What does the point in the middle between two numbers mean? > _[...] cells were removed to a cover glass and treated with plasma for 2 min, then returned to TS broth and centrifuged for 10 min. Cells were harvested and washed twice with PBS, then mixed with tryptic soy agar. The agar block was fixed with **2·5** % glutaraldehyde in **0·1** mol l−1 PBS. Samples were postfixed in 1% (w/v) OsO4 in **0·1** mol l−1 PBS for 2 h at room temperature, washed once with the same buffer, dehydrated in a graded ethanol series and embedded in low‐viscosity medium. Thin sections of the specimens were double‐stained with uranyl acetate and lead citrate..._ What does mean this bolded point? Is it a decimal separator, or has other scientific meaning? If this is decimal point, why is vertically middle aligned? _Source_ : a recent Korea researchers team article

**Short answer**

It's a decimal point.

**Longer answer**

A point in the 'middle' of the neighboring characters is called an interpunct, and was the standard in UK typography for marking a decimal at one point in time (possibly elsewhere as well). You're most likely to encounter it in older issues in UK and UK-inspired journals, and no doubt some have lagged behind the trends for reasons of tradition/stubbornness or whatever else and still use it.

Note that you will also encounter countries that use the _comma_ as a decimal separator; Wikipedia has a list that includes most of mainland Europe and South America, for example.