Vitamin K antagonists (VKA) are a group of substances that reduce blood clotting by reducing the action of vitamin K. They are used as anticoagulant medications in the prevention of thrombosis, and in pest control, as rodenticides. 1  1 Mechanism of action.  2 Coumarins (4-hydroxycoumarins)
Calculate the average atomic mass of oxygen. Solution: ((15.994915*99.757) + (16.999132*0.038) + (17.999160*0.205))/100 = 15.999405 . Using our equation for determining average atomic mass, we see that the average atomic mass for oxygen is 15.999405 amu. If we check the periodic table, we will see that our average atomic mass is the same as the atomic mass indicated on the element oxygen. Ã
Oxygen is a gas and its molecules do exert a pressure but, like glucose, oxygen also has a finite content in the blood, in units of ml O 2 /dl blood. To remain viable tissues require a certain amount of oxygen per minute, a need met by a requisite oxygen content, not oxygen pressure. (Patients can and do live with very low PaO 2 values, as long as their oxygen content and cardiac output are adequate.) The oxygen carrying capacity of one gram of hemoglobin is 1.34 ml.