98 research outputs found

    Nitrogen from hairy vetch (Vicia villosa Roth) as winter green manure for white cabbage in organic horticulture

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    The effect of the nitrogen (N) supply from hairy vetch grown as winter green manure on white cabbage was investigated in field trials performed on an organic farm in north-west Germany over two years. Hairy vetch was either used as green manure or harvested. One of two bare-soil fallow treatments was supplied with hairy vetch shoot mass to serve as reference. In 2002 and 2003, hairy vetch and weeds accumulated 136 and 178 kg ha-1 of shoot N and yielded 3.79 and 4.72 t ha-1, respectively. After ploughing and planting white cabbage (Brassica oleracea L. convar. capitata var. capitata f. alba) for sauerkraut production at the beginning of June, the amount of soil mineral N (SMN) of the topsoil layer was biweekly investigated until canopy for about 6 - 8 weeks. In 2002, already within 2 weeks a maximum of 121 kg SMN ha-1 for the green manure hairy vetch treatment was reached, whereas in 2003 a maximum of only 60 kg SMN ha-1 was observed due to an exceptionally dry and warm season. In 2002, white cabbage shoot yielded an average 4.4 t DM ha-1 (range 3.9 - 5.1 t ha-1 DM) and had accumulated on average 153 kg N ha-1 (range 129 - 178 kg N ha-1). Mean fresh matter yield (FM) of a single head was only 1.2 kg (range 1.1 - 1.3 kg head-1) due to severe pest damage. In the following year, the mean head yield was 5.1 kg FM (range 3.4 - 6.4 kg) and head yield per hectare was 5.8 t DM (range 4.6 - 7.5 t DM ha-1) with a mean head N uptake of 182 kg ha-1 (range 136 - 237 kg N ha-1). The relationship between the weighted arithmetic daily mean of SMN for the first 6 - 8 weeks after the hairy vetch harvest date and the N uptake of cabbage at two sampling dates was significant, as were most correlations between presented core parameters. Although N of hairy vetch used as green manure calculatively recovered on average only about 27% in cabbage shoot N at final harvest, a balanced field N budget can be ensured by using the green manure legume hairy vetch as a basic N source for a subsequent white cabbage cash crop

    Stickstoffversorgung der Zweitfrüchte Feldgemüse und Mais nach Winterzwischenfrucht-Leguminosen

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    Untersucht wurde die Stickstoffzufuhr mit dem Anbau von Leguminosen als Winterzwischenfrüchte (Zottelwicken, Inkarnatklee, Landsberger Gemenge, Wickroggen). Referenzvarianten waren Rübsen, Roggen und Gras in Reinsaat sowie Brache. In Feldversuchen an drei organisch bewirtschafteten Standorten im Rheinland wurden in den Jahren 2002 und 2003 die Zwischenfrüchte und Nachfruchtwirkung geprüft. Bestimmt wurden Ertrag (21 - 62 dt TM/ha), Stickstoffaufnahme (65 - 200 kg N/ha) und Netto-N-Fixierung (im Mittel 100 kg N/ha). Die Zwischenfrüchte wurden im Mai/Juni gemulcht oder beerntet. In den ersten Wochen nach Umbruch der Zwischenfrucht und Saat der Nachfrucht wurde der Verlauf der N-Mineralisierung im Boden gemessen (max. 50 - 180 kg Nmin-N/ha im Ap). Der Ertrag und die N-Aufnahme der Nachfrüchte Weißkohl und Mais betrug 877 - 1.274 dt FM/ha und 125 - 230 kg N/ha bzw. 138 - 196 dt TM/ha und 150 - 280 kg N/ha. Nach dem Verbleib des gemulchten Zwischenfruchtaufwuchses war im Vergleich zu den beernteten Varianten die N-Aufnahme der Nachfrüchte überwiegend signifikant höher. Bei Beerntung der Zwischenfrucht muß ein Großteil des für die Nachfrucht benötigten Stickstoffs aus dem Bodenvorrat gespeist werden, während mit dem Verbleib der Zwischenfrucht gemulcht auf der Fläche eine weitgehend ausgeglichene Stickstoff-Feldbilanz und damit Humusbilanz gestaltet werden kann. Gleichwohl war die mit dem Zwischenfruchtmulch zugeführte N-Menge nicht gleichermaßen als Differenz zwischen den gemulchten und beernteten Varianten der Nachfrucht wiederzufinden. Die N-Nachlieferung aus dem Boden überdeckte teilweise die Wirkung des gemulchten Zwischenfruchtaufwuchses. Mit Winterzwischenfrucht-Leguminosen kann ein mengenmäßig bedeutsamer Beitrag für die innerbetrieblich erzeugte N-Zufuhr geleistet werden. Auf Basis der vorgestellten Feldversuchsergebnisse wird eine Liste an Handlungsempfehlungen vorgestellt

