Review komatiites: from Earth’s geological settings to planetary and astrobiological contexts

23 pages (final publisher version), 55 pages (attached post-print version).-- Published online: 15 February 2007.-- ArXiv pre-print available at: http://arxiv.org/abs/physics/0512118Komatiites are fascinating volcanic rocks. They are among the most ancient lavas of the Earth following the 3.8 Ga pillow basalts at Isua and they represent some of the oldest ultramafic magmatic rocks preserved in the Earth’s crust at 3.5 Ga. This fact, linked to their particular features (high magnesium content, high melting temperatures, low dynamic viscosities, etc.), has attracted the community of geoscientists since their discovery in the early sixties, who have tried to determine their origin and understand their meaning in the context of terrestrial mantle evolution. In addition, it has been proposed that komatiites are not restricted to our planet, but they could be found in other extraterrestrial settings in our Solar System (particularly on Mars and Io). It is important to note that komatiites may be extremely significant in the study of the origins and evolution of Life on Earth. They not only preserve essential geochemical clues of the interaction between the pristine Earth rocks and atmosphere, but also may have been potential suitable sites for biological processes to develop. Thus, besides reviewing the main geodynamic, petrological and geochemical characteristics of komatiites, this paper also aims to widen their investigation beyond the classical geological prospect, calling attention to them as attractive rocks for research in Planetology and Astrobiology.We acknowledge the grant support of the National Institute of Aerospace Technique "Esteban Terradas" (INTA)—Centro de Astrobiología.Peer reviewe

Experimental Tests of Discrete Strengthened Elements of Machine-Building Structures

Computer simulation and bench tests of components and full-scale structures of internal combustion engine are performed in order to evaluate discrete and continual strengthening technology. The contact pressure distributions, friction coefficients, wear, roughness and hardness of the contacting surfaces of the tested machine parts were determined. The numerical characteristics that determine the effectiveness of such combined strengthening method are established. Conceptual fundamentals of discrete continual strengthening have been developed. Positive effects in the “load – contact – friction – wear” chain were found due to the proposed strengthening method. The positive effect of the coordination of micro and macroscale processes and states of loaded parts, which are strengthened by the discrete and continuous method, is also established. It is confirmed that the entire set of tribo-mechanical characteristics is improved with such strengthening, in contrast to traditional methods, an application of which results in improvement in some characteristics at the cost of the others

Обнаружение моментов изменения свойств временных рядов на примере производственных данных в нефтегазодобывающей отрасли

Объект исследования – Обнаружение моментов изменения свойств временных рядов на примере производственных данных в нефтегазодобывающей отрасли. Цель работы: Разработка ПО для алгоритмов скачков параметров нефтегазовых скважин.. В процессе исследования проводились: обзор изменений свойств временных рядов, обзор технологий программирования, программная реализация алгоритма, постановка генератора тестовых данных. В результате было разработано программное обеспечение для обнаружение моментов изменения свойств временных рядов на примере геоинформационных данных, позволяющее обнаружить процесс неполадок, своевременный ремонт и замена оборудования. Область применения: нефтегазовая отрасль, экономическая областьThe object of study - Finding points change the properties of time series data on the example of the production in the oil and gas industry. Objective: Development of software for algorithm jumps parameters of oil and gas wells .. The study was conducted with an overview of changes in the properties of time series an overview of programming techniques, software implementation of the algorithm, setting the generator test data. As a result, we developed software to detect when changes in the properties of time series an example of geospatial data, allowing you to detect process problems, timely repair and replacement of equipment. Applications: oil and gas industry, the economic are

Strong Expression of Chemokine Receptor CXCR4 by Renal Cell Carcinoma Correlates with Advanced Disease

Diverse chemokines and their receptors have been associated with tumor growth, tumor dissemination, and local immune escape. In different tumor entities, the level of chemokine receptor CXCR4 expression has been linked with tumor progression and decreased survival. The aim of this study was to evaluate the influence of CXCR4 expression on the progression of human renal cell carcinoma. CXCR4 expression of renal cell carcinoma was assessed by immunohistochemistry in 113 patients. Intensity of CXCR4 expression was correlated with both tumor and patient characteristics. Human renal cell carcinoma revealed variable intensities of CXCR4 expression. Strong CXCR4 expression of renal cell carcinoma was significantly associated with advanced T-status (P = .039), tumor dedifferentiation (P = .0005), and low hemoglobin (P = .039). In summary, strong CXCR4 expression was significantly associated with advanced dedifferentiated renal cell carcinoma

