2,057 research outputs found

    On inversions and Doob hh-transforms of linear diffusions

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    Let XX be a regular linear diffusion whose state space is an open interval ERE\subseteq\mathbb{R}. We consider a diffusion XX^* which probability law is obtained as a Doob hh-transform of the law of XX, where hh is a positive harmonic function for the infinitesimal generator of XX on EE. This is the dual of XX with respect to h(x)m(dx)h(x)m(dx) where m(dx)m(dx) is the speed measure of XX. Examples include the case where XX^* is XX conditioned to stay above some fixed level. We provide a construction of XX^* as a deterministic inversion of XX, time changed with some random clock. The study involves the construction of some inversions which generalize the Euclidean inversions. Brownian motion with drift and Bessel processes are considered in details.Comment: 19 page

    Kick Scooter Injuries in Children and Adolescents : Minor Fractures and Bruise

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    Background: Kick scooters are popular among children in both transportation and recreational activities. The aim of this retrospective study was to assess the incidence of and injury patterns associated with kick scooter accidents in school-aged children and adolescents. Methods: All 171 patients at the age of 7-15 years who were treated for kick scooter-related injuries in the metropolitan Helsinki area, Southern Finland from January 2008 to December 2013 were included. Electronic medical records were reviewed and Pediatric Trauma Scores and Injury Severity Scores were utilized to assess the injuries. Results: The annual number of patients increased from 7 in 2008 to 55 in 2013. Almost all patients (94%, n = 161) were injured after a fall from their own height. Most patients (n = 118; 69%) were diagnosed with a fracture but only 26 patients (15%) required surgical procedures under general anesthesia. Pediatric Trauma Scores were low and only one patient had an Injury Severity Score > 15 which can be considered major trauma. Conclusion: Most injuries acquired from kick scooter injuries were easily treatable fractures and bruises. Considering the background population of 105,000 in the respective age group and the 6-year period of data collection from tertiary care, scooting seems a safe means of increasing the physical activity levels of school-aged children and adolescents.Peer reviewe

    ABBA regulates plasma-membrane and actin dynamics to promote radial glia extension

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    Radial glia play key roles in neuronal migration, axon guidance, and neurogenesis during development of the central nervous system. However, the molecular mechanisms regulating growth and morphology of these extended cells are unknown. We show that ABBA, a novel member of the IRSp53-MIM protein family, is enriched in different types of radial glia. ABBA binds ATP-actin monomers with high affinity and deforms PtdIns(4,5)P2-rich membranes in vitro through its WH2 and IM domains, respectively. In radial-glia-like C6-R cells, ABBA localises to the interface between the actin cytoskeleton and plasma membrane, and its depletion by RNAi led to defects in lamellipodial dynamics and process extension. Together, this study identifies ABBA as a novel regulator of actin and plasma membrane dynamics in radial glial cells, and provides evidence that membrane binding and deformation activity is critical for the cellular functions of IRSp53-MIM-ABBA family proteins

    Travertine precipitation in the Paleoproterozoic Kuetsjärvi Sedimentary Formation, Pechenga Greenstone Belt, NE Fennoscandian Shield

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    PES was supported by Väisälä Foundation (Finnish Academy of Science and Letters) and the Finnish Doctoral Program in Geology. ATB was supported by NERC grant NE/G00398X/1. VAM was supported by NFR grant 191530/V30 (projects 331000 and 802795). This is a contribution (paper) # 18 to the ICDP FAR-DEEP project.Peer reviewedPublisher PD

    Prediction of neo-adjuvant chemotherapy response in bladder cancer : the impact of clinical parameters and routine biomarkers

