An APT investigation of an amorphous Cr-B-C thin film.

A magnetron sputtered amorphous Cr-B-C thin film was investigated by means of atom probe tomography (APT). The film is constituted of two phases; a Cr-rich phase present as a few nanometer large regions embedded in a Cr-poor phase (tissue phase). The Cr-rich regions form columnar chains oriented parallel to the growth direction of the film. It was found that the Cr-rich regions have a higher B:C ratio than the Cr-poor regions. The composition of the phases was determined as approximately 35Cr-33B-30C and 15Cr-40B-42C (at%), respectively. The results suggest that this type of nanocomposite films has a more complex structure than previously anticipated, which may have an importance for the mechanical and electrical properties.

Interpretation of atom probe tomography data for the intermetallic TiAl+Nb by means of field evaporation simulation.

In this paper simulations of the field evaporation process during field ion microscopy (FIM) and atom probe tomography (APT) are presented and compared with experimental data. The Müller-Schottky-model was extended to include the local atomic arrangement on the evaporation process of atoms. This arrangement was described by the sum of the next-neighbor-binding-energies, which differ for an atom of type A, depending on how many A-A, B-B or A-B bonds are present. Thus simulations of APT-data of intermetallic phases become feasible. In this study simulations of L1(0)-TiAl with additions of Nb are compared with experimental data. Certain artifacts, which appear for experimental data are treated as well.

Investigation of the site occupation of atoms in pure and doped TiAl/Ti3Al intermetallic.

Dual-phase TiAl/Ti3Al-alloys consisting of a lamellar structure, comprising gamma-phase plus a small amount of alpha2-phase, with addition of 1, 5 and 10at% Nb were prepared. The samples were investigated by means of field ion microscopy (FIM) and atom probe tomography (APT). The influence of doping elements on the variation of field evaporation and microstructural parameters in the gamma-phase as studied by FIM and APT will be reported in this contribution. The intermetallic gamma-Phase of TiAl exhibits a L1(0)-structure, which has alternating Ti- and Al-planes in the [001]-superstructure direction. Because of the significant difference in the evaporation field strengths of Ti and Al, it is usually not possible to directly distinguish Ti- and Al-planes in this direction in the APT data. Therefore, it is not possible to assign Nb to any plane, as well. To solve this problem an algorithm, using statistical methods, was developed, which allows to inherently distinguish the planes. A comparison of the results for [100]- and [001]-directions shows that Nb prefers Ti-sites. The sequence of field evaporation field strengths, which follows the trend E(Nb) > E(Al) > E(Ti), could also be deduced.

Two procedures for Kirschner wire osteosynthesis of distal radial fractures. A randomized trial.

BACKGROUND: The treatment of displaced Colles-type fractures of the distal part of the radius remains a challenge. Two procedures for closed reduction and Kirschner wire osteosynthesis of these fractures were compared in a prospective randomized study. METHODS: One hundred consecutive patients with a Colles fracture of the distal part of the radius (AO classification 23-A2, 23-A3, or 23-C1) were treated over an eighteen-month period. One group was managed with the conventional method, described by Willenegger and Guggenbuhl in 1959, in which two Kirschner wires are introduced into the styloid process of the radius. The other group was treated with the Kapandji method, as modified by Fritz et al., in which two Kirschner wires are inserted into the fracture gap and a third is placed through the styloid process. Postoperative care was standardized for both groups and carried out according to a strict procedure. Forty patients who had been operated on according to the modified Kapandji method and forty-one treated with the Willenegger technique were available for follow-up, for a follow-up rate of 81%. The follow-up assessment was performed with a modified version of the Martini score. RESULTS: The median time to follow-up was ten months (range, six to twenty months). The results as assessed with the Martini score were, on the average, good to very good for the patients treated with the Kapandji method and satisfactory to good for the patients treated with the conventional Kirschner wire fixation. The duration of radiographic exposure was significantly shorter with the Kapandji method than with the Willenegger technique. CONCLUSIONS: Conventional Kirschner wire fixation remains a good method of osteosynthesis for the treatment of displaced fractures of the distal part of the radius. We found both the functional and radiographic outcomes of the Kapandji method to be significantly better than those of the Willenegger technique. LEVEL OF EVIDENCE: Therapeutic study, Level I-1a (randomized controlled trial [significant difference]). See Instructions to Authors for a complete description of levels of evidence.

