203 research outputs found

    Intuitive Understanding of sigma Delocalization in Loose and sigma Localization in Tight Helical Conformations of a Saturated Chain Oligosilanes

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    Conformational effects on the amp; 963; electron delocalization in oligosilanes are addressed by Hartree Fock and time dependent density functional theory calculations B3LYP, 6 311G at MP2 optimized geometries of permethylated uniformly helical linear oligosilanes all amp; 969; SinR2n 2 up to n 16 and for backbone dihedral angles amp; 969; 55 180 . The extent of amp; 963; delocalization is judged by the partition ratio of the highest occupied molecular orbital and is reflected in the dependence of its shape and energy and of UV absorption spectra on n. The results agree with known spectra of all transoid loose helix conformers all [ 165] SinMe2n 2 and reveal a transition at amp; 969; amp; 8776;90 from the amp; 963; delocalized limit at amp; 969; 180 toward and close to the physically non realizable amp; 963; localized tight helix limit amp; 969; 0 with entirely different properties. The distinction is also obtained in the Hückel Ladder H and C models of amp; 963; delocalization. An easy intuitive way to understand the origin of the two contrasting limits is to first view the linear chain as two subchains with alternating primary and vicinal interactions amp; 963; hyperconjugation , one consisting of the odd and the other of the even amp; 963; SiSi bonds, and then allow the two subchains to interact by geminal interactions amp; 963; conjugatio

    DSBOX: herramienta docente para el diseño y simulación de entornos de red virtualizados

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    En este trabajo se describe DSBOX, una herramienta gráfica para el diseño y simulación empleando virtualización de pequeñas redes de computadores. Se describe el contexto que ha dado origen a esta herramienta y se detalla su arquitectura y las optimizaciones que se han realizado con el fin de dotar a los alumnos de una herramienta operativa que les facilite la realización de prácticas relacionadas con la seguridad informática y la administración de sistemas. Se presenta también un repositorio de actividades prácticas que hacen uso de la herramienta desarrollada.This paper describes DSBOX, a graphical tool for the design and simulation of small computer networks, employing virtualization software. We describe the context where this tool was created and its architecture and the optimizations that have been made in order to provide our students with a tool giving support to teaching activities in computer security and systems management. Finally, a repository with practical exer-cises using this tool is also described

    ME20-S as a Potential Biomarker for the Evaluation of Uveal Melanoma

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    PURPOSE: We previously identified the presence of the melanocyte-specific secreted (ME20-S) glycoprotein in secretomes of uveal melanoma (UM) cultures. The aim of this study was to test for the presence and levels of ME20-S in the serum of patients with choroidal nevi and UM and correlate these levels with individual clinical data. METHODS: Serum ME20-S levels were determined by ELISA in 111 patients distributed into four categories (53 choroidal nevi, 30 untreated UM, 11 10-year disease-free [DF] UM, 17 hepatic metastatic UM) and 32 age- and sex-matched controls. ME20-S levels were correlated with individual clinical data. RESULTS: The UM and the metastatic groups showed significantly higher levels of serum ME20-S than the other groups (P < 0.001). ME20-S levels in the DF patients did not differ from those in the control group. In addition, log-transformed serum ME20-S levels showed a positive correlation with the thickness of the lesion mass in UM patients (regression coefficient 0.0689, 95% confidence interval 0.0689-0.1123, R2 = 27.1%). CONCLUSIONS: Elevated ME20-S serum levels are associated with tumor size and advanced stages of UM while low levels are characteristic of DF patients. ME20-S might be a promising serum marker for UM and useful for monitoring metastatic disease

    Marine Fish Calendar. 4 Cochin

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    The article provides details about the marine fish landing at Cochin fisheries harbour, Kerala during the period 1981-1985. It was found that the majority of the landing was contributed by purse seine followed by trawlers, drift gill nets, boat seines, hooks and lines etc

    Rendimiento del ASAS Health Index en pacientes con Espondiloartritis de la vida real

