253 research outputs found

    In‐situ microbially induced Ca2+‐alginate polymeric sealant for seepage control in porous materials

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    This paper presents a novel approach of using in-situ microbially induced Ca2+-alginate polymeric sealant for seepage control in porous materials. This process comprises two steps: (i) generation of insoluble calcium carbonate inside the pores of porous materials (such as sand) through a microbially induced carbonate precipitation (MICP) process in-situ and (ii) injection of sodium alginate for in-situ gelation via reaction between alginate and Ca2+ions. The experimental results showed that the hydraulic conductivity/permeability of sand decreased with the increase in alginate concentration. When 5% alginate was used with a CaCO3concentration of 0.18 g g-1sand, the permeability of the alginate-treated sand reduced from 5.0 × 10-4to 2.2 × 10-9 m s-1. The scanning electron microscopy images revealed that a film-type coating was formed around sand particles with spherical round crystals embedded. Furthermore, the in-situ formed Ca-alginate polymeric sealant can also be used for the removal of Cu2+ion and suspended particles from contaminated water by more than 90%. Built on the current research, the envisioned practical application of the proposed method may include clogging fractured rock, reducing seepage and prevent piping through dams, excavation dewatering, and forming barriers for remediating specific contaminants

    Influence of early colour degradation of asphalt pavements on their thermal behaviour

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    Environmental goals such as the reduction of fossil fuel consumption or greenhouse gas (GHG) emissions through the development of new renewable energy sources have led to the emergence of the so called asphalt solar collectors. Moreover, in recent years, engineers are devoting increased interest to the effect of the thermal loads on the mechanical behaviour of pavements. Several approaches to these topics can be found in the literature. However, a study of the influence of the colour degradation suffered by pavements on their thermal behaviour is still necessary since both the efficient application of the asphalt collectors and the proper study of the effect of the solar radiation on the asphalt pavement behaviour are directly affected by the loss of colour occurring as time goes by. Therefore, the thermal behaviour of two different asphalt mixes was studied before and after being subjected to a colour degradation process. The degradation of five different asphalt mixes was studied and the results were compared to those obtained in the access roads to seven low volume car parks. The final results show that there are large differences between the two asphalt mixes with different gradations and densities. The importance attributed by other authors to conductivity was also confirmed. Furthermore, the results showed that it was possible to simulate the early colour degradation suffered by a low volume road. Finally, a slight reduction in temperature and energy collection capacity was measured after the colour degradation process

    Thermostable Direct Hemolysin Downregulates Human Colon Carcinoma Cell Proliferation with the Involvement of E-Cadherin, and β-Catenin/Tcf-4 Signaling

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    BACKGROUND: Colon cancers are the frequent causes of cancer mortality worldwide. Recently bacterial toxins have received marked attention as promising approaches in the treatment of colon cancer. Thermostable direct hemolysin (TDH) secreted by Vibrio parahaemolyticus causes influx of extracellular calcium with the subsequent rise in intracellular calcium level in intestinal epithelial cells and it is known that calcium has antiproliferative activity against colon cancer. KEY RESULTS: In the present study it has been shown that TDH, a well-known traditional virulent factor inhibits proliferation of human colon carcinoma cells through the involvement of CaSR in its mechanism. TDH treatment does not induce DNA fragmentation, nor causes the release of lactate dehydrogenase. Therefore, apoptosis and cytotoxicity are not contributing to the TDH-mediated reduction of proliferation rate, and hence the reduction appears to be caused by decrease in cell proliferation. The elevation of E-cadherin, a cell adhesion molecule and suppression of β-catenin, a proto-oncogene have been observed in presence of CaSR agonists whereas reverse effect has been seen in presence of CaSR antagonist as well as si-RNA in TDH treated cells. TDH also triggers a significant reduction of Cyclin-D and cdk2, two important cell cycle regulatory proteins along with an up regulation of cell cycle inhibitory protein p27(Kip1) in presence of CaSR agonists. CONCLUSION: Therefore TDH can downregulate colonic carcinoma cell proliferation and involves CaSR in its mechanism of action. The downregulation occurs mainly through the involvement of E-cadherin-β-catenin mediated pathway and the inhibition of cell cycle regulators as well as upregulation of cell cycle inhibitors

