Shifts in electron capture to the continuum at low collision energies: Enhanced role of target postcollision interactions

Measurements of electron velocity distributions emitted at 0degrees for collisions of 10- and 20-keV H+ incident ions on H-2 and He show that the electron capture to the continuum cusp formation, which is still possible at these low impact energies, is shifted to lower momenta than its standard position (centered on the projectile velocity), as recently predicted. Classical trajectory Monte Carlo calculations reproduce the observations remarkably well, and indicate that a long-range residual interaction of the electron with the target ion after ionization is responsible for the shifts, which is a general effect that is enhanced at low nuclear velocities.

Effect of Target Polarization in Electron-Ion Recombination

We present results of a study of the effect of target polarization on electron-ion recombination, and show that coherent radiation by the target electrons gives a large contribution to the recombination rate. It significantly modifies the nonresonant photorecombination background. A procedure has been devised whereby this contribution can be evaluated together with the conventional radiative recombination, independently of the dielectronic recombination component. Numerical results are presented for Zn2+, Cd2+, Sn4+, and Xe8+, showing up to an order-of-magnitude enhancement.

The role of target polarization in electron-ion recombination

We investigate the role of dynamic polarization of the target electrons in the process of recombination of electrons with multicharged ions (polarizational recombination). Numerical calculations carried out for a number of Ni- and Ne-like ions demonstrate that the inclusion of polarizational recombination leads to a noticeable increase (up to 30%) in the cross sections for incident electron energies outside the regions of dielectronic resonances. We also present a critical analysis of theoretical approaches used by other authors to describe the phenomenon of polarizational recombination.

Identification of 5-Fluorouracil-inducible Target Genes Using cDNA Microarray Profiling

The fluoropyrimidine 5-Fluorouracil (5-FU) is widely used in the treatment of cancer. To identify novel downstream mediators of tumor cell response to 5-FU, we used DNA microarray technology to identify genes that are transcriptionally activated by 5-FU treatment in the MCF-7 breast cancer cell line. Of 2400 genes analyzed, 619 were up-regulated by >3-fold. Highly up-regulated genes (>6-fold) with signal intensities of >3000 were analyzed by Northern blot. Genes that were consistently found to be up-regulated were spermine/spermidine acetyl transferase (SSAT), annexin II, thymosin-beta-10, chaperonin-10, and MAT-8. Treatment of MCF-7 cells with the antifolate tomudex and DNA-damaging agent oxaliplatin also resulted in up-regulation of each of these targets. The 5-FU-induced activation of MAT-8, thymosin-beta-10, and chaperonin-10 was abrogated by inactivation of p53 in MCF-7 cells, whereas induction of SSAT and annexin II was significantly reduced in the absence of p53. Moreover, each of these genes contained more than one potential p53-binding site, suggesting that p53 may play an important regulatory role in 5-FU-induced expression of these genes. In addition, we found that basal expression levels of SSAT, annexin II, thymosin beta-10, and chaperonin-10 were increased (by approximately 2-3-fold), and MAT-8 expression dramatically increased (by approximately 10-fold) in a 5-FU-resistant colorectal cancer cell line (H630-R10) compared with the parental H630 cell line, suggesting these genes may be useful biomarkers of resistance. These results demonstrate the potential of DNA microarrays to identify novel genes involved in mediating the response of tumor cells to chemotherapy.

Manual versus target-controlled infusions of propofol

Summary Target-controlled infusion systems have been shown to result in the administration of larger doses of propofol, which may result in delayed emergence and recovery from anaesthesia. The aim of this study was to investigate if this was due to a difference in the depth of hypnosis (using the bispectral index monitoring) between the manual and target controlled systems of administration. Fifty unpremedicated patients undergoing elective surgery were randomly allocated to have their anaesthesia maintained with manual or target-controlled propofol infusion schemes. In both groups, the rate of propofol administration was adjusted according to the standard clinical criteria while bispectral index scores were recorded by an observer not involved in the delivery of anaesthesia. The total dose of propofol used was higher in the target controlled group (mean 9.9 [standard deviation 1.6] compared with 8.1 [1.0] mg.kg.h in the manual group [p

Size, albedo, and taxonomic type of potential spacecraft target Asteroid (10302) 1989 ML

The Amor-type near-Earth Asteroid (10302) 1989 ML has an “Earth-like” orbit (period 1.44 yr, eccentricity 0.14, inclination 4.4°), therefore the energy required to reach it from the Earth is relatively small making it a very attractive target for rendezvous missions. We have observed 1989 ML in the thermal infrared using the Spitzer Space Telescope, and compared these data with optical and near-infrared observations. The Spitzer results imply a diameter of 0.28±0.05 km and a geometric albedo of 0.37±0.15; together with the reflectance spectrum they are consistent with the relatively rare E classification.