Statistical similarity between the compression of a porous material and earthquakes

It has been long stated that there are profound analogies between fracture experiments and earthquakes; however, few works attempt a complete characterization of the parallelisms between these so separate phenomena. We study the Acoustic Emission events produced during the compression of Vycor (SiO2). The Gutenberg-Richter law, the modified Omori's law, and the law of aftershock productivity are found to hold for a minimum of 5 decades, are independent of the compression rate, and keep stationary for all the duration of the experiments. The waiting-time distribution fulfills a unified scaling law with a power-law exponent close to 2.45 for long times, which is explained in terms of the temporal variations of the activity rate.Comment: 4 pages and a bit more, 4 figure

Statistical Similarity between the Compression of a Porous Material and Earthquakes

It has long been stated that there are profound analogies between fracture experiments and earthquakes; however, few works attempt a complete characterization of the parallels between these so separate phenomena. We study the acoustic emission events produced during the compression of Vycor (SiO2). The Gutenberg-Richter law, the modified Omori's law, and the law of aftershock productivity hold for a minimum of 5 decades, are independent of the compression rate, and keep stationary for all the duration of the experiments. The waiting-time distribution fulfills a unified scaling law with a power-law exponent close to 2.45 for long times, which is explained in terms of the temporal variations of the activity rate

Statistical similarity between the compression of a porous material and earthquakes

It has been long stated that there are profound analogies between fracture experiments and earthquakes; however, few works attempt a complete characterization of the parallelisms between these so separate phenomena. We study the Acoustic Emission events produced during the compression of Vycor (SiO&sub&2&/sub&). The Gutenberg-Richter law, the modified Omori's law, and the law of aftershock productivity hold for a minimum of 5 decades, are independent of the compression rate, and keep stationary for all the duration of the experiments. The waiting-time distribution fulfills a unified scaling law with a power-law exponent close to 2.45 for long times, which is explained in terms of the temporal variations of the activity rate

An atlas of over 90.000 conserved noncoding sequences provides insight into crucifer regulatory regions

Despite the central importance of noncoding DNA to gene regulation and evolution, understanding of the extent of selection on plant noncoding DNA remains limited compared to that of other organisms. Here we report sequencing of genomes from three Brassicaceae species (Leavenworthia alabamica, Sisymbrium irio and Aethionema arabicum) and their joint analysis with six previously sequenced crucifer genomes. Conservation across orthologous bases suggests that at least 17% of the Arabidopsis thaliana genome is under selection, with nearly one-quarter of the sequence under selection lying outside of coding regions. Much of this sequence can be localized to approximately 90,000 conserved noncoding sequences (CNSs) that show evidence of transcriptional and post-transcriptional regulation. Population genomics analyses of two crucifer species, A. thaliana and Capsella grandiflora, confirm that most of the identified CNSs are evolving under medium to strong purifying selection. Overall, these CNSs highlight both similarities and several key differences between the regulatory DNA of plants and other species

Genomic investigations of unexplained acute hepatitis in children

Since its first identification in Scotland, over 1,000 cases of unexplained paediatric hepatitis in children have been reported worldwide, including 278 cases in the UK1. Here we report an investigation of 38 cases, 66 age-matched immunocompetent controls and 21 immunocompromised comparator participants, using a combination of genomic, transcriptomic, proteomic and immunohistochemical methods. We detected high levels of adeno-associated virus 2 (AAV2) DNA in the liver, blood, plasma or stool from 27 of 28 cases. We found low levels of adenovirus (HAdV) and human herpesvirus 6B (HHV-6B) in 23 of 31 and 16 of 23, respectively, of the cases tested. By contrast, AAV2 was infrequently detected and at low titre in the blood or the liver from control children with HAdV, even when profoundly immunosuppressed. AAV2, HAdV and HHV-6 phylogeny excluded the emergence of novel strains in cases. Histological analyses of explanted livers showed enrichment for T cells and B lineage cells. Proteomic comparison of liver tissue from cases and healthy controls identified increased expression of HLA class 2, immunoglobulin variable regions and complement proteins. HAdV and AAV2 proteins were not detected in the livers. Instead, we identified AAV2 DNA complexes reflecting both HAdV-mediated and HHV-6B-mediated replication. We hypothesize that high levels of abnormal AAV2 replication products aided by HAdV and, in severe cases, HHV-6B may have triggered immune-mediated hepatic disease in genetically and immunologically predisposed children

