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Abstract: A new metallographic preparation technique has been developed for uranium–niobium (U–Nb) alloys. The technique uses a single methodology to optimally elucidate microstructural features without preparation artifacts and permits inclusion retention and identification. Specific examples of the applicability of this metallographic preparation technique are provided for U–6wt.%Nb. This technique has been successfully applied to numerous specimens with various thermomechanical histories to clearly resolve solidification, metastable martensite, and equilibrium structures. These results demonstrate that prior knowledge of a sample’s thermal history is not required for an effective metallographic evaluation and highlight the versatility of this technique. The beneficial features to reduce environmental impact are also discussed. [Copyright &y& Elsevier]

The default mode network (DMN), based in ventromedial prefrontal cortex (vmPFC) and posterior cingulate cortex (PCC), exhibits higher metabolic activity at rest than during performance of externally oriented cognitive tasks. Recent studies have suggested that competitive relationships between the DMN and various task-positive networks involved in task performance are intrinsically represented in the brain in the form of strong negative correlations (anticorrelations) between spontaneous fluctuations in these networks. Most neuroimaging studies characterize the DMN as a homogenous network, thus few have examined the differential contributions of DMN components to such competitive relationships. Here, we examined functional differentiation within the DMN, with an emphasis on understanding competitive relationships between this and other networks. We used a seed correlation approach on resting-state data to assess differences in functional connectivity between these two regions and their anticorrelated networks. While the positively correlated networks for the vmPFC and PCC seeds largely overlapped, the anticorrelated networks for each showed striking differences. Activity in vmPFC negatively predicted activity in parietal visual spatial and temporal attention networks, whereas activity in PCC negatively predicted activity in prefrontal-based motor control circuits. Granger causality analyses suggest that vmPFC and PCC exert greater influence on their anticorrelated networks than the other way around, suggesting that these two default mode nodes may directly modulate activity in task-positive networks. Thus, the two major nodes comprising the DMN are differentiated with respect to the specific brain systems with which they interact, suggesting greater heterogeneity within this network than is commonly appreciated. Hum Brain Mapp, 2009. © 2008 Wiley-Liss, Inc. [ABSTRACT FROM AUTHOR]

Abstract: Examination of spontaneous intrinsic brain activity is drawing increasing interest, thus methods for such analyses are rapidly evolving. Here we describe a novel measure, “network homogeneity”, that allows for assessment of cohesiveness within a specified functional network, and apply it to resting-state fMRI data from adult ADHD and control participants. We examined the default mode network, a medial-wall based network characterized by high baseline activity that decreases during attention-demanding cognitive tasks. We found reduced network homogeneity within the default mode network in ADHD subjects compared to age-matched controls, particularly between the precuneus and other default mode network regions. This confirms previously published results using seed-based functional connectivity measures, and provides further evidence that altered precuneus connectivity is involved in the neuropathology of ADHD. Network homogeneity provides a potential alternative method for assessing functional connectivity of specific large-scale networks in clinical populations. [Copyright &y& Elsevier]

Abstract: Increased intraindividual variability (IIV) is a hallmark of disorders of attention. Recent work has linked these disorders to abnormalities in a “default mode” network, comprising brain regions routinely deactivated during goal-directed cognitive tasks. Findings from a study of the neural basis of attentional lapses suggest that a competitive relationship between the “task-negative” default mode network and regions of a “task-positive” attentional network is a potential locus of dysfunction in individuals with increased IIV. Resting state studies have shown that this competitive relationship is intrinsically represented in the brain, in the form of a negative correlation or antiphase relationship between spontaneous activity occurring in the two networks. We quantified the negative correlation between these two networks in 26 subjects, during active (Eriksen flanker task) and resting state scans. We hypothesized that the strength of the negative correlation is an index of the degree of regulation of activity in the default mode and task-positive networks and would be positively related to consistent behavioral performance. We found that the strength of the correlation between the two networks varies across individuals. These individual differences appear to be behaviorally relevant, as interindividual variation in the strength of the correlation was significantly related to individual differences in response time variability: the stronger the negative correlation (i.e., the closer to 180° antiphase), the less variable the behavioral performance. This relationship was moderately consistent across resting and task conditions, suggesting that the measure indexes moderately stable individual differences in the integrity of functional brain networks. We discuss the implications of these findings for our understanding of the behavioral significance of spontaneous brain activity, in both healthy and clinical populations. [Copyright &y& Elsevier]