Developmental memory performance: inter-task consistency and base-rate variability on the WRAML.

Two studies examined developmental memory test consistency and base-rate variability on the Wide Range Assessment of Memory and Learning (WRAML) using three age cohorts from the standardization sample. Study 1 examined inter-subtest correlation coefficients across the nine subtests of the WRAML and compared across three age cohorts (5, 11, 16 to 17 year olds). An age-related increase in inter-task consistency was found (mean r = .26 and .42 for the youngest and oldest age groups, respectively). However, correlation coefficients were generally in the low to moderate range (rs = .2 to .5) for all three cohorts suggesting considerable performance variability across memory subtests. Study 2 examined base-rate variability in the WRAML standardization sample using several different methods. More specifically, base-rate information is provided for the maximum discrepancy between subtests, profile strengths and weakness (i.e., discrepancies from the mean scaled score), and the prevalence of individuals within the "deficient" performance range (i.e., < = 2 SD below normative means). In addition, performance variability across the four WRAML index scores was examined by determining the prevalence rates for the maximum discrepancy (1) between index scores, and (2) from the General Memory Index compared to the other three index scores. Performance discrepancies tended to be higher among the youngest group. Again, however, considerable performance variability was observed across all three age cohorts. Implications for clinical practice are discussed.

Self-report measures among transplant candidates: the impact of evaluative situations.

Experiment 1 was a between-subjects design comparing transplant candidates completing self-report measures under an evaluative versus an anonymous research condition. A cardiac disease group and a healthy community group served as controls. Transplant candidates in the anonymous research condition reported significantly more depression, anxiety, and negative affectivity as compared with transplant candidates in the evaluative condition and community controls. In contrast, the evaluative transplant group (a) did not differ from the community controls on any of the self-report measures, and (b) reported significantly less depression than cardiac disease controls. Experiment 2 was a within-subjects design with transplant candidates completing self-report measures under both an evaluative and an anonymous research condition. Significantly greater anxiety was reported under the anonymous research condition. Social desirability was significantly related to change in self-reported anxiety and depression across conditions, but was unrelated to change in endorsement of personality characteristics.

Activities of daily living among heart transplant candidates: neuropsychological and cardiac function predictors.

BACKGROUND: The ability of patients to perform day-to-day tasks (e.g., medication management, dietary regulation) is an important concern of transplant teams. METHODS: We studied a clinical series of 75 heart transplant candidates and 38 controls to examine the predictive validity of demographic, neuropsychologic, and cardiac function variables to a performance-based measure of instrumental activities of daily living (IADL) capacity (i.e., Everyday Problems Test, EPT). RESULTS: Multiple regression analyses, controlling for education and race, indicated that neuropsychologic tests accounted for between 34% and 67% of the variance across IADL domains (e.g., cooking, household chores, medication management). The IADL capacity was most consistently predicted by long-standing verbal ability (Shipley Institute of Living Scale-Vocabulary, SILS-VOC) and psychomotor speed and mental flexibility (Trail Making Test-Part B, TMT-B). Similarly, SILS-VOC and TMT-B also tended to show the best operating characteristics (i.e., sensitivity, specificity, positive predictive power, negative predictive power) for detection of dependence across IADL domains. In contrast, cardiac function measures (e.g., cardiac output, mean atrial pressure) were largely unrelated to the patient's performance on the paper-and-pencil EPT task. CONCLUSIONS: Long-standing intellectual ability, and a measure of speeded information processing and mental flexibility are the best predictors of IADL capacity.

