177 research outputs found

    Comparison of Cu-Mg-Al-Ox and Cu/Al2O3 in selective catalytic oxidation of ammonia (NH3-SCO)

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    Copper-based materials are promising catalysts in the selective catalytic oxidation of ammonia into nitrogen and water vapour (NH 3 -SCO). Investigations under applied reaction conditions over such materials seem to be rare and a comprehensive understanding of the involved active copper oxide species could facilitate a knowledge-based catalyst optimization. In the present work, Cu-Mg-Al-O x mixed metal oxides and Cu/Al 2 O 3 active catalysts in NH 3 -SCO were investigated under NH 3 /O 2 /CO 2 /H 2 O/N 2 reaction conditions. Powder XRD, BET, NH 3 -TPD, H 2 -TPR and XAFS methods were used to characterize Cu-Mg-Al-O x (Cu/Mg/Al = 8/63/29, mol%) and 10 wt% Cu/Al 2 O 3 . Cu-Mg-Al-O x hydrotalcite derived mixed metal oxides were obtained by coprecipitation, while Cu/Al 2 O 3 was prepared by incipient wetness impregnation. A highly dispersed copper oxide species formed on Cu-Mg-Al-O x , while a mixture of highly dispersed (CuO x ) and bulk copper oxide species (CuO and CuAl 2 O 4 ) formed on Cu/Al 2 O 3 . The comparison of Cu-Mg-Al-O x and Cu/Al 2 O 3 in NH 3 -SCO provided good insight into the nature of the active species present in both copper-based catalysts. It was found that highly dispersed easily reducible copper oxide species and bulk copper oxide species appear as active species under NH 3 /O 2 /N 2 and NH 3 /O 2 /CO 2 /H 2 O/N 2 reaction conditions, respectively

    Catchment-Scale Analysis Reveals High Cost-Effectiveness of Wetland Buffer Zones as a Remedy to Non-Point Nutrient Pollution in North-Eastern Poland

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    Large-scale re-establishment of wetland buffer zones (WBZ) along rivers is regarded as an effective measure in order to reduce non-point source nitrogen (N) and phosphorus (P) pollution in agricultural catchments. We estimated efficiency and costs of a hypothetical establishment of WBZs along all watercourses in an agricultural landscape of the lower Narew River catchment (north-eastern Poland, 16,444 km2, amounting to 5% of Poland) by upscaling results obtained in five sub-catchments (1087 km2). Two scenarios were analysed, with either rewetting selected wetland polygons that collect water from larger areas (polygonal WBZs) or reshaping and rewetting banks of rivers (linear WBZs), both considered in all ecologically suitable locations along rivers. Cost calculation included engineering works necessary in order to establish WBZs, costs of land purchase where relevant, and compensation costs of income forgone to farmers (needed only for polygonal WBZs). Polygonal WBZs were estimated in order to remove 11%–30% N and 14%–42% P load from the catchment, whereas linear WBZs were even higher with 33%–82% N and 41%–87% P. Upscaled costs of WBZ establishment for the study area were found to be 8.9 M EUR plus 26.4 M EUR per year (polygonal WBZ scenario) or 170.8 M EUR (linear WBZ scenario). The latter value compares to costs of building about 20 km of an express road. Implementation of buffer zones on a larger scale is thus a question of setting policy priorities rather than financial impossibility

    Clear cell variant of diffuse large B-cell lymphoma: a case report

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    <p>Abstract</p> <p>Introduction</p> <p>Diffuse large B-cell lymphoma is a diffuse proliferation of large neoplastic B lymphoid cells with a nuclear size equal to or exceeding the normal macrophage nuclei. We report a case of a clear cell variant of diffuse large B-cell lymphoma involving a lymph node in the neck, which was clinically suspected of being metastatic carcinoma.</p> <p>Case presentation</p> <p>A 39-year-old Caucasian ethnic Albanian man from Kosovo presented with a rapidly enlarging lymph node in his neck, but he also disclosed B symptoms and fatigue. A cytological aspirate of the lymph node revealed pleomorphic features. Our patient underwent a cervical lymph node biopsy (large excision). The mass was homogeneously fish-flesh, pale white tissue replacing almost the whole structure of the lymph node. The lymph node biopsy showed a partial alveolar growth pattern, which raised clinical suspicion that it was an epithelial neoplasm. With regard to morphological and phenotypic features, we discovered large nodules in diffuse areas, comprising large cells with slightly irregular nuclei and clear cytoplasm admixed with a few mononuclear cells. In these areas, there was high mitotic activity, and in some areas there were macrophages with tangible bodies. Staining for cytokeratins was negative. These areas had the following phenotypes: cluster designation marker 20 (CD20) positive, B-cell lymphoma (Bcl)-2-positive, Bcl-6<sup>-</sup>, CD5<sup>-</sup>, CD3<sup>-</sup>, CD21<sup>+ </sup>(in alveolar patterns), prostate-specific antigen-negative, human melanoma black marker 45-negative, melanoma marker-negative, cytokeratin-7-negative and multiple myeloma marker 1-positive in about 30% of cells, and exhibited a high proliferation index marker (Ki-67, 80%).</p> <p>Conclusion</p> <p>According to the immunohistochemical findings, we concluded that this patient has a clear cell variant of diffuse large B-cell lymphoma of activated cell type, post-germinal center cell origin. Our patient is undergoing R-CHOP chemotherapy treatment.</p

