To test the masks, the breath of patients with asthma or COPD were monitored for nitrite, a biomarker for inflammation in both conditions. The results showed that the masks accurately detected the ...

When it was made: These masks date to at least the 16th century; the one photographed above dates to 1885. Yup'ik masks vary dramatically in size and shape, anthropologist Dorothy Jean Ray wrote ...

Choose from Safety Mask stock illustrations from iStock. Find high-quality royalty-free vector images that you won't find anywhere else. Video Back Videos home Signature collection Essentials ...

Choose from Cap Mask Clip Art stock illustrations from iStock. Find high-quality royalty-free vector images that you won't find anywhere else. Video Back Videos home Signature collection Essentials ...