I have noticed a number of these files. What are they and should I be concerned?
Those are Bitdefender specific files.
There is no need to be concerned.
Still there is no concern for e_spyw, emalware, etc ?
These files are of no concern whatsoever. They are used by Bitdefender Virus Scanner to decide whether a file is malware by downloading virus traces (emalware e_spyw, etc) and comparing them. Other apps might identify them as viruses but the traces are harmless. They do make your computer a bit more prone to hacking and if you want you can delete them for comfort (though Bitfender will not work properly).