    Gravitational waves from single neutron stars: an advanced detector era survey

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    With the doors beginning to swing open on the new gravitational wave astronomy, this review provides an up-to-date survey of the most important physical mechanisms that could lead to emission of potentially detectable gravitational radiation from isolated and accreting neutron stars. In particular we discuss the gravitational wave-driven instability and asteroseismology formalism of the f- and r-modes, the different ways that a neutron star could form and sustain a non-axisymmetric quadrupolar "mountain" deformation, the excitation of oscillations during magnetar flares and the possible gravitational wave signature of pulsar glitches. We focus on progress made in the recent years in each topic, make a fresh assessment of the gravitational wave detectability of each mechanism and, finally, highlight key problems and desiderata for future work.Comment: 39 pages, 12 figures, 2 tables. Chapter of the book "Physics and Astrophysics of Neutron Stars", NewCompStar COST Action 1304. Minor corrections to match published versio

    What are the competences in information system required by managers? Curriculum development for management and public administration degrees

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    [EN] This paper analyzes the competences required by executives to manage information system, and consequently, the competences that must define the information system subjects in non-technical degrees, degrees, such as Public Administration or Business Management. This work reviews the literature about business managers competences on Information Technologies (IT) and compares the theory with the traditional body of knowledge about information systems taught at business schools. By analyzing the executives function, their role in the information system management, and, above, all the importance of their decisions in the effective integration of IT in business processes, this work proposes specific development in seven knowledge areas that facilitate the acquisition of these types of executive competencesDevece Carañana, CA.; Peris-Ortiz, M.; Rueda Armengot, C. (2016). What are the competences in information system required by managers? 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    Stakeholder views on secondary findings in whole-genome and whole-exome sequencing:a systematic review of quantitative and qualitative studies

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    Purpose: As whole-exome and whole-genome sequencing (WES/WGS) move into routine clinical practice, it is timely to review data that might inform the debate around secondary findings (SF) and the development of policies that maximize participant benefit. Methods: We systematically searched for qualitative and quantitative studies that explored stakeholder views on SF in WES/WGS. Framework analysis was undertaken to identify major themes. Results: 44 articles reporting the views of 11,566 stakeholders were included. Stakeholders were broadly supportive of returning ‘actionable’ findings, but definitions of actionability varied. Stakeholder views on SF disclosure exist along a spectrum: potential WES/WGS recipients’ views were largely influenced by a sense of rights, while views of genomics professionals were informed by a sense of professional responsibility. Experience of genetic illness and testing resulted in greater caution about SF, suggesting that truly informed decisions require an understanding of the implications and limitations of WES/WGS and possible findings. Conclusion: This review suggests that bidirectional interaction during consent might best facilitate informed decision-making about SF, and that dynamic forms of consent, allowing for changing preferences, should be considered. Research exploring views from wider perspectives and from recipients who have received SF is critical if evidence-based policies are to be achieved.</p

    Colour categories are reflected in sensory stages of colour perception when stimulus issues are resolved

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    Debate exists about the time course of the effect of colour categories on visual processing. We investigated the effect of colour categories for two groups who differed in whether they categorised a blue-green boundary colour as the same- or different-category to a reliably-named blue colour and a reliably-named green colour. Colour differences were equated in just-noticeable differences to be equally discriminable. We analysed event-related potentials for these colours elicited on a passive visual oddball task and investigated the time course of categorical effects on colour processing. Support for category effects was found 100 ms after stimulus onset, and over frontal sites around 250 ms, suggesting that colour naming affects both early sensory and later stages of chromatic processing

    NICE : A Computational solution to close the gap from colour perception to colour categorization

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    The segmentation of visible electromagnetic radiation into chromatic categories by the human visual system has been extensively studied from a perceptual point of view, resulting in several colour appearance models. However, there is currently a void when it comes to relate these results to the physiological mechanisms that are known to shape the pre-cortical and cortical visual pathway. This work intends to begin to fill this void by proposing a new physiologically plausible model of colour categorization based on Neural Isoresponsive Colour Ellipsoids (NICE) in the cone-contrast space defined by the main directions of the visual signals entering the visual cortex. The model was adjusted to fit psychophysical measures that concentrate on the categorical boundaries and are consistent with the ellipsoidal isoresponse surfaces of visual cortical neurons. By revealing the shape of such categorical colour regions, our measures allow for a more precise and parsimonious description, connecting well-known early visual processing mechanisms to the less understood phenomenon of colour categorization. To test the feasibility of our method we applied it to exemplary images and a popular ground-truth chart obtaining labelling results that are better than those of current state-of-the-art algorithms

