65 research outputs found

    How can we model subsurface stormflow at the catchment scale if we cannot measure it?

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    Subsurface stormflow (SSF) can be a dominant run‐off generation process in humid mountainous catchments (e.g., Bachmair & Weiler, 2011; Blume & van Meerveld, 2015; Chifflard, Didszun, & Zepp, 2008). Generally, SSF develops in structured soils where bedrock or a less permeable soil layer is overlaid by a more permeable soil layer and vertically percolating water is deflected, at least partially, in a lateral downslope direction due to the slope inclination. SSF can also occur when groundwater levels rise into more permeable soil layers and water flows laterally through the more permeable layers to the stream (“transmissivity feedback mechanism”; Bishop, Grip, & O'Neill, 1990). The different existing terms for SSF in the hydrological literature such as shallow subsurface run‐off, interflow, lateral flow, or soil water flow reflects the different underlying process concepts developed in various experimental studies in different environments by using different experimental approaches at different spatial and temporal scales (Weiler, McDonnell, Tromp‐van Meerveld, & Uchida, 2005). Intersite comparisons and the extraction of general rules for SSF generation and its controlling factors are still lacking, which hampers the development of appropriate approaches for modelling SSF. But appropriate prediction of SSF is essential due to its clear influence on run‐off generation at the catchment scale (e.g., Chifflard et al., 2010; Zillgens, Merz, Kirnbauer, & Tilch, 2005), on the formation of floods (e.g., Markart et al., 2013, 2015) and on the transport of nutrients or pollutants from the hillslopes into surface water bodies (Zhao, Tang, Zhao, Wang, & Tang, 2013). However, a precise simulation of SSF in models requires an accurate process understanding including, knowledge about water pathways, residence times, magnitude of water fluxes, or the spatial origin of SSF within a given catchment because such factors determine the transport of subsurface water and solutes to the stream. But due to its occurrence in the subsurface and its spatial and temporal variability, determining and quantifying the processes generating SSF is a challenging task as they cannot be observed directly. Therefore, it is logical to ask whether we can really model SSF correctly if we cannot measure it well enough on the scale of interest (Figure 1). This commentary reflects critically on whether current experimental concepts and modelling approaches are sufficient to predict the contribution of SSF to the run‐off at the catchment scale. This applies in particular to the underlying processes, controlling factors, modelling approaches, research gaps, and innovative strategies to trace SSF across different scales

    Therapeutic anticoagulation complications in the elderly: a case report

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    Background: The demographic transition leads to a continuously growing number of elderly patients who receive therapeutic anticoagulation by reason of several comorbidities. Though therapeutic anticoagulation may reduce the number of embolic complications in these patients, major complications such as bleeding complications need to be kept in mind when considering such therapy. However, evidence regarding the choice of anticoagulation agents in chronic kidney disease patients of higher age is limited. In this report, a guideline-based anticoagulation treatment which led to a fulminant atraumatic bleeding complication is discussed. Case presentation: We present the case of an 85-year-old female stage V chronic kidney disease patient who suffered from a diffuse arterial, subcutaneous bleeding in her lower left leg due a therapeutic anticoagulation using low molecular weight heparin (LMWH). Anticoagulation was started in accordance with general recommendations for patients with atrial fibrillation, and the dosage was adapted for the patient's renal function. Nevertheless, the above-mentioned complication occurred, and the bleeding led to a hemorrhagic shock and an acute kidney injury on top of a chronic kidney disease. The hematoma required surgical evacuation and local coagulation in the operating room. In the further course, the patient underwent additional four surgical interventions due to a superinfected skin necrosis, including skin grafting. Furthermore, the patient needed continuous renal replacement therapy, as well as intensive care unit treatment, for a total of 47 days followed by 36 days of geriatric rehabilitation. Afterwards, she was discharged from the hospital to her previous nursing home. Discussion and conclusions: Although therapeutic anticoagulation may sufficiently protect patients at cardiovascular risk, major complications such as bleeding complications may occur at any time. Therefore, physicians need to regularly re-evaluate any prior indication for therapeutic anticoagulation. With this case report, we hope to draw attention to the cohort of geriatric patients and the need for more and well differentiated study settings to preferably prevent any potentially avoidable complications

    Status of the GEO 600 squeezed-light laser

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    In the course of the high-frequency upgrade of GEO 600, its optical configuration was extended by a squeezed-light laser [1]. Recently, a non-classically enhanced measurement sensitivity of GEO 600 was reported [2]. In this paper, a characterization of the squeezed-light laser is presented. Thereupon, the status of the integration into GEO 600 is reviewed, focussing on the sources of optical loss limiting the shot noise reduction by squeezing at the moment. Finally, the possibilities for a future loss reduction are discussed.Comment: Proceeding of the 9th Edoardo Amaldi Conference on Gravitational Wave

