Inter-observer agreement in audit of quality of radiology requests and reports.

AIMS: To assess the quality of the imaging procedure requests and radiologists' reports using an auditing tool, and to assess the agreement between different observers of the quality parameters. MATERIALS AND METHODS: In an audit using a standardized scoring system, three observers reviewed request forms for 296 consecutive radiological examinations, and two observers reviewed a random sample of 150 of the corresponding radiologists' reports. We present descriptive statistics from the audit and pairwise inter-observer agreement, using the proportion agreement and kappa statistics. RESULTS: The proportion of acceptable item scores (0 or +1) was above 70% for all items except the requesting physician's bleep or extension number, legibility of the physician's name, or details about previous investigations. For pairs of observers, the inter-observer agreement was generally high, however, the corresponding kappa values were consistently low with only 14 of 90 ratings >0.60 and 6 >0.80 on the requests/reports. For the quality of the clinical information, the appropriateness of the request, and the requested priority/timing of the investigation items, the mean percentage agreement ranged 67-76, and the corresponding kappa values ranged 0.08-0.24. CONCLUSION: The inter-observer reliability of scores on the different items showed a high degree of agreement, although the kappa values were low, which is a well-known paradox. Current routines for requesting radiology examinations appeared satisfactory, although several problem areas were identified.

Sequence-dependent correction of random coil NMR chemical shifts.

Random coil chemical shifts are commonly used to detect secondary structure elements in proteins in chemical shift index calculations. While this technique is very reliable for folded proteins, application to unfolded proteins reveals significant deviations from measured random coil shifts for certain nuclei. While some of these deviations can be ascribed to residual structure in the unfolded protein, others are clearly caused by local sequence effects. In particular, the amide nitrogen, amide proton, and carbonyl carbon chemical shifts are highly sensitive to the local amino acid sequence. We present a detailed, quantitative analysis of the effect of the 20 naturally occurring amino acids on the random coil shifts of (15)N(H), (1)H(N), and (13)CO resonances of neighboring residues, utilizing complete resonance assignments for a set of five-residue peptides Ac-G-G-X-G-G-NH(2). The work includes a validation of the concepts used to derive sequence-dependent correction factors for random coil chemical shifts, and a comprehensive tabulation of sequence-dependent correction factors that can be applied for amino acids up to two residues from a given position. This new set of correction factors will have important applications to folded proteins as well as to short, unstructured peptides and unfolded proteins.

Random coil chemical shifts in acidic 8 M urea: implementation of random coil shift data in NMRView.

Studies of proteins unfolded in acid or chemical denaturant can help in unraveling events during the earliest phases of protein folding. In order for meaningful comparisons to be made of residual structure in unfolded states, it is necessary to use random coil chemical shifts that are valid for the experimental system under study. We present a set of random coil chemical shifts obtained for model peptides under experimental conditions used in studies of denatured proteins. This new set, together with previously published data sets, has been incorporated into a software interface for NMRView, allowing selection of the random coil data set that fits the experimental conditions best.

Alpha-particle activity of apollo 11 samples.

Nine polishled thin sectionis have been exposed to nulclear track plates, three have been counted by alplia-particle spectrometry, and one has been examined by electron mocroprobe. Interpretation of the results is in a preliminary stage. Alpha track distribiutioni in the autoradiograph of a breccia forms a network that appears related to the rims of accretionary lapilli comiiposinig the breccia. Thorium in a coarse-grained crystalline rock is concenitrated in micron-sized, zirconium-rich crystals. Alplia count rates agree with what would be predicted from previously reported thorium and uranium contents of the same rocks, suggesting secular equilibriunm for the thorium and uranium decay series.