The most common and most likely answer to this crossword clue is the 16 letter word CHANGESÂ OFÂ STATE
I've seen this crossword clue in The Guardian
C
H
A
N
G
E
S
Â
O
F
Â
S
T
A
T
E
Buddy explains!
The straight part
We know that "Eg 10 and 28/transformations between parts of the middle row" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case eg 10 and 28/transformations between parts of the middle row = changes of state.The cryptic/wordplay part
In cryptic crossword there's often an wordplay/cryptic part as well.This part involves a more complex hint, such as an anagram, homophone, hidden word, etc.
Sadly, We don't have an explanation for this specific crossword clue yet.