46 research outputs found

    Aboveground biomass density models for NASA's Global Ecosystem Dynamics Investigation (GEDI) lidar mission

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    NASA's Global Ecosystem Dynamics Investigation (GEDI) is collecting spaceborne full waveform lidar data with a primary science goal of producing accurate estimates of forest aboveground biomass density (AGBD). This paper presents the development of the models used to create GEDI's footprint-level (similar to 25 m) AGBD (GEDI04_A) product, including a description of the datasets used and the procedure for final model selection. The data used to fit our models are from a compilation of globally distributed spatially and temporally coincident field and airborne lidar datasets, whereby we simulated GEDI-like waveforms from airborne lidar to build a calibration database. We used this database to expand the geographic extent of past waveform lidar studies, and divided the globe into four broad strata by Plant Functional Type (PFT) and six geographic regions. GEDI's waveform-to-biomass models take the form of parametric Ordinary Least Squares (OLS) models with simulated Relative Height (RH) metrics as predictor variables. From an exhaustive set of candidate models, we selected the best input predictor variables, and data transformations for each geographic stratum in the GEDI domain to produce a set of comprehensive predictive footprint-level models. We found that model selection frequently favored combinations of RH metrics at the 98th, 90th, 50th, and 10th height above ground-level percentiles (RH98, RH90, RH50, and RH10, respectively), but that inclusion of lower RH metrics (e.g. RH10) did not markedly improve model performance. Second, forced inclusion of RH98 in all models was important and did not degrade model performance, and the best performing models were parsimonious, typically having only 1-3 predictors. Third, stratification by geographic domain (PFT, geographic region) improved model performance in comparison to global models without stratification. Fourth, for the vast majority of strata, the best performing models were fit using square root transformation of field AGBD and/or height metrics. There was considerable variability in model performance across geographic strata, and areas with sparse training data and/or high AGBD values had the poorest performance. These models are used to produce global predictions of AGBD, but will be improved in the future as more and better training data become available

    Mouse mesenchymal stem cells inhibit high endothelial cell activation and lymphocyte homing to lymph nodes by releasing TIMP-1.

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    Mesenchymal stem cells (MSC) represent a promising therapeutic approach in many diseases in view of their potent immunomodulatory properties, which are only partially understood. Here, we show that the endothelium is a specific and key target of MSC during immunity and inflammation. In mice, MSC inhibit activation and proliferation of endothelial cells in remote inflamed lymph nodes (LNs), affect elongation and arborization of high endothelial venules (HEVs) and inhibit T-cell homing. The proteomic analysis of the MSC secretome identified the tissue inhibitor of metalloproteinase-1 (TIMP-1) as a potential effector molecule responsible for the anti-angiogenic properties of MSC. Both in vitro and in vivo, TIMP-1 activity is responsible for the anti-angiogenic effects of MSC, and increasing TIMP-1 concentrations delivered by an Adeno Associated Virus (AAV) vector recapitulates the effects of MSC transplantation on draining LNs. Thus, this study discovers a new and highly efficient general mechanism through which MSC tune down immunity and inflammation, identifies TIMP-1 as a novel biomarker of MSC-based therapy and opens the gate to new therapeutic approaches of inflammatory diseases

    Aboveground biomass density models for NASA's Global Ecosystem Dynamics Investigation (GEDI) lidar mission

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    NASA's Global Ecosystem Dynamics Investigation (GEDI) is collecting spaceborne full waveform lidar data with a primary science goal of producing accurate estimates of forest aboveground biomass density (AGBD). This paper presents the development of the models used to create GEDI's footprint-level (~25 m) AGBD (GEDI04_A) product, including a description of the datasets used and the procedure for final model selection. The data used to fit our models are from a compilation of globally distributed spatially and temporally coincident field and airborne lidar datasets, whereby we simulated GEDI-like waveforms from airborne lidar to build a calibration database. We used this database to expand the geographic extent of past waveform lidar studies, and divided the globe into four broad strata by Plant Functional Type (PFT) and six geographic regions. GEDI's waveform-to-biomass models take the form of parametric Ordinary Least Squares (OLS) models with simulated Relative Height (RH) metrics as predictor variables. From an exhaustive set of candidate models, we selected the best input predictor variables, and data transformations for each geographic stratum in the GEDI domain to produce a set of comprehensive predictive footprint-level models. We found that model selection frequently favored combinations of RH metrics at the 98th, 90th, 50th, and 10th height above ground-level percentiles (RH98, RH90, RH50, and RH10, respectively), but that inclusion of lower RH metrics (e.g. RH10) did not markedly improve model performance. Second, forced inclusion of RH98 in all models was important and did not degrade model performance, and the best performing models were parsimonious, typically having only 1-3 predictors. Third, stratification by geographic domain (PFT, geographic region) improved model performance in comparison to global models without stratification. Fourth, for the vast majority of strata, the best performing models were fit using square root transformation of field AGBD and/or height metrics. There was considerable variability in model performance across geographic strata, and areas with sparse training data and/or high AGBD values had the poorest performance. These models are used to produce global predictions of AGBD, but will be improved in the future as more and better training data become available

    Lipschütz's acute vulvar ulcer: a systematic review.