    O sistema agroindustrial do biodiesel no Paranå: o potencial do mercado fornecedor de matérias-primas vegetais e a participação da agricultura familiar

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    This article aims to analyze the market potential supplier of raw materials plant to produce biodiesel between 2003 and 2010, and verify the inclusion of family farming in the agroindustrial system of biodiesel in ParanĂĄ. The institutional environment consists of the National Program of Biodiesel Production and Use (PNPB) can support family farmers in Parana and increase the biodiesel production in the state to promote regional development by generating income, taxes and setting the man on field. In contrast state and local public policies must do your part and encourage the most varied raw materials for biodiesel production due to climate and soil diversity existing in Parana. This situation can only be auspicious if successful stimulation and integration between the public (federal, state and municipal) and private.Resumo: Este artigo tem por objetivo analisar o potencial do mercado fornecedor de matĂ©rias-primas vegetais para a produção de biodiesel entre os anos 2003 e 2010, e verificar a inserção da agricultura familiar no sistema agroindustrial do biodiesel do ParanĂĄ. O ambiente institucional constituĂ­do pelo Programa Nacional de Produção e Uso do Biodiesel (PNPB) pode subsidiar os agricultores familiares paranaenses e gerar uma dinĂąmica de produção de biodiesel no estado com a promoção do desenvolvimento regional com a geração de renda, impostos, alĂ©m de fixar o homem no campo. Em contrapartida, polĂ­ticas pĂșblicas estaduais e municipais devem fazer a sua parte e estimular a produção das mais variadas matĂ©rias-primas para a geração de biodiesel, dada a diversidade edafoclimĂĄtica existente no ParanĂĄ. Este panorama alvissareiro sĂł poderĂĄ ser bem sucedido se houver estĂ­mulo e integração entre os setores pĂșblicos (federal, estadual e municipal) e privado

    Comparison of diagnostic value of 68 Ga-DOTATOC PET/MRI and standalone MRI for the detection of intracranial meningiomas

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    To evaluate the diagnostic performance of magnetic resonance imaging (MRI) alone in comparison to positron emission tomography/ magnetic resonance imaging (PET/MRI) in patients with meningiomas. 57 patients with a total of 112 meningiomas of the brain were included. PET/MRI, including a fully diagnostic contrast enhanced MRI and PET, were acquired. PET/MRI was used as reference standard. The size and location of meningiomas was recorded. Likelihood-ratio chi-square tests were used to calculate p-values within logistic regression in order to compare different models. A multi-level logistic regression was applied to comply the hierarchical data structure. Multi-level regression adjusts for clustering in data was performed. The majority (n=103) of meningiomas could be identified based on standard MRI sequences compared to PET/MRI. MRI alone achieved a sensitivity of 95% (95% CI 0.78, 0.99) and specificity of 88% (95% CI 0.58, 0.98). Based on intensity of contrast medium uptake, 97 meningiomas could be diagnosed with intense uptake (93.75%). Sensitivity was lowest with 74% for meningiomas2cm(3) and highest with 100% for meningiomas 0.5-1.0 cm(3). Petroclival meningiomas showed lowest sensitivity with 88% compared to sphenoidal meningiomas with 94% and orbital meningiomas with 100%. Specificity of meningioma diagnostic with MRI was high with 100% for sphenoidal and hemispherical-dural meningiomas and meningiomas with 0.5-1.0 and 1.0-2.0 cm(3). Overall MRI enables reliable detection of meningiomas compared to PET/MRI. PET/MRI imaging offers highest sensitivity and specificity for small or difficult located meningiomas

    Antibodies to the endoplasmic reticulum-resident chaperones calnexin, BiP and Grp94 in patients with rheumatoid arthritis and systemic lupus erythematosus

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    Objectives. To investigate the presence of autoantibodies against mammalian chaperones of the endoplasmic reticulum (ER) in patients with RA and other immune-mediated diseases. Methods. Sera from healthy donors, from early RA patients with two follow-up samples, patients with SLE, SSc and IBD were collected and analysed for anti-ER chaperone antibodies. Detection of serum IgG antibodies against immunoglobulin heavy chain binding protein (BiP), glucose-regulated protein 94 (Grp94) and calnexin was carried out using ELISA. The specificity of sera positive for individual ER chaperones was confirmed by immunoblotting. Statistical analysis was performed using Welch's t-test, Mann-Whitney U-test, partial correlation and Pearson's correlation. Results. In patients with RA and SLE, autoantibody titres against BiP, Grp94 and calnexin were significantly higher than those in healthy controls. These autoantibodies were detectable in patients with early RA and titres remained stable for at least 6-12 months. Also several SSc and IBD patients exhibited autoantibodies against these ER chaperones; however, titres and frequencies were lower than in RA or SLE patients. Furthermore, anti-calnexin antibodies correlated significantly with the presence of BiP and Grp94 autoantibodies in patients with RA and SLE. Conclusion. Calnexin and Grp94 were identified as novel autoantigens in RA and calnexin in SLE. Since calnexin, Grp94 and BiP are ER-resident proteins of eukaryotic cells, our data suggest that autoantibody generation against ER chaperones is independent of initial exposure to the corresponding bacterial chaperones; rather, ER chaperones may represent genuine autoantigen

