Introduction
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To prevent contamination
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For ease of insertion
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For hygienic purposes.
Materials and methodology
Research equipment
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† Thermometerenvironment: Beurer HM16, resolution 0.1 °C and accuracy 0.1 °C
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† 2 • Thermometerball: Testo 108, resolution 0.1 °C and accuracy 0.5 °C; thermocouple type T
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† Thermostatwater bath: Julabo P4 basic
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† Balance: Mettler Toledo PG12001-s
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† Water bath (0.8 m • 0.4 m • 0.4 m)
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† Spherical mold, internal diameter 0.2 m, and a volume of 4.19 × 10−3 m3
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† Condoms (latex)
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† Nitrile gloves (acrylonitrile butadiene rubber, NBR)
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† SPSS 22 for Mac
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† Microsoft® Excel® for Mac
Research materials
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† Technical agar, no.3, Oxoid LP0013, ordered January 2014, stored cool and dry
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† Purified water
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† Petroleum jelly
Concentration of agar
Tissue type: | λ (W/(m °C)) | Temperature (°C) | Reference |
---|---|---|---|
Sheep resting skeletal muscle | 0.478 | 21 | [1] |
Human skeletal muscle | 0.449–0.546 | 37 | [2] |
Human subcutaneous adipose | 0.200–0.246 | 37 | [2] |
Human colon | 0.556 ± 0.009 | 37 | [2] |
Human cardiac muscle | 0.492–0.562 | 37 | [2] |
Agar gel preparation and creation of the agar body and subsequent experiments
Statistical analysis
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Without condom versus with condom
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Without nitrile glove versus with nitrile glove
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Without condom versus without nitrile glove
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Ambient temperature condom versus ambient temperature nitrile glove
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And finally, with condom versus with nitrile glove
Results
Starting temperature 36 °C
Independent samples test — 36 °C — without nitrile glove versus with nitrile glove | ||||||||||
---|---|---|---|---|---|---|---|---|---|---|
Levene’s test for equality of variances |
t Test for equality of means | |||||||||
F
| Sig |
t
|
df
| Sig. (two-tailed) | Mean difference | Std. error difference | 95 % confidence interval of the difference | |||
Lower | Upper | |||||||||
17″ | Equal variance assumed | 6.121 | 0.024 | 8.3 | 18 | 0.000 | 1.71000 | 0.20507 | 1.27915 | 2.14085 |
Equal variance not assumed | 8.3 | 10.9 | 0.000 | 1.71000 | 0.20507 | 1.25801 | 2.16199 | |||
