Spitzer spectral observations of the deep impact ejecta.

Spitzer Space Telescope imaging spectrometer observations of comet 9P/Tempel 1 during the Deep Impact encounter returned detailed, highly structured, 5- to 35-micrometer spectra of the ejecta. Emission signatures due to amorphous and crystalline silicates, amorphous carbon, carbonates, phyllosilicates, polycyclic aromatic hydrocarbons, water gas and ice, and sulfides were found. Good agreement is seen between the ejecta spectra and the material emitted from comet C/1995 O1 (Hale-Bopp) and the circumstellar material around the young stellar object HD100546. The atomic abundance of the observed material is consistent with solar and C1 chondritic abundances, and the dust-to-gas ratio was determined to be greater than or equal to 1.3. The presence of the observed mix of materials requires efficient methods of annealing amorphous silicates and mixing of high- and low-temperature phases over large distances in the early protosolar nebula.

The effect of mitomycin C on daily sperm production potential and other spermatogenic parameters in mice.

Thirty CD-1 male mice were randomly allocated to one of three groups and treated daily for five consecutive days via intraperitoneal (IP) injections. Treatments consisted of: 1) control (vehicle), consisting of 0.2 ml dose of phosphate buffered saline, 2) 1.0 mg of Mitomycin C (MC) per kg body weight, and 3) 2.0 mg of MC per kg body weight. All animals were sacrificed 35 days post-initiation of the experiment. Mice administered the higher dose of MC died within the first 19 days after the first injection. Significant differences (P less than 0.001) were observed between the two remaining groups in daily sperm production potential, sperm count per high power field, percent motility and progressive motility. Histological preparation of testicular parenchymal tissue revealed a high degree of seminiferous epithelial destruction and increased vacuolization associated with treatment of MC. These data indicate that MC causes severe pathological changes to spermatogonial cells within the seminiferous tubules, which in turn, induce spermatogenic dysfunctions noted in all parameters measured in this study.