New Boundary Element Method For Analysis Of Surface Subsidence Due To Coal Mining

Rock and coal in coal bearing formation belong to layered sedimentary rocks. Their large-scale subsidence may occur because of coal mining. Thus, it is one of research highlights to develop an analytical tool suitable for these layered rocks. This paper presents a new Boundary Element Method(BEM) for analysis of the surface subsidence due to coal mining. The BEM uses the fundamental solution of layered materials,4-8 noded elements to discretize the boundaries, and effective numerical methods to calculate the singular integrals. An example with exact solutions is used to verify the numerical method. Finally, the numerical method is used to analyze in situ surface subsidence due to coal mining. The result shows that the proposed BEM can analyze the surface subsidence due to coal mining with high efficiency and good accuracy. 煤系地層為成層分布的沉積巖,煤層的開采會引起地表大規模的沉陷,發展適應此類介質的分析方法一直是本領域的研究熱點。本文發展了一種新型的邊界元方法來分析煤層開采引起的地表移動。該邊界元方法基于層狀材料基本解,采用4~8變結點單元離散邊界,并采用有效的數值方法計算各類奇異積分。然后,用有解析解的算例驗證建議數值方法。最后,采用新型邊界元方法分析煤層開采引起的地表移動。本文所建議的方法在分析煤層開采引起的地表沉陷時具有較高的計算精度和效率

The Search for Higher TcT_c in Houston

It is a great pleasure to be invited to join the chorus on this auspicious occasion to celebrate Professor K. Alex Mueller's 90th birthday by Professors Annette Bussman-Holder, Hugo Keller, and Antonio Bianconi. As a student in high temperature superconductivity, I am forever grateful to Professor Alex Mueller and Dr. Georg Bednorz "for their important breakthrough in the discovery of superconductivity in the ceramic materials" in 1986 as described in the citation of their 1987 Nobel Prize in Physics. It is this breakthrough discovery that has ushered in the explosion of research activities in high temperature superconductivity (HTS) and has provided immense excitement in HTS science and technology in the ensuing decades till now. Alex has not been resting on his laurels and has continued to search for the origin of the unusual high temperature superconductivity in cuprates.Comment: Dedicated to Alex Mueller, whose "important breakthrough in the discovery of superconductivity in ceramic materials" in 1986 has changed the world of superconductivit

QTL Mapping of Combining Ability and Heterosis of Agronomic Traits in Rice Backcross Recombinant Inbred Lines and Hybrid Crosses

BACKGROUND: Combining ability effects are very effective genetic parameters in deciding the next phase of breeding programs. Although some breeding strategies on the basis of evaluating combining ability have been utilized extensively in hybrid breeding, little is known about the genetic basis of combining ability. Combining ability is a complex trait that is controlled by polygenes. With the advent and development of molecular markers, it is feasible to evaluate the genetic bases of combining ability and heterosis of elite rice hybrids through QTL analysis. METHODOLOGY/PRINCIPAL FINDINGS: In the present study, we first developed a QTL-mapping method for dissecting combining ability and heterosis of agronomic traits. With three testcross populations and a BCRIL population in rice, biometric and QTL analyses were conducted for ten agronomic traits. The significance of general combining ability and special combining ability for most of the traits indicated the importance of both additive and non-additive effects on expression levels. A large number of additive effect QTLs associated with performance per se of BCRIL and general combining ability, and dominant effect QTLs associated with special combining ability and heterosis were identified for the ten traits. CONCLUSIONS/SIGNIFICANCE: The combining ability of agronomic traits could be analyzed by the QTL mapping method. The characteristics revealed by the QTLs for combining ability of agronomic traits were similar with those by multitudinous QTLs for agronomic traits with performance per se of BCRIL. Several QTLs (1-6 in this study) were identified for each trait for combining ability. It demonstrated that some of the QTLs were pleiotropic or linked tightly with each other. The identification of QTLs responsible for combining ability and heterosis in the present study provides valuable information for dissecting genetic basis of combining ability

Genetic dissection of heterosis using epistatic association mapping in a partial NCII mating design

