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In the paper we report about the progress made at XTREME technologies in the development of EUV sources based on gas discharge produced plasma (GDPP) technologies and laser produced plasma (LPP) technologies. First prototype xenon GDPP sources of the type XTS 13-35 based on the Z-pinch principle with 35 W power in 2π sr have been integrated into micro-exposure tools from Exitech, UK. Specifications of the EUV sources and experience of integration as well as data about component and optics lifetime are presented. In the source development program for Beta exposure tools and high volume manufacturing exposure tools both tin and xenon have been investigated as fuel for the EUV sources. Development progress in porous metal cooling technology as well as pulsed power circuit design has led to GDPP sources with xenon fuel continuous operating with an output power of 200 W in 2π sr at 4500 Hz repetition rate. With tin fuel an output power of 400 W in 2π sr was obtained leaving all other conditions unaltered with respect to the xenon based source. The performance of the xenon fueled sources is sufficiently good to fulfill all requirements up to the beta tool level. For both the xenon and the tin GDPP sources detailed data about source performance are reported, including component lifetime and optics lifetime. The status of the integration of the sources with grazing incidence collector optics is discussed. Theoretical estimations of collection efficiencies are compared with experimental data to determine the loss mechanisms in the beam path. Specifically contamination issues related to tin as target material as well as debris mitigation in tin sources is addressed. As driver lasers for the LPP source research diode-pumped Nd:YAG lasers have been used to generate EUV emitting plasma. As target material xenon has been employed. Conversion efficiencies have been measured and currently the maximum conversion efficiency amounts to 1 %. The laser driver power of 1.2 kW is currently achieved with a masteroscillator power-amplifier industrial Nd:YAG laser configuration. With this laser, xenon based EUV sources have achieved 10 W EUV power at 13.5 nm emitted into 2π sr solid angle. For the xenon LPP sources detailed data about the achieved source performance including component lifetime and optics lifetime are reported. The status of the integration of the sources with normal incidence collector optics is shown. The potentials and limits of Z-pinch GDPP and LPP EUV source technologies to achieve high volume manufacturing specifications are discussed in this paper.

This investigation of a brain cancer cluster in Missouri used two approaches to investigate associations with potential risk factors. In a case-control study in a rural town, we interviewed surrogates of cases and controls about potential risk factors. We found a statistically significant positive association of brain cancer with reported exposure to dental X-rays. Occupation was not associated with the cluster in the rural town. In a standardized proportional mortality study for the state of Missouri, we calculated the observed and expected proportion of brain cancers by occupation and industry in Missouri decedents. We found that motor vehicle manufacturers, beauty shop workers, managers and administrators, elementary school teachers, and hairdressers and cosmetologists had significantly elevated proportions of brain cancer. Brain tumors are inconsistently associated with occupation in the literature. Further study of brain cancer etiology with respect to dental X-ray exposures seems warranted.

Serratia marcescens bacteremia has become ubiquitous recently. S. marcescens bacteremia, either hospital- or community-acquired, can no longer be treated as insignificant. We reviewed 23 episodes of S. marcescens bacteremia in 1985. Among them, 17 patients (74%) were hospital-acquired infections, while 6 (26%) were community-acquired. Nine patients died, and the case fatality rate was 39%. Eleven patients (48%) had no clinically apparent source of infection, 5 (22%) had urinary tract infection, 3 (13%) had pneumonia, 2 (9%) had biliary tract infection, 1 (4%) had intra-abdominal infection, and 1 (4%) had skin and soft-tissue infection. Nosocomial isolates are often resistant to many antibiotics. Amikacin and the beta-lactamase-stable (third generation) cephalosporins are superior to gentamicin in the treatment of nosocomial S. marcescens bacteremia. We here emphasize that the awareness and treatment of S. marcescens bacteremia in daily clinical practice is unequivocally critical.

The first proved outbreak of nosocomial Legionnaires' disease occurred in a psychiatric hospital in Washington D.C. in 1965, but the diagnosis was not established until determination of serum antibodies against Legionella pneumophila by the indirect fluorescent antibody (IFA) test was undertaken, using the bacterial antigen isolated from patients with Legionnaires' disease in the 1976 outbreak in Philadelphia. The second nosocomial outbreak of Legionnaires' disease occurred in three immunocompromised patients who received renal transplantation at the University of Kansas Medical Center and died of extensive lobar pneumonia in 1975. The direct fluorescent antibody (DFA) test revealed L. pneumophila in the lungs of all three patients after the Legionnaires' disease agent was identified. The lack of prospective surveys using sensitive diagnostic procedures by various types has limited our knowledge on the extent of the problem caused by legionella. In fact, nosocomial Legionnaires' disease is a worldwide problem, and control of this disease requires thorough cooperation of physicians, epidemiologists, microbiologists and expert engineers.