    Development and evaluation of a suite of isotope reference gases for methane in air

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    Measurements from multiple laboratories have to be related to unifying and traceable reference material in order to be comparable. However, such fundamental reference materials are not available for isotope ratios in atmospheric methane, which led to misinterpretations of combined data sets in the past. We developed a method to produce a suite of synthetic CH4-in-air standard gases that can be used to unify methane isotope ratio measurements of laboratories in the atmospheric monitoring community. Therefore, we calibrated a suite of pure methane gases of different methanogenic origin against international referencing materials that define the VSMOW (Vienna Standard Mean Ocean Water) and VPDB (Vienna Pee Dee Belemnite) isotope scales. The isotope ratios of our pure methane gases range between -320 and +40% for delta H-2-CH4 and between -70 and -40% for delta C-13-CH4, enveloping the isotope ratios of tropospheric methane (about -85 and -47% for delta H-2-CH4 and delta C-13-CH4 respectively). Estimated uncertainties, including the full traceability chain, are</p

    Inflammation, fibrosis and skeletal muscle regeneration in LGMDR9 are orchestrated by macrophages

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    Aims: Variable degrees of inflammation, necrosis, regeneration and fibrofatty replacement are part of the pathological spectrum of the dystrophic process in alpha dystroglycanopathy LGMDR9 (FKRP-related, OMIM #607155), one of the most prevailing types of LGMDs worldwide. Inflammatory processes and their complex interplay with vascular, myogenic and mesenchymal cells may have a major impact on disease development. The purpose of our study is to describe the specific immune morphological features in muscle tissue of patients with LGMDR9 to enable a better understanding of the phenotype of muscle damage leading to disease progression. Methods: We have analysed skeletal muscle biopsies of 17 patients genetically confirmed as having LGMDR9 by histopathological and molecular techniques. Results: We identified CD206+ MHC class II+ and STAT6+ immune-repressed macrophages dominating the endomysial infiltrate in areas of myofibre regeneration and fibrosis. Additionally, PDGFRβ+ pericytes were located around MHC class II+ activated capillaries residing in close proximity to areas of fibrosis and regenerating fibres. Expression of VEGF was found on many regenerating neonatal myosin+ fibres, myofibres and CD206+ macrophages also co-expressed VEGF. Conclusion: Our results show characteristic immune inflammatory features in LGMDR9 and more specifically shed light on the predominant role of macrophages and their function in vascular organisation, fibrosis and myogenesis. Understanding disease-specific immune phenomena potentially inform about possibilities for anti-fibrotic and anti-inflammatory therapeutic strategies, which may complement Ribitol replacement and gene therapies for LGMDR9 that may be available in the future

    New Biotite and Muscovite Isotopic Reference Materials, USGS57 and USGS58, for δ2H Measurements–A Replacement for NBS 30

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    The advent of continuous-flow isotope-ratio mass spectrometry (CF-IRMS) coupled with a high temperature conversion (HTC) system enabled faster, more cost effective, and more precise δ2H analysis of hydrogen-bearing solids. Accurate hydrogen isotopic analysis by on-line or off-line techniques requires appropriate isotopic reference materials (RMs). A strategy of two-point calibrations spanning δ2H range of the unknowns using two RMs is recommended. Unfortunately, the supply of the previously widely used isotopic RM, NBS 30 biotite, is exhausted. In addition, recent measurements have shown that the determination of δ2H values of NBS 30 biotite on the VSMOW-SLAP isotope-delta scale by on-line HTC systems with CF-IRMS may be unreliable because hydrogen in this biotite may not be converted quantitatively to molecular hydrogen. The δ2HVSMOW-SLAP values of NBS 30 biotite analyzed by on-line HTC systems can be as much as 21 mUr (or ‰) too positive compared to the accepted value of −65.7 mUr, determined by only a few conventional off-line measurements. To ensure accurate and traceable on-line hydrogen isotope-ratio determinations in mineral samples, we here propose two isotopically homogeneous, hydrous mineral RMs with well-characterized isotope-ratio values, which are urgently needed. The U.S. Geological Survey (USGS) has prepared two such RMs, USGS57 biotite and USGS58 muscovite. The δ2H values were determined by both glassy carbon-based on-line conversion and chromium-based on-line conversion, and results were confirmed by off-line conversion. The quantitative conversion of hydrogen from the two RMs using the on-line HTC method was carefully evaluated in this study. The isotopic compositions of these new RMs with 1-σ uncertainties and mass fractions of hydrogen are: USGS57 (biotite) δ2HVSMOW-SLAP = −91.5 ± 2.4 mUr (n =24) Mass fraction hydrogen = 0.416 ± 0.002% (n=4) Mass fraction water = 3.74 ± 0.02% (n=4) USGS58 (muscovite) δ2HVSMOW-SLAP = −28.4 ± 1.6 mUr (n =24) Mass fraction hydrogen = 0.448 ± 0.002% (n=4) Mass fraction water = 4.03 ± 0.02% (n =4). These δ2HVSMOW-SLAP values encompass typical ranges for solid unknowns of crustal and mantle origin and are available to users for recommended two-point calibration

