Tailoring of keV-ion beams by image charge when transmitting through rhombic and rectangular shaped nanocapillaries.

We report on an unexpected effect of tailoring transmission profiles of Ne(7+) ions through nanocapillaries of rhombic and rectangular cross sections in mica. We find that capillaries of rhombic cross sections produce rectangular shaped ion transmission profiles and, vice versa, that capillaries of rectangular geometry give a rhombic beam shape. This shaping effect only occurs for transmitted ions and is absent for the small fraction of neutralized particles. The experimental findings and simulations of the projectile trajectories give clear evidence that the observed effect is due to the image forces experienced by the transmitting ions. This novel beam shaping mechanism suggests applications for the guiding, focusing, and shaping of ion beams.

Evaporative cooling and coherent axial oscillations of highly charged ions in a penning trap.

Externally, in an electron beam ion trap, generated Ar16+ ions were retrapped in a Penning trap and evaporatively cooled in their axial motion. The cooling was observed by a novel extraction technique based on the excitation of a coherent axial oscillation which yields short ion bunches of well-defined energies. The initial temperature of the ion cloud was decreased by a factor of more than 140 within 1 s, while the phase-space density of the coldest extracted ion pulses was increased by a factor of up to about 9.

Prevalence of Bacillus anthracis-like organisms and bacteriophages in the intestinal tract of the earthworm Eisenia fetida.

Stable infection of Bacillus anthracis laboratory strains with environmental bacteriophages confers survival phenotypes in soil and earthworm intestinal niches (R. Schuch and V. A. Fischetti, PLoS One 4:e6532, 2009). Here, the natural occurrence of two such B. anthracis-infective bacteriophages, Wip1 and Wip4, was examined in the intestines of Eisenia fetida earthworms as part of a 6-year longitudinal study at a Pennsylvania forest site. The Wip1 tectivirus was initially dominant before being supplanted by the Wip4 siphovirus, which was then dominant for the next 3 years. In a host range analysis of a wide-ranging group of Bacillus species and related organisms, Wip1 and Wip4 were both infective only toward B. anthracis and certain B. cereus strains. The natural host of Wip4 remained constant for 3 years and was a B. cereus strain that expressed a B. anthracis-like surface polysaccharide at septal positions on the cell surface. Next, a novel metagenomic approach was used to determine the extent to which such B. cereus- and B. anthracis-like strains are found in worms from two geographical locations. Three different enrichment strategies were used for metagenomic DNA isolation, based either on the ability of B. cereus sensu lato to form heat-resistant spores, the sensitivity of B. anthracis to the PlyG lysin, or the selective amplification of environmental phages cocultured with B. anthracis. Findings from this work indicate that B. cereus sensu lato and its phages are common inhabitants of earthworm intestines.

Chlamydial proctitis--unusual presentation as a symptomatic vaginal mass.

Chlamydial cervicitis and salpingitis are being increasingly diagnosed and reported, but chlamydial proctitis is an unusual problem to be found in gynecologic practice. In the reported patient who gave a history of rectal intercourse and presented with a symptomatic vaginal mass, a diagnosis of chlamydial proctitis was made on the basis of biopsy histology, specific monoclonal antibody-immunoperoxidase chlamydia assay, and response to doxycycline therapy.

A student health HMO as a partnership model within an academic medical center.

The Department of Family Practice, College of Medicine, in partnership with the University of Illinois at Chicago, was responsible for the reorganization of the Student Health Service into a health maintenance organization (HMO), Campus Care. Historically, the two campuses of the University of Illinois at Chicago operated student health as an infirmary model. Reorganization of student health into the Campus Care HMO provided expanded health care services to students, preserved more health care dollars in the university system, and provided a nonincremental increase in the size and responsibility of the Department of Family Practice. One year's experience showed that while the capitation was low compared with standard HMOs, the variable and less frequent use of services by the student population resulted in a fiscally viable operation. Numerous transition difficulties were encountered, including the need for rapid systems conversion within a complex university system, reeducation of students as well as traditional university-based practitioners for operation in a managed care system, and the rapid expansion of a small family practice department. The positive experience of the University of Illinois at Chicago supports the notion that family practice is better suited to providing student health care than other primary care disciplines. Three issues are paramount to success: (1) approval, support, and protection by higher level administration from university territorialism, (2) a core family practice faculty with strong leadership and experience in high-volume clinical activity, and (3) a close examination of financial resources in light of expected utilization.

Utilization review, DRGs, and physician autonomy.

Utilization review and the current Medicare prospective payment system are part of a continuum of Federal legislation aimed at controlling scarce health care resources. Physicians have met these attempts to establish standards of utilization and fiscal control with varying levels of cooperation and resistance. This paper examines the physician's perceived threat to professional practice that these allocation strategies represent. The paper addresses four major areas of concern: bureaucratic tensions; income; clinical decision-making; and self-regulation. The paper ends by discussing the benefits for physicians in taking a proactive stance toward these measures.

Two-center double-capture interference in fast He2+ + H2 collisions.

We report the first observation of Young-type interference effects in a two-electron transfer process. These effects change strongly as the projectile velocity changes in fast (1.2 and 2.0 MeV) He(2+) + H(2) collisions as manifested in strong variations of the double-electron capture rates with the H(2) orientation. This is consistent with fully quantum mechanical calculations, which ignore sequential electron transfer, and a simple projectile de Broglie wave picture assuming that two-electron transfer probabilities are higher in collisions where the projectile passes close to either one of the H(2) nuclei.