1,028 research outputs found

    Antegrade pressure measurement as a diagnostic tool in modern pediatric urology

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    The antegrade pressure measurement (APM) or perfusion pressure-flow test (Whitaker test) is a method of antegrade measurement of pressure in the upper urinary tract. In this study, we present the long-term follow-up results of APMs performed in our institution in the late 1980s and early 1990s to see whether the diagnostic decisions that were based on the outcomes of the test prove to be correct in the long term. We conducted a retrospective study by searching our hospital's electronic database. We found a total of 16 APMs performed between 1987 and 1995 (10 boys, six girls; mean age 61 months). In nine cases, action was undertaken immediately after the APM had been performed; in seven cases, this was a surgical procedure (re-implantation/re-calibration or pyeloplasty) after obstruction was demonstrated. In two cases (both postoperative after previous pyeloplasty), absence of obstruction was demonstrated and nephrostomy tubes were subsequently closed. In one case, this resulted in hydronephrosis that had to be treated with a new JJ stent. In all the seven cases in which no action was deemed necessary as a result of the outcome of the APM, long-term follow-up showed that intervention had indeed not been necessary. Although not often used anymore, the APM seems to be a safe and valuable diagnostic tool in the work up for possible urinary tract obstruction in children, especially in cases in which there is serious doubt concerning conservative watchful waitin

    The value of subtraction MRI in detection of amyloid-related imaging abnormalities with oedema or effusion in Alzheimer's patients: An interobserver study

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    BACKGROUND: Immunotherapeutic treatments targeting amyloid-β plaques in Alzheimer's disease (AD) are associated with the presence of amyloid-related imaging abnormalities with oedema or effusion (ARIA-E), whose detection and classification is crucial to evaluate subjects enrolled in clinical trials. PURPOSE: To investigate the applicability of subtraction MRI in the ARIA-E detection using an established ARIA-E-rating scale. METHODS: We included 75 AD patients receiving bapineuzumab treatment, including 29 ARIA-E cases. Five neuroradiologists rated their brain MRI-scans with and without subtraction images. The accuracy of evaluating the presence of ARIA-E, intraclass correlation coefficient (ICC) and specific agreement was calculated. RESULTS: Subtraction resulted in higher sensitivity (0.966) and lower specificity (0.970) than native images (0.959, 0.991, respectively). Individual rater detection was excellent. ICC scores ranged from excellent to good, except for gyral swelling (moderate). Excellent negative and good positive specific agreement among all ARIA-E imaging features was reported in both groups. Combining sulcal hyperintensity and gyral swelling significantly increased positive agreement for subtraction images. CONCLUSION: Subtraction MRI has potential as a visual aid increasing the sensitivity of ARIA-E assessment. However, in order to improve its usefulness isotropic acquisition and enhanced training are required. The ARIA-E rating scale may benefit from combining sulcal hyperintensity and swelling. KEY POINTS: • Subtraction technique can improve detection amyloid-related imaging-abnormalities with edema/effusion in Alzheimer's patients. • The value of ARIA-E detection, classification and monitoring using subtraction was assessed. • Validation of an established ARIA-E rating scale, recommendations for improvement are reported. • Complementary statistical methods were employed to measure accuracy, inter-rater-reliability and specific agreement

    Sampling of An.gambiae s.s mosquitoes using Limburger cheese, heat and moisture as baits in a homemade trap

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    <p>Abstract</p> <p>Background</p> <p>Ample evidence has shown that odour baited traps are likely to provide an objective monitoring tool for the host-seeking fraction of mosquito vectors of diseases like malaria and bancroftian filariasis. Such traps could eventually become part of primary healthcare systems used to study the vector biology and epidemiology of mosquito-borne diseases. I hereby, report a study that sampled <it>Anopheles gambiae sensu stricto </it>mosquitoes in a screen house using a homemade trap baited with a combination of Limburger cheese and moisture, Limburger cheese and heat, or Limburger cheese, moisture and heat.</p> <p>Findings</p> <p>Tests on the efficacy of the developed trap to sample <it>An. gambiae s.s</it>, mosquitoes using Limburger cheese, moisture and heat as baits were carried out in a screen house measuring 11.4 × 7.1 × 2.8 m. The studies were done in three phases. In the first phase the efficacy of the trap to sample <it>An. gambiae s.s</it>. using odour and moisture was tested. The second phase was to test the efficacy of the trap to sample <it>An. gambiae s.s</it>. using Limburger cheese and heat. In the third phase a combination of Limburger cheese, moisture and heat was tested. Tests were carried out for 27 consecutive nights.</p> <p>The designed trap collected a total of 59 <it>An. gambiae s.s</it>. in three trials. The trap baited with Limburger cheese and moisture collected 7 <it>An. gambiae s.s </it>in 7 days. The mean catch per day was 1. The trap baited with Limburger cheese and heat collected zero <it>An. gambiae s.s </it>in 11 days. The mean catch per day was therefore 0. The trap baited with Limburger cheese, moisture and heat collected 52 mosquitoes in 27 days and the mean catch was 1.93.</p> <p>Conclusions</p> <p>This study indicates that a non-electric fan driven trap baited with a combination of Limburger cheese, heat and moisture has a potential as an effective sampling tool for the malaria vector, <it>Anopheles gambiae s.s</it>. However, further optimization studies would be necessary.</p

