4(a): enable the thin strip around each vessel in ‘Geometry’ and run the parameter sweeps ‘Sweep alpha’ and ‘Sweep omega’ together. Use the surface integral ‘Uptake Flux’ to calculate the uptake flux by selecting the area of the cord excluding the thin strip around the vessels. This is saved as a solution.Fig. 4(b): enable the thin strip around each vessel in the ‘Geometry’. To solve the baseline problem, set the model parameters and boundary conditions as described in Eqn (S50) in the Supplement.The COMSOL simulation file ‘3D-repository.mph’ is used to solve the three-dimensional diffusion problem to validate the two-dimensional approach. This file includes the solutions used to produce Fig. S6 in the Supplement.<br>