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 also known to cause small sores or lesions as well as chronic diarrhea (IBS). Manufacturers and suppliers will sometimes substitute guar Gum, xanthan gum and cellulose gum in formulations, without changing product labels. Often, blends of all these ingredients are sold as cellulose gum. If allergic to guar gum, the most common foods to suspect contamination from are frozen dairy/ice treats, soft cheeses (cream cheese, ricotta), salad dressing and baked goods. In July 2007, the European Commission issued a health warning to its member states after high levels of dioxins were detected in a food additive - guar gum -