The spontaneous and induced synthesis of Epstein-Barr virus antigens in Raji cells immobilized on surface coated with anti-lymphocyte globulin

Immobilization of Raji cells on surface coated with anti-lymphocyte globulin (ALG) at low cell densities lead to the synthesis of Epstein-Barr virus (EBV) early antigen (EA) in up to 5% of the cells. At higher cell densities the percentage of antigen-positive cells decreased and at confluency no antigen synthesis was observed. Addition of iododeoxyuridine (IdUrd) to low density cultures increased the expression of EA to 20%, whereas in confluent cultures the cells could not be induced to synthesize EA. Treatment of cells in suspension with ALG failed to induced EA synthesis and did not potentiate the effect of IdUrd. Immobilized Raji cells proved to be suitable targets for superinfection with EBV derived from P3HR1 cultures

The regulated expression of Epstein-Barr virus. III. Proteins specified by EBV during the lytic cycle

The experiments show that 30 virus-induced or virus-specified proteins were synthesized in Raji cells after superinfection with Epstein-Barr virus (EBV) derived from P3HR1 cells. Using a combination of pulse labelling, application of cycloheximide blocks at different times post-infection, treatment with amino acid analogues and inhibition of DNA synthesis it was shown that three groups of proteins appear in Raji cells after superinfection; the synthesis of the proteins in any one group appears to be coordinately regulated. Amongst the six virus-induced proteins which were synthesized immediately after release from an early cycloheximide block one would expect to find those proteins essential for the transition from EBNA to EA synthesis. Using human sera with differing specificities for the various antigen groups 11 proteins were identified as being specifically precipitated by sera having high titres against the EBV-induced early antigen complex

Analysis of Dilepton Invariant Mass Spectrum in C+C at 2 and 1 AGeV

Recently the HADES collaboration has published the invariant mass spectrum of $e^+e^-$ pairs, dN/dM$_{e^+e^-}$, produced in C+C collisions at 2 AGeV. Using electromagnetic probes, one hopes to get in this experiment information on hadron properties at high density and temperature. Simulations show that firm conclusions on possible in-medium modifications of meson properties will only be possible when the elementary meson production cross sections, especially in the pn channel, as well as production cross sections of baryonic resonances are better known. Presently one can conclude that a) simulations overpredict by far the cross section at $M_{e^+e^-} \approx M_{\omega}{^0}$ if free production cross sections are used and that b) the upper limit of the $\eta$ decay into $e^+e^-$ is smaller than the present upper limit of the Particle Data Group. This is the result of simulations using the Isospin Quantum Molecular Dynamics (IQMD) approach.Comment: 28 pages, 15 figures, 3 tables, ps file recommende

Growth of Patterned Surfaces

During epitaxial crystal growth a pattern that has initially been imprinted on a surface approximately reproduces itself after the deposition of an integer number of monolayers. Computer simulations of the one-dimensional case show that the quality of reproduction decays exponentially with a characteristic time which is linear in the activation energy of surface diffusion. We argue that this life time of a pattern is optimized, if the characteristic feature size of the pattern is larger than $(D/F)^{1/(d+2)}$, where $D$ is the surface diffusion constant, $F$ the deposition rate and $d$ the surface dimension.Comment: 4 pages, 4 figures, uses psfig; to appear in Phys. Rev. Let

Loading rate sensitivity of open hole composites in compression

The results are reported of an experimental study on the compressive, time-dependent behavior of graphite fiber reinforced polymer composite laminates with open holes. The effect of loading rate on compressive strength was determined for six material systems ranging from brittle epoxies to thermoplastics at both 75 F and 220 F. Specimens were loaded to failure using different loading rates. The slope of the strength versus elapsed time-to-failure curve was used to rank the materials' loading rate sensitivity. All of the materials had greater strength at 75 F than at 220 F. All the materials showed loading rate effects in the form of reduced failure strength for longer elapsed-time-to-failure. Loading rate sensitivity was less at 220 F than the same material at 70 F. However, C12000/ULTEM and IM7/8551-7 were more sensitive to loading rate than the other materials at 220 F. AS4/APC2 laminates with 24, 32, and 48 plies and 1/16 and 1/4 inch diameter holes were tested. The sensitivity to loading rate was less for either increasing number of plies or larger hole size. The failure of the specimens made from brittle resins was accompanied by extensive delaminations while the failure of the roughened systems was predominantly by shear crippling. Fewer delamination failures were observed at the higher temperature

Investigation of the anisotropy of dissipation processes in single crystal of Yba2Cu3O7-d system

By means of contactless mechanical method of the measurement of energy losses in superconductors, the anisotropy of dissipation processes has been studied in single crystal high-temperature layered superconductors of Yba2Cu3O7-d system, being in mixed state. The observed anisotropy of energy losses indicates the possibility of the existence of the symmetry of order parameter of dx2-y2 type in these single crystals.Comment: 4 pages, 3 figure