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
Gellan gum gel after churning. The benefit of using gellan gum is that the ice cream or sorbet can be set in a dish of flaming alcohol or heated with a propane torch without actually melting. Refer to these websites for more details: Gellan was discovered and developed as a commercial biogum hydrocolloid product by Kelco, then a division of Merck & Co. In the United States, Kelco was responsible for obtaining food approval for gellan gum worldwide. In other markets that are fond of innovative food ingredients such as Japan, the process for obtaining food approval has been undertaken by local