Separation by capillary electrophoresis can be detected by several detection devices. Hypercapnia may increase pulmonary capillary resistance. It is used as a volatile pH modifier in HPLC and capillary electrophoresis. Detection occurs via fluorescence through a window etched in the capillary. Portal veins carry blood between capillary beds. Mesangial cells can contract and relax to regulate capillary flow. Paper based microfluidics rely on the phenomenon of capillary penetration in porous media. The second mechanism of capillary exchange is bulk flow. In comparison with capillary movement, diffusion is a slow process. Pallor mortis results from the collapse of capillary circulation throughout the body. Piracetam may facilitate the deformability of erythrocytes in capillary. These bonds are the cause of water's high surface tension and capillary forces. The condensed refrigerant returns by a combination of gravity and capillary action in the wick. The Young equation provides reasoning for contact angle involvement in capillary condensation. This contributes to the death of pulmonary capillary beds.