Acoustic performance test assessment on sound generated by rainfall on multilayer-etfe-cushion systems

Ethylene-tetra-fluor-ethylene (ETFE) membrane structure presents itself as an innovative construction element, taking advantage of its flexibility, lightweight, transparency and thermal insulation properties. However, for large enclosed areas, concerns exist related to the sound insulation characteristic of the system, especially related to the internal noise levels generated during rainfall conditions. Therefore, aiming to both assess the effect of rain noise on these structural elements, as well as generating a clear picture to this condition to designers and clients, Taiyo Europe promoted a measurement campaign on a predefined set of pneumatic ETFE roof elements. The set of pneumatic cushions investigated was produced from the same 250-micron thick ETFE foil. The number of layers, number of air chambers and the level of the pressure inside the cushion was variable, following a carefully predefined test plan. The elements were tested with and without an additional rain suppressor fabric mesh on top of the specimen. The tested elements were installed on a special outdoor structure designed and built for this purpose. This work will describe the tests performed, as well as an assessment of the results achieved and their impact on the design of enclosed buildings cladded with ETFE pneumatic structures

Importance of the context for the design of the membrane structure

This work underlines the importance of the context for the design of membrane structures. There are many aspects that can influence the design and it is difficult to summarize all of them in few points, especially because structural membranes are mainly chosen by clients and architects because of their capability to reach shapes and limits that other structural types are not able to. However, three main aspects should always be considered while designing a membrane structure: shape, environment and installation. The architects, designers and engineers mainly focalize their attention in one of them together with others like: light, space, structure, ecc., but I believe that these aspects need to be always simultaneously evaluated. The shape is important following the architectural signature and the aesthetical result. The second aspect, environment, can be considered as: natural environment (respect of the Nature), architectural environment (harmony with the existing surrounding), and comfort environment (respect of the comfort for the users). The third aspect that is frequently neglected or underestimated on earlier design stages is the method of installation and how this can influence the result of the final structure. In order to exemplify each of the three mentioned aspects, this work presents three different membrane projects executed by Taiyo Europe. In these three projects, each one of the mentioned aspects was particularly emphasized. The first project, where the shape aspect was particularly important, is the ETFE skylight of the Podium Zaha Hadid realized in Milano (Italy). The second one, where the environment was prevalent, is the PTFE roof covering the prehistorical temple of Tarxien (Malta). The third one is the Cardo and Decumano PVC structure realized for Milano Expo 2015, in this project the installation method was essential once several different structures were being simultaneously executed in a very narrow space. By these examples this work emphasizes the importance of carefully assessing that the shape, environment and installation conditions during the entire develop of a membrane structure

Characterization of the porcine CDKN3 gene as a potential candidate for congenital splay leg in piglets

Congenital splay leg is a hereditary disease observed in newborn piglets. The etiology and pathogenetic mechanism of the disorder are still unknown. The gene for cyclin-dependent protein kinase inhibitor 3 (CDKN3) was identified as a potential candidate gene in a differential display experiment. We analyzed the gene on sequence variations and compared its expression in M. biceps femoris between healthy and affected piglets. Comparative sequencing of the coding region of three healthy and four splay leg piglets revealed twelve single nucleotide polymorphisms (SNP) resulting in six amino acid exchanges in the deduced sequences. However, all polymorphisms were observed in healthy as well as in splay leg piglets thus excluding structural differences of the gene as a cause of the disease. Besides full length transcripts, we found a variety of aberrantly transcribed cDNA in clones derived from M. biceps femoris of healthy as well as of splay leg piglets. All alternative transcripts coexist with normal cDNA. Expression analysis revealed a trend towards higher values in M. biceps femoris of splay leg piglets supporting the results obtained from a differential display

Unconventional superconductivity without doping: infinite-layer nickelates under pressure

High-temperature unconventional superconductivity quite generically emerges from doping a strongly correlated parent compound, often (close to) an antiferromagnetic insulator. The recently developed dynamical vertex approximation is a state-of-the-art technique that has quantitatively predicted the superconducting dome of nickelates. Here, we apply it to study the effect of pressure in the infinite-layer nickelate Sr$_x$Pr$_ {1-x}$NiO$_2$. We reproduce the increase of the critical temperature ($T_c$) under pressure found in experiment up to 12 GPa. According to our results, $T_c$ can be further increased with higher pressures. Even without Sr-doping the parent compound, PrNiO$_2$, will become a high-temperature superconductor thanks to a strongly enhanced self-doping of the \nidxsqysq{} orbital under pressure. With a maximal \Tc{} of 100\,K around 100\,GPa, nickelate superconductors can reach that of the best cuprates.Comment: Main text: 6 pages, 4 figures. Supplementary information: 18 pages, 16 figure

