A large eddy simulation turbulence model for estuary using spline correction

2006-2007 > Academic research: refereed > Publication in refereed journalVersion of RecordPublishe

An incremental shifting vector approach for reliability-based design optimization

© 2015, Springer-Verlag Berlin Heidelberg. This paper proposes a decoupling algorithm for reliability-based design optimization (RBDO) with high performance in terms of efficiency and convergence, which provides an effective tool for reliability design of many complex structures. The algorithm proceeds by performing a shifting vector calculation and then solving a deterministic design optimization in each step, and eventually converges to the optimal solution. An incremental shifting strategy is proposed to ensure stable convergence in the iteration process. In each step, the shifting vector preserves the information from the previous step, and only an adjustment is made for it through a shifting vector increment. A computation method is given for the shifting vector increment, avoiding solving an optimization problem during the reliability analysis and thus greatly reducing the computational cost of the iteration process. Six numerical examples and two engineering applications are presented to validate the effectiveness of the method proposed in this paper

A geographical information system for marine management and its application to Xiamen Bay, China

Use of GIS (geographical information systems) is an effective and efficient method for gathering and processing large quantities of marine data, such as three-dimensional (3-D) time series of velocity vectors and suspended sediment and pollutant concentrations, and for visual display for result interpretation. A MGIS (marine geographical information system) has been developed for Xiamen Bay and other coastal regions in China. The system can handle object spatial property and a variety of data formats. Besides the standard data manipulation, plotting, and retrieval functions of GIS, two hydrodynamic/mass-transport numerical models for tidal flows, sediment transport, and pollutant dispersion have also been incorporated into the MGIS. Most of the modeling pre- and post-processing operations can be finished within the system. The pre-processing includes mesh generation, gathering of boundary and parallel computation information. The post-processing includes result posting, plotting and analysis. The MGIS has been implemented for more than three years and proven to be a useful integrated tool for generating and revealing various kinds of marine environmental information. Output from the MGIS may provide an important tool for harbor management, and feasibility or environmental impact assessment studies for new coastal structures. The system can be easily adopted in other marine areas through loading new databases and re-verifying the numerical model in the new domain

Composition of gut microbiota in infants in China and global comparison

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Overexpression of proto-oncogene FBI-1 activates membrane type 1-matrix metalloproteinase in association with adverse outcome in ovarian cancers

<p>Abstract</p> <p>Background</p> <p>FBI-1 (factor that binds to the inducer of short transcripts of human immunodeficiency virus-1) is a member of the POK (POZ and Kruppel) family of transcription factors and play important roles in cellular differentiation and oncogenesis. Recent evidence suggests that FBI-1 is expressed at high levels in a subset of human lymphomas and some epithelial solid tumors. However, the function of FBI-1 in human ovarian cancers remains elusive.</p> <p>Results</p> <p>In this study, we investigated the role of FBI-1 in human ovarian cancers, in particularly, its function in cancer cell invasion via modulating membrane type 1-matrix metalloproteinase (MT1-MMP). Significantly higher FBI-1 protein and mRNA expression levels were demonstrated in ovarian cancers samples and cell lines compared with borderline tumors and benign cystadenomas. Increased FBI-1 mRNA expression was correlated significantly with gene amplification (P = 0.037). Moreover, higher FBI-1 expression was found in metastatic foci (P = 0.036) and malignant ascites (P = 0.021), and was significantly associated with advanced stage (P = 0.012), shorter overall survival (P = 0.032) and disease-free survival (P = 0.016). <it>In vitro</it>, overexpressed FBI-1 significantly enhanced cell migration and invasion both in OVCA 420 and SKOV-3 ovarian carcinoma cells, irrespective of <it>p53 </it>status, accompanied with elevated expression of MT1-MMP, but not MMP-2 or TIMP-2. Moreover, knockdown of MT1-MMP abolished FBI-1-mediated cell migration and invasion. Conversely, stable knockdown of FBI-1 remarkably reduced the motility of these cells with decreased expression of MT1-MMP. Promoter assay and chromatin immunoprecipitation study indicated that FBI-1 could directly interact with the promoter spanning ~600bp of the 5'-flanking sequence of MT1-MMP and enhanced its expression in a dose-dependent manner. Furthermore, stable knockdown and ectopic expression of FBI-1 decreased and increased cell proliferation respectively in OVCA 420, but not in the p53 null SKOV-3 cells.</p> <p>Conclusions</p> <p>Our results suggested an important role of FBI-1 in ovarian cancer cell proliferation, cell mobility, and invasiveness, and that FBI-1 can be a potential target of chemotherapy.</p

Hypoxia inducible factor 1α gene (HIF-1α) splice variants: potential prognostic biomarkers in breast cancer