Measuring behavior.

In this article, the author provides an overview of the neuropsychologic approach to evaluation of neurologic dysfunction. The various strengths and weaknesses of this methodology are discussed, and the steps of the neuropsychologic evaluation are detailed.

Neuropsychological functioning among heart transplant candidates: a case control study.

Neuropsychological performance was examined among a group of patients with end-stage heart disease undergoing routine evaluation for transplantation using a matched case-control design. Heart transplant candidates and controls were matched case by case for gender, race, education and age range. In order to match all 44 controls, a clinical series of 303 heart transplant candidates evaluated between October 1995 through March 1998 were considered. Although not specifically matched on variables of estimated IQ and socioeconomic status, statistical analysis showed no group differences on these variables. A separate analysis of variance on each neuropsychological test indicated that the heart transplant candidates performed significantly worse than controls on tasks of fine motor speed and dexterity (i.e., Grooved Peg Board), psychomotor speed and mental flexibility (i.e., Trail Making Test, Part B), and abstract reasoning and problem solving ability (i.e., Shipley Institute of Living Scale-Abstraction subtest). Implications of the results and future directions are discussed.

Neuropsychological performance as a function of cardiac status among heart transplant candidates: a replication.

This study examined the relationship between cardiac function and cognitive test performance among candidates for heart transplant. Participants were 26 individuals undergoing heart catheterization within one day of completing a battery of cognitive tests. Partial correlation analyses controlling for age and education were used to examine the relationship between cardiac function and cognitive performance. Results replicate previous findings in that increasing hemodynamic pressure variables, e.g., pulmonary artery systolic pressure, were associated with decreased cognitive performance on a measure of psychomotor speed and attention (Trail Making Test-Part A: r=.53). In contrast, cardiac output and cardiac index appeared to be not significantly related to cognitive performance. Taken together, poor performance on cognitive tests among heart transplant candidates appears to be attentionally mediated.

Neuropsychological functioning in patients with asymptomatic congenital cytomegalovirus infection.

Congenital cytomegalovirus (CMV) infection has an affinity for the central nervous system and has been implicated in a variety of neurological impairments. Analysis of cognitive functioning in children with asymptomatic congenital CMV infection, however, has revealed no general intellectual deficits. The present study was designed to explore neuropsychological test performance in these children, compared with healthy control subjects, providing data from more sensitive measures of neurocognitive functioning. The sample consisted of 109 children diagnosed with asymptomatic congenital CMV infection and 173 control subjects who were compared on tests measuring various aspects of perceptual and motor functioning, memory, problem solving, and traditional intelligence measures. Young (41NDASH6 yr) control patients performed significantly better on the Full-Scale but not the Verbal or Performance intelligence quotient (IQ) measures than patients with asymptomatic congenital CMV infection, without accompanying consistent neuropsychological performance differences. However, no IQ or neuropsychological differences were found between groups of older children. The present study adds to the existing literature finding no reliable, lasting differences in IQ scores and adds to our knowledge by finding no reliable, lasting differences in neuropsychological test performance.

The utility of K-correction to adjust for a defensive response set on the MMPI.

This study examined the utility of the K-correction procedure to adjust for a defensive response set on the MMPI. The sample consisted of 61 patients with end-stage lung disease undergoing psychosocial evaluation for transplantation. Participants were separated into defensive and non-defensive groups using a median split on the K scale (defensive group T score 59) as the cutoff score. The MMPI was scored once in the standard manner and then rescored omitting all K-scale items from the clinical scales. As hypothesized, raw score analysis after omitting K-scale items showed the defensive group endorsed significantly fewer items on all five scales involving K-correction (Scales Hs, Pd, Pt, Sc, Ma). Analysis of K-corrected T scores on Scales Hs, Pd, Pt, and Sc using standard procedures showed a significant group difference only on Scale Hs with a higher T score found among the defensive group. The defensive and nondefensive groups were not significantly different in demographic, medical, or psychiatric characteristics suggesting that the tendency to respond in a defensive manner is the major characteristic that distinguishes the two groups. Taken together, these results provide support for the use of the K-correction procedure when examining MMPI clinical profiles among patients with end-stage pulmonary disease undergoing evaluation for transplantation.

