1,343 research outputs found

    Role of the ABC transporter ABCG2 in human haematopoiesis

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    ABCG2 is a transporter protein that has the ability to efflux many drugs and fluorescent dyes. Primitive haematopoietic stem cells highly express ABCG2 and the expression level decreases as these cells differentiate indicating a possible role of this transporter in HSC. In the present study, we have analyzed the role of ABCG2 in early haematopoietic stem cells by constitutively expressing ABCG2 in human CB derived CD133+ cells. This constitutive expression of ABCG2 demonstrated an enhancement of primary CFCs in vitro, including the most primitive clonogenic cells the CFU-GEMM (n=12, p<0.002). ABCG2 enhances the replating capacity of primary colonies with a mean 3.0 fold increase in the number of 2nd colonies (n=9, p<0.01), indicating a substantial enhancement of the proliferative potential of clonogenic progenitors by constitutive ABCG2 expression. Overexpression of ABCG2 did not have any positive effect on cell expansion in liquid culture as well as the frequency of LTC-IC, however, the production of CFC per LTC-IC was found to be enhanced, again supporting the fact that ABCG2 might play an important role in the differentiation and proliferation of clonogenic progenitors. Using the NOD/SCID mouse model, we were able to demonstrate that enforced expression of ABCG2 in human primitive haematopoietic cells leads to inversion of lymphoid-myeloid ratio, suggesting that ABCG2 perhaps alters the cell fate decisions of multipotent cells with myeloid and lymphoid differentiation capacity. An enhanced production of differentiated myeloid cells was observed on ABCG2 overexpression. In order to analyze the effect of ABCG2 on early haematopoietic cells, NOD/SCID mice transplanted with CB cells either expressing ABCG2 or the empty viral vector, were analyzed for the presence of HSC. Although the number of human CD34+ CD38- cells did not show any difference, the number of CD34+ CD38+ progenitor cells was significantly increased (n=5, p<0.05), indicating that ABCG2 plays a role in the differentiation of clonogenic progenitors. CRU assays were performed to detect the effect of ABCG2 expression on the frequency of SRC and did not show any significant increase in the frequency of SRC. Taken together, these results indicate that ABCG2 is a potent positive regulator of human hematopoiesis at the level of early haematopoietic development

    TOLEARATION OR RECOGNITION. TOWARDS A NEW ACCOUNT OF RELIGIOUS DIVERSITY IN CONTEMPORARY EGYPT

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    If we portrait Egyptian socio-cultural context in the last few years, we can remarkably find out an avoidable form of contradiction which attaches to daily religious aspects. Now we can see a wide distance of intolerance currently exists in Egyptian's practical which reflect on their daily and formal; religious and cultural dialogues. This case of intolerance dramatically led to various acts of violence and hatred between Muslim and Christian. How can we understand the nature of that contradiction and how possibly can we raise it? Therefore the present study suggests a new theoretical frame of reference aims to recognize the world as characterized by different identities rather than different beliefs and values. This research through anthropological method seeks to describe all forms of tolerance in Egyptian daily life, determining the all forms of relationships between tolerance and other variables like religious pattern, educational status, gender and finally socio-economic class

    Artificial neural networks for diagnosis and survival prediction in colon cancer

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    ANNs are nonlinear regression computational devices that have been used for over 45 years in classification and survival prediction in several biomedical systems, including colon cancer. Described in this article is the theory behind the three-layer free forward artificial neural networks with backpropagation error, which is widely used in biomedical fields, and a methodological approach to its application for cancer research, as exemplified by colon cancer. Review of the literature shows that applications of these networks have improved the accuracy of colon cancer classification and survival prediction when compared to other statistical or clinicopathological methods. Accuracy, however, must be exercised when designing, using and publishing biomedical results employing machine-learning devices such as ANNs in worldwide literature in order to enhance confidence in the quality and reliability of reported data

    Ripening of the AlSi9Cu3ZnMg alloy - mechanical and microstructural characterisation

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    Recovered aluminium has poor mechanical properties, to improve them considerably, three main factors have been considered. The first is to add four very low-density elements to the recovered aluminium, including 9% silicon, 3% copper and some traces of zinc and magnesium less than 1% (≤ 1% Zinc, ≤ 1% Mg), which produces the non-standardized casting alloy AlSi9Cu3ZnMg. Then, in order to obtain a fine microstructure, a gravity die-casting is carried out in the as-cast state noted: F. Finally, to further increase the strength of the F-state and essentially obtain high elasticity stresses, high rigidity modulus with low deformations, the AlSi9Cu3ZnMg alloy composed of 60% scrap and 40% new ingots, is subjected to structural hardening by varying the ripening time for 24 hours in increments of 2 hours, thus giving rise to precipitates of various kinds which impede the dislocations sliding.The results thus obtained show that the cured state for 12 hours (M12h) is a good compromise between good strength and maximum ductility.

    Modified Value of Rock Quality Designation Index RQD in Rock Formation

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    The rock quality designation, RQD, is a commonly index used in the description of rock mass quality. This RQD, index value is used to predict the engineering properties of the rock strata under study. The RQD index value was introduced for the engineering applications, such as mining and geotechnical engineering. Calculating of RQD index for rock formation is a great part due to its simplicity. However, this also leads to a number of limitations, including among other, a dependency of RQDm value on the borehole orientation and on the selected threshold value for the minimum intact core length. In this paper, a new modified RQDm index is introduced to overcome the limitations when assessing the ordinary RQD index value. This modified and corrected value of RQDm index will be more conservative to use for predicting the rock properties than the ordinary RQD

    Ripening of the AlSi9Cu3ZnMg alloy - mechanical and microstructural characterisation

    Get PDF
    Recovered aluminium has poor mechanical properties, to improve them considerably, three main factors have been considered. The first is to add four very low-density elements to the recovered aluminium, including 9% silicon, 3% copper and some traces of zinc and magnesium less than 1% (≤ 1% Zinc, ≤ 1% Mg), which produces the non-standardized casting alloy AlSi9Cu3ZnMg. Then, in order to obtain a fine microstructure, a gravity die-casting is carried out in the as-cast state noted: F. Finally, to further increase the strength of the F-state and essentially obtain high elasticity stresses, high rigidity modulus with low deformations, the AlSi9Cu3ZnMg alloy composed of 60% scrap and 40% new ingots, is subjected to structural hardening by varying the ripening time for 24 hours in increments of 2 hours, thus giving rise to precipitates of various kinds which impede the dislocations sliding.The results thus obtained show that the cured state for 12 hours (M12h) is a good compromise between good strength and maximum ductility.

    Dependence Between Report Lag and Claim Amounts in Property and Casualty Insurance

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    An essential tool for comprehending the variable of interest is possessing a variable that can interpret the behavior of another. The concept of dependency has been intensively researched throughout the years, with numerous models. Copulas are a comprehensive tool for simulating the interdependence of the variables. They provide alternative interpretations of the linear and non-linear relationship between associated random variables and their marginal. In Insurance sector, one of the most risks that the insurers face is holding inefficient provision amounts for claims. This paper explains the dependence structure between the claim amount and the report lag period for claims in the insurance companies
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