Photoemission of cooper pairs from aromatic hydrocarbons.

We report the discovery of the formation of an electron Cooper pair approximately 40 eV above the double-ionization threshold in benzene, naphthalene, anthracene, and coronene after absorption of a single photon. We have measured the ratios of doubly to singly charged parent ions of the above mentioned molecules as well as pyrrole and furan by using monochromatized synchrotron radiation up to 100 eV above the corresponding thresholds. We also recorded photoelectron spectra of benzene and naphthalene at selected energies. The electron-pair formation is based on the specific structure of the molecules and does not exist for pyrrole and furan.

Oscillations in the double-photoionization cross section of Li near threshold.

The threshold region of the double-photoionization cross section of lithium was investigated using monochromatized synchrotron radiation and ion time-of-flight spectrometry. While the overall energy dependence can be described by the Wannier power law, we found oscillations in the cross section which are in good agreement with a modulated threshold law as proposed by Temkin [Phys. Rev. Lett. 49, 365 (1982)]]. This behavior may be due to the unequal binding energies of the electrons involved in the double-photoionization process.

Insidious destruction of the hip by Mycobacterium tuberculosis and why early diagnosis is critical.

Tuberculosis has re-emerged as an important problem in the United States. More than 10 million people presently are infected with Mycobacterium tuberculosis in the United States alone. The symptoms at first presentation of the disease have become more diverse. With extrapulmonary manifestations, such as musculoskeletal infections, as the sole presenting sign, it often can be difficult to determine the correct diagnosis early in the course of the disease. The presenting symptoms, physical signs, and radiographic findings of intra-articular tuberculosis can mimic those of other intra-articular diseases, such as rheumatoid arthritis, osteoarthritis, and avascular necrosis. In view of the nonspecific findings early in course of the disease, tubercular infection should be considered in the differential diagnosis when there is insidious articular destruction. Failure to consider tuberculosis can lead to devastating outcomes otherwise preventable with today's chemotherapies.