375 research outputs found

    The Role of Operating Conditions in the Precipitation of Magnesium Hydroxide Hexagonal Platelets Using NaOH Solutions

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    Magnesium hydroxide, Mg(OH)2, is an inorganic compound extensively employed in several industrial sectors. Nowadays, it is mostly produced from magnesium-rich minerals. Nevertheless, magnesium-rich solutions, such as natural and industrial brines, could prove to be a great treasure. In this work, synthetic magnesium chloride and sodium hydroxide (NaOH) solutions were used to recover Mg(OH)2 by reactive crystallization. A detailed experimental campaign was conducted aiming at producing grown Mg(OH)2 hexagonal platelets. Experiments were carried out in a stirred tank crystallizer operated in single- and double-feed configurations. In the single-feed configuration, globular and nanoflakes primary particles were obtained, as always reported in the literature when NaOH is used as a precipitant. However, these products are not complying with flame-retardant applications that require large hexagonal Mg(OH)2 platelets. This work suggests an effective precipitation strategy to favor crystal growth while, at the same time, limiting the nucleation mechanism. The double-feed configuration allowed the synthesis of grown Mg(OH)2 hexagonal platelets. The influence of reactant flow rates, reactant concentrations, and reaction temperature was analyzed. Scanning electron microscopy (SEM) pictures were also taken to investigate the morphology of Mg(OH)2 crystals. The proposed precipitation strategy paves the road to satisfy flame-retardant market requirements

    Identification of H2_2CCC as a diffuse interstellar band carrier

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    We present strong evidence that the broad, diffuse interstellar bands (DIBs) at 4881 and 5450\,\AA are caused by the B\,^1B1_1\,\leftarrow\,X\,^1A1_1 transition of H2_2CCC (l-C3_3H2_2). The large widths of the bands are due to the short lifetime of the B\,^1B1_1 electronic state. The bands are predicted from absorption measurements in a neon matrix and observed by cavity ring-down in the gas phase and show exact matches to the profiles and wavelengths of the two broad DIBs. The strength of the 5450\,\AA DIB leads to a l-C3_3H2_2 column density of 5×1014\sim5\times10^{14} cm2^{-2} towards HD\,183143 and 2×1014\sim2\times10^{14}\,cm2^{-2} to HD\,206267. Despite similar values of EE(BVB-V), the 4881 and 5450\,\AA DIBs in HD\,204827 are less than one third their strength in HD\,183143, while the column density of interstellar C3_3 is unusually high for HD\,204827 but undetectable for HD\,183143. This can be understood if C3_3 has been depleted by hydrogenation to species such as l-C3_3H2_2 towards HD\,183143. There are also three rotationally resolved sets of triplets of l-C3_3H2_2 in the 6150-6330\,\AA region. Simulations, based on the derived spectroscopic constants and convolved with the expected instrumental and interstellar line broadening, show credible coincidences with sharp, weak DIBs for the two observable sets of triplets. The region of the third set is too obscured by the α\alpha-band of telluric O2_2.Comment: 22 pages, 9 figure

    Treatment of Intracranial Aneurysms with Self-Expandable Braided Stents: A Systematic Review and Meta-Analysis

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    International audience; BACKGROUND:The safety and efficacy of treatment with self-expandable braided stents (LEO and LVIS) required further investigation.PURPOSE:Our aim was to analyze the outcomes after treatment with braided stents.DATA SOURCES:A systematic search of 3 databases was performed for studies published from 2006 to 2017.STUDY SELECTION:According to Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines, we included studies reporting patients treated with LEO or LVIS stents.DATA ANALYSIS:Random-effects meta-analysis was used to pool the following: aneurysm occlusion rate, complications, and neurologic outcomes.DATA SYNTHESIS:Thirty-five studies evaluating 1426 patients treated with braided stents were included in this meta-analysis. Successful stent delivery and complete aneurysm occlusion were 97% (1041/1095; 95% CI, 95%-98%) (I2 = 44%) and 88.3% (1097/1256; 95% CI, 85%-91%) (I2 = 72%), respectively. Overall, treatment-related complications were 7.4% (107/1317; 95% CI, 5%-9%) (I2 = 44%). Ischemic/thromboembolic events (48/1324 = 2.4%; 95% CI, 1.5%-3.4%) (I2 = 27%) and in-stent thrombosis (35/1324 = 1.5%; 95% CI, 0.6%-1.7%) (I2 = 0%) were the most common complications. Treatment-related morbidity was 1.5% (30/1324; 95% CI, 0.9%-2%) and was comparable between the LEO and LVIS groups. Complication rates between the anterior (29/322 = 8.8%; 95% CI, 3.4%-12%) (I2 = 41%) versus posterior circulation (10/84 = 10.5%; 95% CI, 4%-16%) (I2 = 0%) and distal (30/303 = 8%; 95% CI, 4.5%-12%) (I2 = 48%) versus proximal aneurysms (14/153 = 9%; 95% CI, 3%-13%) (I2 = 46%) were comparable (P > .05).LIMITATIONS:Limitations were selection and publication biases.CONCLUSIONS:In this analysis, treatment with the LEO and LVIS stents was relatively safe and effective. The most common complications were periprocedural thromboembolisms and in-stent thrombosis. The rate of complications was comparable among anterior and posterior circulation aneurysms, as well as for proximal and distally located lesions

