Ab initio simulations of Cu binding sites in the N-terminal region of PrP

The prion protein (PrP) binds Cu2+ ions in the octarepeat domain of the N-terminal tail up to full occupancy at pH=7.4. Recent experiments show that the HGGG octarepeat subdomain is responsible for holding the metal bound in a square planar coordination. By using first principle ab initio molecular dynamics simulations of the Car-Parrinello type, the Cu coordination mode to the binding sites of the PrP octarepeat region is investigated. Simulations are carried out for a number of structured binding sites. Results for the complexes Cu(HGGGW)+(wat), Cu(HGGG) and the 2[Cu(HGGG)] dimer are presented. While the presence of a Trp residue and a H2O molecule does not seem to affect the nature of the Cu coordination, high stability of the bond between Cu and the amide Nitrogens of deprotonated Gly's is confirmed in the case of the Cu(HGGG) system. For the more interesting 2[Cu(HGGG)] dimer a dynamically entangled arrangement of the two monomers, with intertwined N-Cu bonds, emerges. This observation is consistent with the highly packed structure seen in experiments at full Cu occupancy.Comment: 4 pages, conference proceedin

LCA of Different Construction Choices for a Double-Track Railway Line for Sustainability Evaluations

The international commitment to achieve carbon neutrality in the next few decades has oriented human activities towards the preservation of natural and non-renewable resources. In this context, a great research effort has been devoted to the search for sustainable solutions for the infrastructure construction sector, based on a thorough assessment of the environmental impact (EI). In this regards, Life Cycle Assessment (LCA) is considered one of the main components of Environmental Impact Assessment (EIA) and, for a comprehensive analysis, all the costs incurred by stakeholders during the useful life of the infrastructure should also be taken into account, applying the Life Cycle Cost (LCC) methodology. So far, there is a lack of combined LCA and LCC analyses of railway projects to support a proper sustainable decision-making process at a project level. Therefore, this study aimed to contributed to this topic by determining the environmental effect and related costs of different planning and construction choices in terms of material and maintenance strategies. For this purpose, first, an LCA of typical railway infrastructures with a ballasted track was developed. The case study considered two different functional units of a double-track railway line: 1 km of embankment section and 1 km of a cut section, in straight alignment. After defining five alternative railway infrastructure scenarios with different materials (virgin or recycled material) and construction methods (e.g., lime stabilization), two different railway track maintenance approaches were analysed. SimaPro was used to analyse the case study, and the results were compared with those obtained using the PaLATE software, suitably adapted for use in the railway sector. Finally, a cost analysis was carried out using Life Cycle Cost (LCC) methodology for all the scenarios analysed. The results obtained in terms of EI and related costs of each scenario provide useful information, allowing a sustainable planning approach: as a general result, the initial construction phase always involves the larger part of the total environmental impact while the material production is the most polluting phase, reaching percentages always higher than 50% of the total

PA design and statistical analysis through X-par driven load-pull and EM simulations

Modeling the active device is a key step for the successful statistical analysis of power amplifiers: the nonlinear model must not only depend on the most relevant device fabrication parameters, but should also work accurately in source/load-pull analysis, since variations of the passive embedding network effectively act as a load-pull at the active device ports. We demonstrate that the X-parameter model extracted from physics-based nonlinear TCAD simulations is extremely accurate for load-pull analysis. The X-parameter model is coupled to electromagnetic simulations to assist the variability-aware design of a GaAs MMIC X-band power amplifier (PA): concurrent variations of the active device doping and of the capacitor dielectric layer thickness are considered as the main contributions to PA variability. Two possible output matching networks, with distributed or semi-lumped design, are compared: already for moderate doping variations the PA output power spread is dominated by the active device variability, while passive network variations are always the relevant contribution to PA efficiency

Global Assessment of PA variability through concurrent Physics-based X-parameter and Electro-Magnetic simulations

The novel technique introduced in [1] is exploited to address a full variability analysis of a GaAs MMIC X-band power amplifier, including the statistical variations of several technological parameters, both in the active and passive components. The active device is modelled by means of X-parameters, directly extracted from physics-based analysis. A non-50 O X-Par model is used to take into account the input port mismatch with respect to the conventional 50 O reference. The scattering parameters of the passive structures are extracted from accurate electromagnetic simulations and then imported into the circuit simulator through data intercharge files (e.g. MDIF or CITIfile) as a function of the most important MMIC fabrication parameters, e.g. the thickness of the MIM capacitor dielectric layer. The analysis shows that more than 10% of output power variations can be ascribed to the concurrent MIM and doping variations in conventional GaAs MMIC technology

RELAÇÃO Genética e Potencial de Virulência de Isolados de Escherichia Coli Enteroagregativa de Crianças de Comunidades Quilombolas

