14,756 research outputs found

    Investigating the effect of tunnelling on existing tunnels

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    A major research project investigating the effect of tunnelling on existing tunnels has been completed at Imperial College London. This subject is always of great concern during the planning and execution of underground tunnelling works in the urban environment. Many cities already have extensive existing tunnel networks and so it is necessary to construct new tunnels at a level beneath them. The associated deformations that take place during tunnelling have to be carefully assessed and their impact on the existing tunnels estimated. Of particular concern is the serviceability of tunnels used for underground trains where the kinematic envelope must not be impinged upon. The new Crossrail transport line under construction in London passes beneath numerous tunnels including a number of those forming part of the London Underground networ

    Parent-Child Joint Behaviors in Novel Object Play Create High-Quality Data for Word Learning.

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    This research takes a dyadic approach to study early word learning and focuses on toddlers' (N = 20, age: 17-23 months) information seeking and parents' information providing behaviors and the ways the two are coupled in real-time parent-child interactions. Using head-mounted eye tracking, this study provides the first detailed comparison of children's and their parents' behavioral and attentional patterns in two free-play contexts: one with novel objects with to-be-learned names (Learning condition) and the other with familiar objects with known names (Play condition). Children and parents in the Learning condition modified their individual and joint behaviors when encountering novel objects with to-be-learned names, which created clearer signals that reduced referential ambiguity and potentially facilitated word learning

    Evaporation induced flow inside circular wells

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    Flow field and height averaged radial velocity inside a droplet evaporating in an open circular well were calculated for different modes of liquid evaporation.Comment: 5 page, 3 figures, submitted to European Physical Journal

    Estimating prevalence of distant metastatic breast cancer: a means of filling a data gap

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    PURPOSE: To develop and validate a method for estimating numbers of people with distant cancer metastases, for evidence-based service planning. METHODS: Estimates were made employing an illness-death model with distant metastatic cancer as the illness state- and site-specific mortality as an outcome, using MIAMOD software. To demonstrate the method, we estimated numbers of females alive in Australia following detection of distant metastatic breast cancer during 1980-2004, using data on patient survival from an Australian population-based cancer registry. We validated these estimates by comparing them with direct prevalence counts. RESULTS: Relative survival at 10 years following detection of distant metastases was low (5-20 %), with better survival experienced by: (1) females where distant metastatic disease was detected at initial diagnosis rather than subsequently (e.g., at recurrence); (2) those diagnosed in more recent calendar years; and (3) younger age groups. For Australian females aged less than 85 years, the modeled cumulative risk of detection of distant metastatic breast cancer (either at initial diagnosis or subsequently) declined over time, but numbers of cases with this history rose from 71 per 100,000 in 1980 to 84 per 100,000 in 2004. The model indicated that there were approximately 3-4 prevalent distant metastatic breast cancer cases for every breast cancer death. Comparison of estimates with direct prevalence counts showed a reasonable level of agreement. CONCLUSIONS: The method is straightforward to apply and we recommend its use for breast and other cancers when registry data are insufficient for direct prevalence counts. This will provide estimates of numbers of people who would need ongoing medical surveillance and care following detection of distant metastase

    Absolute quantitation of DNA methylation of 28 candidate genes in prostate cancer using pyrosequencing

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    This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.Aberrant DNA methylation plays a pivotal role in carcinogenesis and its mapping is likely to provide biomarkers for improved diagnostic and risk assessment in prostate cancer (PCa). We quantified and compared absolute methylation levels among 28 candidate genes in 48 PCa and 29 benign prostate hyperplasia (BPH) samples using the pyrosequencing (PSQ) method to identify genes with diagnostic and prognostic potential. RARB, HIN1, BCL2, GSTP1, CCND2, EGFR5, APC, RASSF1A, MDR1, NKX2-5, CDH13, DPYS, PTGS2, EDNRB, MAL, PDLIM4, HLAa, ESR1 and TIG1 were highly methylated in PCa compared to BPH (p < 0.001), while SERPINB5, CDH1, TWIST1, DAPK1, THRB, MCAM, SLIT2, CDKN2a and SFN were not. RARB methylation above 21% completely distinguished PCa from BPH. Separation based on methylation level of SFN, SLIT2 and SERPINB5 distinguished low and high Gleason score cancers, e.g. SFN and SERPINB5 together correctly classified 81% and 77% of high and low Gleason score cancers respectively. Several genes including CDH1 previously reported as methylation markers in PCa were not confirmed in our study. Increasing age was positively associated with gene methylation (p < 0.0001). Accurate quantitative measurement of gene methylation in PCa appears promising and further validation of genes like RARB, HIN1, BCL2, APC and GSTP1 is warranted for diagnostic potential and SFN, SLIT2 and SERPINB5 for prognostic potential

    Geometric phase outside a Schwarzschild black hole and the Hawking effect

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    We study the Hawking effect in terms of the geometric phase acquired by a two-level atom as a result of coupling to vacuum fluctuations outside a Schwarzschild black hole in a gedanken experiment. We treat the atom in interaction with a bath of fluctuating quantized massless scalar fields as an open quantum system, whose dynamics is governed by a master equation obtained by tracing over the field degrees of freedom. The nonunitary effects of this system are examined by analyzing the geometric phase for the Boulware, Unruh and Hartle-Hawking vacua respectively. We find, for all the three cases, that the geometric phase of the atom turns out to be affected by the space-time curvature which backscatters the vacuum field modes. In both the Unruh and Hartle-Hawking vacua, the geometric phase exhibits similar behaviors as if there were thermal radiation at the Hawking temperature from the black hole. So, a measurement of the change of the geometric phase as opposed to that in a flat space-time can in principle reveal the existence of the Hawking radiation.Comment: 14 pages, no figures, a typo in the References corrected, version to appear in JHEP. arXiv admin note: text overlap with arXiv:1109.033

    Microcystic cyanobacteria extract induces cytoskeletal disruption and intracellular glutathione alteration in hepatocytes.

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    Microcystins are a group of highly liver-specific toxins, although their exact mechanisms of action remain unclear. We examined the effects of microcystic cyanobacteria extract (MCE) collected from a contaminated water source on the organization of cellular microtubules (MTs) and microfilaments (MFs) in hepatocytes. We also investigated the effects on lactate dehydrogenase (LDH) leakage and intracellular glutathione (GSH). Primary cultured rat hepatocytes exposed to MCE (equivalent to 125 microg/mL lyophilized algae cells) showed a characteristic disruption of MTs and MFs in a time-dependent manner. Under these conditions, MCE caused aggregation of MTs and MFs and a severe loss of MTs in some cells. Moreover, MCE-induced cytoskeletal alterations preceded the LDH leakage. On the other hand, the treatment of cells with MCE led to a dose-dependent increase of intracellular GSH. However, time-course study showed a biphasic change of intracellular GSH levels with a significant increase in the initial stage followed by a decrease after prolonged treatment. Furthermore, pretreatment with N-acetylcystein (NAC), a GSH precursor, significantly enhanced the intracellular GSH level and decreased the MCE-induced cytotoxicity as well as cytoskeleton changes. In contrast, buthionine-(S, R)-sulfoximine, a specific GSH synthesis inhibitor, increased the cell susceptibility to MCE-induced cytotoxicity by depleting the intracellular GSH level. These findings suggest that intracellular GSH plays an important role in MCE-induced cytotoxicity and cytoskeleton changes in primary cultured rat hepatocytes. Increasing intracellular GSH levels protect cells from MCE-induced cytotoxicity and cytoskeleton changes
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