33″ | Equal variance assumed | 3.754 | 0.069 | 7.9 | 18 | 0.000 | 0.99000 | 0.12583 | 0.72564 | 1.25436 |
Equal variance not assumed | 7.9 | 11.1 | 0.000 | 0.99000 | 0.12583 | 0.71327 | 1.26673 | |||
50″ | Equal variance assumed | 4.862 | 0.041 | 7.5 | 18 | 0.000 | 0.69000 | 0.09220 | 0.49630 | 0.88370 |
Equal variance not assumed | 7.5 | 12.7 | 0.000 | 0.69000 | 0.09220 | 0.49037 | 0.88963 | |||
1′ | Equal variance assumed | 2.714 | 0.117 | 7.4 | 18 | 0.000 | 0.27000 | 0.03667 | 0.19297 | 0.34703 |
Equal variance not assumed | 7.4 | 15.5 | 0.000 | 0.27000 | 0.03667 | 0.19205 | 0.34795 | |||
1.5′ | Equal variance assumed | 0.658 | 0.428 | 4.6 | 18 | 0.000 | 0.18000 | 0.03944 | 0.09714 | 0.26286 |
Equal variance not assumed | 4.6 | 17.3 | 0.000 | 0.18000 | 0.03944 | 0.09690 | 0.26310 | |||
2′ | Equal variance assumed | 1.827 | 0.193 | 3.2 | 18 | 0.005 | 0.14000 | 0.04397 | 0.04762 | 0.23238 |
Equal variance not assumed | 3.2 | 17.3 | 0.005 | 0.14000 | 0.04397 | 0.04734 | 0.23266 | |||
2.5′ | Equal variance assumed | 0.512 | 0.484 | 2.6 | 18 | 0.020 | 0.10000 | 0.03916 | 0.01773 | 0.18227 |
Equal variance not assumed | 2.6 | 16.6 | 0.021 | 0.10000 | 0.03916 | 0.01723 | 0.18277 | |||
3′ | Equal variance assumed | 0.136 | 0.717 | 4.0 | 18 | 0.001 | 0.14000 | 0.03496 | 0.06655 | 0.21345 |
Equal variance not assumed | 4.0 | 17.8 | 0.001 | 0.14000 | 0.03496 | 0.06649 | 0.21351 | |||
3.5′ | Equal variance assumed | 4.669 | 0.044 | 2.2 | 18 | 0.038 | 0.09000 | 0.04014 | 0.00567 | 0.17433 |
Equal variance not assumed | 2.2 | 14.4 | 0.041 | 0.09000 | 0.04014 | 0.00411 | 0.17589 | |||
4′ | Equal variance assumed | 0.469 | 0.502 | 1.4 | 18 | 0.175 | 0.05000 | 0.03543 | −0.02444 | 0.12444 |
Equal variance not assumed | 1.4 | 17.7 | 0.176 | 0.05000 | 0.03543 | −0.02454 | 0.12454 | |||
4.5′ | Equal variance assumed | 0.000 | 1.000 | 2.0 | 18 | 0.062 | 0.06000 | 0.03018 | −0.00342 | 0.12342 |
Equal variance not assumed | 2.0 | 18.0 | 0.062 | 0.06000 | 0.03018 | −0.00342 | 0.12342 | |||
5′ | Equal variance assumed | 0.426 | 0.522 | 2.3 | 18 | 0.033 | 0.08000 | 0.03464 | 0.00722 | 0.15278 |
Equal variance not assumed | 2.3 | 17.4 | 0.033 | 0.08000 | 0.03464 | 0.00704 | 0.15296 |
Independent samples test — 36 °C — without condom versus with condom | ||||||||||
---|---|---|---|---|---|---|---|---|---|---|
Levene’s test for equality of variances |
t Test for equality of means | |||||||||
F
| Sig |
t
|
df
| Sig. (two-tailed) | Mean difference | Std. error difference | 95 % confidence interval of the difference | |||
Lower | Upper | |||||||||
17″ | Equal variance assumed | 6.661 | 0.019 | 10.5 | 18 | 0.000 | 2.39000 | 0.22747 | 1.91209 | 2.86791 |
Equal variance not assumed | 10.5 | 10.4 | 0.000 | 2.39000 | 0.22747 | 1.88573 | 2.89427 | |||
33″ | Equal variance assumed | 4.474 | 0.049 | 8.29 | 18 | 0.000 | 1.46000 | 0.17607 | 1.09009 | 1.82991 |
Equal variance not assumed | 8.29 | 10.5 | 0.000 | 1.46000 | 0.17607 | 1.07039 | 1.84961 | |||
50″ | Equal variance assumed | 1.982 | 0.176 | 7.99 | 18 | 0.000 | 0.96000 | 0.12019 | 0.70750 | 1.21250 |
Equal variance not assumed | 7.99 | 11.5 | 0.000 | 0.96000 | 0.12019 | 0.69699 | 1.22301 | |||
