3,905 research outputs found

    Local electronic structure of the peptide bond probed by resonant inelastic soft X-ray scattering.

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    The local valence orbital structure of solid glycine, diglycine, and triglycine is studied using soft X-ray emission spectroscopy (XES), resonant inelastic soft X-ray scattering (RIXS) maps, and spectra calculations based on density-functional theory. Using a building block approach, the contributions of the different functional groups of the peptides are separated. Cuts through the RIXS maps furthermore allow monitoring selective excitations of the amino and peptide functional units, leading to a modification of the currently established assignment of spectral contributions. The results thus paint a new-and-improved picture of the peptide bond, enhance the understanding of larger molecules with peptide bonds, and simplify the investigation of such molecules in aqueous environment

    Staging of cutaneous melanoma

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    The American Joint Committee on Cancer (AJCC) staging of cutaneous melanoma is a continuously evolving system. The identification of increasingly more accurate prognostic factors has led to major changes in melanoma staging over the years, and the current system described in this review will likely be modified in the near future. Likewise, application of new imaging techniques has also changed the staging work-up of patients with cutaneous melanoma. Chest and abdominal computed tomography (CT) scanning is most commonly used for evaluation of potential metastatic sites in the lungs, lymph nodes and liver, and is indicated in patients with new symptoms, anaemia, elevated lactate dehydrogenase or a chest X-ray abnormality. CT scans should be restricted to patients with high-risk melanoma (stage IIC, IIIB, IIIC and stage IIIA with a macroscopic sentinel lymph node). Magnetic resonance imaging (MRI) of the brain is a mandatory test in patients with stage IV, optional in stage III and not used in patients with stage I and II disease. Positron emission tomography (PET)/CT is more accurate than CT or MRI alone in the diagnosis of metastases and should complement conventional CT/MRI imaging in the staging work-up of patients who have solitary or oligometastatic disease where surgical resection is most relevant

    DISTRIBUTION OF VISUAL ATTENTION WHEN COMPARING PAIRED FACES IN TYPICALLY DEVELOPING INFANTS AND INFANTS AT RISK OF DEVELOPING AUTISM

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    Infant eye tracking research has assessed the visual scanning of static and dynamic singularly presented faces. Yet, little is know about how infants visually compare paired faces. The current study characterizes the distribution of visual attention to paired faces for infants who where later diagnosed as being typically developing (TD), non-typically developing (NT), or having an autism spectrum disorder (ASD). The study sample was comprised of infant siblings of children with ASD (high-risk infants; HR) and infant siblings of typically developing children (low-risk infants; LR). Eye tracking data were collected at 11 months of age while all infants completed a visual paired comparison task. Stimuli were six face pairs, displayed for eight seconds each, created from twelve colored photographs of naturalistic female faces equivalent in facial expression. Participants were then asked to return at 24, 36, and/or 48 months of age for follow-up diagnostic assessment at which point they were categorized into the TD, NT, or ASD groups. When viewing paired faces, all three groups demonstrated a greater proportion of time looking to the bottom than the top half of the faces. Only the typically developing group looked longer to the right side of the face than the left; that is, demonstrated a left visual field (LVF) bias. The NT group spent significantly less time looking to the mouth regions than did the TD and ASD groups. With respect to paired face comparisons, there were no significant group differences in the overall number of congruent saccades. However, there were group differences in the proportion of congruent mouth-to-mouth saccades. Infants with ASD made the largest number of mouth-to-mouth comparisons, followed by the TD group, and the NT group. Group differences were also found in the proportion of scans that went from a non-internal facial feature of one pair member to a non-internal feature of the other pair member. Essentially, NT developing infants made more extraneous comparisons than did TD infants
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