<p>Abstract</p> <p>Background</p> <p>Hypoxia-inducible factor 1 (HIF-1) is a master transcriptional regulator of genes regulating oxygen homeostasis. The HIF-1 protein is composed of two HIF-1α and HIF-1β/aryl hydrocarbon receptor nuclear translocator (ARNT) subunits. The prognostic relevance of HIF-1α protein overexpression has been shown in breast cancer. The impact of HIF-1α alternative splice variant expression on breast cancer prognosis in terms of metastasis risk is not well known.</p> <p>Methods</p> <p>Using real-time quantitative reverse transcription PCR assays, we measured mRNA concentrations of total <it>HIF-1α </it>and 4 variants in breast tissue specimens in a series of 29 normal tissues or benign lesions (normal/benign) and 53 primary carcinomas. In breast cancers <it>HIF-1α </it>splice variant levels were compared to clinicopathological parameters including tumour microvessel density and metastasis-free survival.</p> <p>Results</p> <p><it>HIF-1α </it>isoforms containing a three base pairs TAG insertion between exon 1 and exon 2 (designated <it>HIF-1α</it>^<it>TAG</it>) and <it>HIF-1α</it>^{<it>736 </it>}mRNAs were found expressed at higher levels in oestrogen receptor (OR)-negative carcinomas compared to normal/benign tissues (<it>P </it>= 0.009 and <it>P </it>= 0.004 respectively). In breast carcinoma specimens, lymph node status was significantly associated with <it>HIF-1α</it>^{<it>TAG </it>}mRNA levels (<it>P </it>= 0.037). Significant statistical association was found between tumour grade and <it>HIF-1α</it>^{<it>TAG </it>}(<it>P </it>= 0.048), and total <it>HIF-1α </it>(<it>P </it>= 0.048) mRNA levels. <it>HIF-1α</it>^{<it>TAG </it>}mRNA levels were also inversely correlated with both oestrogen and progesterone receptor status (<it>P </it>= 0.005 and <it>P </it>= 0.033 respectively). Univariate analysis showed that high <it>HIF-1α</it>^{<it>TAG </it>}mRNA levels correlated with shortened metastasis free survival (<it>P </it>= 0.01).</p> <p>Conclusions</p> <p>Our results show for the first time that mRNA expression of a <it>HIF-1α</it>^{<it>TAG </it>}splice variant reflects a stage of breast cancer progression and is associated with a worse prognosis.</p> <p>See commentary: <url>http://www.biomedcentral.com/1741-7015/8/45</url></p

Yield Strength of Transparent MgAl2O4 Nano-Ceramic at High Pressure and Temperature

We report here experimental results of yield strength and stress relaxation measurements of transparent MgAl2O4 nano-ceramics at high pressure and temperature. During compression at ambient temperature, the differential strain deduced from peak broadening increased significantly with pressure up to 2 GPa, with no clear indication of strain saturation. However, by then, warming the sample above 400°C under 4 GPa, stress relaxation was obviously observed, and all subsequent plastic deformation cycles are characterized again by peak broadening. Our results reveal a remarkable reduction in yield strength as the sintering temperature increases from 400 to 900°C. The low temperature for the onset of stress relaxation has attracted attention regarding the performance of transparent MgAl2O4 nano-ceramics as an engineering material

Resonances in J/ψ→ϕπ+π−J/\psi \to \phi \pi ^+\pi ^- and ϕK+K−\phi K^+K^-

A partial wave analysis is presented of $J/\psi \to \phi \pi ^+\pi ^-$ and $\phi K^+K^-$ from a sample of 58M $J/\psi$ events in the BES II detector. The $f_0(980)$ is observed clearly in both sets of data, and parameters of the Flatt\' e formula are determined accurately: $M = 965 \pm 8$ (stat) $\pm 6$ (syst) MeV/c$^2$, $g_1 = 165 \pm 10 \pm 15$ MeV/c$^2$, $g_2/g_1 = 4.21 \pm 0.25 \pm 0.21$. The $\phi \pi \pi$ data also exhibit a strong $\pi \pi$ peak centred at $M = 1335$ MeV/c$^2$. It may be fitted with $f_2(1270)$ and a dominant $0^+$ signal made from $f_0(1370)$ interfering with a smaller $f_0(1500)$ component. There is evidence that the $f_0(1370)$ signal is resonant, from interference with $f_2(1270)$. There is also a state in $\pi \pi$ with $M = 1790 ^{+40}_{-30}$ MeV/c$^2$ and $\Gamma = 270 ^{+60}_{-30}$ MeV/c$^2$; spin 0 is preferred over spin 2. This state, $f_0(1790)$, is distinct from $f_0(1710)$. The $\phi K\bar K$ data contain a strong peak due to $f_2'(1525)$. A shoulder on its upper side may be fitted by interference between $f_0(1500)$ and $f_0(1710)$.Comment: 17 pages, 6 figures, 1 table. Submitted to Phys. Lett.

Measurement of the Branching Fraction of J/psi --> pi+ pi- pi0

Using 58 million J/psi and 14 million psi' decays obtained by the BESII experiment, the branching fraction of J/psi --> pi+ pi- pi0 is determined. The result is (2.10+/-0.12)X10^{-2}, which is significantly higher than previous measurements.Comment: 9 pages, 8 figures, RevTex

Search for K_S K_L in psi'' decays

K_S K_L from psi'' decays is searched for using the psi'' data collected by BESII at BEPC, the upper limit of the branching fraction is determined to be B(psi''--> K_S K_L) < 2.1\times 10^{-4} at 90% C. L. The measurement is compared with the prediction of the S- and D-wave mixing model of the charmonia, based on the measurements of the branching fractions of J/psi-->K_S K_L and psi'-->K_S K_L.Comment: 5 pages, 1 figur