The Influence of National Societal Contexts on the Media Reputation of Multinational Corporations: A Comparison between Switzerland and the US

This comparative study looks at how media reputation of multinational corporations (MNCs) is shaped by national societal contexts. Swiss and US MNCs from the banking and pharmaceutical industry were analyzed. As main predictors media system (Swiss vs. US) and the country of origin of the MNCs (home vs. abroad) were defined. Results show that the overall media reputation of MNCs is predominantly negative in Swiss and US media. However, reputation in US media is significantly more negative than in Swiss media. Independent of the media system reputation of MNCs in home media is more favorable than in abroad media

Development and characterization of a triple combination gene therapy vector inhibiting HIV-1 multiplication

BACKGROUND: RNA-based approaches are promising for long-term gene therapy against HIV-1. They can target virtually any step of the viral replication cycle. It is also possible to combine anti-HIV-1 transgenes targeting different facets of HIV replication to compensate for limitations of any individual construct, maximizing efficacy and decreasing chances of escape mutations. We have previously developed two strategies to inhibit HIV-1 multiplication. One was a short hairpin RNA targeting the host factor cyclophilin A implicated in HIV-1 replication. Additionally, an antisense derivative of U7 small nuclear RNA was designed to induce the skipping of the HIV-1 Tat and Rev internal exons. RESULTS: In the present study, we have established an additional tRNAval promoter-driven shRNA against the coding sequence of viral infectivity factor. When human T-cell lines or primary CD4+ T cells are transduced with a triple lentiviral vector encoding these three therapeutic RNAs, HIV-1 multiplication is very efficiently suppressed. Moreover, all three therapeutic RNAs exhibit antiviral effects at early stages of the viral replication cycle (i.e. prior to viral cDNA integration or gene expression). CONCLUSIONS: These findings make this triple lentiviral vector an attractive candidate for a gene therapy against HIV/AIDS

Ultrathin conductive carbon nanomembranes as support films for structural analysis of biological specimens

Rhinow D, Vonck J, Schranz M, Beyer A, Gölzhäuser A, Hampp N. Ultrathin conductive carbon nanomembranes as support films for structural analysis of biological specimens. PHYSICAL CHEMISTRY CHEMICAL PHYSICS. 2010;12(17):4345-4350.Ultrathin carbon nanomembranes (CNM) have been tested as supports for both cryogenic high-resolution transmission electron microscopy (cryo-EM) as well as atomic force microscopy (AFM) of biological specimens. Purple membrane ( PM) from Halobacterium salinarum, a 2-D crystalline monolayer of bacteriorhodopsin ( BR) and lipids, was used for this study. Due to their low thickness of just 1.6 nm CNM add virtually no phase contrast to the transmission pattern. This is an important advantage over commonly used amorphous carbon support films which become instable below a thickness of similar to 20 nm. Moreover, the electrical conductivity of CNM can be tuned leading to conductive carbon nanomembranes (cCNM). cCNM support films were analyzed for the first time and were found to ideally meet all requirements of cryo-EM of insulating biological samples. A projection map of PM on cCNM at 4 angstrom resolution has been calculated which proves that the structural integrity of biological samples is preserved up to the high-resolution range. CNM have also proven to be suitable supports for AFM analysis of biological samples. PM on CNM was imaged at molecular resolution and single molecule force spectra were recorded which show no differences compared to force spectra of PM obtained with other substrates. This is the first demonstration of a support film material which meets the requirements of both, cryo-EM and AFM, thus enabling comparative structural studies of biomolecular samples with unchanged sample-substrate interactions. Beyond high-resolution cryo-EM of biological samples, cCNM are attractive new substrates for other biophysical techniques which require conductive supports, i.e. scanning tunneling microscopy (STM) and electrostatic force microscopy (EFM)