3D Modelling for Solar Erythemal UV Protection Provided by Human Hair

Round 1

Reviewer 1 Report

This manuscript contributes to the scientific knowledge and deserves to be published after minor revision as follows:

Abstract, line 15: "UltraViolet" should be "ultraviolet"

Figure 6: The x axis on the five graphs should be "solar zenith angle" instead of "hour".

 

Author Response

We would like to thank the reviewer for careful and thorough reading of this manuscript and for the thoughtful comments and constructive suggestions, which help to improve the quality of the paper.

Our response follows (the reviewer’s comments are in italics).

 

This manuscript contributes to the scientific knowledge and deserves to be published after minor revision as follows:

Abstract, line 15: "UltraViolet" should be "ultraviolet"

The correction has been made.

 

Figure 6: The x axis on the five graphs should be "solar zenith angle" instead of "hour".

We prefer to leave the x-axis in “hours” to give a more understandable information to the general public, since changing the x axis in SZA would compromise a result more difficult to interpret (the resulting shape would be circular and not linear) and PPFs values as function of SZAs have been shown in Table 3 Nevertheless, we understand your remark and we decide to clarify the corresponding SZAs in the legend of Figure 6. The sentence now reads (L229-230): “The marked hours in the plots (6, 9, 12, 15, 18) correspond to the following SZA: 71.1°, 40.9°, 26°, 47.9°, 78.2°.”

Reviewer 2 Report

In Table 3, most of the values for “random” section is larger than their corresponding values in “upright” section and smaller than their corresponding values in “parallel” section. However, the “right” and “left” columns do not follow this pattern, where the values in random section is smaller than upright and parallel sections. It seems that the results are contradictory to common sense, where “random” hair would get a PPF level between “upright” and “parallel” hair. Could the authors add an explanation for this outcome? Similar question as Q1 for Figure 6, it seems that “random” hair could have PPF lower than “upright” and “parallel” hair in certain time point. Is there any explanation?

 

Author Response

We would like to thank the reviewer for careful and thorough reading of this manuscript and for the thoughtful comments and constructive suggestions, which help to improve the quality of the paper.

Our response follows (the reviewer’s comments are in italics).

 

In Table 3, most of the values for “random” section is larger than their corresponding values in “upright” section and smaller than their corresponding values in “parallel” section. However, the “right” and “left” columns do not follow this pattern, where the values in random section is smaller than upright and parallel sections. It seems that the results are contradictory to common sense, where “random” hair would get a PPF level between “upright” and “parallel” hair. Could the authors add an explanation for this outcome? Similar question as Q1 for Figure 6, it seems that “random” hair could have PPF lower than “upright” and “parallel” hair in certain time point. Is there any explanation?

 

We thank the reviewer for her/his supporting interest on our study topic. As correctly remarked, for the left and right side the evaluation of the model is not trivial as the results depend more visibly on the position of the sun, both at the zenithal and azimuthal levels. After noon, for example, the sun would be in the western half of the sky, but the precise position on the x-y planes depends on the azimuth values that change seasonally. Therefore, it is not always easy to find a general explanation. In our case, we can observe that for the right and left sides, the random behavior is once again smaller than upright alignment, in agreement with the common sense, but in some cases smaller than parallel alignment as well. This is probably due to the fact that upright alignment, in lateral zones, can provide more protection since the hair strand is in often perpendicular to UV rays, thus creating more shadow on the anatomical zone considered (even if upright alignment for right and left areas is more realistic for beard, rather than hair). On the contrary, a random behaviour, that by definition it is not in an upright position, would protect less areas in terms of shade.

The above explanation has been added in L236-245: “For the left and right side, the evaluation of the model is not trivial as the results depend more significantly on the position of the sun, both at the zenithal and azimuthal levels. Therefore, it is not always easy to find a general explanation. In our case, we can observe that for the right and left sides, the random PPFs are once again smaller than upright alignment, in agreement with the common sense, but in some cases smaller than parallel alignment as well. This is probably due to the fact that upright alignment, in lateral zones, can provide more protection since the hair strand is in often perpendicular to UV rays, providing then more shade on the anatomical zone considered. However, upright alignment for right and left areas is more realistic for beard, rather than hair. On the contrary, a random behavior, that is not in an upright position by definition, would protect less areas in terms of shade.”