Analysis of Partition Functions for Metallocenes: Ferrocene, Ruthenocene, and Osmocene.

We present a calculation of the torsional potential of the three metallocenes of the iron group, that is, ferrocene, ruthenocene, and osmocene, calculated with the GAUSSIAN program suite. Both a variational method (through computation of the exact energy levels) and our Chebyshev imaginary time propagation method are used to calculate the hindered rotation partition function, demonstrating the efficiency of the Chebyshev scheme. The transition from a semirigid through a hindered rotor to the free rotor regime is demonstrated, and the effect of the hindered rotation (as opposed to a harmonic) treatment on the thermodynamics of metallocenes is demonstrated.

Staging of uterine cervical cancer with MRI: guidelines of the European Society of Urogenital Radiology.

OBJECTIVE: To design clear guidelines for the staging and follow-up of patients with uterine cervical cancer, and to provide the radiologist with a framework for use in multidisciplinary conferences. METHODS: Guidelines for uterine cervical cancer staging and follow-up were defined by the female imaging subcommittee of the ESUR (European Society of Urogenital Radiology) based on the expert consensus of imaging protocols of 11 leading institutions and a critical review of the literature. RESULTS: The results indicated that high field Magnetic Resonance Imaging (MRI) should include at least two T2-weighted sequences in sagittal, axial oblique or coronal oblique orientation (short and long axis of the uterine cervix) of the pelvic content. Axial T1-weighted sequence is useful to detect suspicious pelvic and abdominal lymph nodes, and images from symphysis to the left renal vein are required. The intravenous administration of Gadolinium-chelates is optional but is often required for small lesions (<2 cm) and for follow-up after treatment. Diffusion-weighted sequences are optional but are recommended to help evaluate lymph nodes and to detect a residual lesion after chemoradiotherapy. CONCLUSIONS: Expert consensus and literature review lead to an optimized MRI protocol to stage uterine cervical cancer. MRI is the imaging modality of choice for preoperative staging and follow-up in patients with uterine cervical cancer.

Birth of Siberian tiger (Panthera tigris altaica) cubs after transvaginal artificial insemination.

A captive 9-yr-old female Siberian tiger (Panthera tigris altaica) at the Lisbon Zoo was treated with equine chorionic gonadotropin followed 80 hr later by human chorionic gonadotropin to stimulate follicular development and ovulation, respectively. Forty-one hours after the second hormone administration, the tiger was subjected to transvaginal artificial insemination with diluted fresh semen containing 500 x 10(6) motile spermatozoa obtained from an 8-yr-old male Siberian tiger via electroejaculation. After anesthesia, the female tiger was placed in an inclined position with the hind limbs elevated during and after the insemination and was maintained in this position for 15 min to minimize semen reflux. An anesthetic reversal agent was then administered. After a 103-day gestation, the female gave birth to three apparently healthy cubs that survived 24-48 hr. These results demonstrate that transvaginal artificial insemination can be successfully performed in the Siberian tiger to produce full-term offspring.

[Epidermoid carcinoma of the stomach]. / Carcinoma epidermóide do estômago.

A case of pure squamous cell carcinoma of the stomach in a 63-year-old woman has been reported. The tumor was located in pyloric antrum and histologic examination disclosed a well differentiated squamous cell carcinoma, with many horn pearls. Histogenesis of similar cases of this unusual tumor have been briefly discussed.