591 research outputs found

    Photocatalysis applied to concrete products - part 2 : influencing factors and product performance

    Get PDF
    The second part of this three-part article series addresses the influence of physicochemical parameters on the degradation performance of concrete products containing photocatalytic active TiO2. The influence of process conditions like irradiance, relative humidity, pollutant concentration and flow rate on the degradation mechanism is investigated. Furthermore, a short overview on photo catalytic powders (especially TiO2) and their influence on the degradation of NO are presented. In addition the application of TiO2 coatings and their microstructural analysis is explained

    Photocatalysis applied to concrete products - part 2 : influencing factors and product performance

    Get PDF
    The second part of this three-part article series addresses the influence of physicochemical parameters on the degradation performance of concrete products containing photocatalytic active TiO2. The influence of process conditions like irradiance, relative humidity, pollutant concentration and flow rate on the degradation mechanism is investigated. Furthermore, a short overview on photo catalytic powders (especially TiO2) and their influence on the degradation of NO are presented. In addition the application of TiO2 coatings and their microstructural analysis is explained

    Modeling the series of (n x 2) Si-rich reconstructions of beta-SiC(001): a prospective atomic wire?

    Full text link
    We perform ab initio plane wave supercell density functional calculations on three candidate models of the (3 x 2) reconstruction of the beta-SiC(001) surface. We find that the two-adlayer asymmetric-dimer model (TAADM) is unambiguously favored for all reasonable values of Si chemical potential. We then use structures derived from the TAADM parent to model the silicon lines that are observed when the (3 x 2) reconstruction is annealed (the (n x 2) series of reconstructions), using a tight-binding method. We find that as we increase n, and so separate the lines, a structural transition occurs in which the top addimer of the line flattens. We also find that associated with the separation of the lines is a large decrease in the HOMO-LUMO gap, and that the HOMO state becomes quasi-one-dimensional. These properties are qualititatively and quantitatively different from the electronic properties of the original (3 x 2) reconstruction.Comment: 22 pages, including 6 EPS figure

    Second Generation of Antisense Oligonucleotides: From Nuclease Resistance to Biological Efficacy in Animals

    Get PDF
    From efforts to improve the biophysical properties of antisense oligonucleotides by incorporating backbone- or sugar-modified nucleoside analogs, 2'-O-methoxyethyl ribonucleosides 8b were identified as building blocks for a second generation of antisense oligonucleotides. Compounds containing these modifications were demonstrated to combine the benefit of a high binding affinity to the RNA complement with a large increase in nuclease resistance, allowing the use of regular phosphodiester linkages. Chimeric oligonucleotides with 2'-O-methoxyethyl ribonucleosides, 8b, in the wings and a central DNA-phosphorothioate window were shown to efficiently downregulate C-'raf' kinase and PKC-α messenger-RNA in tumor cell lines resulting in a profound inhibition of cell proliferation. The same compounds were able to effectively reduce the growth of tumors in animal models at low concentrations indicating the potential utility of these second generation antisense oligonucleotides for therapeutic applications

    Did the dislocation risk after primary total hip arthroplasty decrease over time? A meta-analysis across six decades

    Get PDF
    Background: While continuous optimization is attempted to decrease the incidence of dislocation after total hip arthroplasty (THA), dislocation remains a major complication. This meta-analysis aims to analyze the evolution of the dislocation risk after primary THA over the decades and to evaluate its potential publication bias. Patients and methods: A systematic search was performed according to the PRISMA guidelines for this meta-analysis in the literature published between 1962 and 2020. MEDLINE, Cochrane and Embase databases were searched for studies reporting the dislocation risk and length of follow-up. Studies that reported on revision rates only and did not mention separate dislocations were excluded. All study designs were eligible. Study quality was assessed by existing quality assessment tools adjusted for arthroplasty research. Overall risk and yearly dislocation rates were calculated and related to historical time frame, study design, sample size and length of follow-up. Results: In total, 174 studies were included with an overall moderate quality. In total there were 85.209 dislocations reported in 5.030.293 THAs, showing an overall dislocation risk of 1.7%, with a median follow-up of 24 months. The overall dislocation risk classified per decade decreased from 3.7% in 1960–1970 to 0.7% in 2010–2020. The yearly dislocation rate decreased from 1.8 to 0.7% within these same decades. There was no significant correlation between the reported dislocation risk and the duration of follow-up (p = 0.903) or sample size (p = 0.755). The reported dislocation risk was higher in articles with registry data compared to other study designs (p = 0.021). Conclusion: The dislocation risk in THA has been decreasing over the past decades to 0.7%. Non-selective registry studies reported a higher dislocation risk compared to studies with selective cohorts and RCTs. This indicates that the actual dislocation risk is higher than often reported and ‘real-world data’ are reflected better in large-scale cohorts and registries

    Cross section ratio and angular distributions of the reaction p + d -> 3He + eta at 48.8 MeV and 59.8 MeV excess energy