1′ | Equal variance assumed | 0.971 | 0.338 | 4.18 | 18 | 0.001 | 0.43000 | 0.10290 | 0.21381 | 0.64619 |
Equal variance not assumed | 4.18 | 12.1 | 0.001 | 0.43000 | 0.10290 | 0.20601 | 0.65399 | |||
1.5′ | Equal variance assumed | 0.116 | 0.737 | 3.74 | 18 | 0.002 | 0.23000 | 0.06155 | 0.10068 | 0.35932 |
Equal variance not assumed | 3.74 | 17.6 | 0.002 | 0.23000 | 0.06155 | 0.10047 | 0.35932 | |||
2′ | Equal variance assumed | 0.316 | 0.581 | 3.29 | 18 | 0.004 | 0.17000 | 0.05175 | 0.06128 | 0.27872 |
Equal variance not assumed | 3.29 | 17.5 | 0.004 | 0.17000 | 0.05175 | 0.06106 | 0.27894 | |||
2.5′ | Equal variance assumed | 0.018 | 0.894 | 2.75 | 18 | 0.013 | 0.13000 | 0.04726 | 0.03071 | 0.22929 |
Equal variance not assumed | 2.75 | 17.3 | 0.013 | 0.13000 | 0.04726 | 0.03045 | 0.22955 | |||
3′ | Equal variance assumed | 1.200 | 0.288 | 2.12 | 18 | 0.048 | 0.10000 | 0.04714 | 0.00096 | 0.19904 |
Equal variance not assumed | 2.12 | 17.3 | 0.049 | 0.10000 | 0.04714 | 0.00068 | 0.19932 | |||
3.5′ | Equal variance assumed | 0.474 | 0.500 | 1.63 | 18 | 0.120 | 0.08000 | 0.04899 | −0.02292 | 0.18292 |
Equal variance not assumed | 1.63 | 17.9 | 0.120 | 0.08000 | 0.04899 | −0.02296 | 0.18296 | |||
4′ | Equal variance assumed | 0.445 | 0.513 | 1.84 | 18 | 0.082 | 0.08000 | 0.04346 | −0.01131 | 0.17131 |
Equal variance not assumed | 1.84 | 18.0 | 0.082 | 0.08000 | 0.04346 | −0.01132 | 0.17132 | |||
4.5′ | Equal variance assumed | 0.472 | 0.501 | 1.27 | 18 | 0.219 | 0.06000 | 0.04714 | −0.03904 | 0.15904 |
Equal variance not assumed | 1.27 | 18.0 | 0.219 | 0.06000 | 0.04714 | −0.03905 | 0.15905 |
Independent samples test — 36 °C — with nitrile glove versus with condom | ||||||||||
---|---|---|---|---|---|---|---|---|---|---|
Levene’s test for equality of variances |
t Test for equality of means | |||||||||
F
| Sig |
t
|
df
| Sig. (two-tailed) | Mean difference | Std. error difference | 95 % confidence interval of the difference | |||
Lower | Upper | |||||||||
17″ | Equal variance assumed | 0.072 | 0.792 | 2.5 | 18 | 0.023 | 0.73000 | 0.29335 | 0.11369 | 1.34631 |
Equal variance not assumed | 2.5 | 18 | 0.023 | 0.73000 | 0.29335 | 0.11310 | 1.34690 | |||
33″ | Equal variance assumed | 0.632 | 0.437 | 2.5 | 18 | 0.024 | 0.51000 | 0.20669 | 0.07575 | 0.94425 |
Equal variance not assumed | 2.5 | 16 | 0.025 | 0.51000 | 0.20669 | 0.07221 | 0.94779 | |||
50″ | Equal variance assumed | 0.021 | 0.885 | 2.2 | 18 | 0.040 | 0.31000 | 0.14004 | 0.01579 | 0.60421 |
Equal variance not assumed | 2.2 | 17 | 0.041 | 0.31000 | 0.14004 | 0.01404 | 0.60596 | |||
1′ | Equal variance assumed | 2.401 | 0.139 | 1.8 | 18 | 0.096 | 0.17000 | 0.09690 | −0.03357 | 0.37357 |
Equal variance not assumed | 1.8 | 9.8 | 0.111 | 0.17000 | 0.09690 | −0.04650 | 0.38650 | |||
15′ | Equal variance assumed | 7.579 | 0.013 | 1.6 | 18 | 0.136 | 0.08000 | 0.05121 | −0.02758 | 0.18758 |
Equal variance not assumed | 1.6 | 13 | 0.143 | 0.08000 | 0.05121 | −0.03105 | 0.19105 | |||
20′ | Equal variance assumed | 2.817 | 0.111 | 2.0 | 18 | 0.062 | 0.13000 | 0.06540 | −0.00741 | 0.26741 |
Equal variance not assumed | 2.0 | 15 | 0.066 | 0.13000 | 0.06540 | −0.00952 | 0.26952 | |||
