[en] Bile metabolites were measured in fish collected from the Eastern Cornbelt Plains (ECBP) Ecoregion to determine the distribution and levels of exposure to combustion by-products and petroleum. Bile was collected from the gall bladder of 1 to 6 white suckers from 118 sites across Ohio (107), Indiana (8) and Michigan (3) using a randomized EMAP statistical sampling design. Diluted bile was measured at 380/430 nm to estimate the exposure to BaP-type compounds and 290/335 nm to estimate naphthalene-type compounds. Fixed fluorescence readings were normalized to the concentration of protein in bile. Mean values for all sites had skewed distributions. For BAP the mean, standard deviation, skewness and kurtosis were 129.3, 137.3, 2.7 and 8.5, respectively. The corresponding values for NAPH were 29.1, 19.2, and 4.9 and 34.3. The range for the lowest 10% of sites was from 0 to 24.1 for BAP, and was from 8.5 to 15.8 for NAPH. The range for the highest 10% was from 276.9 to 757.3 for BAP, and was from 45.7 to 181.9 for NAPH. For first order stream sites, the range for the lower 10% and the upper 10% were from 29.2 to 34.2 and from 436 to 757.3 for BAP. The corresponding numbers for NAPH were from 17 to 18.5 and 45.7 to 84.9. For second order stream sites, the above ranges were from 3.5 to 21.9 and from 282.2 to 723.8 for BAP. The corresponding numbers for NAPH were from 8.5 to 14.3 and from 37.6 to 63.4. For the third order stream sites, the lower and upper 10% ranges were from 0 to 22.6 and from 207.1 to 421.8 for BAP. The respective numbers for NAPH were from 12.1 to 15.5 and from 53.6 to 181.9

[en] An array of highly sensitive biomagnetic sensors of the superconducting quantum interference detector (SQUID) type can identify disease in vivo by detecting and imaging microscopic amounts of nanoparticles. We describe in detail procedures and parameters necessary for implementation of in vivo detection through the use of antibody-labelled magnetic nanoparticles as well as methods of determining magnetic nanoparticle properties. We discuss the weak field magnetic sensor SQUID system, the method of generating the magnetic polarization pulse to align the magnetic moments of the nanoparticles, and the measurement techniques to measure their magnetic remanence fields following this pulsed field. We compare these results to theoretical calculations and predict optimal properties of nanoparticles for in vivo detection

[en] Fermilab is working on the design of an 8 GeV superconducting RF H^- linac called the Proton Driver. The energy of H^- beam will be an order of magnitude higher than the existing ones. This brings up a number of technical challenges to transport and injection of H^- ions. This paper will focus on the subjects of stripping losses (including stripping by blackbody radiation, field and residual gas) and carbon foil stripping efficiency, along with a brief discussion on other issues such as Stark states lifetime of hydrogen atoms, single and multiple Coulomb scattering, foil heating and stress, radiation activation, collimation and jitter correction, etc

No abstract available

[en] Direct ionization of hydrogen atoms by laser irradiation is investigated as a potential new scheme to generate proton beams without stripping foils. The time-dependent Schroedinger equation describing the atom-radiation interaction is numerically solved obtaining accurate ionization cross-sections for a broad range of laser wavelengths, durations and energies. Parameters are identified where the Doppler frequency up-shift of radiation colliding with relativistic particles can lead to efficient ionization over large volumes and broad bandwidths using currently available lasers

[en] We report the first observation of nonresonant excess photon absorption (for ionization as well as detachment) in competition with the single photon process. A 35keV negative hydrogen ion beam is irradiated with focused Nd:YAG laser pulses; the 1.165eV photon energy exceeds the electron binding energy by 0.41eV. The time of flight spectrum of detached electrons exhibits the absorption of one and two photons. The detached electrons exit with a P wave angular distribution for the one-photon detachment and primarily a D wave for the two photon excess photon detachment. copyright 1997 The American Physical Society

[en] As new magnetic nanoparticle-based technologies are developed and new target cells are identified, there is a critical need to understand the features important for magnetic isolation of specific cells in fluids, an increasingly important tool in disease research and diagnosis. To investigate magnetic cell collection, cell-sized spherical microparticles, coated with superparamagnetic nanoparticles, were suspended in (1) glycerine–water solutions, chosen to approximate the range of viscosities of bone marrow, and (2) water in which 3, 5, 10 and 100% of the total suspended microspheres are coated with magnetic nanoparticles, to model collection of rare magnetic nanoparticle-coated cells from a mixture of cells in a fluid. The magnetic microspheres were collected on a magnetic needle, and we demonstrate that the collection efficiency versus time can be modeled using a simple, heuristically-derived function, with three physically-significant parameters. The function enables experimentally-obtained collection efficiencies to be scaled to extract the effective drag of the suspending medium. The results of this analysis demonstrate that the effective drag scales linearly with fluid viscosity, as expected. Surprisingly, increasing the number of non-magnetic microspheres in the suspending fluid results increases the collection of magnetic microspheres, corresponding to a decrease in the effective drag of the medium. (paper)

[en] Superparamagnetic nanoparticles can be attached in great numbers to pathogenic cells using specific antibodies so that the magnetically-labeled cells themselves become superparamagnets. The cells can then be manipulated and drawn out of biological fluids, as in a biopsy, very selectively using a magnetic needle. We examine the origins and uncertainties in the forces exerted on magnetic nanoparticles by static magnetic fields, leading to a model for trajectories and collection times of dilute superparamagnetic cells in biological fluids. We discuss the design and application of such magnetic needles and the theory of collection times. We compare the mathematical model to measurements in a variety of media including blood

[en] One-photon detachment and two-photon nonresonant excess photon detachment of electrons from the H^- ion (outer-electron binding energy = 0.7542 eV) are observed with 1.165 eV laser pulses from a Nd:YAG laser (where YAG denotes yttrium aluminum garnet). A Penning ion source produces a pulsed 8 μA, 35 keV H^- beam that intersects a laser beam cylindrically focused down to a 17 μm full width at half maximum waist in the ion beam direction, creating a high-intensity interaction region with peak intensities of up to 10¹¹ W/cm². The interaction time is 7 ps. The detached electrons are detected by a time-of-flight apparatus enabling us to detect a very small two-photon signal in the presence of a very large signal from single photon detachments. By rotating the linear polarization angle, we study the angular distribution of the electrons for both one- and two-photon detachments. The spectra are modeled to determine the asymmetry parameters and one- and two-photon cross sections. We find β₂ to be 2.54+0.44/-0.60 and β₄ to be 2.29+0.07/-0.31, corresponding to a D state of 89+3/-12% of the S wave and D wave detachments for the two-photon results. The relative phase angle between the S and D amplitudes is measured to be less than 59 degree sign . The measured cross sections are found to be consistent with theoretical predictions. The one-photon photodetachment cross section is measured to be (3.6±1.7)x10^-17 cm². The two-photon photodetachment generalized cross section is (1.3±0.5)x10^-48 cm⁴ sec, consistent with theoretical calculations of the cross section. The three-photon generalized cross section is less than 4.4x10^-79 cm⁶ sec². (c) 1999 The American Physical Society