An evaporating colloidal particle–laden droplet leaves behind a ring-like residue after drying. We routinely observe this ubiquitous phenomenon for dried coffee drops; thus, it is known as the "coffee ...

Providers who manage GERD or IBD should know how obstructive sleep apnea can influence gastrointestinal disorders.

A few years ago, physicists were surprised to learn that stacking and subtly twisting two atomically thin layers of an ...