25′ | Equal variance assumed | 1.665 | 0.213 | 1.7 | 18 | 0.105 | 0.12000 | 0.07040 | −0.02790 | 0.26790 |
Equal variance not assumed | 1.7 | 14 | 0.110 | 0.12000 | 0.07040 | −0.03092 | 0.27092 | |||
30′ | Equal variance assumed | 3.561 | 0.075 | 1.8 | 18 | 0.091 | 0.15000 | 0.08386 | −0.02619 | 0.32619 |
Equal variance not assumed | 1.8 | 11 | 0.101 | 0.15000 | 0.08386 | −0.03459 | 0.33459 | |||
35′ | Equal variance assumed | 3.577 | 0.075 | 2.3 | 18 | 0.031 | 0.19000 | 0.08145 | 0.01889 | 0.36111 |
Equal variance not assumed | 2.3 | 12 | 0.039 | 0.19000 | 0.08145 | 0.01181 | 0.36819 | |||
40′ | Equal variance assumed | 3.157 | 0.092 | 2.2 | 18 | 0.040 | 0.19000 | 0.08596 | 0.00941 | 0.37059 |
Equal variance not assumed | 2.2 | 13 | 0.046 | 0.19000 | 0.08596 | 0.00402 | 0.37596 | |||
45′ | Equal variance assumed | 3.383 | 0.082 | 2.4 | 18 | 0.029 | 0.23000 | 0.09690 | 0.02643 | 0.43357 |
Equal variance not assumed | 2.4 | 12 | 0.036 | 0.23000 | 0.09690 | 0.01847 | 0.44153 | |||
55′ | Equal variance assumed | 1.241 | 0.280 | 2.3 | 18 | 0.032 | 0.24000 | 0.10349 | 0.02257 | 0.45743 |
Equal variance not assumed | 2.3 | 17 | 0.033 | 0.24000 | 0.10349 | 0.02121 | 0.45879 | |||
60′ | Equal variance assumed | 0.098 | 0.757 | 2.1 | 18 | 0.048 | 0.25000 | 0.11799 | 0.00211 | 0.49789 |
Equal variance not assumed | 2.1 | 18 | 0.048 | 0.25000 | 0.11799 | 0.00196 | 0.49804 |
Starting temperature 30 °C
Independent samples test — 30 °C — without nitrile glove versus with nitrile glove | ||||||||||
---|---|---|---|---|---|---|---|---|---|---|
Levene’s test for equality of variances |
t Test for equality of means | |||||||||
F
| Sig |
t
|
df
| Sig. (two-tailed) | Mean difference | Std. error difference | 95 % confidence interval of the difference | |||
Lower | Upper | |||||||||
17″ | Equal variance assumed | 10.75 | 0.011 | 6.41 | 8 | 0.000 | 1.08000 | 0.16852 | 0.69139 | 1.46861 |
Equal variance not assumed | 6.41 | 4.3 | 0.002 | 1.08000 | 0.16852 | 0.62438 | 1.53562 | |||
33″ | Equal variance assumed | 7.144 | 0.028 | 4.53 | 8 | 0.002 | 0.58000 | 0.12806 | 0.28469 | 0.87531 |
Equal variance not assumed | 4.53 | 4.5 | 0.008 | 0.58000 | 0.12806 | 0.23994 | 0.92006 | |||
50″ | Equal variance assumed | 2.246 | 0.172 | 3.73 | 8 | 0.006 | 0.38000 | 0.10198 | 0.14483 | 0.61517 |
Equal variance not assumed | 3.73 | 4.8 | 0.014 | 0.38000 | 0.10198 | 0.11525 | 0.64475 | |||
1′ | Equal variance assumed | 0.108 | 0.750 | 1.43 | 8 | 0.189 | 0.12000 | 0.08367 | −0.07293 | 0.31293 |
Equal variance not assumed | 1.43 | 7.5 | 0.192 | 0.12000 | 0.08367 | −0.07518 | 0.31518 | |||
60′ | Equal variance assumed | 0.094 | 0.767 | 2.56 | 8 | 0.034 | 0.14000 | 0.05477 | −0.01369 | 0.26631 |
Equal variance not assumed | 2.56 | 8.0 | 0.034 | 0.14000 | 0.05477 | −0.01360 | 0.26640 |
Independent samples test — 30 °C — without condom versus with condom | ||||||||||
---|---|---|---|---|---|---|---|---|---|---|
Levene’s test for equality of variances | t Test for equality of means | |||||||||
F
| Sig |
t
|
df
| Sig. (two-tailed) | Mean difference | Std. error difference | 95 % confidence interval of the difference | |||
Lower | Upper | |||||||||