Heterosis refers to the phenomenon in which an F1 hybrid exhibits enhanced growth or agronomic performance. However, previous theoretical studies on heterosis have been based on bi-parental segregating populations instead of F1 hybrids. To understand the genetic basis of heterosis, here we used a subset of F1 hybrids, named a partial North Carolina II design, to perform association mapping for dependent variables: original trait value, general combining ability (GCA), specific combining ability (SCA) and mid-parental heterosis (MPH). Our models jointly fitted all the additive, dominance and epistatic effects. The analyses resulted in several important findings: 1) Main components are additive and additive-by-additive effects for GCA and dominance-related effects for SCA and MPH, and additive-by-dominant effect for MPH was partly identified as additive effect; 2) the ranking of factors affecting heterosis was dominance > dominance-by-dominance > over-dominance > complete dominance; and 3) increasing the proportion of F1 hybrids in the population could significantly increase the power to detect dominance-related effects, and slightly reduce the power to detect additive and additive-by-additive effects. Analyses of cotton and rapeseed datasets showed that more additive-by-additive QTL were detected from GCA than from trait phenotype, and fewer QTL were from MPH than from other dependent variables

DNA methylation-associated inactivation of TGFβ-related genes DRM/Gremlin, RUNX3, and HPP1 in human cancers

The transforming growth factor β (TGFβ)-signalling pathway is deregulated in many cancers. We examined the role of gene silencing via aberrant methylation of DRM/Gremlin and HPP1, which inhibit TGFβ signalling, and RUNX3, which facilitates TGFβ-signalling, of all genes that are thought to be tumour suppressors, are aberrantly expressed, and are thus thought to have important role in human cancers. We examined DRM/Gremlin mRNA expression in 44 cell lines and the promoter methylation status of DRM/Gremlin, HPP1, and RUNX3 in 44 cell lines and 511 primary tumours. The loss of DRM/Gremlin mRNA expression in human cancer cell lines is associated with DNA methylation, and treatment with the methylation inhibitor-reactivated mRNA expression (n=13). Methylation percentages of the three genes ranged from 0–83% in adult tumours and 0–50% in paediatric tumours. Methylation of DRM/Gremlin was more frequent in lung tumours in smokers, and methylation of all three genes was inversely correlated with prognosis in patients with bladder or prostate cancer. Our results provide strong evidence that these TGFβ-related genes are frequently deregulated through aberrant methylation in many human malignancies

Coaction of Spheroid-Derived Stem-Like Cells and Endothelial Progenitor Cells Promotes Development of Colon Cancer

Although some studies described the characteristics of colon cancer stem cells (CSCs) and the role of endothelial progenitor cells (EPCs) in neovascularization, it is still controversial whether an interaction exists or not between CSCs and EPCs. In the present study, HCT116 and HT29 sphere models, which are known to be the cells enriching CSCs, were established to investigate the roles of this interaction in development and metastasis of colon cancer. Compared with their parental counterparts, spheroid cells demonstrated higher capacity of invasion, higher tumorigenic and metastatic potential. Then the in vitro and in vivo relationship between CSCs and EPCs were studied by using capillary tube formation assay and xenograft models. Our results showed that spheroid cells could promote the proliferation, migration and tube formation of EPCs through secretion of vascular endothelial growth factor (VEGF). Meanwhile, the EPCs could increase tumorigenic capacity of spheroid cells through angiogenesis. Furthermore, higher microvessel density was detected in the area enriching cancer stem cells in human colon cancer tissue. Our findings indicate that spheroid cells possess the characteristics of cancer stem cells, and the coaction of CSCs and EPCs may play an important role in the development of colon cancer

Mastermind Mutations Generate a Unique Constellation of Midline Cells within the Drosophila CNS

Background: The Notch pathway functions repeatedly during the development of the central nervous system in metazoan organisms to control cell fate and regulate cell proliferation and asymmetric cell divisions. Within the Drosophila midline cell lineage, which bisects the two symmetrical halves of the central nervous system, Notch is required for initial cell specification and subsequent differentiation of many midline lineages. Methodology/Principal Findings: Here, we provide the first description of the role of the Notch co-factor, mastermind, in the central nervous system midline of Drosophila. Overall, zygotic mastermind mutations cause an increase in midline cell number and decrease in midline cell diversity. Compared to mutations in other components of the Notch signaling pathway, such as Notch itself and Delta, zygotic mutations in mastermind cause the production of a unique constellation of midline cell types. The major difference is that midline glia form normally in zygotic mastermind mutants, but not in Notch and Delta mutants. Moreover, during late embryogenesis, extra anterior midline glia survive in zygotic mastermind mutants compared to wild type embryos. Conclusions/Significance: This is an example of a mutation in a signaling pathway cofactor producing a distinct centra