American University in Cairo

About: American University in Cairo is a education organization based out in Cairo, Egypt. It is known for research contribution in the topics: Population & Context (language use). The organization has 2472 authors who have published 5339 publications receiving 73741 citations.

Gastric adenocarcinoma has a unique microRNA signature not present in esophageal adenocarcinoma

Abstract: BACKGROUND MicroRNAs (miRNAs) play critical roles in tumor development and progression. The finding that a single miRNA can regulate hundreds of genes places miRNAs at critical hubs of signaling pathways. For the current study, the authors investigated the miRNA expression profile of gastric adenocarcinomas and compared it with esophageal adenocarcinomas to better identify a unique miRNA signature of gastric adenocarcinoma. METHODS miRNA expression profiles were obtained using 2 different proprietary microarray platforms on primary gastric adenocarcinoma tissue samples. The cross comparison of results identified 17 up-regulated miRNAs and 12 down-regulated miRNAs that overlapped in both platforms. Quantitative real-time polymerase chain reaction was performed for independent validation of a representative set of 8 miRNAs in gastric and esophageal adenocarcinomas compared with normal gastric mucosa or esophageal mucosa, respectively. RESULTS The deregulation of miR-146b-5p, miR-375, miR-148a, miR-31, and miR-451 was associated significantly with gastric adenocarcinomas. Conversely, deregulation of miR-21 (up-regulation) and miR-133b (down-regulation) was detectable in both gastric and esophageal adenocarcinomas. It was noteworthy that miR-200a was significantly down-regulated in gastric adenocarcinoma samples (P = .04) but was up-regulated in esophageal adenocarcinoma samples (P = .001). In addition, the expression level of miR-146b-5p displayed a strong correlation with the tumor stage of gastric cancer. CONCLUSIONS Gastric adenocarcinoma displayed a unique miRNA signature that distinguished it from esophageal adenocarcinoma. This specific signature may reflect differences in the etiology and/or molecular signaling in these 2 closely related cancers. The current findings suggest important miRNA candidates that can be investigated for their biological functions and for their possible diagnostic, prognostic, and therapeutic role in gastric adenocarcinoma. Cancer 2013;119:1985–1993. © 2013 American Cancer Society.

Military expenditures and inequality in the middle east and north africa: a panel analysis

Abstract: Middle Eastern and North African (MENA) countries have been characterized by the preponderant role of their military forces in economic matters, as demonstrated by the high levels of military spending and the growing industrial complex. While extensive research examines the relationship between military expenditure and economic growth, little attention has been paid to the effect of military expenditure on economic inequality. Studying inequality in MENA countries provides an opportunity to assess factors that shape the countries’ level of economic well-being, which has greater public policy implications in terms of how society allocates its scarce resources among competing needs. This paper examines two important issues. In the first part of the paper, we examine the relationship between military spending and inequality in MENA countries using a panel regression for country-level observations over the period 1987–2005. The empirical results indicate that military spending has a strong and negative effect...

Fabrication of nanostructured W–Y2O3 materials by chemical methods

Abstract: A novel method for the fabrication of highly uniform oxide dispersion-strengthened (ODS) materials made by chemical processing is presented. The powders are fabricated by a two-step route starting with a chemical synthesis at room temperature, producing nanocrystalline yttrium doped tungsten trioxide hydrate precursor powders. Thermogravimetric analysis with evolved gas analysis revealed the presence of ammonium nitrate in the precursors. The second step is the reduction of the precursor in a hydrogen atmosphere at 600 and 800 °C. The reduced powders, containing W-1.2%Y2O3, showed two types of tungsten particles, cube-shaped with a size less than 250 nm and finer particles (<50 nm) of both spherical and cubic shape. The powder was consolidated by spark plasma sintering at 1100 °C, producing a bulk material with a relative density of 88%. Characterization of the sintered materials by high resolution scanning electron microscopy revealed a uniform microstructure with tungsten grains of less than 300 nm and nanosized oxide particles uniformly dispersed at the tungsten grain boundaries, as well as inside the tungsten grains. Experimental determination of the elastic properties was conducted by nanoindentation tests and fracture toughness was studied by radial indentation cracking.

Multiple pheromone types and other extensions to the Ant-Miner classification rule discovery algorithm

Abstract: Ant-Miner is an ant-based algorithm for the discovery of classification rules. This paper proposes five extensions to Ant-Miner: (1) we utilize multiple types of pheromone, one for each permitted rule class, i.e. an ant first selects the rule class and then deposits the corresponding type of pheromone; (2) we use a quality contrast intensifier to magnify the reward of high-quality rules and to penalize low-quality rules in terms of pheromone update; (3) we allow the use of a logical negation operator in the antecedents of constructed rules; (4) we incorporate stubborn ants, an ACO variation in which an ant is allowed to take into consideration its own personal past history; (5) we use an ant colony behavior in which each ant is allowed to have its own values of the α and β parameters (in a sense, to have its own personality). Empirical results on 23 datasets show improvements in the algorithm’s performance in terms of predictive accuracy and simplicity of the generated rule set.