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    Introducción: el cuestionario “Assessment of Spondyloarthritis International Society Health In- dex” (ASAS-HI) fue desarrollado para medir de manera global la funcionalidad y el estado de salud en pacientes con espondiloartritis (EspA). Se han propuesto puntos de corte para determinar diferentes estados de salud que fueron poco evaluados en pacientes de la vida real. Objetivos: describir el estado de salud medido por ASAS-HI en pacientes argentinos con EspA axial (EspAax) y periférica (EspAp) en la práctica diaria y evaluar los factores asociados al pobre estado de salud. Materiales y métodos: Estudio de corte transversal, analítico y multicéntrico. Se incluyeron consecutivamente pacientes con EspAax y EspAp según criterios ASAS, de 15 centros argentinos. Análisis estadístico: se realizó estadística descriptiva, análisis bivariado y multivariado (regresión logística múltiple) para evaluar los factores asociados al pobre estado de salud (ASAS-HI ≥12). Para analizar la validez de constructo de la herramienta se realizó correlación de Spearman entre el ASAS-HI y otros parámetros de evaluación de la enfermedad. Resultados: se incluyeron 274 pacientes con EspA, con una edad media de 49 (±14) años y una duración mediana de la enfermedad de 62 meses (p25-75: 24-135), 155 (56,6%) de los pacientes eran de sexo masculino, 129 pacientes (47%) con EspAax y 145 (52,9%) EspAp. Según el ASAS-HI 119 pacientes (43,4%) presentaban buen estado de salud, 117 (42,7%) tenían estado de salud moderado y 38 (13.9%) pobre estado de salud. En los pacientes con EspAp el valor de ASAS-HI mediano fue de 7 (p25-75: 3-10). El ASAS-HI correlacionó positivamente con: DAS28: rho: 0.5 (p<0.001) y HAQ: rho: 0.54 (p<0.001). La variable asociada de manera independiente con pobre estado de salud fue el DAS28 (OR: 1.9, IC95% 1.1- 3.4, p: 0.029). En los pacientes con EspAax el valor de ASAS-HI mediano fue de 6 (p25-75: 2.75-10). El ASAS-HI mostró correlación con: BASDAI: rho: 0.7 (p<0.001), ASDAS-ERS: rho: 0.7 (p<0,001), ASQoL: rho: 0.8 (p<0.001), BASFI rho: 0.75 (p<0.001). La variable que se asoció de manera independiente a pobre estado de salud fue el ASDAS-ERS (OR 6.6, IC95% 2-22, p 0.002). Conclusión: Un pobre estado de salud se asoció independientemente a mayor actividad de la enfermedad en pacientes con EspAax y EspAp. El ASAS-HI correlacionó con otros parámetros de la enfermedad, lo que refuerza la validez de constructo de esta nueva herramienta

    Indentation of the Pamirs with respect to the northern margin of Tibet: constraints from the Tarim basin sedimentary record

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    The Pamirs represent the indented westward continuation of the northern margin of the Tibetan Plateau, dividing the Tarim and Tajik basins. Their evolution may be a key factor influencing aridification of the Asian interior, yet the tectonics of the Pamir Salient are poorly understood. We present a provenance study of the Aertashi section, a Paleogene to late Neogene clastic succession deposited in the Tarim basin to the north of the NW margin of Tibet (the West Kunlun) and to the east of the Pamirs. Our detrital zircon U-Pb ages coupled with zircon fission track, bulk rock Sm-Nd, and petrography data document changes in contributing source terranes during the Oligocene to Miocene, which can be correlated to regional tectonics. We propose a model for the evolution of the Pamir and West Kunlun (WKL), in which the WKL formed topography since at least ~200 Ma. By ~25 Ma, movement along the Pamir-bounding faults such as the Kashgar-Yecheng Transfer System had commenced, marking the onset of Pamir indentation into the Tarim-Tajik basin. This is coincident with basinward expansion of the northern WKL margin, which changed the palaeodrainage pattern within the Kunlun, progressively cutting off the more southerly WKL sources from the Tarim basin. An abrupt change in the provenance and facies of sediments at Aertashi has a maximum age of 14 Ma; this change records when the Pamir indenter had propagated sufficiently far north that the North Pamir was now located proximal to the Aertashi region

