The aluminum beverage tab and a soldier with chronic abdominal pain.

Since its introduction in the 1960s, the aluminum pull-tab has been an uncommon cause of aspiration and intestinal obstruction. In many cases, the inability to visualize aluminum on imaging studies delayed diagnosis and therapy or missed the foreign body altogether. Early reports of injury secondary to pull-tab ingestion or aspiration spurred the beverage industry to re-engineer the pop-tab in the 1980s. The new design meant to reduce injury by keeping the tab attached permanently to the can. Despite this innovation, the aluminum pop-tab continues to be a cause of injury. Here, we describe the inadvertent ingestion of an aluminum pop-tab by a 22-year-old patient that resulted in chronic intermittent abdominal distress due to recurrent bowel obstruction for 4 years. This case is unique in the length of delayed diagnosis and demonstrates the elusive nature of an aluminum foreign body.

Parotid Oncocytoma on 99mTc-Sestamibi Scintigraphy and SPECT/CT.

ABSTRACT: Oncocytomas in the parotid gland are a rare benign neoplasm composed of mitochondrial-rich oncocytes. Here we present the case of an 85-year-old man with a history of biopsy-proven right parotid gland oncocytoma who underwent 99mTc-sestamibi scintigraphy and SPECT/CT in the context of primary hyperparathyroidism. Focal intense uptake of radiotracer is detected within the right parotid gland on sestamibi scintigraphy. SPECT/CT confirms the localization of sestamibi uptake to the hyperattenuating parotid gland oncocytoma.

Convergence of internal and external structure for the California Child Q-set.

The language of personality traits includes single-word trait descriptors, and longer phrases or sentences. Evidence has accumulated that abstract, semantic relationships among single words have the same underlying structure as the empirical relationships when words are applied to individuals. The present study examines whether these two kinds of structure are also isomorphic for longer trait descriptors. Empirical descriptions and judgements of semantic similarity were collected among the descriptors comprising the California Child Q-set, or CCQ, and analysed with multidimensional scaling. Canonical correlation showed the solutions to be closely related to one another, and to independent sets of ratings available for the CCQ items. Informants' similarity judgements were not affected by the context in which they were made. The dominant dimensions of the solutions reproduce dimensions found previously for the single-word personality lexicon, indicating the two trait-descriptive languages to be closely parallel.

Constructing personality maps, mapping personality constructs: multidimensional scaling recovers the big five factors from internal and external structure.

This report examines the structure of similarities underlying the lexicon of personality-trait description, when "similarity" is defined and measured in terms of (a) semantic judgment and (b) covariance in actual use. A lexicon of 60 trait adjectives was examined, using several procedures for collecting semantic judgments. Similarity data of both kinds were analyzed with multidimensional scaling (MDS) to provide a parsimonious representation of underlying structure. The convergence between semantic judgments and covariance within trait-attribution data was substantial; both kinds of data evinced the same structure when collected for subsets of adjectives. Canonical correlation was employed to find the number of dimensions shared across MDS solutions. Interpretation of the results was facilitated by individual-differences MDS, which can select an optimal set of underlying dimensions, and at the same time accommodate the differences between data sets that arise when data-collection procedures differ in the relative emphasis they place upon those dimensions. We interpret the small number and shared nature of the dimensions by arguing that the lexicon's structure relates to trait perception rather than personality structure per se, even when probed with trait-attribution covariance.

An empirical taxonomy of social-psychological risk indicators in youth suicide .

The current study integrates descriptive (though primarily social-psychological) statements about youth suicide into a coherent, empirically supported taxonomy. Drawing from relevant literature, a set of 107 items characterizing these contributions about youth suicide was created. Seventy-two participants sorted these statements according to their "face-value" by following two separate procedures. Analyses of these two data sets using multi-dimensional scaling resulted in a common "map" depicting inter-item (dis)similarities. Non-arbitrary rotation of this map revealed three bipolar and orthogonal dimensions labelled as under- and overengagement, rejection-turmoil, and self- to death-identification. It is suggested this dimensional analysis could provide a viable frame for examining and interpreting descriptions about suicide risk and may serve to extend theoretical accounts.

Twins and odd-ones-out: a twin study of genetic contributions to variability in personal colour space.

BACKGROUND: Individuals differ in the biological substrate of vision, often as a result of genetic differences. There are also subtle variations within the normal population in aspects of colour behaviour (for example, colour naming and unique-hue judgements) but it is surprisingly hard to connect these to the genetic variation. Perceptions of inter-colour similarities (and variations in the structure of colour space, reconstructed from them) may show a closer link to the biological basis of vision. METHODS: To quantify the spectrum of variation, each subject used caps from the D-15 panel test to make 70 odd-one-out triad judgements. Analysis yielded the parameters of individual observers' colour structure: specifically, the weights they placed on the axes of a standard colour space. Similarities between 19 pairs of monozygotic twins and between 16 pairs of dizygotic twins were compared. RESULTS: Monozygotic pairs were significantly more concordant than dizygotic or unrelated pairs. DISCUSSION: The procedure provides sufficiently precise measurements to replicate earlier findings from more complex, time-consuming methods. By extension to other family relationships, the triadic procedure can clarify the genetic contribution. Weighting of colour axes is an important form of variation among normal individuals, with a contribution to these weights from genetic factors.