    USGS44, a new high purity calcium carbonate reference material for δ13 C measurements

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    RATIONALE: The stable carbon isotopic (δ13 C) reference material (RM) LSVEC Li2 CO3 has been found to be unsuitable for δ13 C standardization work because its δ13 C value increases with exposure to atmospheric CO2 . A new CaCO3 RM, USGS44, has been prepared to alleviate this situation. METHODS: USGS44 was prepared from 8 kg of Merck high purity CaCO3 . Two sets of δ13 C values of USGS44 were determined. The first set of values was determined by on-line combustion, continuous-flow (CF) isotope-ratio mass spectrometry (IRMS) of NBS 19 CaCO3 (δ13 CVPDB = +1.95 milliurey (mUr) exactly, where mUr = 0.001 = 1 ‰), and LSVEC Li2 CO3 (δ13 CVPDB = -46.6 mUr exactly), and normalized to the two-anchor δ13 CVPDB-LSVEC isotope-delta scale. The second set of values was obtained by dual-inlet (DI) IRMS of CO2 evolved by reaction of H3 PO4 with carbonates, corrected for cross contamination, and normalized to the single anchor δ13 CVPDB scale. RESULTS: USGS44 is stable and isotopically homogeneous to within 0.02 mUr in 100-μg amounts. It has a δ13 CVPDB-LSVEC value of -42.21 ± 0.05 mUr. Single-anchor δ13 CVPDB values of -42.08 ± 0.01 and -41.99 ± 0.02 mUr were determined by DI-IRMS with corrections for cross contamination. CONCLUSIONS: The new high-purity, well homogenized calcium carbonate isotopic reference material USGS44 is stable and has a δ13 CVPDB-LSVEC value of -42.21 ± 0.05 mUr for both EA-IRMS and DI-IRMS measurements. As a carbonate relatively depleted in 13 C, it is intended for daily use as a secondary isotopic reference material to normalize stable carbon isotope-delta measurements to the δ13 CVPDB-LSVEC scale. It is useful in quantifying drift with time, determining mass-dependent isotopic fractionation (linearity correction), and adjusting isotope-ratio-scale contraction. Due to its fine grain size (smaller than 63 μm), it is not suitable as a δ18 O reference material. A δ13 CVPDB-LSVEC value of -29.99 ± 0.05 mUr was determined for NBS 22 oil

    The impact of 18F-FDG PET on the management of patients with suspected large vessel vasculitis

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    Purpose: We aimed to assess the impact of 18F-fluorodeoxyglucose (FDG) positron emission tomography (PET) on the management of patients with suspected large vessel vasculitis. Methods: An international expert panel determined diagnoses and clinical management in patients with suspected large vessel vasculitis, with and without the results of 18F-FDG PET, respectively. The accuracy of the clinical diagnosis and the resulting clinical management with and without the 18F-FDG PET results were compared using logistic regression models. Results: The analysis included 30 patients referred to a tertiary care centre with large vessel vasculitis and 31 controls. 18F-FDG PET had an overall sensitivity of 73.3% [95% confidence interval (CI) 54.1-87.7%], a specificity of 83.9% (95% CI 66.3-94.5%), a positive predictive value of 81.5% (95% CI 61.9-93.7%) and a negative predictive value of 76.5% (95% CI 58.8-89.3%). The diagnostic accuracy of 18F-FDG PET was higher in patients not receiving immunosuppressive drugs (93.3 vs 64.5%, p = 0.006). Taken in context with other available diagnostic modalities, the addition of 18F-FDG PET increased the clinical diagnostic accuracy from 54.1 to 70.5% (p = 0.04). The addition of 18F-FDG PET increased the number of indicated biopsies from 22 of 61 patients (36.1%) to 25 of 61 patients (41.0%) and changed the treatment recommendation in 8 of 30 patients (26.7%) not receiving immunosuppressive medication and in 7 of 31 patients (22.6%) receiving immunosuppressive medication. Conclusion: 18F-FDG PET is a sensitive and specific imaging tool for large vessel vasculitis, especially when performed in patients not receiving immunosuppressive drugs. It increases the overall diagnostic accuracy and has an impact on the clinical management in a significant proportion of patient
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