    Individuals with Fear of Blushing Explicitly and Automatically Associate Blushing with Social Costs

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    To explain fear of blushing, it has been proposed that individuals with fear of blushing overestimate the social costs of their blushing. Current information-processing models emphasize the relevance of differentiating between more automatic and more explicit cognitions, as both types of cognitions may independently influence behavior. The present study tested whether individuals with fear of blushing expect blushing to have more negative social consequences than controls, both on an explicit level and on a more automatic level. Automatic associations between blushing and social costs were assessed in a treatment-seeking sample of individuals with fear of blushing who met DSM-IV criteria for social anxiety disorder (n = 49) and a non-anxious control group (n = 27) using a single-target Implicit Association Test (stIAT). In addition, participants’ explicit expectations about the social costs of their blushing were assessed. Individuals with fear of blushing showed stronger associations between blushing and negative outcomes, as indicated by both stIAT and self-report. The findings support the view that automatic and explicit associations between blushing and social costs may both help to enhance our understanding of the cognitive processes that underlie fear of blushing

    Myocardial perfusion reserve and contractile pattern after beta-blocker therapy in patients with idiopathic dilated cardiomyopathy

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    In Idiopathic Dilated Cardiomyopathy (IDC) an imbalance between myocardial oxygen consumption and supply has been postulated. The ensuing subclinical myocardial ischemia may contribute to progressive deterioration of LV function. beta-blocker is the therapy of choice in these patients. However, not all patients respond to the same extent. The aim of this study was to elucidate whether differences between responders and non-responders can be identified with respect to regional myocardial perfusion reserve (MPR) and contractile performance. Patients with newly diagnosed IDC underwent Positron Emission Tomography (PET) scanning using both (13)N-ammonia as a perfusion tracer (baseline and dipyridamole stress), and (18)F-fluoro-deoxyglucose as a metabolism tracer, and a dobutamine stress MRI. MRI and PET were repeated 6 months after maximal beta-blocker therapy. MPR (assessed by PET) as well as wall motion score (WMS, assessed by MRI) were evaluated in a 17 segment-model. Functional response to beta-blocker therapy was assigned as a stable or improved LVEF or diminished LVEF. Sixteen patients were included (age 47.9 +/- A 11.5 years; 12 males, LVEF 28.6 +/- A 8.4%). Seven patients showed improved LVEF (9.7 +/- A 3.1%), and nine patients did not show improved LVEF (-3.4 +/- A 3.9%). MPR improved significantly in responders (1.56 +/- A .23 to 1.93 +/- A .49, P = .049), and MPR decreased in non-responders; however, not significantly (1.98 +/- A .70 to 1.61 +/- A .28, P = .064), but was significantly different between both groups (P = .017) after beta-blocker therapy. A significant correlation was found between change in perfusion reserve and change in LVEF: a decrease in perfusion reserve was associated with a decrease in LVEF and vice versa. Summed rest score of wall motion in responders improved from 26 to 21 (P = .022) whereas in non-responders no change was observed from 26 to 25) (P = ns). Summed stress score of wall motion in responders improved from 23 to 21 (P = .027) whereas in non-responders no change was observed from 27 to 26) (P = ns). In IDC patients, global as well as regional improvement after initiation of beta-blocker treatment is accompanied by an improvement in regional perfusion parameters. On the other hand in IDC patients with further left ventricular function deterioration after initiation of beta-blocker therapy this is accompanied by a decrease in perfusion reserve