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    Purpose To investigate the role of clinical parameters and immunohistochemical (IHC) biomarkers in their feasibility to predict the effect of neo-adjuvant chemotherapy (NAC) in patients with muscle-invasive urothelial bladder cancer (MIBC). Materials and methods The first 76 consecutive patients with MIBC treated with NAC and radical cystectomy in two University hospitals in Finland between 2008 and 2013 were chosen for this study. After excluding patients with non-urothelial cancer, less than two cycles of chemotherapy, no tissue material for IHC analysis or non-muscle-invasive bladder cancer in re-review, 59 patients were included in the final analysis. A tissue microarray block was constructed from the transurethral resection samples and IHC stainings of Ki-67, p53, Her-2 and EGFR were made. The correlations between histological features in transurethral resection samples and immune-histochemical stainings were calculated. The associations of clinicopathological parameters and IHC stainings with NAC response were evaluated. Factors affecting survival were estimated. Results The complete response rate after NAC was 44%. A higher number of chemotherapy cycles was associated with better response to neo-adjuvant chemotherapy. No response to neo-adjuvant chemotherapy and female gender was associated with decreased cancer-specific survival. The IHC stainings used failed to show an association with neo-adjuvant chemotherapy response and overall or cancer specific survival. Conclusions Patients who do not respond to neo-adjuvant chemotherapy do significantly worse than responders. This study could not find clinical tools to distinguish responders from non-responders. Further studies preferably with larger cohorts addressing this issue are warranted to improve the selection of patients for neo-adjuvant chemotherapy.Peer reviewe

    Evolution of defences in large tropical plant genera: perspectives for exploring insect diversity in a tri-trophic context

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    Divergence and escalation in defences promote chemical diversity in plants, and consequently the diversity of insect herbivores. This diversification cascades to insect parasitoids through direct effects on host herbivore susceptibility, changes in herbivore community composition, or disparity in plant volatiles. Large tropical plant genera represent an ideal model for studying these trends due to the high diversity of sympatric species and their insects. Novel measures of chemical structural similarity should be used to analyse evolutionary trends in both direct and indirect defences. Host chemical data need to be combined with detailed herbivore and parasitoid data. This will help to identify truly active compounds. Furthermore, resolved genomic phylogenies for plants and insects should be included to assign directionality in the processes

    Topological organization of whole-brain white matter in HIV infection

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    Infection with human immunodeficiency virus (HIV) is associated with neuroimaging alterations. However, little is known about the topological organization of whole-brain networks and the corresponding association with cognition. As such, we examined structural whole-brain white matter connectivity patterns and cognitive performance in 29 HIV+ young adults (mean age = 25.9) with limited or no HIV treatment history. HIV+ participants and demographically similar HIV− controls (n = 16) residing in South Africa underwent magnetic resonance imaging (MRI) and neuropsychological testing. Structural network models were constructed using diffusion MRI-based multifiber tractography and T(1)-weighted MRI-based regional gray matter segmentation. Global network measures included whole-brain structural integration, connection strength, and structural segregation. Cognition was measured using a neuropsychological global deficit score (GDS) as well as individual cognitive domains. Results revealed that HIV+ participants exhibited significant disruptions to whole-brain networks, characterized by weaker structural integration (characteristic path length and efficiency), connection strength, and structural segregation (clustering coefficient) than HIV− controls (p < 0.05). GDSs and performance on learning/recall tasks were negatively correlated with the clustering coefficient (p < 0.05) in HIV+ participants. Results from this study indicate disruption to brain network integrity in treatment-limited HIV+ young adults with corresponding abnormalities in cognitive performance

    Long-Term Survival and Quality of Life After Hypothermic Circulatory Arrest in Aortic Surgery

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    Background and Aims: Hypothermic circulatory arrest carries a high risk of mortality and neurological complications. An important part of assessing surgical treatment is the evaluation of long-term survival and postoperative health-related quality of life. Material and Methods: In this prospective study, 30 patients undergoing hypothermic circulatory arrest during surgery of the thoracic aorta, and 31 comparison patients undergoing elective coronary artery surgery without hypothermic circulatory arrest were evaluated for long-term survival and health-related quality of life, using the RAND 36-Item Health Survey questionnaire. The results were compared to national age- and sex-matched reference populations of the chronically ill and healthy adults. Results: After 4.6-8.0 years, available study (88%) and comparison (59%) patients were interviewed. The life expectancy was similar with 4- and 8-year survival of 90%, and 87% for the study group, and 94%, and 94% for the comparison group, respectively (log rank test, p = 0.62). The RAND-36 scores for study and comparison groups were congruent in all dimensions, describing physical, mental, and social domains. The study patients' health-related quality of life results were similar to the national reference population with chronic illnesses. Conclusion: After hypothermic circulatory arrest, patients undergoing surgery of the thoracic aorta achieve a similar long-term life expectancy and health-related quality of life as do patients undergoing coronary surgery without hypothermic circulatory arrest, and a health-related quality of life similar to the national reference population with chronic illnesses. These results justify operative treatment in this high-risk patient population.Peer reviewe
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