2,652 research outputs found

    Wet Weather Impact on Trihalomethane Formation Potential in tributaries to Drinking Water Reservoirs

    Get PDF
    During rain storm events, land surface runoff and resuspension of bottom sediments cause an increase in Trihalomethane (THM) precursors in rivers. These precursors, when chlorinated at water treatment facilities will lead to the formation of THMs and hence impact drinking water resources. In order to evaluate the wet weather impact on the potential formation of THMs, river samples were collected before, during and after three rain storms ranging from 15.2 to 24.9 mm precipitation. The samples were tested for THM formation potential and other indicators including UV254 absorbance, turbidity and volatile suspended solid (VSS). Average levels of THMs increased from 61 microg/l during dry weather to 131 microg/l during wet weather, and then went back to 81 microg/l after rain ended. Wet weather values of THM are well above the maximum contaminant level (MCL) 80 microg/l, set by EPA for drinking water. THM indicators also exhibited similar trends. Average levels increased from 0.6 to 1.8 abs; 2.6 to 6 ntu; and 7.5 to 15 mg/l respectively for UV254, turbidity and VSS. A positive correlation was observed between THM formation and THM indicators. The t-test of significance (p-value) was less than 0.05 for all indicators, and R values ranged from 0.85 to 0.92 between THMs and the indicators, and 0.72 to 0.9 among indicators themselves

    A General Theorem and Proof for the Identification of Composed CFA Models

    Get PDF
    In this article, we present a general theorem and proof for the global identification of composed CFA models. They consist of identified submodels that are related only through covariances between their respective latent factors. Composed CFA models are frequently used in the analysis of multimethod data, longitudinal data, or multidimensional psychometric data. Firstly, our theorem enables researchers to reduce the problem of identifying the composed model to the problem of identifying the submodels and verifying the conditions given by our theorem. Secondly, we show that composed CFA models are globally identified if the primary models are reduced models such as the CT-C model or similar types of models. In contrast, composed CFA models that include non-reduced primary models can be globally underidentified for certain types of cross-model covariance assumptions. We discuss necessary and sufficient conditions for the global identification of arbitrary composed CFA models and provide a Python code to check the identification status for an illustrative example. The code we provide can be easily adapted to more complex models

    Empirical study of competitive intelligence practice: Evidence from UK retail banking.

    Get PDF
    Winner of Best Paper in Track Prize sponsored by European Journal of MarketingThis paper presents the findings of an empirical study of the major UK retail banks, the purpose of which was to investigate, not only how they operate their competitive intelligence gathering activities, but the degree to which they “buy-in” to the information sharing attitude. The findings were applied to a best practice model which provides a clear picture of the current status of CI in these establishments and the attitudes of senior managers toward such activity. Recommendations are made on the improvements which would be required for the sector to be considered effective and efficient operators of CI practice

    Chemical modification of rat liver cytosolic NADP+-linked isocitrate dehydrogenase by N-ethylmaleimide Evidence for essential sulphydryl groups

    Get PDF
    AbstractIncubation of rat liver cytosolic isocitrate dehydrogenase with N-ethylmaleimide (NEM) resulted in the inactivation of the enzyme following pseudo-first order kinetics. Isocitrate affords considerable protection against inactivation whereas NADP+ enhances modification of the enzyme, suggesting localization of the modified group at the active site. Correlation of loss of activity with incorporation of [14C]NEM indicated that two sulphydryl residues/sub-unit are modified of which only one is shown to be involved in catalysis. pH dependence of the inactivation process implicates a reactive group of pKa 8.1 in catalysis. We conclude that a unique cysteine residue is essential for maximal catalytic activity of isocitrate dehydrogenase

    Unmasking the interplay between mTOR and Nox4: novel insights into the mechanism connecting diabetes and cancer

    Get PDF
    Cancer was recently annexed to diabetic complications. Furthermore, recent studies suggest that cancer can increase the risk of diabetes. Consequently, diabetes and cancer share many risk factors, but the cellular and molecular pathways correlating diabetes and colon and rectal cancer (CRC) remain far from understood. In this study, we assess the effect of hyperglycemia on cancer cell aggressiveness in human colon epithelial adenocarcinoma cells in vitro and in an experimental animal model of CRC. Our results show that Nox (NADPH oxidase enzyme) 4-induced reactive oxygen species (ROS) production is deregulated in both diabetes and CRC. This is paralleled by inactivation of the AMPK and activation of the mammalian target of rapamycin (mTOR) C1 signaling pathways, resulting in 8-oxo-7,8-dihydro-2'-deoxyguanosine (8-oxodG) accumulation, induction of DNA damage, and exacerbation of cancer cell aggressiveness, thus contributing to the genomic instability and predisposition to increased tumorigenesis in the diabetic milieu. Pharmacologic activation of AMPK, inhibition of mTORC1, or blockade of Nox4 reduce ROS production, restore the homeostatic signaling of 8-oxoguanine DNA glycosylase/8-oxodG, and lessen the progression of CRC malignancy in a diabetic milieu. Taken together, our results identify the AMPK/mTORC1/Nox4 signaling axis as a molecular switch correlating diabetes and CRC. Modulating this pathway may be a strategic target of therapeutic potential aimed at reversing or slowing the progression of CRC in patients with or without diabetes.-Mroueh, F. M., Noureldein, M., Zeidan, Y. H., Boutary, S., Irani, S. A. M., Eid, S., Haddad, M., Barakat, R., Harb, F., Costantine, J., Kanj, R., Sauleau, E.-A., Ouhtit, A., Azar, S. T., Eid, A. H., Eid, A. A. Unmasking the interplay between mTOR and Nox4: novel insights into the mechanism connecting diabetes and cancer.Scopu
    corecore