Mineralogy and trace elements of the Cretaceous Greymouth coals and their combustion products.

Understanding the spatial distribution trends and modes of occurrence (e.g. physical and chemical forms) of trace elements in coal seams is a key factor to any assessment of their potential impacts on the environment and human health. Two Cretaceous coal seams (E and Main) from the Greymouth coalfield, which is one of the most important coal-producing basins in New Zealand, were chosen for this study. The main objectives of this study are: (a) to delineate the concentration and spatial distribution of trace elements in the two coal seams, (b) to determine the modes of occurrence of trace elements in these coals, (c) to develop models of how trace elements from the Greymouth coalfield behave during combustion, and to assess the potential environmental impacts from mining and combustion of these coals. Examination of 184 samples from both the E and Main seams as well as 94 Main seam-composite samples from a drilling coal quality database, showed that both seams are characterized by great thickness (up to 35m) and low ash yield (<0.6% in some cases). The coals are laterally discontinuous as a result of both faulting and rapid sedimentary facies changes. In general a reverse relationship exists between ash content and coal thickness. Modeling of the lateral variations of major elements in the coal seams identified two possible inorganic sources for these coals. Furthermore, morphological features of minerals (quartz and clays) and the secondary mobilisation of liptinitic materials suggest that the Greymouth coals may have undergone extensive leaching in both peat and post-burial stages. Based on the physical and chemical evidence, a model for the leaching mechanisms has been proposed to explain how the leaching processes may have operated in the Greymouth coals. The major points of this model are: 1. Abundant organic acids in peat stage favor plant degradation and produce ~90% of the inorganics as exchangeable ions, which are active and readily leachable. 2. With rising temperature (30 to 70°C) in the lignite stage, minerals partly dissolve and become mobile. The porous structure of lignite allows exchangeable ions to be leached out of the coalbed through incipient cleats and/or micropores. 3. In the subbituminous to bituminous stages (70 to 170°C), organically bound inorganic elements are expelled due to organic matter breakdown and leached away by percolating solutions through cleat networks. Concentrations of all trace elements of interest are relatively low compared with many overseas coals of similar rank and age, although a few environmentally sensitive elements (As, Pb, Cl) are locally enriched. Due to the low concentrations in the coal beds studied, it is impossible to determine the modes of occurrence of trace elements by direct identification and examination of the host minerals. Thus, a group of direct (SEMEDXA, microprobe and INAA analysis of trace elements in minerals) and complimentarily indirect (float-sink test, sequential leaching tests, inter-elemental correlations) techniques and approaches have been employed to determine the modes of occurrence of trace elements in the Greymouth coals. The following results have been obtained: (1) Most trace elements including some hazardous air pollutants (HAPs) (As, Be, Cr, Hg, Sb and U) are predominantly associated with minerals (mainly clays) in the coal. (2) Some trace elements (B, Br, Cd, Cl, Co, Ni and Se) are bound organically or as sub-micron-sized minerals intimately admixed in the organic matrix. (3) REE, Th and Yare mainly associated with phosphates. (4) The mineral crocoite (PbCr04) is identified for the first time in coal and is a major host for Pb and Cr6+. (5) Some elements usually only associated with sulphides (e.g., As, Hg, Sb and Zn) are mainly within clays in the Greymouth coal seams studied. In addition to examining the distribution and mode of occurrence of trace elements in the Greymouth coal seams, their combustion characteristics were also investigated. The distribution and partitioning of trace elements during combustion was as follows: (1) Most trace elements including some HAPs (As, Co, Cr, Ni, Pb) are predominantly partitioned in the bottom ash, especially in three major phases (Fe-oxides, Si-Al-O glass, and Fe-bearing silicate). As and Mn are predominantly partitioned in the Fe-oxides; most other trace elements are partitioned between the other two phases. (2) In contrast, Sand Hg, and to a lesser extent, B, Cd and Cl, are chiefly partitioned in the flue gas fraction. However, a proportion of Hg (<10%) is probably absorbed onto the surface of fly ash particles, and this fraction of Hg may be freely released into the soil or water. (3) Although the low ash Greymouth coals have the advantage of generating small volumes of solid combustion ashes, one of the consequences is that combustion can enrich the trace elements in the ashes very significantly. For example, B, S, and Cl were enriched to 1100 ppm, 4.4% and 2000 ppm, respectively. Due to the low concentrations of toxic metals in the Greymouth coals and their combustion ashes, no major adverse potential environmental impacts would be expected based on the knowledge gained in this study. But it is prudent to further investigate the release of some toxic metals in the surface and subsurface waters in the coal mining areas and the long-term stockpile sites in the future

