Coal forms from the accumulation of plant debris, usually in a swamp environment. When plant debris dies and falls into the swamp the standing water of the swamp protects it from decay. Swamp waters are usually deficient in oxygen, which would react with the plant debris and cause it to decay.
Porokeratosis is generally considered to be a benign condition though malignant transformation has been seen in all but the punctate variety, necessitating regular followup of patients with porokeratosis (Maubec et al., 2005; Sasson & Krain, 1996).
Myringoplasty is the closure of the perforation of pars tensa of the tympanic membrane. When myringoplasty is combined with ossicular reconstruction, it is called tympanoplasty.The operation is performed with the patient supine and face turned to one side.he chances of re-infection and persistent discharge is less after surgery. Myringoplasty should not be performed if there is active discharge from the middle ear, or if the patient has uncontrolled nasal allergy, or when the other ear is dead and in children less than 3 years of age.