Positronium Laser Cooling via the 1

We report on laser cooling of a large fraction of positronium (Ps) in free flight by strongly saturating the 1^{3}S-2^{3}P transition with a broadband, long-pulsed 243 nm alexandrite laser. The ground state Ps cloud is produced in a magnetic and electric field-free environment. We observe two different laser-induced effects. The first effect is an increase in the number of atoms in the ground state after the time Ps has spent in the long-lived 2^{3}P states. The second effect is one-dimensional Doppler cooling of Ps, reducing the cloud's temperature from 380(20) to 170(20) K. We demonstrate a 58(9)% increase in the fraction of Ps atoms with v_{1D}<3.7×10^{4} ms^{-1}.

Observation and modeling of bound-free transitions to the X1Σ+ and a3Σ+ states of KCs.

The oscillation continuum in laser-induced fluorescence spectra of bound-free c3Σ+ → a3Σ+ and (4)1Σ+ → X1Σ+ transitions of the KCs molecule was recorded by a Fourier-transform spectrometer and modeled under the adiabatic approximation. The required interatomic potentials for ground a3Σ+ and X1Σ+ states were reconstructed in an analytical Chebyshev-polynomial-expansion form in the framework of the regularization direct-potential-fit procedure based on the simultaneous consideration of experimental line positions from Ferber et al. [Phys. Rev. A 80, 062501 (2009)] and the present ab initio calculation of short-range repulsive potential data. It was proved that the repulsive part over the dissociation limit of the derived a3Σ+ potential reproduces the experiment better than the potentials reported in the literature. It is also shown that all empirical and semi-empirical potentials available for the X1Σ+ state reproduce the bound-free (4)1Σ+ → X1Σ+ spectrum with equal quality in the range of observations.

Characterization of microbial and chemical composition of shuttle wet waste with permanent gas and volatile organic compound analyses.

Solid-waste treatment in space for Advanced Life Support, ALS, applications requires that the material can be safely processed and stored in a confined environment. Many solid-wastes are not stable because they are wet (40-90% moisture) and contain levels of soluble organic compounds that can contribute to the growth of undesirable microorganisms with concomitant production of noxious odors. In the absence of integrated Advanced Life Support systems on orbit, permanent gas, trace volatile organic and microbiological analyses were performed on crew refuse returned from the volume F "wet" trash of three consecutive Shuttle missions (STS-105, 109, and 110). These analyses were designed to characterize the short-term biological stability of the material and assess potential crew risks resulting from microbial decay processes during storage. Waste samples were collected post-orbiter landing and sorted into packaging material, food waste, toilet waste, and bulk liquid fractions deposited during flight in the volume F container. Aerobic and anaerobic microbial loads were determined in each fraction by cultivation on R2A and by acridine orange direct count (AODC). Dry and ash weights were performed to determine both water and organic content of the materials. Experiments to determine the aerobic and anaerobic biostability of refuse stored for varying periods of time were performed by on-line monitoring of CO2 and laboratory analysis for production of hydrogen sulfide and methane. Volatile organic compounds and permanent gases were analyzed using EPA Method TO15 by USEPA et al. [EPA Method TO15, The Determination of Volatile Organic Compounds (VOCs) in Ambient Air using SUMMA, Passivated Canister Sampling and Gas Chromatographic Analysis,1999] with gas chromatography/mass spectrometry and by gas chromatography with selective detectors. These baseline measures of waste stream content, labile organics, and microbial load in the volume F Shuttle trash provide data for waste subsystem analysis and atmospheric management within the ALS Project.

Surgical treatment of gastric cancer in Latvia: results of centralized experience.

BACKGROUND: Although the mortality for gastric cancer is decreasing in Western Europe and United States, it still remains high in Eastern Europe. This study was aimed at evaluating short- and long-term results of surgical treatment of gastric cancer performed in Latvia Oncology Center. METHODS: Retrospectively collected data from 461 patients who underwent gastrectomy with curative intent in Latvia Oncology Center from January 2001 to December 2005 were analyzed statistically. RESULTS: An average (range) of 92.2 (81-102) R0-R1 gastrectomies was performed each year. Post-operative complications occurred in 75 patients (16.3%); in-hospital mortality was 3.3%. The overall 5-year survival was 50.8%. In 444 cases (96.3%) there was histopathologic confirmation of R0-resection with a 5-year survival of 52.5% (P<0.001). Considering pT category, 5-year survival was 88.6% for pT1 patients, 65% for pT2, 42.3% for pT3 and 27% for pT4 (P<0.001). Considering pN category, 5-year survival was 67% for pN0 patients, 30% for pN1 and 29% for pN2-3 (P<0.001). CONCLUSIONS: Clinico-pathologic characteristics of patients who underwent resection with curative intent are comparable to other Western experiences. Short- as well as long-term results are also similar if not for pN+ patients where no difference between pN1 and pN2 cases was observed.