This article discusses whether or to what extent flocculation plays a role in the saline deep-sea environment and whether sediment plumes generated by deep-sea mining activities are affected by the ...process of flocculation. The results of our laboratory study demonstrate that deep sea mineral clay with a median floc size of 20μm can flocculate quickly within 2.5 min of mixing to form flocs with a median floc size of about 50–150μm and outliers as large as 500μm in size due to the presence of natural organic matter. At high shear (turbulent mixing), a threshold of about 125s−1 was found above which, organic matter can successfully bind to clay. Above 125s−1, the steady-state floc size is also found to increase linearly with shear. In low energetic conditions (when flocs experience mainly differential settling), the median floc sizes are found to be 2 or 3 times larger than at turbulent mixing. As expected, the rate of flocculation is greater at higher clay concentrations. At long mixing times, the median floc size is found to decrease due to the breaking/reconformation of flocs. Experiments performed to study the ageing of flocs at rest demonstrated that a dynamic process was ongoing between the organic matter and the clay. It is hypothesized that the organic matter present has amphiphilic properties. Over time, the organic matter would rearrange itself such as to maximize its contact area with the mineral clay, resulting in two effects, depending on the structure of the flocs. In the case of flocs formed at high shear, it led to a rupture of flocs. A slow agitation of settled flocs, having previously experienced low shear conditions, on the other hand, led to aggregation. Overall, the results found in the present article show that flocculation likely plays a significant role in deep-sea areas.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UILJ, UL, UM, UPCLJ, UPUK, ZAGLJ, ZRSKP
Well‐established histopathological prognostic factors are lacking in primary central nervous system (CNS) lymphomas (PCNSL). The present study investigated the presence and prognostic role of tumour ...necrosis (TN) and reactive perivascular T‐cell infiltrate (RPVI), defined as a rim of small reactive T‐lymphocytes occurring alone or located between the vascular wall and large neoplastic cells, in tumour samples from 100 immunocompetent patients with PCNSL. World Health Organization histotypes of the patients were: 96 diffuse large B‐cell lymphomas, two Burkitt‐like lymphomas, one anaplastic large T‐cell lymphoma and one unclassified B‐cell lymphoma. TN was observed in 24 (24%) cases and RPVI in 26 (36%) of 73 assessable cases. Patients with RPVI‐positive lesions exhibited a significantly better overall survival (OS) than patients with RPVI‐negative lymphoma, particularly among patients treated with high‐dose methotrexate‐based chemotherapy (3‐year OS: 59 ± 14% vs. 42 ± 9%, P = 0·02). By contrast, the presence of TN did not demonstrate prognostic significance. Multivariate analysis confirmed an independent association between RPVI and survival. In conclusion, the presence of RPVI is independently associated with survival in PCNSL. This parameter can be easily and routinely assessed at diagnosis on histopathological specimens.
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BFBNIB, FZAB, GIS, IJS, KILJ, NLZOH, NUK, OILJ, SBCE, SBMB, UL, UM, UPUK
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•New expressions for the complex conductivity of granular material are derived.•The expressions are valid for any ionic strength.•The expressions predict well the response of glass ...beads, sands and sandstones.
The low-frequency dielectric spectroscopy of granular material, where the porosity is representative for sands and sandstones, is until now always modeled using theories based on the work of Schwartz (1962). The theory for the low-frequency dielectric spectroscopy of suspensions, on the other hand, has been developed much further over the last decades both numerically and analytically.
In this article new analytical expressions for the complex conductivity of granular material, such as sands and sandstones in an electrolyte solution, are presented. These expressions have been derived using the theories developed for suspensions. We show that the new expressions enable to predict the measured complex conductivity of various granular material, such as packed glass beads, sands and sandstones. Because of the typical grain size of sand and sandstone particles, for any ionic strength the double layer is much thinner that the particle size. Contrary to existing theories for granular materials, the expressions we derived are valid for any ionic strength and no adjustable parameters are required.
