Gold nanoparticle and mean inactivation dose of human intestinal colon cancer HT-29 cells

Background: Mean inactivation dose is a useful radiobiological parameter for the comparison of human cell survival curves. Objectives: Given the importance and accuracy of these parameters, in the present study, the radio sensitivity enhancement of colon cancer (HT-29) cells in the presence of gold nanoparticles (GNPs) were studied using the mean inactivation dose (MID). Materials and Methods: Naked-GNPs with 50 nm diameters were incubated with HT-29 cells. The cytotoxicity and uptake of these particles on HT-29 cells were assessed. After determining the optimum GNPs concentration, the cells were incubated with gold nanoparticle for 24 hours. The change in the MID value as well as the radio sensitization enhancement under irradiation with 9 MV X-ray beams in the presence of GNPs were evaluated by multiple (3-(4, 5-dimethylthiazol-2-yl)-5-(3-carboxymethoxyphenyl)-2-(4-sulfophenyl)-2H-tetrazolium)MTS assay. Results: Cell survival in the presence of GNPs was more than 90% and the maximum uptake of GNPs was observed at 60 μM of gold nanoparticles. In contrast, in the presence of GNPs combined with radiation, cell survival and MID value significantly decreased, so that the radio sensitization enhancement was 1.4. Conclusions: Due to the significant reduction in the mean inactivation dose of colon cancer cells in the presence of gold nanoparticles, it seems that GNPs are suitable options to achieve a new approach in order to improve radiotherapy efficiency without increasing the prescribed radiation dose

Loss of heterozygosity is related to p53 mutations and smoking in lung cancer

Carcinogenesis results from an accumulation of several genetic alterations. Mutations in the p53 gene are frequent and occur at an early stage of lung carcinogenesis. Loss of multiple chromosomal regions is another genetic alteration frequently found in lung tumours. We have examined the association between p53 mutations, loss of heterozygosity (LOH) at frequently deleted loci in lung cancer, and tobacco exposure in 165 tumours from non-small cell lung cancer (NSCLC) patients. A highly significant association between p53 mutations and deletions on 3p, 5q, 9p, 11p and 17p was found. There was also a significant correlation between deletions at these loci. 86% of the tumours with concordant deletion in the 4 most involved loci (3p21, 5q11–13, 9p21 and 17p13) had p53 mutations as compared to only 8% of the tumours without deletions at the corresponding loci (P< 0.0001). Data were also examined in relation to smoking status of the patients and histology of the tumours. The frequency of deletions was significantly higher among smokers as compared to non-smokers. This difference was significant for the 3p21.3 (hMLH1 locus), 3p14.2 (FHIT locus), 5q11–13 (hMSH3 locus) and 9p21 (D9S157 locus). Tumours with deletions at the hMLH1 locus had higher levels of hydrophobic DNA adducts. Deletions were more common in squamous cell carcinomas than in adenocarcinomas. Covariate analysis revealed that histological type and p53 mutations were significant and independent parameters for predicting LOH status at several loci. In the pathogenesis of NSCLC exposure to tobacco carcinogens in addition to clonal selection may be the driving force in these alterations. © 2001 Cancer Research Campaign http://www.bjcancer.co

Monoclinic superstructure in the orthorhombic Ce10W22O81 from transmission electron microscopy

International audienceA complex rare earth tungstate structure, present in a two-phased powder, was solved by electron diffraction, precession and high resolution electron microscopy. The orthorhombic space group Pbnm and the atomic positions deduced from X-rays diffraction experiments were confirmed for Ce10W22O81. A C2/c monoclinic superstructure, with cell parameters a = 7.8 Å, b = 36.1 Å, c = 22.2 Å and β = 100.2°, was evidenced and attributed to a partial oxidation of Ce3+ leading to interstitial oxygen ions

Help-Seeking Attitudes of United Arab Emirates Students

© Division of Counseling Psychology of the American Psychological Association. The psychological help-seeking patterns of college students in the United Arab Emirates (UAE) have only recently begun to be examined. Initial suggestions indicate that the majority of Emirati students treat help seeking from counselors as a last resort, which may be linked to aspects of Emirati culture including feared loss of societal face, stigma associated with seeking help, and discouragement of self-disclosure to individuals outside of the family. The relationship among fear of losing face, stigma, self-disclosure expectations (i.e., risks and benefits), and help-seeking attitudes was examined using structural equation modeling with 407 Emirati college students. Loss of face and stigma were related to self-disclosure expectations, which in turn were related to help-seeking attitudes. Gender differences were also examined with results indicating significant mean differences across all variables, as well as across two paths of the structural model. These findings are discussed within the cultural context of the UAE

How and Why is An Answer (Still) Correct? Maintaining Provenance in Dynamic Knowledge Graphs

Knowledge graphs (KGs) have increasingly become the backbone of many critical knowledge-centric applications. Most large-scale KGs used in practice are automatically constructed based on an ensemble of extraction techniques applied over diverse data sources. Therefore, it is important to establish the provenance of results for a query to determine how these were computed. Provenance is shown to be useful for assigning confidence scores to the results, for debugging the KG generation itself, and for providing answer explanations. In many such applications, certain queries are registered as standing queries since their answers are needed often. However, KGs keep continuously changing due to reasons such as changes in the source data, improvements to the extraction techniques, refinement/enrichment of information, and so on. This brings us to the issue of efficiently maintaining the provenance polynomials of complex graph pattern queries for dynamic and large KGs instead of having to recompute them from scratch each time the KG is updated. Addressing these issues, we present HUKA which uses provenance polynomials for tracking the derivation of query results over knowledge graphs by encoding the edges involved in generating the answer. More importantly, HUKA also maintains these provenance polynomials in the face of updates---insertions as well as deletions of facts---to the underlying KG. Experimental results over large real-world KGs such as YAGO and DBpedia with various benchmark SPARQL query workloads reveals that HUKA can be almost 50 times faster than existing systems for provenance computation on dynamic KGs

Accelerating Universe from an Evolving Lambda in Higher Dimension

We find exact solutions in five dimensional inhomogeneous matter dominated model with a varying cosmological constant. Adjusting arbitrary constants of integration one can also achieve acceleration in our model. Aside from an initial singularity our spacetime is regular everywhere including the centre of the inhomogeneous distribution. We also study the analogous homogeneous universe in (4+d) dimensions. Here an initially decelerating model is found to give late acceleration in conformity with the current observational demands. We also find that both anisotropy and number of dimensions have a role to play in determining the time of flip, in fact the flip is delayed in multidimensional models. Some astrophysical parameters like the age, luminosity distance etc are also calculated and the influence of extra dimensions is briefly discussed. Interestingly our model yields a larger age of the universe compared to many other quintessential models.Comment: 18 pages, 9 figure

Physical structure of the photodissociation regions in NGC 7023: Observations of gas and dust emission with <i>Herschel</i>

The determination of the physical conditions in molecular clouds is a key step towards our understanding of their formation and evolution of associated star formation. We investigate the density, temperature, and column density of both dust and gas in the photodissociation regions (PDRs) located at the interface between the atomic and cold molecular gas of the NGC 7023 reflection nebula. We study how young stars affect the gas and dust in their environment. Our approach combining both dust and gas delivers strong constraints on the physical conditions of the PDRs. We find dense and warm molecular gas of high column density in the PDRs