Abstract: Various methods and apparatus for determining an ability of a region of skin to withstand exposure to harmful radiation, as well as a safe exposure time of the skin to harmful radiation, are disclosed. In various embodiments, methods and apparatus according to the invention provide real time information about the cumulative effects of exposure to harmful radiation, such as ultraviolet radiation, based on an individual's skin type, or “natural” protection factor, and the actual effectiveness of any sunscreen applied on the individual's skin, independently of the labeled sun protection factor (SPF) of the sunscreen. In one embodiment, the invention periodically measures the individual's skin darkness (natural protection factor), the dynamic actual effectiveness of sunscreen, if applied, and a total exposure level of the skin to potentially harmful radiation, and determines a safe exposure time of the skin to the radiation.

Abstract: A non-aqueous electrolyte for use in an electrochemical cell comprising: (a) at least one organic solvent; (b) at least one electrolytically active salt represented by the formula: M′+m(ZRnXq−n)m in which: M′ is selected from a group consisting of magnesium, calcium, aluminum, lithium and sodium; Z is selected from a group consisting of aluminum, boron, phosphorus, antimony and arsenic; R represents radical selected from the following groups: alkyl, alkenyl, aryl, phenyl, benzyl, and amido; X is a halogen (I, Br, Cl, F); m=1-3; and n=0-5 and q=6 in the case of Z=phosphorus, antimony and arsenic, and n=0-3 and q=4 in the case of Z=aluminum and boron. Rechargeable, high energy density electrochemical cells containing an intercalation cathode, a metal anode, and an electrolyte of the above-described type are also disclosed.