Expression of chemokine receptor CXCR4 in esophageal squamous cell and adenocarcinoma

BACKGROUND: Prognosis of esophageal cancer is poor despite curative surgery. The chemokine receptor CXCR4 has been proposed to distinctly contribute to tumor growth, dissemination and local immune escape in a limited number of malignancies. The aim of our study was to evaluate the role of CXCR4 in tumor spread of esophageal cancer with a differentiated view of the two predominant histologic types – squamous cell and adenocarcinoma. METHODS: Esophageal cancer tissue samples were obtained from 102 consecutive patients undergoing esophageal resection for cancer with curative intent. The LSAB+ System was used to detect the protein CXCR4. Tumor samples were classified into two groups based on the homogeneous staining intensity. A cut-off between CXCR4w (= weak expression) and CXCR4s (= strong expression) was set at 1.5 (grouped 0 – 1.5 versus 2.0 – 3). Long-term survival rates were calculated using life tables and the Kaplan-Meier method. Using the Cox's proportional hazards analysis, a model of survival prediction was established. RESULTS: The overall expression rate for CXCR4 in esophageal squamous cell carcinoma was 94.1%. Subdividing these samples, CXCR4w was found in 54.9% and CXCR4s in 45.1%. In adenocarcinoma, an overall expression rate of 89.1% was detected with a weak intensitiy in 71.7% compared to strong staining in 29.3% (p = 0.066 squamous cell versus adenocarcinoma). The Cox's proportional hazards analysis identified the pM-category with a hazard ratio (HR) of 1.860 (95% CI: 1.014–3.414) (p = 0.045), the histologic tumor type (HR: 0.334; 95% CI: 0.180–0.618) (p = 0.0001) and the operative approach (transthoracic > transhiatal esophageal resection) (HR: 0.546; 95% CI: 0.324–0.920) (p = 0.023) as independent factors with a possible influence on the long-term prognosis in patients with esophageal carcinoma, whereas CXCR4 expression was statistically not significant (>0.05). CONCLUSION: Expression of the chemokine receptor CXCR4 in esophageal cancer is of major relevance in both histologic entities – squamous cell and adenocarcinoma. Though with lack of statistical significance, strong CXCR4 expression revealed a poorer long-term prognosis following curative esophagectomy in both histologic subtypes. Thus, the exact biological functions of CXCR4 in terms of tumor dissemination of esophageal cancer is yet undetermined. Inhibition of esophageal cancer progression by CXCR4 antagonists might be a promising therapeutic option in the future

The functional cancer map: A systems-level synopsis of genetic deregulation in cancer

<p>Abstract</p> <p>Background</p> <p>Cancer cells are characterized by massive dysegulation of physiological cell functions with considerable disruption of transcriptional regulation. Genome-wide transcriptome profiling can be utilized for early detection and molecular classification of cancers. Accurate discrimination of functionally different tumor types may help to guide selection of targeted therapy in translational research. Concise grouping of tumor types in cancer maps according to their molecular profile may further be helpful for the development of new therapeutic modalities or open new avenues for already established therapies.</p> <p>Methods</p> <p>Complete available human tumor data of the Stanford Microarray Database was downloaded and filtered for relevance, adequacy and reliability. A total of 649 tumor samples from more than 1400 experiments and 58 different tissues were analyzed. Next, a method to score deregulation of KEGG pathway maps in different tumor entities was established, which was then used to convert hundreds of gene expression profiles into corresponding tumor-specific pathway activity profiles. Based on the latter, we defined a measure for functional similarity between tumor entities, which yielded to phylogeny of tumors.</p> <p>Results</p> <p>We provide a comprehensive, easy-to-interpret functional cancer map that characterizes tumor types with respect to their biological and functional behavior. Consistently, multiple pathways commonly associated with tumor progression were revealed as common features in the majority of the tumors. However, several pathways previously not linked to carcinogenesis were identified in multiple cancers suggesting an essential role of these pathways in cancer biology. Among these pathways were 'ECM-receptor interaction', 'Complement and Coagulation cascades', and 'PPAR signaling pathway'.</p> <p>Conclusion</p> <p>The functional cancer map provides a systematic view on molecular similarities across different cancers by comparing tumors on the level of pathway activity. This work resulted in identification of novel superimposed functional pathways potentially linked to cancer biology. Therefore, our work may serve as a starting point for rationalizing combination of tumor therapeutics as well as for expanding the application of well-established targeted tumor therapies.</p