Escherichia coli enteroagregativa (EAEC) é um patotipo emergente responsável por diarreia aguda e persistente, caracterizado por marcante heterogeneidade quanto aos potenciais fatores de virulência entre os isolados. EAEC pode ser classificada em típica (tEAEC) e atípica (aEAEC) com base na presença do regulon AggR, sugerindo-se uma maior virulência para tEAEC, embora aEAEC esteja relacionada a surtos de diarreia. Tivemos como objetivo determinar a relação genética e o potencial de virulência in vivo de isolados de tEAEC e aEAEC de crianças de comunidades quilombolas. Para análise da heterogeneidade clonal, empregamos a técnica de eletroforese em campo pulsado (PFGE) após digestão com enzima de restrição XbaI em 73 amostras previamente caracterizadas quanto ao repertório de genes de virulência. A virulência de 20 amostras de EAEC (10 tEAEC e 10 aEAEC) além de cepas referência de tEAEC (EAEC 042), aEAEC (C1096) e E. coli não patogênica HB101 foi investigada em modelo de Galleria mellonella. Foi analisada a sobrevivência das larvas após inoculação de 104 a 107 UFC/larva e determinada a carga bacteriana da hemolinfa após inoculação de 105 UFC/larva das cepas referência, em diferentes períodos após infecção. Além disso, avaliamos características fenotípicas de virulência de 10 amostras de EAEC, (produção de enzimas, sideróforos e de biofilme). Para análise epidemiológica a nível global, 10 isolados foram submetidos à tipagem molecular pela técnica de Multilocus Sequence Typing (MLST). Evidenciamos 58 pulsotipos distintos e sem relação com o perfil de genes de virulência e a comunidade de origem, para a maior parte das amostras. No modelo de G. mellonella, observamos que: (i) mortalidade das larvas foi dependente da concentração inoculada de tEAEC e aEAEC; (ii) cepas e amostras de aEAEC foram tão virulentas quanto de tEAEC, porém, a virulência média foi maior para as tEAEC; (iii) Não houve relação entre número de genes de virulência e a virulência no modelo; (iv) em contraposição às cepas EAEC 042 e EAEC C1096, a cepa E. coli HB101 não provoca melanização e é eliminada da hemolinfa com 2 horas após infecção. Em relação às características fenotípicas de virulência: (i) nenhuma amostra produziu fosfolipase, protease ou esterase; (ii) apenas uma amostra produziu hemolisina; (iii) todas as amostras analisadas produziram sideróforos; (iv) somente uma amostra não produziu biofilme. As 10 amostras analisadas pelo MLST pertencem a STs distintos e, portanto, representam diferentes linhagens evolutivas. Os STs: 443, 730, 1178, 1286 e 2481, detectados nas nossas amostras, não haviam sido descritos para EAEC até o momento. Em conclusão, os resultados obtidos demonstram uma alta heterogeneidade de EAEC nas comunidades quilombolas mesmo estas sendo semi-isoladas, visto que a maior parte das amostras não apresentou relação genotípica entre si. Além disso, novos STs foram observados em amostras de EAEC e ao contrário do que se sugere na literatura, pelo modelo de estudo, as aEAEC podem ser tão virulentas quanto as tEAEC

Specificity of the failure to inhibit responses in overweight children

Poor response inhibition has been associated with obesity, excessive food intake, and other consumptive behaviours, including alcohol use. However, the correlation between obesity and addictive behaviours like alcoholism is low: people who are obese appear to have a specific problem in restraining food intake. This would imply that obese people have more difficulties in inhibiting responses towards food, compared to other rewarding stimuli. In the present study eighty-nine children (ages 7-9) were tested with the stop signal task, in which responses towards food pictures or toy pictures had to be inhibited. Results showed that children were less effective in inhibiting responses towards food and percentage overweight predicted a lower ability to inhibit responses in general. When dichotomizing the sample in overweight and lean children, it appeared that overweight children were specifically less effective in inhibition towards food cues, compared to lean children. In conclusion: The results confirm weight related inhibitory problems and might explain the increased overeating to food cues in overweight children, as reported in the literature

Targeting a phospho-STAT3-miRNAs pathway improves vesicular hepatic steatosis in an in vitro and in vivo model

Non-alcoholic fatty liver disease (NAFLD) is a leading cause of chronic liver disease. Although genetic predisposition and epigenetic factors contribute to the development of NAFLD, our understanding of the molecular mechanism involved in the pathogenesis of the disease is still emerging. Here we investigated a possible role of a microRNAs-STAT3 pathway in the induction of hepatic steatosis. Differentiated HepaRG cells treated with the fatty acid sodium oleate (fatty dHepaRG) recapitulated features of liver vesicular steatosis and activated a cell-autonomous inflammatory response, inducing STAT3-Tyrosine-phosphorylation. With a genome-wide approach (Chromatin Immunoprecipitation Sequencing), many phospho-STAT3 binding sites were identified in fatty dHepaRG cells and several STAT3 and/or NAFLD-regulated microRNAs showed increased expression levels, including miR-21. Innovative CARS (Coherent Anti-Stokes Raman Scattering) microscopy revealed that chemical inhibition of STAT3 activity decreased lipid accumulation and deregulated STAT3-responsive microRNAs, including miR-21, in lipid overloaded dHepaRG cells. We were able to show in vivo that reducing phospho-STAT3-miR-21 levels in C57/BL6 mice liver, by long-term treatment with metformin, protected mice from aging-dependent hepatic vesicular steatosis. Our results identified a microRNAs-phosphoSTAT3 pathway involved in the development of hepatic steatosis, which may represent a molecular marker for both diagnosis and therapeutic targeting