Leaching of Potential Hazardous Elements of Coal Cleaning Rejects

The geochemical characteristics of coal cleaning rejects (CCR) in Santa Catarina State, Brazil, were investigated. Around 3.5 million ton/ year of coal waste are dumped in Santa Catarina State. Coal beneficiation by froth flotation results in large amounts of CCR composed of coaly and mineral matter, the latter characterized by the occurrence of sulphide minerals and a broad array of leachable elements. The total and leachable contents of more than 60 elements were analyzed. Atmospheric exposure promotes sulphide oxidation that releases substantial sulphate loads as well as Ca2+, K+, Mg2+, Cl- and Al3+. The metals with the most severe discharges were Zn, Cu, Mn, Co, Ni and Cd. Most trace pollutants in the CCR displayed a marked pH-dependent solubility, being immobile in near-neutral samples. The results highlight the complex interactions among mineral matter solubility, pH and the leaching of potentially hazardous elements. © 2010 Springer Science+Business Media B.V

Sequential solvent extraction for the modes of occurrence of selenium in coals of different ranks from the Huaibei Coalfield, China

Forms of selenium in bituminous coal, anthracite, and cokeite (natural coke) from Huaibei Coalfield, Anhui, China, have been determined by sequential solvent extraction. The selenium content in bulk samples is 4.0, 2.4, and 2.0 μg/g in bituminous coal, anthracite, and cokeite, respectively. The six forms of selenium determined by six-step solvent extraction are water-leachable, ion-exchangeable, organic matter-associated, carbonate-associated, silicate-associated, and sulfide-associated. The predominant forms of selenium in bituminous coal are organic matter-associated (39.0%), sulfide-associated (21.1%), and silicate bound (31.8%); these three forms account for 92% of the total. The organic matter bound-selenium decrease dramatically from bituminous coal (39.0%) to anthracite (11.6%) and to cokeite (0%), indicating that organic matter bound selenium is converted to other forms during metamorphism of the coal, most likely sulfide-form. The sulfide-associated form increased remarkably from bituminous coal (21.1%) to anthracite (50.4%) and cokeite (54.5%), indicating the formation of selenium sulfide, possibly in pyrite during the transformation of bituminous coal to anthracite and cokeite. The silicate-associated selenium in bituminous coal (31.8%) is much higher than that in anthracite (16.4%) and cokeite (15.8%), indicating that silicate-associated selenium is partly converted to sulfide during metamorphism

Canalization of the evolutionary trajectory of the human influenza virus

Since its emergence in 1968, influenza A (H3N2) has evolved extensively in genotype and antigenic phenotype. Antigenic evolution occurs in the context of a two-dimensional 'antigenic map', while genetic evolution shows a characteristic ladder-like genealogical tree. Here, we use a large-scale individual-based model to show that evolution in a Euclidean antigenic space provides a remarkable correspondence between model behavior and the epidemiological, antigenic, genealogical and geographic patterns observed in influenza virus. We find that evolution away from existing human immunity results in rapid population turnover in the influenza virus and that this population turnover occurs primarily along a single antigenic axis. Thus, selective dynamics induce a canalized evolutionary trajectory, in which the evolutionary fate of the influenza population is surprisingly repeatable and hence, in theory, predictable.Comment: 29 pages, 5 figures, 10 supporting figure

Immunoglobulin G; structure and functional implications of different subclass modifications in initiation and resolution of allergy.

IgE and not IgG is usually associated with allergy. IgE lodged on mast cells in skin or gut and basophils in the blood allows for the prolonged duration of allergy through the persistent expression of high affinity IgE receptors. However, many allergic reactions are not dependent on IgE and are generated in the absence of allergen specific and even total IgE. Instead, IgG plasma cells are involved in induction of, and for much of the pathogenesis of, allergic diseases. The pattern of IgG producing plasma cells in atopic children and the tendency for direct or further class switching to IgE are the principle factors responsible for long-lasting sensitization of mast cells in allergic children. Indirect class switching from IgG producing plasma cells has been shown to be the predominant pathway for production of IgE while a Th2 microenvironment, genetic predisposition, and the concentration and nature of allergens together act on IgG plasma cells in the atopic tendency to undergo further immunoglobulin gene recombination. The seminal involvement of IgG in allergy is further indicated by the principal role of IgG4 in the natural resolution of allergy and as the favourable immunological response to immunotherapy. This paper will look at allergy through the role of different antibodies than IgE and give current knowledge of the nature and role of IgG antibodies in the start, maintenance and resolution of allergy

Definitions, Criteria and Global Classification of Mast Cell Disorders with Special Reference to Mast Cell Activation Syndromes: A Consensus Proposal

