Spatial variations in aromatic hydrocarbon emission in a dust-rich galaxy.

Dust grains absorb half of the radiation emitted by stars throughout the history of the universe, re-emitting this energy at infrared wavelengths. Polycyclic aromatic hydrocarbons (PAHs) are large organic molecules that trace millimetre-size dust grains and regulate the cooling of interstellar gas within galaxies. Observations of PAH features in very distant galaxies have been difficult owing to the limited sensitivity and wavelength coverage of previous infrared telescopes.

Grading Osteoarthritic Changes of the Zygapophyseal Joints from Radiographs: A Reliability Study.

Objective: This study tested the reliability of a 5-point ordinal scale used to grade the severity of degenerative changes of zygapophyseal (Z) joints on standard radiographs.

Methods: Modifications were made to a Kellgren grading system to improve agreement for grading the severity of osteoarthritic changes in lumbar Z joints. These included adding 1 grade of no degeneration, multiple radiographic views, and structured examiner training.

Symptomatic expansile vertebral hemangioma causing conus medullaris compression.

Objective: To present a case of symptomatic, expansile L1 vertebral hemangioma.

Clinical Features: A 46-year-old man presented with progressive neurologic changes and insidious onset of low back pain.

Intervention And Outcome: After a trial of 3 visits of conservative chiropractic care, no improvement was noted.