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5. Patents (Tables) | 12 Months Ended
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Dec. 31, 2020
Goodwill and Intangible Assets Disclosure [Abstract] |
Schedule of intangible assets |
|  | 2020 |  |  | 2019 |
Gross carrying amount - patents |  | $ | 336,834 |  |  | $ | 330,588 |
Accumulated amortization - patents(1) |  |  | (319,922 | ) |  |  | (322,774 | )
Patents, net |  | $ | 16,912 |  |  | $ | 7,814 |

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