Simulation of preheating effects in shock wave experiments

We have analyzed the shock wave propagation experiments performed at LULI and presented at ECLIM'94. The targets were aluminium foils with thickness from 5 to 25 μm. Simulations were performed with the SARA-1D multigroup radiation code. We have shown a small level of preheating caused by the absorption of X-rays with energies close to the K-edge of aluminum. Several sets of opacities were used in order to study this effect, including experimental values for cold aluminum. Simulations show a small level of visible emission induced by X-ray preheating before the arrival of the shock

Detection of minority point mutations by modified PCR technique: a new approach for a sensitive diagnosis of tumor-progression markers.

The detection of point mutations correlated with diseases, in enzymatically amplified DNA sequences (Polymerase Chain Reaction), is currently performed by digestion of PCR products when an existing restriction site disappears at least in one allele of the amplified mutated sequence or by allele specific radiolabeled probes in all other cases. These methods are the most sensitive but they cannot detect a mutation if it is present in less than 5% of the studied cells. We describe here a method based on the introduction of an artificial restriction site, using a modified primer during the PCR, which creates a RFLP indicative of the studied mutation. This RFLP is detected by a radiolabeled oligonucleotide probe which is not related to the mutation. Our approach multiplies the sensitivity by a factor of 1000 and it is practical for use in screening purposes and the detection, after treatment, of the residual disease in human malignancies. Using this method we detected 20% more mutations at codon 12 in the Ki ras oncogene in DNA from colorectal cancers that were undetectable with all the previous methods

Experimental observation of the shift and width of the aluminium

Experimental measurements of the shift and width of the aluminium K-absorption edge in laser shock-compressed plasma is presented. The spectrometer used in these experiments allows an accurate wavelength calibration and fiduciary and hence provides precise measurements of both the shift and the width of the absorption edge. Results have been obtained for compressions up to approximately $\times 2$ and temperatures up to about 1.5 eV. The values of shift and width are compared with a new model with which there is very good agreement

Optical Smoothing for Shock-Wave Generation: Application to the Measurements of Equations of State

Experimental results are presented on shock-wave generation in solid samples, irradiated directly by optically smoothed laser beams. Random phase plates and phased zone plates have been successfully used. In particular, the last technique allowed the production of uniform shock fronts that have been used for equation of state experiments at pressures above 10 Mbar. Pressures higher than 35 Mbar were achieved in gold, by using laser pulses with energy E approximate to 100 J, and structured, two-step, two-material targets