Search

Serum beta-2 microglobulin and C-reactive protein levels were measured in 52 patients with acute adenovirus conjunctivitis and 58 healthy subjects, by ELISA technique. Serum beta-2 microglobulin levels were found to be significantly increased while there was no change in C-reactive protein levels. Serum beta-2 microglobulin levels closely paralleled the severity of the disease. The increased beta-2 microglobulin level in serum showed a significant fall to normal level on clinical improvement. There was no difference in the serum beta-2 microglobulin levels in virus-isolation positive and negative patients.

We report observation of the de Haas-van Alphen oscillations in the mixed state as well as in the normal state of LuNi2B2C. Two oscillations alpha and eta are observed in the mixed state. In particular, the alpha oscillation can be studied not only deep in the mixed state as a function of magnetic field but also as a function of field direction. The damping rate of the oscillations due to superconductivity is found to be very anisotropic. For fields far below H-c2, the damping behavior is anomalous and cannot be explained only in terms of the superconducting gap. We argue that both the anisotropy of the gap and a disorder of the flux line lattice are responsible for the anisotropic and anomalous behavior of the damping in the mixed state.

The response of the vortices in a dynamic state is studied in single crystals of Bi2212 using the technique of non-resonant microwave absorption (NRMA). It is observed that with the magnetic field (H) normal to the $CuO_2$ planes, the NRMA signal has two components-a low-field narrow derivative and a broad high-field signal. We study their orientational dependence and observe a sudden increase in the low-field dissipation as the field becomes nearly parallel to $CuO_2$ planes. We interpret it as a signature of lock-in-transition

We have studied the magnetic field dependent non-resonant rf losses in as-grown Bi2212 single crystals prior to and after irradiation with 250 MeV $^{107}Ag^{17+}$ ions. In the pristine state the losses from the inter-unit cell and intra-unit cell weak links are identified. The interesting feature is that the losses from inter-unit cell weak links reappear as the columnar tracks age with time suggesting that temperature cycling and thermal effects have important consequences on the robustness of the tracks. The losses from the intra-unit cell weak links although suppressed after irradiation, disappear suddenly at a certain temperature below Tc. This is unlike in the pristine state where the losses decrease smoothly as the temperature is decreased