    Evaluation of receptor and chemical transport models for PM10 source apportionment

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    In this study, the performance of two types of source apportionment models was evaluated by assessing the results provided by 40 different groups in the framework of an intercomparison organised by FAIRMODE WG3 (Forum for air quality modelling in Europe, Working Group 3). The evaluation was based on two performance indicators: z-scores and the root mean square error weighted by the reference uncertainty (RMSEu), with pre-established acceptability criteria. By involving models based on completely different and independent input data, such as receptor models (RMs) and chemical transport models (CTMs), the intercomparison provided a unique opportunity for their cross-validation. In addition, comparing the CTM chemical profiles with those measured directly at the source contributed to corroborate the consistency of the tested model results. The most commonly used RM was the US EPA- PMF version 5. RMs showed very good performance for the overall dataset (91% of z-scores accepted) while more difficulties were observed with the source contribution time series (72% of RMSEu accepted). Industrial activities proved to be the most difficult sources to be quantified by RMs, with high variability in the estimated contributions. In the CTMs, the sum of computed source contributions was lower than the measured gravimetric PM10 mass concentrations. The performance tests pointed out the differences between the two CTM approaches used for source apportionment in this study: brute force (or emission reduction impact) and tagged species methods. The sources meeting the z-score and RMSEu acceptability criteria tests were 50% and 86%, respectively. The CTM source contributions to PM10 were in the majority of cases lower than the RM averages for the corresponding source. The CTMs and RMs source contributions for the overall dataset were more comparable (83% of the z-scores accepted) than their time series (successful RMSEu in the range 25% - 34%). The comparability between CTMs and RMs varied depending on the source: traffic/exhaust and industry were the source categories with the best results in the RMSEu tests while the most critical ones were soil dust and road dust. The differences between RMs and CTMs source reconstructions confirmed the importance of cross validating the results of these two families of models

    The role of clonal communication and heterogeneity in breast cancer

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    Background: Cancer is a rapidly evolving, multifactorial disease that accumulates numerous genetic and epigenetic alterations. This results in molecular and phenotypic heterogeneity within the tumor, the complexity of which is further amplified through specific interactions between cancer cells. We aimed to dissect the molecular mechanisms underlying the cooperation between different clones. Methods: We produced clonal cell lines derived from the MDA-MB-231 breast cancer cell line, using the UbC-StarTrack system, which allowed tracking of multiple clones by color: GFP C3, mKO E10 and Sapphire D7. Characterization of these clones was performed by growth rate, cell metabolic activity, wound healing, invasion assays and genetic and epigenetic arrays. Tumorigenicity was tested by orthotopic and intravenous injections. Clonal cooperation was evaluated by medium complementation, co-culture and co-injection assays. Results: Characterization of these clones in vitro revealed clear genetic and epigenetic differences that affected growth rate, cell metabolic activity, morphology and cytokine expression among cell lines. In vivo, all clonal cell lines were able to form tumors; however, injection of an equal mix of the different clones led to tumors with very few mKO E10 cells. Additionally, the mKO E10 clonal cell line showed a significant inability to form lung metastases. These results confirm that even in stable cell lines heterogeneity is present. In vitro, the complementation of growth medium with medium or exosomes from parental or clonal cell lines increased the growth rate of the other clones. Complementation assays, co-growth and co-injection of mKO E10 and GFP C3 clonal cell lines increased the efficiency of invasion and migration. Conclusions: These findings support a model where interplay between clones confers aggressiveness, and which may allow identification of the factors involved in cellular communication that could play a role in clonal cooperation and thus represent new targets for preventing tumor progression
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