    Comparative genomic and transcriptomic analysis revealed genetic characteristics related to solvent formation and xylose utilization in Clostridium acetobutylicum EA 2018

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    <p>Abstract</p> <p>Background</p> <p><it>Clostridium acetobutylicum</it>, a gram-positive and spore-forming anaerobe, is a major strain for the fermentative production of acetone, butanol and ethanol. But a previously isolated hyper-butanol producing strain <it>C. acetobutylicum </it>EA 2018 does not produce spores and has greater capability of solvent production, especially for butanol, than the type strain <it>C. acetobutylicum </it>ATCC 824.</p> <p>Results</p> <p>Complete genome of <it>C. acetobutylicum </it>EA 2018 was sequenced using Roche 454 pyrosequencing. Genomic comparison with ATCC 824 identified many variations which may contribute to the hyper-butanol producing characteristics in the EA 2018 strain, including a total of 46 deletion sites and 26 insertion sites. In addition, transcriptomic profiling of gene expression in EA 2018 relative to that of ATCC824 revealed expression-level changes of several key genes related to solvent formation. For example, <it>spo0A </it>and <it>adhEII </it>have higher expression level, and most of the acid formation related genes have lower expression level in EA 2018. Interestingly, the results also showed that the variation in CEA_G2622 (CAC2613 in ATCC 824), a putative transcriptional regulator involved in xylose utilization, might accelerate utilization of substrate xylose.</p> <p>Conclusions</p> <p>Comparative analysis of <it>C. acetobutylicum </it>hyper-butanol producing strain EA 2018 and type strain ATCC 824 at both genomic and transcriptomic levels, for the first time, provides molecular-level understanding of non-sporulation, higher solvent production and enhanced xylose utilization in the mutant EA 2018. The information could be valuable for further genetic modification of <it>C. acetobutylicum </it>for more effective butanol production.</p

    Neoplastic transformation of rat liver epithelial cells is enhanced by non-transferrin-bound iron

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    <p>Abstract</p> <p>Background</p> <p>Iron overload is associated with liver toxicity, cirrhosis, and hepatocellular carcinoma in humans. While most iron circulates in blood as transferrin-bound iron, non-transferrin-bound iron (NTBI) also becomes elevated and contributes to toxicity in the setting of iron overload. The mechanism for iron-related carcinogenesis is not well understood, in part due to a shortage of suitable experimental models. The primary aim of this study was to investigate NTBI-related hepatic carcinogenesis using T51B rat liver epithelial cells, a non-neoplastic cell line previously developed for carcinogenicity and tumor promotion studies.</p> <p>Methods</p> <p>T51B cells were loaded with iron by repeated addition of ferric ammonium citrate (FAC) to the culture medium. Iron internalization was documented by chemical assay, ferritin induction, and loss of calcein fluorescence. Proliferative effects were determined by cell count, toxicity was determined by MTT assay, and neoplastic transformation was assessed by measuring colony formation in soft agar. Cyclin levels were measured by western blot.</p> <p>Results</p> <p>T51B cells readily internalized NTBI given as FAC. Within 1 week of treatment at 200 μM, there were significant but well-tolerated toxic effects including a decrease in cell proliferation (30% decrease, p < 0.01). FAC alone induced little or no colony formation in soft agar. In contrast, FAC addition to cells previously initiated with N-methyl-N'-nitro-N-nitrosoguanidine (MNNG) resulted in a concentration dependent increase in colony formation. This was first detected at 12 weeks of FAC treatment and increased at longer times. At 16 weeks, colony formation increased more than 10 fold in cells treated with 200 μM FAC (p < 0.001). The iron chelator desferoxamine reduced both iron uptake and colony formation. Cells cultured with 200 μM FAC showed decreased cyclin D1, decreased cyclin A, and increased cyclin B1.</p> <p>Conclusion</p> <p>These results establish NTBI as a tumor promoter in T51B rat liver epithelial cells. Changes in cyclin proteins suggest cell cycle disregulation contributes to tumor promotion by NTBI in this liver cell model.</p
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