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We evaluated a commercial positron emission mammography (PEM) camera, the PEM Flex Solo II. This system comprises two 6 · 16.4 cm detectors that scan together covering up to a 24 · 16.4 cm field of view (FOV). There are no specific standards for testing this detector configuration. We performed several tests important to breast imaging, and we propose tests that should be included in standardized testing of PEM systems. Methods: We measured spatial resolution, uniformity, countingrate linearity, recovery coefficients, and quantification accuracy using the system's software. Image linearity and coefficient of variation at the edge of the FOV were also characterized. Anecdotal examples of clinical patient data are presented. Results: The spatial resolution was 2.4 mm in full width at half maximum for image planes parallel to the detector faces. The background variability was approximately 5%, and quantification accuracy and recovery coefficients varied within the FOV. Positioning linearity began at approximately 13 mm from the edge of the detector housing. The coefficient of variation was significantly higher close to the edge of the FOV because of limited sensitivity in these image planes. Conclusion: A reconstructed spatial resolution of 2.4 mm represented a significant improvement over conventional whole-body PET scanners and should reduce the lower threshold on lesion size and tracer uptake for detection in the breast. Limited-angle tomography and a lack of data corrections result in spatially variable quantitative results. PEM acquisition geometry limits sampling statistics at the chest-wall edge of the camera, resulting in high variance in that portion of the image. Example patient images demonstrate that lesions can be detected at the chest-wall edge despite variance artifacts, and fine structure is visualized routinely throughout the FOV in the focal plane. The PEM Flex camera should enable the functional imaging of breast cancer earlier in the disease process than whole-body PET. Posi tron emission mammography (PEM) is a technique using 2 annihilation-photon detectors and limited-angle tomographic reconstruction to image radiotracer distributions within the breast. Because of their smaller size and closer proximity to the source, dedicated PEM cameras can provide better spatial resolution and count sensitivity than whole-body PET (WB PET). PEM is undergoing clinical trials and has been suggested for breast cancer detection, characterization, treatment planning, and assessment of response to therapy. PEM, like WB PET, provides functional imaging information. Radiographic mammography, ultrasound, and MRI primarily provide anatomic information. PEM can thus provide complementary information to conventional breast imaging modalities. Screening mammography is believed to be an important factor in recent declines in breast cancer mortality (1). Despite the successes of earlier detection by mammography, however, breast cancer is the second-leading cause of cancer-related deaths in North American women. This stat...

The physics of thermonuclear ignition in inertial confinement fusion (ICF) is presented in the familiar frame of a Lawson-type criterion. The product of the plasma pressure and confinement time Pτ for ICF is cast in terms of measurable parameters and its value is estimated for cryogenic implosions. An overall ignition parameter χ including pressure, confinement time, and temperature is derived to complement the product Pτ. A metric for performance assessment should include both χ and Pτ. The ignition parameter and the product Pτ are compared between inertial and magnetic-confinement fusion. It is found that cryogenic implosions on OMEGA [T. R. Boehly et al., Opt. Commun. 133, 495 (1997)] have achieved Pτ∼1.5 atm s comparable to large tokamaks such as the Joint European Torus [P. H. Rebut and B. E. Keen, Fusion Technol. 11, 13 (1987)] where Pτ∼1 atm s. Since OMEGA implosions are relatively cold (T∼2 keV), their overall ignition parameter χ∼0.02–0.03 is ∼5× lower than in JET (χ∼0.13), where the average temperature is about 10 keV.

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To cause disease and persist in a host, pathogenic and commensal microbes must adhere to tissues. Colonization and infection depend on specific molecular interactions at the host-microbe interface that involve microbial surface proteins, or adhesins. To date, adhesins are only known to bind to host receptors non-covalently. Here we show that the streptococcal surface protein SfbI mediates covalent interaction with the host protein fibrinogen using an unusual internal thioester bond as a ‘chemical harpoon’. This cross-linking reaction allows bacterial attachment to fibrin and SfbI binding to human cells in a model of inflammation. Thioester-containing domains are unexpectedly prevalent in Gram-positive bacteria, including many clinically relevant pathogens. Our findings support bacterial-encoded covalent binding as a new molecular principle in host-microbe interactions. This represents an as yet unexploited target to treat bacterial infection and may also offer novel opportunities for engineering beneficial interactions.DOI: http://dx.doi.org/10.7554/eLife.06638.001

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A new method for shockless compression and acceleration of solid materials is presented. A plasma reservoir pressurized by a laser-driven shock unloads across a vacuum gap and piles up against an Al sample thus providing the drive. The rear surface velocity of the Al was measured with a line VISAR, and used to infer load histories. These peaked between approximately 0.14 and 0.5 Mbar with strain rates approximately 10(6)-10(8) s(-1). Detailed simulations suggest that apart from surface layers the samples can remain close to the room temperature isentrope. The experiments, analysis, and future prospects are discussed.