Clinical pathways in head injury: improving the quality of care with early rehabilitation.

PURPOSE: To improve the management of all hospital admissions with head injuries, including mild and moderate by developing a clinical pathway and a head injury team. METHODS: A head injury team was set up to take over the care of all admissions with head injury and to manage appropriate referrals and discharges. A key role was to facilitate communication between the different services involved in head injury care, arrange follow-up, support relatives and to educate healthcare staff. RESULTS: In the first year, the team took over the care of 196 admissions of whom 128 attended for 3-month follow-up with 66% having a good outcome. Patients and relatives feedback was excellent with an average score of 4.8/5 on overall satisfaction rating. Other centers in the United Kingdom are aiming to set up similar pathways, and the team has presented on head injury pathways extensively. CONCLUSIONS: A clinical pathway can improve the quality of care for all admissions with head injury and enhance the role for rehabilitation at an early stage.

Colour-space distortion in women who are heterozygous for colour deficiency.

We examined colour perception among a group of women heterozygous for colour vision deficiency. Judgements of colour dissimilarity were collected by presenting colour stimuli in groups of three for odd-one-out decisions. The judgements were summarised as one consensus colour space for the heterozygotes and another for age-matched controls. Individual differences MDS was also applied, resulting in a single colour space which can be adjusted to fit each subject's responses individually by compressing it along its axes. Heterozygous women showed a trend towards colour-space compression in a red-green dimension, or reduced salience of that dimension compared to controls, though less extreme than found in overt colour deficiency.

Multidimensional scaling of D15 caps: color-vision defects among tobacco smokers?

Tobacco smoke contains a range of toxins including carbon monoxide and cyanide. With specialized cells and high metabolic demands, the optic nerve and retina are vulnerable to toxic exposure. We examined the possible effects of smoking on color vision: specifically, whether smokers perceive a different pattern of suprathreshold color dissimilarities from nonsmokers. It is already known that smokers differ in threshold color discrimination, with elevated scores on the Roth 28-Hue Desaturated panel test. Groups of smokers and nonsmokers, matched for sex and age, followed a triadic procedure to compare dissimilarities among 32 pigmented stimuli (the caps of the saturated and desaturated versions of the D15 panel test). Multidimensional scaling was applied to quantify individual variations in the salience of the axes of color space. Despite the briefness, simplicity, and "low-tech" nature of the procedure, subtle but statistically significant differences did emerge: on average the smoking group were significantly less sensitive to red-green differences. This is consistent with some form of injury to the optic nerve.

Escher in color space: individual-differences multidimensional scaling of color dissimilarities collected with a gestalt formation task.

The structure of color perception can be examined by collecting judgments about color dissimilarities. In the procedure used here, stimuli are presented three at a time on a computer monitor and the spontaneous grouping of most-similar stimuli into gestalts provides the dissimilarity comparisons. Analysis with multidimensional scaling allows such judgments to be pooled from a number of observers without obscuring the variations among them. The anomalous perceptions of color-deficient observers produce comparisons that are represented well by a geometric model of compressed individual color spaces, with different forms of deficiency distinguished by different directions of compression. The geometrical model is also capable of accommodating the normal spectrum of variation, so that there is greater variation in compression parameters between tests on normal subjects than in those between repeated tests on individual subjects. The method is sufficiently sensitive and the variations sufficiently large that they are not obscured by the use of a range of monitors, even under somewhat loosely controlled conditions.

Projection structure of the photosynthetic reaction centre-antenna complex of Rhodospirillum rubrum at 8.5 A resolution.

Two-dimensional crystals of the reaction-centre-light-harvesting complex I (RC-LH1) of the purple non- sulfur bacterium Rhodospirillum rubrum have been formed from detergent-solubilized and purified protein complexes. Unstained samples of this intrinsic membrane protein complex have been analysed by electron cryomicroscopy (cryo EM). Projection maps were calculated to 8.5 A from two different crystal forms, and show a single reaction centre surrounded by 16 LH1 subunits in a ring of approximately 115 A diameter. Within each LH1 subunit, densities for the alpha- and beta-polypeptide chains are clearly resolved. In one crystal form the LH1 forms a circular ring, and in the other form the ring is significantly ellipsoidal. In each case, the reaction centre adopts preferred orientations, suggesting specific interactions between the reaction centre and LH1 subunits rather than a continuum of possible orientations with the antenna ring. This experimentally determined structure shows no evidence of any other protein components in the closed LH1 ring. The demonstration of circular or elliptical forms of LH1 indicates that this complex is likely to be flexible in the bacterial membrane.