25 research outputs found

    Experimental progress in positronium laser physics

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    Pervasive gaps in Amazonian ecological research

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    Biodiversity loss is one of the main challenges of our time, and attempts to address it require a clear understanding of how ecological communities respond to environmental change across time and space. While the increasing availability of global databases on ecological communities has advanced our knowledge of biodiversity sensitivity to environmental changes, vast areas of the tropics remain understudied. In the American tropics, Amazonia stands out as the world's most diverse rainforest and the primary source of Neotropical biodiversity, but it remains among the least known forests in America and is often underrepresented in biodiversity databases. To worsen this situation, human-induced modifications may eliminate pieces of the Amazon's biodiversity puzzle before we can use them to understand how ecological communities are responding. To increase generalization and applicability of biodiversity knowledge, it is thus crucial to reduce biases in ecological research, particularly in regions projected to face the most pronounced environmental changes. We integrate ecological community metadata of 7,694 sampling sites for multiple organism groups in a machine learning model framework to map the research probability across the Brazilian Amazonia, while identifying the region's vulnerability to environmental change. 15%–18% of the most neglected areas in ecological research are expected to experience severe climate or land use changes by 2050. This means that unless we take immediate action, we will not be able to establish their current status, much less monitor how it is changing and what is being lost

    Water-soluble silicon nanocrystals as NIR luminescent probes for time-gated biomedical imaging

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    Luminescent probes based on silicon nanocrystals (SiNCs) have many advantages for bioimaging compared to more conventional quantum dots: abundancy of silicon combined with its biocompatibility; tunability of the emission color of SiNCs in the red and NIR spectral region to gain deeper tissue penetration; long emission lifetimes of SiNCs (hundreds of \u3bcs) enabling time-gated acquisitions to avoid background noise caused by tissue autofluorescence and scattered excitation light. Here we report a new three-step synthesis, based on a low temperature thiol-ene click reaction that can afford SiNCs, colloidally stable in water, with preserved bright red and NIR photoluminescence (band maxima at 735 and 945 nm for nanocrystals with diameters of 4 and 5 nm, respectively) and long emission lifetimes. Their luminescence is insensitive to dioxygen and sensitive to pH changes in the physiological range, enabling pH sensing. In vivo studies demonstrated tumor accumulation, 48 hours clearance and a 3-fold improvement of the signal-to-noise ratio compared to steady-state imaging

    The intensive care delirium research agenda:a multinational, interprofessional perspective

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    Delirium, a prevalent organ dysfunction in critically ill patients, is independently associated with increased morbidity. This last decade has witnessed an exponential growth in delirium research in hospitalized patients, including those critically ill, and this research has highlighted that delirium needs to be better understood mechanistically to help foster research that will ultimately lead to its prevention and treatment. In this invited, evidence-based paper, a multinational and interprofessional group of clinicians and researchers from within the fields of critical care medicine, psychiatry, pediatrics, anesthesiology, geriatrics, surgery, neurology, nursing, pharmacy, and the neurosciences sought to address five questions: (1) What is the current standard of care in managing ICU delirium? (2) What have been the major recent advances in delirium research and care? (3) What are the common delirium beliefs that have been challenged by recent trials? (4) What are the remaining areas of uncertainty in delirium research? (5) What are some of the top study areas/trials to be done in the next 10 years? Herein, we briefly review the epidemiology of delirium, the current best practices for management of critically ill patients at risk for delirium or experiencing delirium, identify recent advances in our understanding of delirium as well as gaps in knowledge, and discuss research opportunities and barriers to implementation, with the goal of promoting an integrated research agenda
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