    T-Cell Receptor Repertoire Sequencing and Its Applications: Focus on Infectious Diseases and Cancer

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    The immune system is a dynamic feature of each individual and a footprint of our unique internal and external exposures. Indeed, the type and level of exposure to physical and biological agents shape the development and behavior of this complex and diffuse system. Many pathological conditions depend on how our immune system responds or does not respond to a pathogen or a disease or on how the regulation of immunity is altered by the disease itself. T-cells are important players in adaptive immunity and, together with B-cells, define specificity and monitor the internal and external signals that our organism perceives through its specific receptors, TCRs and BCRs, respectively. Today, high-throughput sequencing (HTS) applied to the TCR repertoire has opened a window of opportunity to disclose T-cell repertoire development and behavior down to the clonal level. Although TCR repertoire sequencing is easily accessible today, it is important to deeply understand the available technologies for choosing the best fit for the specific experimental needs and questions. Here, we provide an updated overview of TCR repertoire sequencing strategies, providers and applications to infectious diseases and cancer to guide researchers' choice through the multitude of available options. The possibility of extending the TCR repertoire to HLA characterization will be of pivotal importance in the near future to understand how specific HLA genes shape T-cell responses in different pathological contexts and will add a level of comprehension that was unthinkable just a few years ago

    Feasibility study (I stage) of CO2 geological storage by ECBM tecniques in the Sulcis Coal Province (SW Sardinia).

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    An ECBM feasibility study started for the Sulcis Coal Province (SW Sardinia, Italy): available geochemical, structural-geology, stratigraphic and reservoir engineering considerations as well as the newly gathered experimental data are discussed, including: fluid geochemistry (major and minor elements, dissolved gases, C and He isotopic ratios) of different strata/reservoir, coal composition and experimental data on CO2/CH4 adsorption-desorption on coal. A MapInfo GIS structure was built up including stratigraphic, geo-structural, hydro-geochemical, coal-compositional and environmental-impact information as well as the CO2 sources location and typology. Despite preliminary, these data highlighted both the challenging positive and negative aspects of the Sulcis Coal Province versus the exploitation of the ECBM technique. The most important objective of this phase I of the project is the selection of the best Sulcis ECBM test-pilot site, which will be followed (Phase II-2007) by the choice of a scaled up site and possibly by a future network (Phase III-2008). CO2 geological storage and CH4 production potentials in Sulcis have been grossly evaluated as a whole, in the frame of the Sardinia region CO2 sources, including the coal-fired power plants, both existent and foreseen (hundreds of millions of tonnes of CO2 are possible to be stored underground in the next decades).UnpublishedTrondheim, Norway4.4. Scenari e mitigazione del rischio ambientaleope

    Feasibility study (I stage) of CO2 geological storage by ECBM tecniques in the Sulcis Coal Province (SW Sardinia).