Binding of ATP to vascular endothelial growth factor isoform VEGF-A165 is essential for inducing proliferation of human umbilical vein endothelial cells

<p>Abstract</p> <p>Background</p> <p>ATP binding is essential for the bioactivity of several growth factors including nerve growth factor, fibroblast growth factor-2 and brain-derived neurotrophic factor. Vascular endothelial growth factor isoform 165 (VEGF-A₁₆₅) induces the proliferation of human umbilical vein endothelial cells, however a dependence on ATP-binding is currently unknown. The aim of the present study was to determine if ATP binding is essential for the bioactivity of VEGF-A₁₆₅.</p> <p>Results</p> <p>We found evidence that ATP binding toVEGF-A₁₆₅induced a conformational change in the secondary structure of the growth factor. This binding appears to be significant at the biological level, as we found evidence that nanomolar levels of ATP (4-8 nm) are required for the VEGF-A₁₆₅-induced proliferation of human umbilical vein endothelial cells. At these levels, purinergic signaling by ATP <it>via </it>P2 receptors can be excluded. Addition of alkaline phosphate to cell culture lowered the ATP concentration in the cell culture medium to 1.8 nM and inhibited cell proliferation.</p> <p>Conclusions</p> <p>We propose that proliferation of endothelial cells is induced by a VEGF-A₁₆₅-ATP complex, rather than VEGF-A₁₆₅alone.</p

Interface between graphene and liquid Cu from molecular dynamics simulations

Controllable synthesis of defect-free graphene is crucial for applications since the properties of graphene are highly sensitive to any deviations from the crystalline lattice. We focus here on the emerging use of liquid Cu catalysts, which has high potential for fast and efficient industrial-scale production of high-quality graphene. The interface between graphene and liquid Cu is studied using force field and ab initio molecular dynamics, revealing a complete or partial embedding of finite-sized flakes. By analyzing flakes of different sizes we find that the size-dependence of the embedding can be rationalized based on the energy cost of embedding versus bending the graphene flake. The embedding itself is driven by the formation of covalent bonds between the under-coordinated edge C atoms and the liquid Cu surface, which is accompanied by a significant charge transfer. In contrast, the central flake atoms are located around or slightly above 3 {\AA} from the liquid Cu surface and exhibit weak vdW-bonding and much lower charge transfer. The structural and electronic properties of the embedded state revealed in our work provides the atomic-scale information needed to develop effective models to explain the special growth observed in experiments where various interesting phenomena such as flake self-assembly and rotational alignment, high growth speeds and low defect densities in the final graphene product have been observed.Comment: This article may be downloaded for personal use only. Any other use requires prior permission of the author and AIP Publishing. This article appeared in J. Chem. Phys. 153, 074702 (2020) and may be found at https://doi.org/10.1063/5.002012

Pb10−xCux(PO4)6O: a Mott or charge transfer insulator in need of further doping for (super)conductivity

We briefly review the status quo of research on the putative superconductor Pb9Cu(PO4)6O also known as LK-99. Further, we provide ab initio derived tight-binding parameters for a two- and five-band model, and solve these in dynamical-mean-field theory. The interaction-to-bandwidth ratio makes LK-99 a Mott or charge transfer insulator. Electron or hole doping (which is different from substituting Pb by Cu and thus differs from LK-99) is required to make it metallic and potentially superconducting

Selenium and the role of defects for photovoltaic applications

We present first principles calculations of the electronic properties of trigonal selenium with emphasis on photovoltaic applications. The band gap and optical absorption spectrum of pristine selenium is calculated from many-body perturbation theory yielding excellent agreement with experiments. We then investigate the role of intrinsic as well as extrinsic defects and estimate the equilibrium concentrations resulting from realistic synthesis conditions. The intrinsic defects are dominated by vacancies, which act as acceptor levels and implies $p$-doping in agreement with previous predictions and measurements, and we show that these do not give rise to significant non-radiative recombination. The charge balance remains dominated by vacancies when extrinsic defects are included, but these may give rise to sizable non-radiative recombination rates, which could severely limit the performance of selenium based solar cells. Our results thus imply that the pollution by external elements is a decisive factor for the photovoltaic efficiency, which will be of crucial importance when considering synthesis conditions for any type of device engineering.Comment: 15 page