This was finally demonstrated in 2003, when researchers at the Institut dAstrophysique Spatiale in Orsay, France, measured the alpha emission half-life of 209Bi to be 2.01×1019 years (3 Bq/Mg), over a billion times longer than the current estimated age of the universe. Owing to its extraordinarily long half-life, for all presently known medical and industrial applications, bismuth can be treated as if it is stable and nonradioactive. The radioactivity is of academic interest because bismuth is one of a few elements whose radioactivity was suspected and theoretically predicted before being detected in the laboratory. Bismuth has the longest known alpha decay half-life, although tellurium-128 has a double beta decay half-life of over 2.2×1024 years. Bismuths extremely long half-life means that less than approximately one-billionth of the bismuth present at the formation of the planet Earth would have decayed into thallium since then. Several isotopes of bismuth with short half-lives occur within the radioactive disintegration chains of actinium, radium, and thorium, and more have been synthesized experimentally. Bismuth-213 is also found on the decay chain of neptunium-237 and uranium-233.Commercially, the radioactive isotope bismuth-213 can be produced by bombarding radium with bremsstrahlung photons from a linear particle accelerator. In 1997, an antibody conjugate with bismuth-213, which has a 45-minute half-life and decays with the emission of an alpha particle, was used to treat patients with leukemia. This isotope has also been tried in cancer treatment, for example, in the targeted alpha therapy (TAT) program. Chemical compounds
Bismuth forms trivalent and pentavalent compounds, the trivalent ones being more common.
A neutral stomach pH is required to keep platelets in place and prevent clot lysis. Tranexamic acid and antifibrinolytic agents are not useful in treating peptic ulcer disease.Early endoscopic therapy can help to stop bleeding by using cautery, endoclip, or epinephrine injection. Treatment is indicated if there is active bleeding in the stomach, visible vessels, or an adherent clot. Endoscopy is also helpful in identifying people who are suitable for hospital discharge. Prokinetic agents such as erythromycin and metoclopramide can be given before endoscopy to improve endoscopic view. Either high- or low-dose PPIs are equally effective in reducing bleeding after endoscopy. High-dose intravenous PPI is defined as a bolus dose of 80 mg followed by an infusion of 8 mg per hour for 72 hours—in other words, the continuous infusion of PPI of greater than 192 mg per day. Intravenous PPI can be changed to oral once there is no high risk of rebleeding from peptic ulcer.For those with hypovolemic shock and ulcer size of greater than 2 cm, there is a high chance that the endoscopic treatment would fail. Therefore, surgery and angiographic embolism are reserved for these complicated cases. However, there is a higher rate of complication for those who underwent surgery to patch the stomach bleeding site when compared to repeated endoscopy. Angiographic embolisation has a higher rebleeding rate but a similar rate of death to surgery. Anticoagulants
According to expert opinion, for those who are already on anticoagulants, the international normalized ratio (INR) should be kept at 1.5.