University of Siena

About: University of Siena is a education organization based out in Siena, Italy. It is known for research contribution in the topics: Population & Cancer. The organization has 12179 authors who have published 33334 publications receiving 1008287 citations. The organization is also known as: Università degli studi di Siena & Universita degli studi di Siena.

An extensive field survey combined with a phylogenetic analysis reveals rapid and widespread invasion of two alien whiteflies in China.

Abstract: Background To understand the processes of invasions by alien insects is a pre-requisite for improving management. The whitefly Bemisia tabaci is a cryptic species complex that contains some of the most invasive pests worldwide. However, extensive field data to show the geographic distribution of the members of this species complex as well as the invasion by some of its members are scarce. Methodology/Principal Findings We used field surveys and published data to assess the current diversity and distribution of B. tabaci cryptic species in China and relate the indigenous members to other Asian and Australian members of the complex. The survey covered the 16 provinces where indigenous B. tabaci occur and extends this with published data for the whole of China. We used molecular markers to identify cryptic species. The evolutionary relationships between the different Asian B. tabaci were reconstructed using Bayesian methods. We show that whereas in the past the exotic invader Middle East-Asia Minor 1 was predominant across China, another newer invader Mediterranean is now the dominant species in the Yangtze River Valley and eastern coastal areas, and Middle East-Asia Minor 1 is now predominant only in the south and south eastern coastal areas. Based on mtCO1 we identified four new cryptic species, and in total we have recorded 13 indigenous and two invasive species from China. Diversity was highest in the southern and southeastern provinces and declined to north and west. Only the two invasive species were found in the northern part of the country where they occur primarily in protected cropping. By 2009, indigenous species were mainly found in remote mountainous areas and were mostly absent from extensive agricultural areas. Conclusions/Significance Invasions by some members of the whitefly B. tabaci species complex can be rapid and widespread, and indigenous species closely related to the invaders are replaced.

PIM1-dependent phosphorylation of histone H3 at serine 10 is required for MYC-dependent transcriptional activation and oncogenic transformation

Abstract: The serine/threonine kinase human Pim1 (hereafter PIM1) cooperates with human c-Myc (hereafter MYC) in cell cycle progression and tumorigenesis. However, the nature of this cooperation is still unknown. Here we show that, after stimulation with growth factor, PIM1 forms a complex with the dimer of MYC with MAX (Myc-associated factor X) via the MYC BoxII (MBII) domain. MYC recruits PIM1 to the E boxes of the MYC-target genes FOSL1 (FRA-1) and ID2, and PIM1 phosphorylates serine 10 of histone H3 (H3S10) on the nucleosome at the MYC-binding sites, contributing to their transcriptional activation. MYC and PIM1 colocalize at sites of active transcription, and expression profile analysis revealed that PIM1 contributes to the regulation of 20% of the MYC-regulated genes. Moreover, PIM1-dependent H3S10 phosphorylation contributes to MYC transforming capacity. These results establish a new function for PIM1 as a MYC cofactor that phosphorylates the chromatin at MYC-target loci and suggest that nucleosome phosphorylation, at E boxes, contributes to MYC-dependent transcriptional activation and cellular transformation.

Analytical maximum-likelihood method to detect patterns in real networks

Abstract: In order to detect patterns in real networks, randomized graph ensembles that preserve only part of the topology of an observed network are systematically used as fundamental null models. However, the generation of them is still problematic. Existing approaches are either computationally demanding and beyond analytic control or analytically accessible but highly approximate. Here, we propose a solution to this long-standing problem by introducing a fast method that allows one to obtain expectation values and standard deviations of any topological property analytically, for any binary, weighted, directed or undirected network. Remarkably, the time required to obtain the expectation value of any property analytically across the entire graph ensemble is as short as that required to compute the same property using the adjacency matrix of the single original network. Our method reveals that the null behavior of various correlation properties is different from what was believed previously, and is highly sensitive to the particular network considered. Moreover, our approach shows that important structural properties (such as the modularity used in community detection problems) are currently based on incorrect expressions, and provides the exact quantities that should replace them.

Influence of ceramic and cement thickness on the masking of various types of opaque posts.

Abstract: Statement of problem: Dark-colored posts may negatively affect the esthetics of all-ceramic single unit crowns as the thin layers of luting cement may not be sufficiently opaque. Purpose: This in vitro study evaluated the influence of the color of 2 commercially available nonmetallic opaque posts (carbon fiber and zirconia) and an experimental esthetic post, and the shade and thickness of luting cements on the esthetics of all-ceramic restorations. Material and methods: Sample disks at several thickness values were made in glass-ceramic (IPS-Empress), an experimental ceramic, a zirconia, a carbon fiber post material, a resin composite material (Z100) as reference, and a luting cement (Variolink II). A laboratory procedure, with 3 possible combinations of stapling the disks, was used. This was performed for 4 substrates, 3 cement colors at 2 thickness values, and 3 heights of ceramic disks. For each combination, the shift in color was measured with a spectrophotometer. Readings were performed for 3 conditions: (1) ability of ceramic to mask the aspect of the abutment in relation to its thickness (1.0, 1.5, or 2.0 mm); (2) effect of a change in cement color (W, Y, or B) on the final color of the ceramic; and (3) influence of cement film thickness (0.1 or 0.2 mm) on the final color of the ceramic. Results: When ceramic thickness was 1 mm, all other variables were visually appreciable. For ceramic thickness of 1.5 mm, color differences decreased and most differences were appreciable only with laboratory instruments. For ceramic thickness of 2.0 mm, there were no detectable, clinically relevant differences. Conclusion: The final esthetic result of the all-ceramic IPS-Empress glass-ceramic restoration was not affected by the presence of different substrates with different colors when the thickness was more than 2.0 mm. When ceramic thickness decreases to 1.5 mm, it is advised to take the substrate aspects into consideration. If the ceramic thickness is less than 1.0 mm, the use of a full ceramic crown is contraindicated because color matching of the abutment is required to ensure an acceptable esthetic result. Differences in cement thickness (0.1 or 0.2 mm) may slightly affect the final result. As this parameter can be controlled by the operator only to a certain extent, it cannot be considered as a procedure to correct color. Availability of different cement shades allows only minor esthetic corrections, which might be instrumentally detectable but are clinically not relevant. (J Prosthet Dent 2000;83:412-7.)