Aim: To determine and compare rates of descending aortic enlargement and complications in chronic aortic dissection with and without a proximal aortic graft. Methods and materials: Fifty-two patients with dissection involving the descending aorta and who had undergone at least two computed tomography (CT) examinations at our institution between November, 1993 and February, 2004 were identified, including 24 non-operated patients (four type A, 20 type B) and 28 operated patients (type A). CT examinations per patient ranged from two to 10, and follow-up ranged from 1–123 months (mean 49 months, median 38.5 months). On each CT image, the aortic short axis (SA), false lumen (FL), and true lumen (TL) diameters were measured at the longitudinal midpoint of the dissection and at the point of maximum aortic diameter. Complications were tabulated, including aortic rupture and aortic enlargement requiring surgery. Results: For non-operated patients, the midpoint and maximum point SA, TL, and FL diameters increased significantly over time. For operated patients, the midpoint and maximum point SA and FL diameters increased significantly over time. In both groups, aortic enlargement was predominantly due to FL expansion. Diameter increases in non-operated patients were significantly larger than those in operated patients. The rate of change in aortic diameter was constant, regardless of aortic size. Four non-operated and six operated patients developed aortic complications. Conclusions: In patients with a dissection involving the descending thoracic aorta, the FL increased in diameter over time, at a constant rate, and to a greater degree in non-operated patients (mostly type B) compared with operated patients (all type A). [Copyright &y& Elsevier]

Abstract: Anterior cingulate cortex (ACC) is a nexus of information processing and regulation in the brain. Reflecting this central role, ACC is structurally and functionally heterogeneous, a fact long appreciated in studies of non-human primates. Human neuroimaging studies also recognize this functional heterogeneity, with meta-analyses and task-based studies demonstrating the existence of motor, cognitive and affective subdivisions. In contrast to task-based approaches, examinations of resting-state functional connectivity enable the characterization of task-independent patterns of correlated activity. In a novel approach to understanding ACC functional segregation, we systematically mapped ACC functional connectivity during rest. We examined patterns of functional connectivity for 16 seed ROIs systematically placed throughout caudal, rostral, and subgenual ACC in each hemisphere. First, our data support the commonly observed rostral/caudal distinction, but also suggest the existence of a dorsal/ventral functional distinction. For each of these distinctions, more fine-grained patterns of differentiation were observed than commonly appreciated in human imaging studies. Second, we demonstrate the presence of negatively predicted relationships between distinct ACC functional networks. In particular, we highlight negative relationships between rostral ACC-based affective networks (including the “default mode network”) and dorsal–caudal ACC-based frontoparietal attention networks. Finally, interhemispheric activations were more strongly correlated between homologous regions than in non-homologous regions. We discuss the implications of our work for understanding ACC function and potential applications to clinical populations. [Copyright &y& Elsevier]

Abstract: Brain activations underlying cognitive processes are subject to modulation as a result of increasing cognitive demands, individual differences, and practice. The present study investigated these modulatory effects in a cognitive control task which required inhibition of prepotent responses based on the contents of working memory (WM) and which enabled a novel dissociation of item-specific and task-skill effects resulting from brief practice. Distinct responses in areas underlying WM and inhibitory control in the absence of behavioral changes reflected different effects of item repetition and general task practice on tonic working memory and phasic inhibitory processes. Item repetition was associated with decreases in both unique and common areas subserving WM and inhibitory control. In contrast, general task practice was reflected in decreases in the level of tonic WM activity required to maintain a consistently high level of task performance but increased activity in a number of core inhibitory regions including dorsolateral and inferior PFC and inferior parietal cortex. Furthermore, both practice and individual differences in task performance were associated with the ability to modulate and maintain activity in frontostriatal areas mediating attentional control, suggesting that the areas that differ between individuals can be modulated by practice within an individual. These results raise the possibility that a fundamental human ability, reflexive cognitive control, is amenable to practice. [Copyright &y& Elsevier]

