We study the structure and dynamics of the gap created by a protoplanet in an accretion disc. The hydrodynamic equations for a flat, two-dimensional, non-selfgravitating protostellar accretion disc with an embedded, Jupiter sized protoplanet on a circular orbit are solved. To simulate possible accretion of mass onto the protoplanet we continually remove mass from the interior of the planet’s Ro...

Anterior spinal fusion is one of the most commonly performed procedures of the cervical spine for traumatic, degenerative, or malignant conditions that require excision of intervertebral discs or vertebral bodies. Autogenous bone grafting has been shown to have a 95% or greater fusion rate for single-level surgery. The introduction of artificial spacers or bone substitutes has reduced the probl...

BACKGROUND Anterior cervical discectomy and fusion (ACDF) is an established treatment for degenerative disease of the cervical disc, but adjacent segment degeneration or instability may develop long term. The aim of this study was to investigate the risk factors for adjacent segment degeneration following ACDF compared with the use of the Bryan artificial disc for cervical disc arthroplasty (CD...

STUDY DESIGN Retrospective review. PURPOSE This study aims to define the role of lumbar fusion for persistent back pains after the lumbar disc replacement. OVERVIEW OF LITERATURE Little is written about lumbar fusion after optimally placed lumbar arthroplasty in patients with persistent lower back pains. METHODS Retrospective review of cases of lumbar artificial disc requiring subsequent ...

PURPOSE Xerostomia can diminish the quality of life, leads to changes in normal chemical composition of saliva and oral microbiata, and increases the risk for opportunistic infections, such as Candida albicans. Various artificial salivas have been considered for patients with xerostomia. However, the knowledge on the antifungal and antiadhesive activity of artificial saliva substitutes is limit...