How to write an aside in a journal article? So the question is simple: What is the common way of saying something in parentheses in a journal paper like engineering or mathematics.

Assume you are talking about a mathematical approach, but in the middle you want to point out to something else, or mention an special case. I give an example:


  ...our approach is based on the following linear equations....
  
  Eq.(1).....
  
  (now here I want to make a big parenthesis or a break to discuss about something regarding the approach which is not too long to be considered as an Appendix, maybe only one paragraph )
  
  One can think of the other approach such as .....


So the question is it, how this feature is normally handled in papers, and what is the latex function to do so.
There are sometimes "remark" blocks that some authors use for discussing aspects that are of substantial interest to some readers but do not strictly belong to the core of the story that you are telling. If you are preparing your document with LaTeX, then such text blocks are called "environments".

An example is given in the Springer Lecture Notes in Computer Science guide for preparing papers, page 4 at the bottom.