Objective: To describe the frequency, clinical, and laboratory features of patients diagnosed with multiple sclerosis (MS) or MS-like illnesses (MSL) among a large, prospectively followed cohort of anti-phospholipid antibody (aPL)-positive patients. Methods: Between 1990 and 1995 patients referred to a university-affiliated rheumatology clinic were prospectively evaluated for aPL based on questionnaires designed to detect aPL-related symptoms and/or a family history of aPL-related illnesses. Magnetic resonance imaging (MRI) was performed when significant neurological features were present. A subgroup of all patients diagnosed with MS or MSL was identified and their clinical, laboratory, and imaging findings were reviewed. Results: Of 322 patients evaluated for aPL-related symptoms or events, 189 (59%) were positive for at least one class of aPL. Twenty-six of 322 patients (8%) carried a diagnosis of MS or MSL, either at the initial evaluation or during the study period. Twenty-three of the 26 individuals (88%) tested positive for aPL, while the remaining 3 (11%) tested repeatedly negative. Eighteen of the 23 patients (78%) had either more than one class of aPL or had multiple positive titers. IgM aCL was noted in 18 of the 23 patients (78%). Oligoclonal bands were noted in five patients. Antinuclear antibodies (ANA) and low complement levels were frequently observed. Blinded MRI readings showed lesions consistent with MS in the majority of cases. Clinically, 7 patients had transverse myelitis (TM), while optic neuritis (ON) was present in 8 patients. Most patients had either occult symptoms of rheumatic disease or contributory family histories. None had a defined underlying connective-tissue disease. Conclusion: A substantial number of aPL-positive patients have a concurrent diagnosis of MS or MSL, frequently presenting with elevated IgM aCL, optic neuritis, and transverse myelitis. The anti-phospholipid syndrome (APS) should be strongly considered as an alternative diagnosis to MS in these patients. [ABSTRACT FROM AUTHOR]

Comments on other articles about Alexander Bogdanov in this issue of `Russian Review.' Scholarship on Bogdanov is divided; Tangle of contradictions; Two lines of consistency: Lenin's political practice and Bogdanov's philosophy; Disagreement withJohn Eric Marot; More.

Although pair bonding has been studied for several decades, only somewhat recently have researchers began studying the neural consequences of separation from a pair bond partner. Here we examined the impact of partner separation on the socially monogamous Mongolian gerbil. Using a within-subjects design, we assessed nonsocial, nonreproductive, and reproductive behavior in male gerbils pre- and post- either 4 weeks of cohabitation with or separation from a pair bond partner. We then conducted an immediate early gene study to examine the influence of partner separation on hypothalamic oxytocin and vasopressin neural responses to interactions with a novel, opposite-sex conspecific. [ABSTRACT FROM AUTHOR]

Abstract: Risk avoidance is a hallmark of psychopathological conditions such as anxiety disorders. Yet few studies have examined its neural basis. The present work sought to identify the neural correlates of risk avoidance. While functional MRI scans were acquired, healthy adults (N =23) played a Wheel of Fortune game during which they chose to bet or pass on each of 104 proposed gamble trials. Participants also completed the Cognitive Appraisal of Risky Events (CARE, ), a self-report measure of “real world” risky behavior. As expected, decision-making was associated with activation, as measured by increased BOLD responses, of the striatum, insula, anterior cingulate cortex, dorsolateral prefrontal cortex, and parietal lobe. Risk avoidance during probabilistic trials (percent of trials passed) was significantly correlated with precuneus and striatal responses to trials with a certain outcome (No-Risk). Similarly, “real world” risk avoidance, as measured by the CARE, was significantly correlated with precuneus activity during No-Risk trials. Collectively, these data suggest that precuneus and striatal responses to decision-making under certainty represent putative neural markers of risk avoidance in the laboratory and in the “real world.” Further, they underline the need to extend neuroimaging research on risk avoidance, and associated anxiety disorders, to posterior cortical regions. [Copyright &y& Elsevier]

Abstract: An aging study of compositionally homogeneous U–5.6Nb and U–7.7Nb (wt.%) was undertaken to improve the understanding of the decomposition of metastable martensitic phases in the U–Nb system. Artificially aging these depleted (238U) uranium alloys at 373, 473, 523 and 573K for times up to 70 days resulted in significant age hardening. However, the microstructural changes giving rise to this hardening are subtle and elude standard light optical and electron microscopy techniques; this subtlety motivated the present study of aging-related changes by X-ray diffraction. A sealed tube X-ray diffractometer was used to record powder diffraction patterns from these aged polycrystalline U–Nb samples along with a CeO2 standard. Data were analyzed using GSAS for full-pattern Rietveld refinements. Planar defects as well as strain broadening appear to have caused unusual peak profiles, which makes data interpretation challenging. Lattice parameter and unit cell volume trends are presented. U–5.6Nb experienced a reversal in the b lattice parameter and unit cell volume during aging, which has both similarities and differences to aging in dilute U–Ti and U–Mo alloys. The longest-time aging unit cell volume trends of U–5.6Nb indicate Nb depletion of the matrix phase, while the corresponding behavior at all aging times in U–7.7Nb is indicative of Nb enrichment in its matrix phase. [Copyright &y& Elsevier]

