Cellulose nitrate was once the standard film variety used by the motion picture industry — up until about the 1940s. That substance is unstable and highly flammable; cellulose nitrate fires are difficult to extinguish and produce dangerous gases, including corrosive nitrogen oxides and carbon monoxide. Many important films produced on cellulose nitrate have been forever lost due to degradative oxidation . More recent film stock employs cellulose acetate, the so-called "safety film." Unfortunately, even this improved film is subject to degradation, though it can be preserved for more than a century if stored under cold, dry conditions.
After appropriately restraining the animal to allow access to the ear, cleanse the skin at the implant needle puncture site. It is subcutaneous between the skin and cartilage on the back side of the ear and below the midline of the ear. The implant must not be placed closer to the head than the edge of the cartilage ring farthest from the head. The location of insertion of the needle is a point toward the tip of the ear and at least a needle length away from the intended deposition site. Care should be taken to avoid injuring the major blood vessels or cartilage of the ear.
Injectable steroids are injected into muscle tissue, not into the veins. They are slowly released from the muscles into the rest of the body, and may be detectable for months after last use. Injectable steroids can be oil-based or water-based. Injectable anabolic steroids which are oil-based have longer half-life than water-based steroids. Both steroid types have much longer half-lives than oral anabolic steroids. And this is proving to be a drawback for injectables as they have high probability of being detected in drug screening since their clearance times tend to be longer than orals. Athletes resolve this problem by using injectable testosterone early in the cycle then switch to orals when approaching the end of the cycle and drug testing is imminent.