1,721,157 research outputs found
PET radiotracers for molecular imaging in dementia
No full textMolecular imaging with various biomarkers plays a significant role in the diagnostic assessment of patients with dementing disorders, by detecting functional and pathophysiologic changes in the brain. PET imaging, in particular, allows the measurements of different molecular targets, such as functional markers of neurodegeneration (glucose metabolism), markers for pathological aggregates (such as amyloid, tau and synuclein aggregates) and neuroinflammation, and also markers of several neurotransmission systems. In the current view, neurodegenerative diseases are associated with the development of pathologic changes that play a different role in disease onset and evolution, often starting long before the onset of clinically detectable impairment. Molecular imaging represents thus a unique tool to collect relevant information contributing to accurate diagnosis, treatment and response monitoring. In this article, we review the current literature focusing on the PET radiotracers used for molecular imaging in dementia
Biological effects of anti-CD34-coated ePTFE vascular grafts. Early in vivo experimental results
No full textTo assess the biological activity of anti-CD34 antibody-coated ePTFE vascular prostheses
Structural Basis of Bone Fragility in Young Subjects with Inflammatory Bowel Disease: A High-resolution pQCT Study of the SWISS IBD Cohort (SIBDC)
No full textBackground: The onset of inflammatory bowel disease (IBD) during childhood/adolescence compromises peak bone mass acquisition and predisposes to fractures later in life. However, the structural basis for bone fragility in young adults with IBD remains unknown.
Methods: One hundred two young subjects from the Swiss IBD cohort were included. Areal bone mineral density (aBMD) at distal radius, hip, and spine as well as morphometric vertebral fractures were assessed using dual-energy x-ray absorptiometry technique. Volumetric (v)BMD, trabecular, and cortical bone microstructure at the distal radius and tibia were assessed by high-resolution peripheral quantitative computed tomography. Areal, vBMD, and microstructure were compared between patients with IBD and healthy matched controls (n 1⁄4 389). Multiple regression analysis was used to evaluate variables associated with bone microarchitecture and fractures.
Results: Clinical fractures were reported in 37 IBD subjects (mean age 23 yrs), mostly of the forearm; 5 subjects had morphometric vertebral fractures. After adjusting for age, sex, and height, tibia trabecular (Tb)vBMD, thickness, and distribution were significantly associated with fractures, whereas aBMD was not. After adjusting for aBMD, radius Tb distribution and tibia (Tb)vBMD and trabecular thickness still remained associated with fractures. Compared with healthy controls, patients with IBD had significantly lower aBMD at all sites, as well as alteration in (Tb)vBMD and trabecular microstructure at the distal radius and tibia, and these alterations were correlated with disease severity.
Conclusions: Young patients with IBD have low aBMD and altered trabecular bone microarchitecture compared with healthy controls. The latter is independently associated with fractures and may predispose increased susceptibility to fragility fractures throughout life
Structured reporting : a fusion reactor hungry for fuel
Full text linkAnalysis of a serum sample, and whole blood on citrate and EDTA. We compare the results to those of December 20th. We observe a slight rise in blood glucose level, but the value is still within normal limits. Erythrocytes sedimentate at a rather fair rate of 25 millimetres per hour, which can be considered just mildly abnormal, taking into account the patient’s gender and age. We notice serum creatinine is 140 micromoles per litre, which corresponds, according to Cockroft-Gault, to a creatinine clearance of 67 millilitres per minute. The other chemical constituents and haematological evaluations are unremarkable, except for a rise in the number of neutrophils, which has tripled in comparison with the last examination.
Impression
Biochemically, we see little evolution in this slightly overweight, middle-aged patient with a history of arterial hypertension, but there is a possible suspicion of an acute infection. These results need to be correlated to the clinical presentation.
Does this report look familiar? It is unlikely that you have ever received a similar one from your clinical biochemist. Results of biochemical and haematological tests are nearly always presented in a neat, tabular format, with some space for results that cannot be quantified, and for expert comment. In addition, many hospital information systems allow referring clinicians to represent consecutive results graphically, which can help to improve insight into the course of the disease
Going Beyond Counting First Authors in Author Co-citation Analysis
Full text linkThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
PET/CT trois phases à la 18F-fluorocholine dans l'évaluation de la récidive du cancer de la prostate
No full textLe cancer de la prostate est la néoplasie maligne se développant le plus souvent chez l'homme de plus de 50 ans. Souvent asymptomatique il est découvert lors de l'analyse sanguine du PSA ("Prostatic Specific Antigen") dont le taux est essentiel pour le suivi des cancers déclarés. Ce travail décrit un nouveau protocole PET/CT à la 18F-fluorocholine utilisé pour l'acquisition d'une imagerie en 3 temps qui a permis de poser le diagnostic de récidive même en cas de faible PSA (<2ng/ml) après épreuve histopathologique (gold standard) des critères d'interprétations. Ce protocole noua a permis également d'éviter les prinicipaux pièges d'interprétation comme l'activité urinaire ou sanguine. Il décrit également comment ces critères d'interprétation peuvent être appliqués à l'analyse des ganglions métastatiques. Un accent est mis sur la place grandissante du PET/CT à la 18F-fluorocholine dans le bilan et la prise en charge de la récidive du cancer de la prostate, dont le diagnostic précoce permet de choisir le traitement le plus adéquat
Variations on the Author
Full text link“Variations on the Author” discusses two of Eduardo Coutinho’s recent films (Um Dia na Vida, from 2010, and Últimas Conversas, posthumously released in 2015) and their contribution to the general question of documentary authorship. The director’s filmography is characterized by a consistent yet self-effacing form of authorial self-inscription: Coutinho often features as an interviewer that rather than express opinions propels discourses; an interviewer that is good at listening. This mode of self-inscription characterizes him as an author who is not expressive but who is nonetheless markedly present on the screen. In Um Dia na Vida, however, Coutinho is completely absent form the image, while Últimas Conversas, on the contrary, includes a confessional prologue that moves the director from the margins to the center of his films. This article examines the ways in which these works stand out in the filmography of a director who offers new insights into the notion of cinematic authorship
Appropriate Similarity Measures for Author Cocitation Analysis
Full text linkWe provide a number of new insights into the methodological discussion about author cocitation analysis. We first argue that the use of the Pearson correlation for measuring the similarity between authors’ cocitation profiles is not very satisfactory. We then discuss what kind of similarity measures may be used as an alternative to the Pearson correlation. We consider three similarity measures in particular. One is the well-known cosine. The other two similarity measures have not been used before in the bibliometric literature. Finally, we show by means of an example that our findings have a high practical relevance.information science;Pearson correlation;cosine;similarity measure;author cocitation analysis
Development of the Thin TOF-PET scanner based on fast timing monolithic silicon pixel sensors
No full textThe Thin-TOF PET (TT-PET) project aims at the construction of a small-animal PET scanner based on monolithic silicon pixel sensors. The iterative image reconstruction was developed using a maximum a posteriori probability estimation algorithm. Reconstructed images from Monte-Carlo data show high signal-to-noise ratio with unprecedented spatial resolution. The detector ASICs were designed with the support of a Technology CAD simulation framework. A measurement setup based on a 22Na radioactive source showed that the single layer detection efficiency of the demonstrator chip is approximately 0.19%, which is in good agreement with the simulations. The same setup was used to measure the time resolution, that resulted to be 70ps (RMS). This result, although excellent for a silicon sensor, is a factor two below the specification of the TT-PET project. It is created by a systematic error in the measurement of the charge that will be corrected in future chips
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