Erythema nodosum is a dermatologic condition characterized by painful, erythematous nodules on the anterior surfaces of the lower extremities. Its association with a variety of conditions has been previously described. We present three cases of erythema nodosum in patients with elevated anticardiolipin antibodies. In one patient, a temporal relationship was seen in the simultaneous detection of antibodies and skin lesions. We propose an association between erythema nodosum and the antiphospholipid antibody syndrome (APS). Lupus (2000) 9, 641–645. [ABSTRACT FROM AUTHOR]

Low-enriched uranium-10 wt.% molybdenum (LEU-10wt.%Mo) is of interest for the fabrication of monolithic fuels to replace highly-enriched uranium (HEU) dispersion fuels in high performance research and test reactors around the world. In this work, depleted uranium-10 wt.%Mo (DU-10wt.%Mo) is used to simulate the solidification and microstructural evolution of LEU-10wt.%Mo. Electron backscatter diffraction (EBSD) and complementary electron probe microanalysis (EPMA) reveal significant microsegregation present in the metastable γ-phase after solidification. Homogenization is performed at 800 and 1000 °C for times ranging from 1 to 32 h to explore the time–temperature combinations that will reduce the extent of microsegregation, as regions of higher and lower Mo content may influence local mechanical properties and provide preferred regions for γ-phase decomposition. We show for the first time that EBSD can be used to qualitatively assess microstructural evolution in DU-10wt.%Mo after homogenization treatments. Complementary EPMA is used to quantitatively confirm this finding. Homogenization at 1000 °C for 2–4 h may the regions that contain 8 wt.% Mo or lower, whereas homogenization at 1000 °C for longer than 8 h effectively saturates Mo chemical homogeneity, but results in substantial grain growth. The appropriate homogenization time will depend upon additional microstructural considerations, such as grain growth and intended subsequent processing. Higher carbon LEU-10wt.%Mo generally contains more inclusions within the grains and at grain boundaries after solidification. The effect of these inclusions on microstructural evolution (e.g. grain growth) during homogenization and as potential γ-phase decomposition nucleation sites is unclear, but likely requires additional study. [ABSTRACT FROM AUTHOR]

Abstract: The amygdala is composed of structurally and functionally distinct nuclei that contribute to the processing of emotion through interactions with other subcortical and cortical structures. While these circuits have been studied extensively in animals, human neuroimaging investigations of amygdala-based networks have typically considered the amygdala as a single structure, which likely masks contributions of individual amygdala subdivisions. The present study uses resting state functional magnetic resonance imaging (fMRI) to test whether distinct functional connectivity patterns, like those observed in animal studies, can be detected across three amygdala subdivisions: laterobasal, centromedial, and superficial. In a sample of 65 healthy adults, voxelwise regression analyses demonstrated positively-predicted ventral and negatively-predicted dorsal networks associated with the total amygdala, consistent with previous animal and human studies. Investigation of individual amygdala subdivisions revealed distinct differences in connectivity patterns within the amygdala and throughout the brain. Spontaneous activity in the laterobasal subdivision predicted activity in temporal and frontal regions, while activity in the centromedial nuclei predicted activity primarily in striatum. Activity in the superficial subdivision positively predicted activity throughout the limbic lobe. These findings suggest that resting state fMRI can be used to investigate human amygdala networks at a greater level of detail than previously appreciated, allowing for the further advancement of translational models. [Copyright &y& Elsevier]