    PET and MRI for the evaluation of regional myocardial perfusion and wall thickening after myocardial infarction

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    Deterioration of left ventricular (LV) function after myocardial infarction (MI) is a major cause of heart failure. Myocardial perfusion performance may play an important role in deterioration or improvement in LV function after MI. The aim of this study was to evaluate the myocardial perfusion reserve (MPR) and stress perfusion in deteriorating and non-deteriorating LV segments in patients after MI by PET and MRI, respectively. Regional wall thickening of 352 segments in 22 patients was assessed at 4 and 24 months after MI by cardiac MRI. PET was performed to evaluate MPR and adenosine stress N-13-ammonia perfusion 24 months after MI. Segments were divided into four groups according to deterioration or improvement in wall thickening. Normal functional segments at 4 months after MI that remained stable had a significantly higher mean MPR and mean stress perfusion PET value than deteriorated segments (p < 0.001). Furthermore, dysfunctional segments that improved had a significantly higher mean stress perfusion PET value than dysfunctional segments that remained dysfunctional (p < 0.001). This study demonstrated the additional value of myocardial perfusion assessment in relation to the functional integrity of the injured myocardium. Segmental functional LV improvement after MI was associated with better regional myocardial perfusion characteristics. Furthermore, the amount of wall thickening reduction was associated with regional myocardial perfusion abnormalities in patients after MI

    Loneliness, social support and cardiovascular reactivity to laboratory stress

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    Self-reported or explicit loneliness and social support have been inconsistently associated with cardiovascular reactivity (CVR) to stress. The present study aimed to adapt an implicit measure of loneliness, and use it alongside the measures of explicit loneliness and social support, to investigate their correlations with CVR to laboratory stress. Twenty-five female volunteers aged between 18 and 39 years completed self-reported measures of loneliness and social support, and an Implicit Association Test (IAT) of loneliness. The systolic blood pressure (SBP), diastolic blood pressure (DBP) and heart rate (HR) reactivity indices were measured in response to psychosocial stress induced in the laboratory. Functional support indices of social support were significantly correlated with CVR reactivity to stress. Interestingly, implicit, but not explicit, loneliness was significantly correlated with DBP reactivity after one of the stressors. No associations were found between structural support and CVR indices. Results are discussed in terms of validity of implicit versus explicit measures and possible factors that affect physiological outcomes

    The AFLOW Fleet for Materials Discovery

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    The traditional paradigm for materials discovery has been recently expanded to incorporate substantial data driven research. With the intent to accelerate the development and the deployment of new technologies, the AFLOW Fleet for computational materials design automates high-throughput first principles calculations, and provides tools for data verification and dissemination for a broad community of users. AFLOW incorporates different computational modules to robustly determine thermodynamic stability, electronic band structures, vibrational dispersions, thermo-mechanical properties and more. The AFLOW data repository is publicly accessible online at aflow.org, with more than 1.7 million materials entries and a panoply of queryable computed properties. Tools to programmatically search and process the data, as well as to perform online machine learning predictions, are also available.Comment: 14 pages, 8 figure

    ARPES: A probe of electronic correlations

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    Angle-resolved photoemission spectroscopy (ARPES) is one of the most direct methods of studying the electronic structure of solids. By measuring the kinetic energy and angular distribution of the electrons photoemitted from a sample illuminated with sufficiently high-energy radiation, one can gain information on both the energy and momentum of the electrons propagating inside a material. This is of vital importance in elucidating the connection between electronic, magnetic, and chemical structure of solids, in particular for those complex systems which cannot be appropriately described within the independent-particle picture. Among the various classes of complex systems, of great interest are the transition metal oxides, which have been at the center stage in condensed matter physics for the last four decades. Following a general introduction to the topic, we will lay the theoretical basis needed to understand the pivotal role of ARPES in the study of such systems. After a brief overview on the state-of-the-art capabilities of the technique, we will review some of the most interesting and relevant case studies of the novel physics revealed by ARPES in 3d-, 4d- and 5d-based oxides.Comment: Chapter to appear in "Strongly Correlated Systems: Experimental Techniques", edited by A. Avella and F. Mancini, Springer Series in Solid-State Sciences (2013). A high-resolution version can be found at: http://www.phas.ubc.ca/~quantmat/ARPES/PUBLICATIONS/Reviews/ARPES_Springer.pdf. arXiv admin note: text overlap with arXiv:cond-mat/0307085, arXiv:cond-mat/020850
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