I know the ng means nanogram

But I’m curious how would I say the above line of 2.1 ng/kg

For context I got it from this paragraph

a lethal dose of 1.3–2.1 ng/kg in humans

Would it be

2.1 nanogram per kilogram?

Also if I wanted to write that as a decimal number how would i write that?

  • Ephera@lemmy.ml
    12·
    5 months ago

    Yeah, personally I would say that it’s per kg bodyweight.

    But I would also do my darndest to try write it, since “ng/kg” is kind of just nonsense. It makes it look like you could divide the grams out of that to get a fixed ratio, which is not correct at all.

    • towerful@programming.dev
      8·
      5 months ago

      But it is a fixed ratio.
      If it was in pounds, metric tons, moles or atomic mass units… It doesn’t change the ratio, the actual number.

      Would it be acceptable to drop the unit all together?
      “Lethal dose is 0.000000012 : 1 (substance : bodyweight)” (I made up the number).
      I’m not sure if there is a better way of writing the ratio.

      Could a fraction be more applicable?
      “lethal dose is 1/600000 of bodyweight”

      I’m sure it’s written as ng/kg to show the base units are the same, and the rest is just “fiddling” scientific notation

      • Successful_Try543@feddit.de
        6·
        5 months ago

        moles

        would not work, as they are no mass unit. 1 mol of Botox does not have the same weight as 1 mol of human (If that is defined at all, as organisms are no pure substances).

      • Ephera@lemmy.ml
        1·
        5 months ago

        Well, what I meant with that, is that it’s semantically important that it’s ng of the substance per kg bodyweight.

        If it was ng of the substance per kg of the substance, then in proper mathematical physics, the unit would disappear completely.

        So, for example:
        42000000000 ng of the substance / kg of the substance

        Is equivalent to:
        42000000000 * 0.000000001 * kg of the substance / kg of the substance

        Which means in the end, you just have: 42

        As my physics teacher would often say: Is that 42 potatoes or sausages or what is it?
        A number without a unit is just devoid of meaning…