quantum mechanics - Strong gravity at the micro level?

I have read this:

https://resonance.is/black-holes-elementary-particles-revisiting-pioneering-investigation-particles-may-micro-black-holes/

where it says:

For the case of hadrons, it is at least logically possible that the gravitational coupling between matter and the geometry of space-time is much stronger than for macroscopic systems. The value of the gravitational coupling factor has never been measured within an atom or a subatomic particle. The standard use of the Newtonian value in this domain is based purely on an untested assumption.

I used to understand that gravity was the weakest force on the micro level. This statement states the opposite.

Question:

1. 
   

   Is it true that the value of the gravitational coupling constant has never been measure within an atom or between elementary particles?

   
   
   


2. 
   

   Is it true that gravity is much stronger on the micro level then on the macro level?

   
   

Answer

I don't think the author is asserting that gravity is stronger on the micro level, I think they are just saying that it is possible. As far as measuring gravity within an atom (or between elementary particles), this is incredibly difficult because electromagnetic interactions (forces) dominate at this scale. As far as I know, no measurement has been made of gravity at that scale. It would be a truly remarkable precision measurement to measure the gravitational interaction between, say, a proton and an electron.