Visual reproduction subtest of the Wechsler Memory Scale-Revised: analysis of construct validity.

This study assessed the construct validity of Visual Reproduction (VR) Cards A (Flags) and B (Boxes) from the original Wechsler Memory Scale (WMS) compared to Flags and Boxes from the revised edition of the WMS (WMS-R). Independent raters scored Flags and Boxes using both the original and revised scoring criteria and correlations were obtained with age, education, IQ, and four separate criterion memory measures. Results show that for Flags, there is a tendency for the revised scoring criteria to produce improved construct validity. For Boxes, however, there was a trend in the opposite direction, with the revised scoring criteria demonstrating worse construct validity. Factor analysis suggests that Flags are a more distinct measure of visual memory, whereas Boxes are more complex and significantly associated with conceptual reasoning abilities. Using the revised scoring criteria, Boxes were found to be more strongly related to IQ than Flags. This difference was not found using the original scoring criteria.

Determinants of cognitive performance in systemic lupus erythematosus.

Patients with systemic lupus erythematosus (SLE) may have a variety of neuropsychiatric syndromes. Assessment of cognitive functioning for these patients is complicated by increased prevalence and disease severity among groups obtained lower scores on measures of cognitive functioning in normative national samples. Cognitive ability was quantified in a diverse cohort of patients with SLE and a demographically matched group of control participants. Hierarchical regression demonstrated a small increase (6%) in explained variation in cognitive functioning when presence of SLE was added to the equation derived from demographic variables. No significant interaction was found between race and disease. These results suggest that increased frequency of cognitive impairment in African Americans with SLE is due to the additive effects of psychosocial variables.

Intellectual assessment of children with asymptomatic congenital cytomegalovirus infection.

The findings of previous studies examining the neurocognitive development of children with clinically inapparent (asymptomatic) cytomegalovirus (CMV) infection have demonstrated mixed results. These studies have generally depended on small sample sizes (i.e., < 50). We examined the intellectual development of children with asymptomatic congenital CMV infection using a sample larger than previous studies. Two hundred and four cases aged 5 to 200 months were compared with 177 uninfected siblings ranging in age from 6 to 203 months. Parents were administered the Developmental Profile, a measure of developmental achievement. Children who were older than 30 months were administered an objective intelligence measure. Results of this study showed that children with asymptomatic congenital CMV infection do not demonstrate intellectual impairment, and that they perform similarly to uninfected siblings. Parents tended to overestimate their child's level of functioning regardless of whether the child had CMV infection.

A defensive response set and the relation between cognitive and emotional functioning: a replication.

This study was designed to examine the hypothesis that a defensive self-report response set tends to attenuate the strength of the relationship between self-reported emotional functioning and cognitive tests, particularly the functioning of verbal memory. 75 patients with end-stage lung disease were administered the MMPI and a cognitive test battery as part of a psychosocial evaluation for transplantation. Patients were separated into defensive and nondefensive groups using the MMPI F - K Gough Dissimulation index (raw score F minus K < or = -15). Cognitive factor scores were generated and correlated with non-K-corrected raw scores of MMPI Scales 2, 7, and 8. Correlation coefficients were compared across groups. As predicted, increases on Scales 2 and 7 were significantly associated with decreased functioning of verbal memory (r = -.35 and -.34, respectively) among the nondefensive group but were unrelated in the defensive group. It is argued that the attenuation of the relationship between self-reported emotional status and verbal memory functioning is, in part, due to a restricted range of symptom endorsement on the MMPI among the defensive group. These findings replicate those previously reported using a sample of patients with cardiac disease.