Abstract: Background: Systemic corticosteroids are routinely used in the management of acute asthma, however the optimum route of administration for patients requiring hospitalisation is unclear. Intravenous (IV) corticosteroids are used in practice, but they may not offer any advantage over oral corticosteroids. Aim: To compare the efficacy of oral and IV administration of corticosteroids in the treatment of adults hospitalised with acute asthma. Method: Adults admitted to hospital for treatment of acute asthma were randomised to receive oral prednisolone 100mg once daily or hydrocortisone 100mg IV 6 hourly for 72h following admission. All patients concurrently received inhaled corticosteroids and bronchodilators. Improvements in peak expiratory flow rate (PEF) from baseline were compared for 72h. Results: Forty-seven patients were randomized, 30 females, 17 males. Twenty-four received oral prednisolone and 23 received IV hydrocortisone. At baseline the oral and IV groups were similar (mean, SD) in age (38.3, 12.8 vs 37.3, 12.9, P=0.80) and initial percent predicted (PP) PEF (61, 16.7 vs 69, 13.0, P=0.11). After 72h both groups had similar improvements in PEF (27%, 26 vs 27%, 19, P=0.96). Conclusion: Corticosteroids administered orally and IV had similar efficacy in the treatment of adults hospitalised with acute asthma. [Copyright &y& Elsevier]

To compare the management of paediatric patients with mild or moderate asthma in paediatric-only emergency departments (POEDs) to treatment in a mixed adult-child emergency departments (mixed EDs). Prospective, observational study conducted in 36 Australian emergency departments (EDs) for 2 weeks in 2001. Children aged 1−15 years with acute asthma classified as mild or moderate severity. Details of demography, severity assessment, and type of treatment facility, treatment and disposition were collected. Analysis used descriptive statistics, comparison of proportions by χ2, and multiple logistic regression. Two-hundred and nine children were treated at POEDs and 257 at mixed EDs. The groups had similar severity. Spacers to deliver beta-agonists were used more frequently in POEDs (67.5% vs 24.2%; P < 0.01). Children treated at POEDs with a mild attack were more likely to be admitted (20.6% vs 9.5%; P < 0.02) and given salbutamol (82.8% vs 71.9%; P = 0.03). For children with moderate asthma, oral steroid prescription on hospital discharge was more common for those treated in a mixed ED (81.0% v 95.7%; P = 0.01). Ipratropium bromide (IB) was widely used at both types of ED but more commonly used in mixed EDs (41.7% vs 54.9%; P < 0.01). There were no differences in length-of-stay, representation rate within one month and oral steroid use for attack. Less than 2/3 of children with mild asthma attacks received steroid treatment in the ED. Treatment was similar between the two types of ED. IB was overused in mild asthma and oral steroids were underused in moderate asthma, by both ED types. Spacers were under-utilized in mixed EDs. [ABSTRACT FROM AUTHOR]

We have measured the electrical resistivity, magnetoresistance and Hall effect on several new single-crystal samples and one polycrystalline sample of α-U. The residual resistivity ratios of these samples vary from 13 to 315. Matthiessen's law appears to hold above the onset of the charge-density wave phase transitions that begin near 43 K, but not below this temperature. Sharp features at all three charge-density wave transitions are observed and the effects of high magnetic fields on them are presented and discussed. The magnetoresistance is anisotropic, reaches 1000% at 2 K and 18 T and does not exhibit Kohler scaling. The Hall coefficient is positive, independent of magnetic field and slightly temperature dependent above about 40 K in agreement with earlier studies. Below 40 K the Hall coefficient changes sign as the temperature falls, varies with field and becomes much more strongly negative at the lowest temperatures than has been reported. Some of our results suggest that a spin-density wave may coexist with the charge-density wave states. Superconductivity is observed in two of our samples; we argue that it is intrinsic to α-U and suggest that it is consistent with a two-band model. Several parameters characterizing the transport and superconductivity of α-U are estimated. [ABSTRACT FROM AUTHOR]

Focuses on a study which described the results of a systematic treatment program designed to modify renal and cardiovascular disease in an aboriginal community. Methodology; Results; Conclusion.

Abstract: UPt3 exhibits anomalous, possibly time-fluctuating antiferromagnetic (AFM) order below 6K. Th substitution induces conventional AFM order with the same magnetic structure. Recent μSR studies on U1− x Th x Pt3 for showed that the transition into the conventional AFM state was sharp for , but broadened for (Phys. Rev. B 84 (2003) 224421), indicative of a crossover behavior. We present X-ray diffraction and transmission electron microscopy (TEM) results that show no significant material inhomogeneity in those samples. However, specific heat measurements corroborate the μSR measurements and show signs of an increase near 7K for . This supports the conjecture that Th impurities slow down the fluctuating AFM, rendering them observable on the timescale of thermodynamic measurements. [Copyright &y& Elsevier]