Radioactive tracer such as a cell or tissue, or as a flow tracer to track fluid flow. Radioactive tracers are also used to determine the location of fractures created by hydraulic fracturing in natural gas production. Radioactive tracers form the basis of a variety of imaging systems, such as, PET scans, SPECT scans and technetium scans. Radiocarbon dating uses the naturally occurring carbon-14 isotope as an isotopic label. Isotopes of a chemical element differ only in the mass number. For example, the isotopes of hydrogen can be written as H, H and H, with the mass number at top left. When the
Guar gum of petroleum products . The largest market for guar gum is in the food industry. In the US, differing percentages are set for its allowable concentration in various food applications. In Europe, guar gum has EU food additive code E412. Xanthan gum and guar gum are the most frequently used gums in gluten-free recipes and gluten-free products. Applications include: Guar gum, as a water-soluble fiber, acts as a bulk-forming laxative, so is claimed to be effective in promoting regular bowel movements and relieving constipation and chronic related functional bowel ailments, such as diverticulosis, Crohn's disease, colitis and irritable bowel syndrome.