    Get PDF
    An ECBM feasibility study started for the Sulcis Coal Province (SW Sardinia, Italy): available geochemical, structural-geology, stratigraphic and reservoir engineering considerations as well as the newly gathered experimental data are discussed, including: fluid geochemistry (major and minor elements, dissolved gases, C and He isotopic ratios) of different strata/reservoir, coal composition and experimental data on CO2/CH4 adsorption-desorption on coal. A MapInfo GIS structure was built up including stratigraphic, geo-structural, hydro-geochemical, coal-compositional and environmental-impact information as well as the CO2 sources location and typology. Despite preliminary, these data highlighted both the challenging positive and negative aspects of the Sulcis Coal Province versus the exploitation of the ECBM technique. The most important objective of this phase I of the project is the selection of the best Sulcis ECBM test-pilot site, which will be followed (Phase II-2007) by the choice of a scaled up site and possibly by a future network (Phase III-2008). CO2 geological storage and CH4 production potentials in Sulcis have been grossly evaluated as a whole, in the frame of the Sardinia region CO2 sources, including the coal-fired power plants, both existent and foreseen (hundreds of millions of tonnes of CO2 are possible to be stored underground in the next decades)

    Improving mental and neurological health research in Latin America: a qualitative study

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    <p>Abstract</p> <p>Background</p> <p>Research evidence is essential to inform policies, interventions and programs, and yet research activities in mental and neurological (MN) health have been largely neglected, particularly in low- and middle-income countries. Many challenges have been identified in the production and utilization of research evidence in Latin American countries, and more work is needed to overcome this disadvantageous situation. This study aims to address the situation by identifying initiatives that could improve MN health research activities and implementation of their results in the Latin American region.</p> <p>Methods</p> <p>Thirty-four MN health actors from 13 Latin American countries were interviewed as part of an initiative by the Global Forum for Health Research and the World Health Organization to explore the status of MN health research in low- and middle-income countries in Africa, Asia and Latin-America.</p> <p>Results</p> <p>A variety of recommendations to increase MN health research activities and implementation of their results emerged in the interviews. These included increasing skilled human resources in MN health interventions and research, fostering greater participation of stakeholders in the generation of research topics and projects, and engendering the interest of national and international institutions in important MN health issues and research methodologies. In the view of most participants, government agencies should strive to have research results inform the decision-making process in which they are involved. Thus these agencies would play a key role in facilitating and funding research. Participants also pointed to the importance of academic recognition and financial rewards in attracting professionals to primary and translational research in MN health. In addition, they suggested that institutions should create intramural resources to provide researchers with technical support in designing, carrying out and disseminating research, including resources to improve scientific writing skills.</p> <p>Conclusion</p> <p>Fulfillment of these recommendations would increase research production in MN health in Latin American countries. This, in turn, will raise the profile of these health problems, and consequently will underscore the need of continued high-quality and relevant research, thus fostering a virtuous cycle in the decision-making process to improve MN health care.</p

    Characterizing Long COVID: Deep Phenotype of a Complex Condition.

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    BACKGROUND: Numerous publications describe the clinical manifestations of post-acute sequelae of SARS-CoV-2 (PASC or long COVID ), but they are difficult to integrate because of heterogeneous methods and the lack of a standard for denoting the many phenotypic manifestations. Patient-led studies are of particular importance for understanding the natural history of COVID-19, but integration is hampered because they often use different terms to describe the same symptom or condition. This significant disparity in patient versus clinical characterization motivated the proposed ontological approach to specifying manifestations, which will improve capture and integration of future long COVID studies. METHODS: The Human Phenotype Ontology (HPO) is a widely used standard for exchange and analysis of phenotypic abnormalities in human disease but has not yet been applied to the analysis of COVID-19. FINDINGS: We identified 303 articles published before April 29, 2021, curated 59 relevant manuscripts that described clinical manifestations in 81 cohorts three weeks or more following acute COVID-19, and mapped 287 unique clinical findings to HPO terms. We present layperson synonyms and definitions that can be used to link patient self-report questionnaires to standard medical terminology. Long COVID clinical manifestations are not assessed consistently across studies, and most manifestations have been reported with a wide range of synonyms by different authors. Across at least 10 cohorts, authors reported 31 unique clinical features corresponding to HPO terms; the most commonly reported feature was Fatigue (median 45.1%) and the least commonly reported was Nausea (median 3.9%), but the reported percentages varied widely between studies. INTERPRETATION: Translating long COVID manifestations into computable HPO terms will improve analysis, data capture, and classification of long COVID patients. If researchers, clinicians, and patients share a common language, then studies can be compared/pooled more effectively. Furthermore, mapping lay terminology to HPO will help patients assist clinicians and researchers in creating phenotypic characterizations that are computationally accessible, thereby improving the stratification, diagnosis, and treatment of long COVID. FUNDING: U24TR002306; UL1TR001439; P30AG024832; GBMF4552; R01HG010067; UL1TR002535; K23HL128909; UL1TR002389; K99GM145411
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