The grains are represented by monodispersed charged spheres. We also discuss how the expressions can be adapted in the case the particles are not spherical and the grains are polydisperse.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UL, UM, UPCLJ, UPUK, ZRSKP
In the mining industry, tailings are conventionally stored in artificial ponds that are susceptible to ruptures, as occurred in Southeast Brazil in November 2015. The Fundão failure dumped ...approximately 40 million m3 of very fine iron-rich tailing material into the Doce River watershed, where part reached the adjacent continental shelf. Part of the spilled material remained suspended in the water column after reaching the ocean. Zeta potential measurements (pH and salt dependence) were conducted to verify the flocculation tendency of suspensions. Surface sediment samples were collected in areas representative of key stages of tailings transport through the river and subsequent deposit on the continental shelf. A surface sediment sample from the continental shelf prior to the failure was used as a control. Previously published data suggested an influence from goethite on the flocculation of samples containing iron ore tailing sludge. Here we show that although a flocculation tendency was observed under influence of salts, the presence and quantity of iron oxyhydroxide were determinant in the flocculation pattern of contaminated sedimentary samples. Only sediment from the continental shelf before the mining dam breach exhibited classical zeta potential behavior dependence on pH and salinity expected in natural sediments containing clay minerals. Sediments contaminated with the iron ore tailing sludge displayed a clear influence of goethite on their zeta potential.
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•Material from an iron ore mining dam breach has been exported by the Doce River onto the continental shelf.•Surface charge of suspended particles in aqueous solution was determined to understand flocculation tendencies.•Contaminated sediment showed zeta potential behavior similar to goethite.•When in marine waters pH, zeta potential had sudden jump in the negative values and left the flocculation tendency zone.•The amount of tailings in the sediment had a different influence on the behavior of the zeta potential.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UILJ, UL, UM, UPCLJ, UPUK, ZAGLJ, ZRSKP
Background Reported data regarding intraocular lymphoma (IOL) management are anecdotal. Cases of IOL included in an international multicentre series of 378 immunocompetent patients with primary ...central nervous system lymphomas (PCNSLs) were reviewed. Patients and methods Staging included slit-lamp examination in 170 patients: IOL was diagnosed in 22 cases (13%). A concomitant brain lesion was detected in 21 cases. Planned treatment was chemotherapy followed by radiotherapy in 13 cases, chemotherapy alone in three and radiotherapy, followed by or not by chemotherapy in five; one patient was not treated. Chemotherapy included high-dose methotrexate in 12 cases. Ten patients received intrathecal chemotherapy. Radiotherapy consisted of whole brain irradiation, followed by or not by a tumour bed boost; ocular irradiation was planned in 15 cases. Irradiation in one patient without brain lesions was limited to the orbits only (50 Gy). Results IOL was positively correlated to systemic symptoms and meningeal disease. Fifteen patients (71%) achieved an objective response; 16 patients experienced a failure (2-year failure-free survival 34 ± 10%). Failures involved the eyes in eight cases, with a 2-year time to ocular relapse of 59 ± 11%. Ocular failure was less common in patients treated with chemotherapy plus ocular irradiation and was associated with a significantly shorter survival. Seven patients are alive median follow-up 53 months, 2-year overall survival (OS): 39 ± 11%, five of whom were treated with ocular irradiation. The patient with isolated IOL is alive and disease-free at 14 months. OS of the entire series was similar to that of PCNSL patients with negative slit-lamp examination. Conclusions IOL is usually associated with concomitant brain disease and shows a survival similar to that of the rest of PCNSLs. Chemotherapy combined with ocular irradiation resulted in better control of ocular disease, which seems to be associated with survival. In view of the potential role of ocular irradiation, the use of chemotherapy alone in phase II trials should be critically reconsidered in PCNSL patients with ocular disease.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UILJ, UL, UM, UPCLJ, UPUK, ZAGLJ, ZRSKP
La plèvre myéloïde Mrabti, H.; Chelghoum, M.; Odier, L. ...