17″ | Equal variance assumed | 5.434 | 0.048 | 7.3 | 8 | 0.000 | 0.88000 | 0.12000 | 0.60328 | 1.15672 |
Equal variance not assumed | 7.3 | 6.257 | 0.000 | 0.88000 | 0.12000 | 0.58927 | 1.17073 | |||
33″ | Equal variance assumed | 4.020 | 0.080 | 6.3 | 8 | 0.000 | 0.56000 | 0.08832 | 0.35634 | 0.76366 |
Equal variance not assumed | 6.3 | 5.670 | 0.001 | 0.56000 | 0.08832 | 0.34081 | 0.77919 | |||
50″ | Equal variance assumed | 5.592 | 0.046 | 5.7 | 8 | 0.000 | 0.44000 | 0.07746 | 0.26138 | 0.61862 |
Equal variance not assumed | 5.7 | 4.569 | 0.003 | 0.44000 | 0.07746 | 0.23509 | 0.64491 | |||
1′ | Equal variance assumed | 2.667 | 0.141 | 2.1 | 8 | 0.067 | 0.30000 | 0.14142 | −0.02612 | 0.62612 |
Equal variance not assumed | 2.1 | 4.420 | 0.095 | 0.30000 | 0.14142 | −0.07837 | 0.67837 |
Starting temperature 27 °C
Independent samples test — 27 °C — without nitrile glove versus with nitrile glove | ||||||||||
---|---|---|---|---|---|---|---|---|---|---|
Levene’s test for equality of variances |
t Test for equality of means | |||||||||
F
| Sig. |
t
|
df
| Sig. (two-tailed) | Mean difference | Std. error difference | 95 % confidence interval of the difference | |||
Lower | Upper | |||||||||
17″ | Equal variance assumed | 1.57 | 0.246 | 6.0 | 8 | 0.000 | 0.58000 | 0.09695 | 0.35642 | 0.80358 |
Equal variance not assumed | 6.0 | 7.07 | 0.001 | 0.58000 | 0.09695 | 0.35123 | 0.80877 | |||
33″ | Equal variance assumed | 0.030 | 0.868 | 4.7 | 8 | 0.002 | 0.42000 | 0.08944 | 0.21374 | 0.62626 |
Equal variance not assumed | 4.7 | 7.92 | 0.002 | 0.42000 | 0.08944 | 0.21339 | 0.62661 | |||
50″ | Equal variance assumed | 0.526 | 0.489 | 4.4 | 8 | 0.002 | 0.32000 | 0.07348 | 0.15054 | 0.48946 |
Equal variance not assumed | 4.4 | 7.50 | 0.003 | 0.32000 | 0.07348 | 0.14854 | 0.49146 | |||
1′ | Equal variance assumed | 0.060 | 0.812 | 2.1 | 8 | 0.073 | 0.14000 | 0.06782 | −0.01640 | 0.29640 |
Equal variance not assumed | 2.1 | 7.87 | 0.073 | 0.14000 | 0.06782 | −0.01687 | 0.29687 |
Independent samples test — 27 °C — without condom versus with condom | ||||||||||
---|---|---|---|---|---|---|---|---|---|---|
Levene’s test for equality of variances |
t Test for equality of means | |||||||||
F
| Sig. |
t
|
df
| Sig. (two-tailed) | Mean difference | Std. error difference | 95 % confidence interval of the difference | |||
Lower | Upper | |||||||||
17″ | Equal variance assumed | 1.252 | 0.296 | 6.2 | 8 | 0.000 | 0.48000 | 0.07746 | 0.30138 | 0.65862 |
Equal variance not assumed | 6.2 | 6.2 | 0.001 | 0.48000 | 0.07746 | 0.29213 | 0.66787 | |||
33″ | Equal variance assumed | 6.171 | 0.038 | 5.5 | 8 | 0.001 | 0.34000 | 0.06164 | 0.19785 | 0.48215 |
Equal variance not assumed | 5.5 | 4.9 | 0.003 | 0.34000 | 0.06164 | 0.18084 | 0.49916 | |||
50″ | Equal variance assumed | 2.415 | 0.159 | 4.7 | 8 | 0.002 | 0.24000 | 0.05099 | 0.12242 | 0.35758 |
Equal variance not assumed | 4.7 | 6.2 | 0.003 | 0.24000 | 0.05099 | 0.11621 | 0.36379 | |||
1′ | Equal variance assumed | 8.393 | 0.020 | 1.2 | 8 | 0.252 | 0.08000 | 0.06481 | −0.06945 | 0.22945 |
Equal variance not assumed | 1.2 | 5.3 | 0.269 | 0.08000 | 0.06481 | −0.08382 | 0.24382 |