    Polymorphisms in the Hsp70 gene locus are genetically associated with systemic lupus erythematosus

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    Background Heat shock proteins (Hsps) play a role in the delivery and presentation of antigenic peptides and are thought to be involved in the pathogenesis of multifactorial diseases. Objective To investigate genes encoding cytosolic Hsp70 proteins for associations of allelic variants with systemic lupus erythematosus (SLE). Methods Case-control studies of two independent Caucasian SLE cohorts were performed. In a haplotype-tagging single-nucleotide polymorphism approach, common variants of HspA1L, HspA1A and HspA1B were genotyped and principal component analyses were performed for the cohort from the Oklahoma Medical Research Foundation (OMRF). Relative quantification of mRNA was carried out for each Hsp70 gene in healthy controls. Conditional regression analysis was performed to determine if allelic variants in Hsp70 act independently of HLA-DR3. Results On analysis of common genetic variants of HspA1L, HspA1A and HspA1B, a haplotype significantly associated with SLE in the Erlangen-SLE cohort was identified, which was confirmed in the OMRF cohort. Depending on the cohorts, OR ranging from 1.43 to 1.88 and 2.64 to 3.16 was observed for individuals heterozygous and homozygous for the associated haplotype, respectively. Patients carrying the risk haplotype or the risk allele more often displayed autoantibodies to Ro and La in both cohorts. In healthy controls bearing this haplotype, the amount of HspA1A mRNA was significantly increased, whereas total Hsp70 protein concentration was not altered. Conclusions Allelic variants of the Hsp70 genes are significantly associated with SLE in Caucasians, independently of HLA-DR3, and correlate with the presence of autoantibodies to Ro and La. Hence, the Hsp70 gene locus appears to be involved in SLE pathogenesis

    Shortened Tracer Uptake Time in GA-68-DOTATOC-PET of Meningiomas Does Not Impair Diagnostic Accuracy and PET Volume Definition

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    Ga-68-DOTATOC-PET/MRI can affect the planning target volume (PTV) definition of meningiomas before radiosurgery. A shorter tracer uptake time before image acquisition could allow the examination of more patients. The aim of this study was to investigate if shortening uptake time is possible without compromising diagnostic accuracy and PET volume. Fifteen patients (f = 12; mean age 52 years (34-80 years)) with meningiomas were prospectively examined with dynamic [68Ga]Ga-68-labeled [DOTA0-Phe1-Tyr3] octreotide (Ga-68-DOTATOC)-PET/MRI over 70 min before radiosurgery planning. Meningiomas were delineated manually in the PET dataset. PET volumes at each time point were compared to the reference standard 60 min post tracer injection (p.i.) using the Friedman test followed by a Wilcoxon signed-rank test and Bonferroni correction. In all patients, the earliest time point with 100% lesion detection compared to 60 min p.i. was identified. PET volumes did not change significantly from 15 min p.i. (p = 1.0) compared to 60 min p.i. The earliest time point with 100% lesion detection in all patients was 10 min p.i. In patients with meningiomas undergoing Ga-68-DOTATOC-PET, the tracer uptake time can safely be reduced to 15 min p.i. with comparable PET volume and 100% lesion detection compared to 60 min p.i

    The bacterial cell envelope as delimiter of anti-infective bioavailability - An in vitro permeation model of the Gram-negative bacterial inner membrane.

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    Gram-negative bacteria possess a unique and complex cell envelope, composed of an inner and outer membrane separated by an intermediate cell wall-containing periplasm. This tripartite structure acts intrinsically as a significant biological barrier, often limiting the permeation of anti-infectives, and so preventing such drugs from reaching their target. Furthermore, identification of the specific permeation-limiting envelope component proves difficult in the case of many anti-infectives, due to the challenges associated with isolation of individual cell envelope structures in bacterial culture. The development of an in vitro permeation model of the Gram-negative inner membrane, prepared by repeated coating of physiologically-relevant phospholipids on Transwell(Âź) filter inserts, is therefore reported, as a first step in the development of an overall cell envelope model. Characterization and permeability investigations of model compounds as well as anti-infectives confirmed the suitability of the model for quantitative and kinetically-resolved permeability assessment, and additionally confirmed the importance of employing bacteria-specific base materials for more accurate mimicking of the inner membrane lipid composition - both advantages compared to the majority of existing in vitro approaches. Additional incorporation of further elements of the Gram-negative bacterial cell envelope could ultimately facilitate model application as a screening tool in anti-infective drug discovery or formulation development
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