In attempts to make octaphenyldibenzofuran (7) and octaphenyldibenzothiophene (8), 2,5‐dibromofuran (4) 2,5‐dibromothiophene (5), respectively, were heated with tetracyclone (2) under forcing conditions, but only single addition products, such as 2‐bromo‐4,5,6,7‐tetraphenylbenzofuran (10) 2‐bromo‐4,5,6,7‐tetraphenylbenzothiophene (12) observed. However, when 2,5‐dibromothiophene‐1,1‐dioxide (6)...

  In this study two groups of dental study models were selected to evaluate the relationship between the tooth size, arch dimensions , and dental crowding. The first group consisting of 56 pairs of dental study models (28 males and 28 females) with normal occlusion ( without dental crowding) ranging in  age from 16 to 20 years, were selected among 4445 students from Kerman by multi stage rando...