High-Pressure Studies of Hydrogen-Bonded Energetic Material 3,6-Dihydrazino--tetrazine Using DFT.

Hydrogen bonding is an important noncovalent interaction that plays a key role in most of the CHNO-based energetic materials, which has a great impact on the structural, stability, and vibrational properties. By analyzing the structural changes, IR spectra, and the Hirshfeld surfaces, we investigated the high-pressure behavior of 3,6-dihydrazino--tetrazine (DHT) to provide detailed description of hydrogen bonding interactions using dispersion-corrected density functional theory. The strengthening of hydrogen bonding is observed by the pressure-induced weakening of covalent N-H bonds, which is consistent with the red shift of NH/NH stretching vibrational modes.

An osteological study of occipitocervical synostosis: its embryological and clinical significance.

Background: Synostosis or fusion of atlas with occipital bone is known as occipitocervical synostosis, occipitalization of the atlas, or atlanto-occipital fusion. This is a rare congenital malformation at craniovertebral junction. Its incidence ranges from 0.

The flexor indicis profundus - its morphology and clinical significance.

The knowledge on the anatomical variations of the deep flexor muscles is important due to its evolutionary significance. The flexor digitorum profundus is the deep flexor muscle of the forearm. It is a composite muscle with a dual nerve supply.