La revue de medecine interne,
7/2008, Volume:
29, Issue:
7
Journal Article
Peer reviewed
La métaplasie myéloïde idiopathique associée à une myélofibrose fait partie des syndromes myéloprolifératifs. Le siège pleural de l’hématopoïèse extramédullaire est exceptionnel et d’évolution ...souvent péjorative.
Nous rapportons l’observation d’une patiente de 64 ans, porteuse d’une myélofibrose idiopathique avec une hématopoïèse extramédullaire pleurale, stabilisée par un traitement à base d’hydroxyurée.
Les aspects cliniques, biologiques, histologiques, thérapeutiques et évolutifs de la plèvre myéloïde seront discutés.
Agnogenic myeloid metaplasia, associated with myelofibrosis, is a myeloproliferative disorder. Extramedullary hematopoiesis in the pleura is rare and its prognosis is often severe.
Herein we report a 64-year-old woman, who presented with pleural extramedullary hematopoiesis, treated by hydroxyurea-based chemotherapy with disease control.
Clinical, histological, therapeutic and evolutive aspects of this uncommon entity will be reviewed.
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IJS, IMTLJ, KILJ, KISLJ, NUK, SAZU, SBCE, SBJE, UL, UM, UPCLJ, UPUK
Microspheres with high specific activities of radionuclides are very interesting for internal radiotherapy treatments. This work focuses on the formulation and characterization of inorganic ...microspheres with a high content of holmium and therefore a high specific radioactivity of holmium-166. Two novel formulations of inorganic microspheres were obtained by dispersing solid holmium acetylacetonate microspheres (Ho2(AcAc)3-ms) in NaH2PO4 or NaOH solutions followed by 2 h incubation at room temperature. By exchange of acetylacetonate with phosphate or hydroxyl ions, holmium phosphate microspheres (HoPO4-ms) and holmium hydroxide microspheres (Ho(OH)3-ms) were formed respectively. The inorganic microspheres had a significantly smaller diameter (28.5 ± 4.4 μm (HoPO4-ms) and 25.1 ± 3.5 μm (Ho(OH)3-ms)) than those of Ho2(AcAc)3-ms (32.6 ± 5.2 μm). The weight percentage of holmium-165 in the microspheres increased significantly from 47% (Ho2(AcAc)3-ms) to 55% (HoPO4-ms) and 73% (Ho(OH)3-ms). After preparation of both HoPO4-ms and Ho(OH)3-ms, the stable holmium-165 isotope was partly converted by neutron activation into radioactive holmium-166 to yield radioactive microspheres. High specific activities were achieved ranging from 21.7 to 59.9 MBq/mg (166HoPO4-ms) and from 28.8 to 79.9 MBq/mg (166Ho(OH)3-ms) depending on the neutron activation time. The structure of both microspheres was preserved up to neutron activations of 6 h in a thermal neutron flux of 4.72 × 1016 n m−2 s−1. After activation, both microspheres revealed excellent stability in administration fluids (saline and phosphate buffer) having less than 0.05% of holmium released after 72 h incubation. Finally, the hemocompatibility of these inorganic microspheres was evaluated and it was shown that the microspheres did cause neither hemolysis nor depletion or inhibition of the coagulation factors of the intrinsic blood coagulation pathway meaning that the microspheres have a good hemocompatibility. Overall, this work shows that radioactive inorganic microspheres with high specific activities of holmium-166 can be prepared which potentially can be used for internal radionuclide therapy.
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•Two inorganic microspheres (Ho-phosphate, Ho-hydroxide) are developed which are suitable for internal radionuclide therapy.•The holmium content obtained in the novel microspheres is ~55 wt% (Ho-phosphate) and ~73 wt% (Ho-hydroxide).•The higher specific activity allows to increase patient absorbed dose and makes the logistics more flexible.•The new microspheres are stable in administration fluids after neutron activation and show a good hemocompatibility.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UILJ, UL, UM, UPCLJ, UPUK, ZAGLJ, ZRSKP
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