    Full text link
    We present new data for angular distributions and on the cross section ratio of the p + d -> 3He + eta reaction at excess energies of Q = 48.8 MeV and Q = 59.8 MeV. The data have been obtained at the WASA-at-COSY experiment (Forschungszentrum J\"ulich) using a proton beam and a deuterium pellet target. While the shape of obtained angular distributions show only a slow variation with the energy, the new results indicate a distinct and unexpected total cross section fluctuation between Q = 20 MeV and Q = 60 MeV, which might indicate the variation of the production mechanism within this energy interval.Comment: 9 pages, 9 figure

    Neutron-Proton Scattering in the Context of the dd^*(2380) Resonance

    Get PDF
    New data on quasifree polarized neutron-proton scattering, in the region of the recently observed dd^* resonance structure, have been obtained by exclusive and kinematically complete high-statistics measurements with WASA at COSY. This paper details the determination of the beam polarization, checks of the quasifree character of the scattering process, on all obtained AyA_y angular distributions and on the new partial-wave analysis, which includes the new data producing a resonance pole in the 3D3^3D_3-3G3^3G_3 coupled partial waves at (2380±10i40±52380\pm10 - i40\pm5) MeV -- in accordance with the dd^* dibaryon resonance hypothesis. The effect of the new partial-wave solution on the description of total and differential cross section data as well as specific combinations of spin-correlation and spin-transfer observables available from COSY-ANKE measurements at TdT_d = 2.27 GeV is discussed

    QTL for phytosterol and sinapate ester content in Brassica napus L. collocate with the two erucic acid genes

    Get PDF
    Improving oil and protein quality for food and feed purposes is an important goal in rapeseed (Brassica napus L.) breeding programs. Rapeseed contains phytosterols, used to enrich food products, and sinapate esters, which are limiting the utilization of rapeseed proteins in the feed industry. Increasing the phytosterol content of oil and lowering sinapate ester content of meal could increase the value of the oilseed rape crop. The objective of the present study was to identify quantitative trait loci (QTL) for phytosterol and sinapate ester content in a winter rapeseed population of 148 doubled haploid lines, previously found to have a large variation for these two traits. This population also segregated for the two erucic acid genes. A close negative correlation was found between erucic acid and phytosterol content (Spearman’s rank correlation, rs = −0.80**). For total phytosterol content, three QTL were detected, explaining 60% of the genetic variance. The two QTL with the strongest additive effects were mapped on linkage groups N8 and N13 within the confidence intervals of the two erucic acid genes. For sinapate ester content four QTL were detected, explaining 53% of the genetic variance. Again, a close negative correlation was found between erucic acid and sinapate ester content (rs = −0.66**) and the QTL with the strongest additive effects mapped on linkage groups N8 and N13 within the confidence intervals of the two erucic acid genes. The results suggests, that there is a pleiotropic effect of the two erucic acid genes on phytosterol and sinapate ester content; the effect of the alleles for low erucic acid content is to increase phytosterol and sinapate ester content. Possible reasons for this are discussed based on known biosynthetic pathways

    Charge Symmetry Breaking in dd->4He{\pi}0 with WASA-at-COSY

    Get PDF
    Charge symmetry breaking (CSB) observables are a suitable experimental tool to examine effects induced by quark masses on the nuclear level. Previous high precision data from TRIUMF and IUCF are currently used to develop a consistent description of CSB within the framework of chiral perturbation theory. In this work the experimental studies on the reaction dd->4He{\pi}0 have been extended towards higher excess energies in order to provide information on the contribution of p-waves in the final state. For this, an exclusive measurement has been carried out at a beam momentum of p=1.2 GeV/c using the WASA-at-COSY facility. The total cross section amounts to sigma(tot) = (118 +- 18(stat) +- 13(sys) +- 8(ext)) pb and first data on the differential cross section are consistent with s-wave pion production.Comment: 14 pages, 5 figure

    Evidence for a New Resonance from Polarized Neutron-Proton Scattering

    Get PDF
    Exclusive and kinematically complete high-statistics measurements of quasifree polarized np\vec{n}p scattering have been performed in the energy region of the narrow resonance structure dd^* with I(JP)=0(3+)I(J^P) = 0(3^+), MM \approx 2380 MeV/c2c^2 and Γ\Gamma \approx 70 MeV observed recently in the double-pionic fusion channels pndπ0π0pn \to d\pi^0\pi^0 and pndπ+πpn \to d\pi^+\pi^-. The experiment was carried out with the WASA detector setup at COSY having a polarized deuteron beam impinged on the hydrogen pellet target and utilizing the quasifree process dpnp+pspectator\vec{d}p \to np + p_{spectator}. That way the npnp analyzing power AyA_y was measured over a large angular range. The obtained AyA_y angular distributions deviate systematically from the current SAID SP07 NN partial-wave solution. Incorporating the new AyA_y data into the SAID analysis produces a pole in the 3D33G3^3D_3 - ^3G_3 waves as expected from the dd^* resonance hypothesis
    corecore