    Presentation of Graves' orbitopathy within European Group On Graves' Orbitopathy (EUGOGO) centres from 2012 to 2019 (PREGO III)

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    Background: Graves' orbitopathy (GO) is subject to epidemiological and care-related changes. Aim of the survey was to identify trends in presentation of GO to the European Group On Graves' Orbitopathy (EUGOGO) tertiary referral centres and initial management over time. Methods: Prospective observational multicentre study. All new referrals with diagnosis of GO within September-December 2019 were included. Clinical and demographic characteristics, referral timelines and initial therapeutic decisions were recorded. Data were compared with a similar EUGOGO survey performed in 2012. Results: Besides age (mean age: 50.5±13 years vs 47.7±14 years; p 0.007), demographic characteristics of 432 patients studied in 2019 were similar to those in 2012. In 2019, there was a decrease of severe cases (9.8% vs 14.9; p&lt;0.001), but no significant change in proportion of active cases (41.3% vs 36.6%; p 0.217). After first diagnosis of GO, median referral time to an EUGOGO tertiary centre was shorter (2 (0-350) vs 6 (0-552) months; p&lt;0.001) in 2019. At the time of first visit, more patients were already on antithyroid medications (80.2% vs 45.0%; p&lt;0.001) or selenium (22.3% vs 3.0%; p&lt;0.001). In 2019, the initial management plans for GO were similar to 2012, except for lid surgery (2.4% vs 13.9%; p&lt;0.001) and prescription of selenium (28.5% vs 21.0%; p 0.027). Conclusion: GO patients are referred to tertiary EUGOGO centres in a less severe stage of the disease than before. We speculate that this might be linked to a broader awareness of the disease and faster and adequate delivered treatment

    Gaia Focused Product Release: Radial velocity time series of long-period variables

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    The third Gaia Data Release (DR3) provided photometric time series of more than 2 million long-period variable (LPV) candidates. Anticipating the publication of full radial-velocity (RV) in DR4, this Focused Product Release (FPR) provides RV time series for a selection of LPVs with high-quality observations. We describe the production and content of the Gaia catalog of LPV RV time series, and the methods used to compute variability parameters published in the Gaia FPR. Starting from the DR3 LPVs catalog, we applied filters to construct a sample of sources with high-quality RV measurements. We modeled their RV and photometric time series to derive their periods and amplitudes, and further refined the sample by requiring compatibility between the RV period and at least one of the GG, GBPG_{\rm BP}, or GRPG_{\rm RP} photometric periods. The catalog includes RV time series and variability parameters for 9\,614 sources in the magnitude range 6G/mag146\lesssim G/{\rm mag}\lesssim 14, including a flagged top-quality subsample of 6\,093 stars whose RV periods are fully compatible with the values derived from the GG, GBPG_{\rm BP}, and GRPG_{\rm RP} photometric time series. The RV time series contain a mean of 24 measurements per source taken unevenly over a duration of about three years. We identify the great most sources (88%) as genuine LPVs, with about half of them showing a pulsation period and the other half displaying a long secondary period. The remaining 12% consists of candidate ellipsoidal binaries. Quality checks against RVs available in the literature show excellent agreement. We provide illustrative examples and cautionary remarks. The publication of RV time series for almost 10\,000 LPVs constitutes, by far, the largest such database available to date in the literature. The availability of simultaneous photometric measurements gives a unique added value to the Gaia catalog (abridged)Comment: 36 pages, 38 figure
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