The relationship between cardiac function and neuropsychological status among heart transplant candidates.

BACKGROUND: Cognitive deficits among heart transplant candidates have been well documented. This study was designed to examine the hypothesis that impaired cognitive test performance among heart transplant candidates may be attributed, in part, to decreased cerebral perfusion secondary to poor cardiac function. METHODS AND RESULTS: Sixty-two patients participated in the study who underwent heart catheterization within 1 day of completing a battery of cognitive tests. Multiple demographic and patient characteristics were examined for their potential moderating role in the relationship between measures of cardiac function and cognitive performance including age, education, race, gender, psychiatric history, medication usage, cardiac surgical history, and self-reported symptoms of depression and anxiety. Only age and education were significantly related to cognitive performance (P < .01). Thus, partial correlation analyses controlling for age and education were used to examine the relationship between cardiac function and cognitive performance. In general, increasing hemodynamic pressure variables (ie, pulmonary artery pressure and right atrial pressure), and to a lesser extent cardiac output and cardiac index, were related (r = - .32 to - .43; P < .01) to decreased performance on cognitive tasks that assessed simple attention, speed of mental processing, and mental flexibility (Digit Span-Forward, Trail Making Test-Part B, Symbol Digits Modalities Test, and Stroop Neuropsychological Screening Test). Left ventricular ejection fraction, systemic and pulmonary vascular resistance, and mean arterial pressure were largely unrelated to cognitive performance in this sample of patients with end stage cardiac disease. CONCLUSIONS: Hemodynamic pressure variables seem to be most consistently related (ie, inversely) to cognitive functioning among heart transplant candidates.

Does memory test performance in children become more consistent with age? Cross-sectional comparisons using the WRAML. Wide Range Assessment of Memory and Learning.

This study examined intertask consistency on the Wide Range Assessment of Memory and Learning (WRAML), using two age cohorts of children. Eighty-one neurologically impaired children and 76 matched (i.e., age, gender, race) controls were separated into two age groups, 5- to 9- and 10- to 14-year-olds. Performance on four subtests from the WRAML Memory Screening Index were examined. For the older neurologic sample, all six intertask correlations were significant (mean r = .58) while only three of the six correlation coefficients were significant among the younger neurologic group (mean r = .26). In contrast, only three of the six intertask coefficients were statistically significant in both the younger and older controls. A possible explanation for these divergent findings and clinical implications of intertask variability on memory measures are discussed.

Hearing loss and congenital symptomatic cytomegalovirus infection: a case report of multidisciplinary longitudinal assessment and intervention.

More than 6000 children born annually in this country have hearing loss resulting from congenital cytomegalovirus (CMV) infection, the leading nonhereditary congenital cause of hearing loss in children. This exemplary congenital symptomatic CMV case focuses on the results of longitudinal audiologic, educational, medical, psychological, and visual evaluations and intervention. Decreased ocular motor control and visual acuity were observed as was bilateral deterioration of hearing from 3 days though 9 years of age. Treatment with dexamethasone and histamine resulted in almost complete reversal of the most recent progression of hearing loss in the left ear.

Neuropsychological testing in obsessive-compulsive disorder: a clinical review.

The role of neuropsychological testing in assessment of obsessive-compulsive disorder (OCD) is examined by review of 8 case reports and 14 patient series. Investigators generally agreed on localization of dysfunctional areas (e.g., prefrontal and frontal regions, limbic system, basal ganglia). They disagreed as to hemisphere and frontal lobe side impairment, involvement of other brain areas, pathophysiological connections, and impact of developmental phases and of concomitant cognitive and affective conditions. Conclusions about OCD pathogenesis are limited by test and sample variability. The authors outline an integrative approach based on sensorial and cognitive information disruptions that require activation of less specialized circuits. OCD may be syndromic, and subgroups may exist based on related but differentiable biochemical pathways.