Activation of tissue mast cells (MCs) and their abnormal growth and accumulation in various organs are typically found in primary MC disorders also referred to as mastocytosis. However, increasing numbers of patients are now being informed that their clinical findings are due to MC activation (MCA) that is neither associated with mastocytosis nor with a defined allergic or inflammatory reaction. In other patients with MCA, MCs appear to be clonal cells, but criteria for diagnosing mastocytosis are not met. A working conference was organized in 2010 with the aim to define criteria for diagnosing MCA and related disorders, and to propose a global unifying classification of all MC disorders and pathologic MC reactions. This classification includes three types of `MCA syndromes' (MCASs), namely primary MCAS, secondary MCAS and idiopathic MCAS. MCA is now defined by robust and generally applicable criteria, including (1) typical clinical symptoms, (2) a substantial transient increase in serum total tryptase level or an increase in other MC-derived mediators, such as histamine or prostaglandin D 2, or their urinary metabolites, and (3) a response of clinical symptoms to agents that attenuate the production or activities of MC mediators. These criteria should assist in the identification and diagnosis of patients with MCAS, and in avoiding misdiagnoses or overinterpretation of clinical symptoms in daily practice. Moreover, the MCAS concept should stimulate research in order to identify and exploit new molecular mechanisms and therapeutic targets. Copyright (C) 2011 S. Karger AG, Base

MOA-2011-BLG-293Lb: A test of pure survey microlensing planet detections

Because of the development of large-format, wide-field cameras, microlensing surveys are now able to monitor millions of stars with sufficient cadence to detect planets. These new discoveries will span the full range of significance levels including planetary signals too small to be distinguished from the noise. At present, we do not understand where the threshold is for detecting planets. MOA-2011-BLG-293Lb is the first planet to be published from the new surveys, and it also has substantial followup observations. This planet is robustly detected in survey+followup data (Delta chi^2 ~ 5400). The planet/host mass ratio is q=5.3+/- 0.2*10^{-3}. The best fit projected separation is s=0.548+/- 0.005 Einstein radii. However, due to the s-->s^{-1} degeneracy, projected separations of s^{-1} are only marginally disfavored at Delta chi^2=3. A Bayesian estimate of the host mass gives M_L = 0.43^{+0.27}_{-0.17} M_Sun, with a sharp upper limit of M_L < 1.2 M_Sun from upper limits on the lens flux. Hence, the planet mass is m_p=2.4^{+1.5}_{-0.9} M_Jup, and the physical projected separation is either r_perp = ~1.0 AU or r_perp = ~3.4 AU. We show that survey data alone predict this solution and are able to characterize the planet, but the Delta chi^2 is much smaller (Delta chi^2~500) than with the followup data. The Delta chi^2 for the survey data alone is smaller than for any other securely detected planet. This event suggests a means to probe the detection threshold, by analyzing a large sample of events like MOA-2011-BLG-293, which have both followup data and high cadence survey data, to provide a guide for the interpretation of pure survey microlensing data.Comment: 29 pages, 6 figures, Replaced 7/3/12 with the version accepted to Ap

Trace Elements in Coal - Modes of Ocurrence Analysis.

The objective is to provide modes of occurrence information for the CQ Inc. (CQ) effort being performed under DOE Contract entitled HAPs-Rx: Precombustion Removal of Hazardous Air Pollutant Precursors. This work attempts to provide semi-quantative date on modes of occurrence of 15 elements. Coals investigated include as-mined coals and cleaned fines from the Northern Appalachian and Southern Application, and Eastern Interior regions, and as-mined and natural fines from the Powder River Basin. Study techniques include scanning electron microscopy, electron micropole analysis, and leaching procedures. Microprobe data analysis indicate that pyrite grains in Northern Appalachian and Eastern Interior, and Powder River Basin coals and most of the pyrite grains of the Southern Appalachian coal contain low As concentrations, generally in the 100-500 ppm range. However, the Southern Appalachian coal contains some pyrite grains with much higher As contents, in excess of 4.0 wt. percent As. Micropole analyses and data from leaching experiments indicate that arsenic is primarily associated with pyrite in the bituminous coals. These techniques also indicate that Cr is primarily associated with illite. Other HAP`s elements have multiple associations

Dynamin I phosphorylation by GSK3 controls activity-dependent bulk endocytosis of synaptic vesicles.

Glycogen synthase kinase 3 (GSK3) is a critical enzyme in neuronal physiology; however, it is not yet known whether it has any specific role in presynaptic function. We found that GSK3 phosphorylates a residue on the large GTPase dynamin I (Ser-774) both in vitro and in primary rat neuronal cultures. This was dependent on prior phosphorylation of Ser-778 by cyclin-dependent kinase 5. Using both acute inhibition with pharmacological antagonists and silencing of expression with short hairpin RNA, we found that GSK3 was specifically required for activity-dependent bulk endocytosis (ADBE) but not clathrin-mediated endocytosis. Moreover we found that the specific phosphorylation of Ser-774 on dynamin I by GSK3 was both necessary and sufficient for ADBE. These results demonstrate a presynaptic role for GSK3 and they indicate that a protein kinase signaling cascade prepares synaptic vesicles for retrieval during elevated neuronal activity