Compound C inhibits nonsense-mediated RNA decay independently of AMPK

The nonsense mediated RNA decay (NMD) pathway safeguards the integrity of the transcriptome by targeting mRNAs with premature translation termination codons (PTCs) for degradation. It also regulates gene expression by degrading a large number of non-mutant RNAs (including mRNAs and noncoding RNAs) that bear NMD-inducing features. Consequently, NMD has been shown to influence development, cellular response to stress, and clinical outcome of many genetic diseases. Small molecules that can modulate NMD activity provide critical tools for understanding the mechanism and physiological functions of NMD, and they also offer potential means for treating certain genetic diseases and cancer. Therefore, there is an intense interest in identifying small-molecule NMD inhibitors or enhancers. It was previously reported that both inhibition of NMD and treatment with the AMPK-selective inhibitor Compound C (CC) induce autophagy in human cells, raising the possibility that CC may be capable of inhibiting NMD. Here we show that CC indeed has a NMD-inhibitory activity. Inhibition of NMD by CC is, however, independent of AMPK activity. As a competitive ATP analog, CC does not affect the kinase activity of SMG1, an essential NMD factor and the only known kinase in the NMD pathway. However, CC treatment down-regulates the protein levels of several NMD factors. The induction of autophagy by CC treatment is independent of ATF4, a NMD target that has been shown to promote autophagy in response to NMD inhibition. Our results reveal a new activity of CC as a NMD inhibitor, which has implications for its use in basic research and drug development

Freeway Traffic Density and On-Ramp Queue Control via ILC Approach

A new queue length information fused iterative learning control approach (QLIF-ILC) is presented for freeway traffic ramp metering to achieve a better performance by utilizing the error information of the on-ramp queue length. The QLIF-ILC consists of two parts, where the iterative feedforward part updates the control input signal by learning from the past control data in previous trials, and the current feedback part utilizes the tracking error of the current learning iteration to stabilize the controlled plant. These two parts are combined in a complementary manner to enhance the robustness of the proposed QLIF-ILC. A systematic approach is developed to analyze the convergence and robustness of the proposed learning scheme. The simulation results are further given to demonstrate the effectiveness of the proposed QLIF-ILC

Abolishing the Exemption of Liability for Fault in Ship Management in the Nautical Fault Exemption System

梁永刚，大连海事大学研宄生院2005级海商法硕士研宄生。 李忠胜，威海市威东航运公司运航部经理。【中文摘要】航海过失免责一般表述为：船长、船员、引航员或承运人的受雇人 在驾驶船舶或管理船舶中的行为、疏忽或不履行职责所造成的货物灭失或损坏， 免除承运人的赔偿责任。迄今为止，航海过失免责一直是承运人可援用的最重要 的免责条款，航海过失免责制度的存废也一直是各国和国际海上货物运输立法关 注的焦点之一。本文通过分析航海过失免责的内涵，探悉航海过失免责产生和发 展的社会经济根源，考察当今船货双方利益和风险的分担情况，综合考虑相关因 素，得出对航海过失免责制度进行合理性变革的结论。 【Abstract】The nautical fault exemption generally refers to the carrier,s exemption from liability for the loss or damage of goods arising or resulting from the act, neglect, or default of the master, mariner, pilot, or the servants of the carrier in the navigation or management of the ship. To date, the nautical fault exemption has always been the most important exemption clause for carriers, and countries and legislation on international maritime cargo transport have paid much attention to the question of whether the nautical fault exemption system should continue to exist or be abolished. This paper analyzes the meaning of the nautical fault exemption, explores the socioeconomic roots of its emergence and development, and examines the current allocation of interests and risks between the ship owner and the cargo owner. After taking the relevant factors into account, the paper concludes that the nautical fault exemption system should undergo certain reforms

Context-dependent pro- and anti-resection roles of ZKSCAN3 in the regulation of fork processing during replication stress

Uncontrolled resection of replication forks under stress can cause genomic instability and influence cancer formation. Extensive fork resection has also been implicated in the chemosensitivity of BReast CAncer gene BRCA-deficient cancers. However, how fork resection is controlled in different genetic contexts and how it affects chromosomal stability and cell survival remains incompletely understood. Here, we report a novel function of the transcription repressor ZKSCAN3 in fork protection and chromosomal stability maintenance under replication stress. We show disruption of ZKSCAN3 function causes excessive resection of replication forks by the exonuclease Exo1 and homologous DNA recombination/repair protein Mre11 following fork reversal. Interestingly, in BRCA1-deficient cells, we found ZKSCAN3 actually promotes fork resection upon replication stress. We demonstrate these anti- and pro-resection roles of ZKSCAN3, consisting of a SCAN box, Kruppel-associated box, and zinc finger domain, are mediated by its SCAN box domain and do not require the Kruppel-associated box or zinc finger domains, suggesting that the transcriptional function of ZKSCAN3 is not involved. Furthermore, despite the severe impact on fork structure and chromosomal stability, depletion of ZKSCAN3 did not affect the short-term survival of BRCA1-proficient or BRCA1-deficient cells after treatment with cancer drugs hydroxyurea, PARPi, or cisplatin. Our findings reveal a unique relationship between ZKSCAN3 and BRCA1 in fork protection and add to our understanding of the relationships between replication fork protection, chromosomal instability, and chemosensitivity