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    In previously healthy subjects, vulvar ulcers are mostly caused by sexually transmitted microorganisms. Lipschütz's acute vulvar ulceration, first reported in 1912, is a non-sexually acquired condition characterized by sudden onset of a few genital ulcers. We systematically review presentation, underlying causes, and disease duration of Lipschütz's ulceration. A comprehensive source of Excerpta Medica, National Library of Medicine, and Web of Science databases was performed. Reports including cases of apparently previously healthy females affected by Lipschütz's ulceration were selected. A predefined database was used to extract data on demographics, history, clinical and microbiological findings, and treatment.The search disclosed 158 cases. Almost 90% of cases were ≤ 20 years of age and sexually inactive. Lesions were usually one to about three, painful, ≥ 10 mm large, well-delimited, with a fibrinous and necrotic center and a symmetric distribution. Voiding disorders and enlarged inguinal lymph nodes were observed in a large subset of cases. Canker sores were noted in 10% of patients. Lipschütz's vulvar ulceration occurred concomitantly with an infectious disease in 139 cases. Infectious mononucleosis syndrome (N = 40) was the most frequently detected well-defined infection, followed by mycoplasma species infections (N = 11). The disease resolved after ≤ 3 weeks.Conclusions: Lipschütz's ulceration mainly affects both sexually inactive and, less frequently, sexually active subjects ≤ 20 years of age, presents with ≤ 3 vulvar ulcers, resolves without recurrences within 3 weeks and is temporarily associated with an infection, most frequently a flu-like illness or an infectious mononucleosis syndrome. What is Known: • Lipschütz's acute vulvar ulceration is a non-sexually acquired condition, which is characterized by a sudden onset of a few necrotic and painful genital ulcers. • The condition tends to resolve spontaneously and is usually triggered by an infection. What is New: • The condition mainly affects subjects ≤ 20 years of age, tends to resolve within 3 weeks, and is usually temporarily associated with a flu-like illness or an infectious mononucleosis syndrome. • Systemic corticosteroids do not reduce disease duration

    Lipschütz’s acute vulvar ulcer : a systematic review

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    In previously healthy subjects, vulvar ulcers are mostly caused by sexually transmitted microorganisms. Lipsch\ufctz\u2019s acute vulvar ulceration, first reported in 1912, is a non-sexually acquired condition characterized by sudden onset of a few genital ulcers. We systematically review presentation, underlying causes, and disease duration of Lipsch\ufctz\u2019s ulceration. A comprehensive source of Excerpta Medica, National Library of Medicine, and Web of Science databases was performed. Reports including cases of apparently previously healthy females affected by Lipsch\ufctz\u2019s ulceration were selected. A predefined database was used to extract data on demographics, history, clinical and microbiological findings, and treatment. The search disclosed 158 cases. Almost 90% of cases were 64 20 years of age and sexually inactive. Lesions were usually one to about three, painful, 65 10 mm large, well-delimited, with a fibrinous and necrotic center and a symmetric distribution. Voiding disorders and enlarged inguinal lymph nodes were observed in a large subset of cases. Canker sores were noted in 10% of patients. Lipsch\ufctz\u2019s vulvar ulceration occurred concomitantly with an infectious disease in 139 cases. Infectious mononucleosis syndrome (N = 40) was the most frequently detected well-defined infection, followed by mycoplasma species infections (N = 11). The disease resolved after 64 3 weeks. Conclusions: Lipsch\ufctz\u2019s ulceration mainly affects both sexually inactive and, less frequently, sexually active subjects 64 20 years of age, presents with 64 3 vulvar ulcers, resolves without recurrences within 3 weeks and is temporarily associated with an infection, most frequently a flu-like illness or an infectious mononucleosis syndrome.What is Known: \u2022 Lipsch\ufctz\u2019s acute vulvar ulceration is a non-sexually acquired condition, which is characterized by a sudden onset of a few necrotic and painful genital ulcers. \u2022 The condition tends to resolve spontaneously and is usually triggered by an infection.What is New: \u2022 The condition mainly affects subjects 64 20 years of age, tends to resolve within 3 weeks, and is usually temporarily associated with a flu-like illness or an infectious mononucleosis syndrome. \u2022 Systemic corticosteroids do not reduce disease duration

    Expression of interleukin-8 gene in inflammatory bowel disease is related to the histological grade of active inflammation.

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    Interleukin-8 (IL-8) is a potent cytokine for recruitment and activation of neutrophils. To visualize its distribution in the intestinal mucosa and to understand better its possible role in the induction and promotion of inflammatory bowel disease, expression of the IL-8 gene was analyzed in resected bowel segments of 14 patients with active Crohn's disease or ulcerative colitis. In situ hybridization with IL-8 anti-sense RNA probes revealed strong and specific signals in the histologically affected mucosa. The number of cells expressing IL-8 gene correlated with the histological grade of active inflammation. In accordance with the characteristic histological signs of active disease, IL-8-expressing cells were diffusely distributed over the entire affected mucosa in patients with ulcerative colitis, whereas in patients with Crohn's disease, IL-8-expressing cells showed a focal distribution pattern. Cells expressing IL-8 were mainly located at the base of ulcers, in inflammatory exudates on mucosal surfaces, in crypt abscesses, and at the border of fistulae. Analysis of semi-serial sections pointed to macrophages, neutrophils, and epithelial cells as possible sources of this cytokine in active inflammatory bowel disease. We consistently failed to detect IL-8 messenger RNA in the mucosa of uninvolved bowel segments and in normal-appearing control mucosa of patients with colon cancer. In contrast, tissue specimens from two patients with acute appendicitis displayed IL-8-expressing cells in the mucosa. These results support the notion that IL-8 plays and important but nonspecific role in the pathogenesis of inflammatory bowel disease and that the production of IL-8 messenger RNA is restricted to areas with histological signs of inflammatory activity and mucosal destruction
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