Density functional theory for colloidal mixtures of hard platelets, rods, and spheres

A geometry-based density functional theory is presented for mixtures of hard spheres, hard needles and hard platelets; both the needles and the platelets are taken to be of vanishing thickness. Geometrical weight functions that are characteristic for each species are given and it is shown how convolutions of pairs of weight functions recover each Mayer bond of the ternary mixture and hence ensure the correct second virial expansion of the excess free energy functional. The case of sphere-platelet overlap relies on the same approximation as does Rosenfeld's functional for strictly two-dimensional hard disks. We explicitly control contributions to the excess free energy that are of third order in density. Analytic expressions relevant for the application of the theory to states with planar translational and cylindrical rotational symmetry, e.g. to describe behavior at planar smooth walls, are given. For binary sphere-platelet mixtures, in the appropriate limit of small platelet densities, the theory differs from that used in a recent treatment [L. Harnau and S. Dietrich, Phys. Rev. E 71, 011504 (2004)]. As a test case of our approach we consider the isotropic-nematic bulk transition of pure hard platelets, which we find to be weakly first order, with values for the coexistence densities and the nematic order parameter that compare well with simulation results.Comment: 39 pages, 8 figure

Design & KI

In diesem Bericht werden die wichtigsten Begriffe aus dem Bereich des (Produkt)Designs aus dem Blickwinkel der künstlichen Intelligenz untersucht. Der Schwerpunkt liegt dabei nicht so sehr auf den technischen Details von existierenden Designsystemen als vielmehr in der Untersuchung der wesentlichen Konzepte wie Designmodelle, Modelle des wissensbasierten Designs, innovatives Design, etc. auf einem informellen Level, die der grundsätzlichen Beschreibung des Vorgehens eines Experten beim Design genügen

Peroxynitrous Acid Generated In Situ from Acidified H2O2 and NaNO2. A Suitable Novel Antimicrobial Agent?

Peroxynitrite (ONOO−) and peroxynitrous acid (ONOOH) are known as short acting reactive species with nitrating and oxidative properties, which are associated with their antimicrobial effect. However, to the best of our knowledge, ONOOH/ONOO- are not yet used as antimicro-bial actives in practical applications. The aim is to elucidate if ONOOH generated in situ from acidified hydrogen peroxide (H2O2 ) and sodium nitrite (NaNO2 ) may serve as an antimicrobial active in disinfectants. Therefore, the dose-response relationship and mutagenicity are investigated. Antimicrobial efficacy was investigated by suspension tests and mutagenicity by the Ames test. Tests were conducted with E. coli. For investigating the dose-response relationship, pH values and concentrations of H2O2 and NaNO2 were varied. The antimicrobial efficacy is correlated to the dose of ONOOH, which is determined by numerical computations. The relationship can be described by the efficacy parameter W, corresponding to the amount of educts consumed during exposure time. Sufficient inactivation was observed whenever W ≥ 1 mM, yielding a criterion for inactivation of E. coli by acidified H2O2 and NaNO2 . No mutagenicity of ONOOH was noticed. While further investigations are necessary, results indicate that safe and effective usage of ONOOH generated from acidified H2O2 and NaNO2 as a novel active in disinfectants is conceivable. © 2021 by the authors. Licensee MDPI, Basel, Switzerland

Von IDA bis IMCOD : Expertensysteme im CIM-Umfeld

Kürzer werdende Produktzyklen bei höher werdenden Qualitätsansprüchen erfordern flexiblere und intelligentere Systeme für komplexere Aufgaben. Die im Sinne der CIM-Idee fortschreitende Integration unterschiedlicher Aufgabenbereiche und ihrer jeweiligen Systeme stellt hohe Anforderungen an die Informationstechnologie. Die Künstliche Intelligenz und speziell die Expertensystemforschung liefern hier erfolgversprechende Ansätze und Perspektiven. Die Systeme MOLTKE und IDA stehen als Beispiele für einzelne Expertensysteme in den Bereichen Diagnose und Konfiguration. Die Ergebnisse des ARC-TEC Projekts erreichen zwischen Konstruktion und Planung bereits eine stärkere Integration. Das Projekt IMCOD untersucht schließlich Ansätze, die Möglichkeiten der Verbindung verschiedener Systeme mit beschränkten Kompetenzbereichen, um einen besseren Produktentwurf zu erzielen.The shortness in product cycles with increasing quality demands requires more flexible and more intelligent systems for very complex tasks. The proceeding integration of the many different task areas within the CIM-idea and their individual systems requests high demands to the information technology. AI, especially expert system research, provides a successful approach and perspectives. The examples for single expert systems in diagnostics and configuration are the systems MOLTKE and IDA. The results of the ARC-TEC projects already reach a strong integration of construction and planning. The project IMCOD finally surveys the possibility of connecting different systems with limited competence areas to obtain better products

Non-touching plasma–liquid interaction – where is aqueous nitric oxide generated?

Mass transport through graphene is receiving increasing attention due to the potential for molecular sieving. Experimental studies are mostly limited to the translocation of protons, ions, and water molecules, and results for larger molecules through graphene are rare. Here, we perform controlled radical polymerization with surface-anchored self-assembled initiator monolayer in a monomer solution with single-layer graphene separating the initiator from the monomer. We demonstrate that neutral monomers are able to pass through the graphene (via native defects) and increase the graphene defects ratio (Raman ID/IG) from ca. 0.09 to 0.22. The translocations of anionic and cationic monomers through graphene are significantly slower due to chemical interactions of monomers with the graphene defects. Interestingly, if micropatterned initiator-monolayers are used, the translocations of anionic monomers apparently cut the graphene sheet into congruent microscopic structures. The varied interactions between monomers and graphene defects are further investigated by quantum molecular dynamics simulations

Evidence for accretion in a nearby, young brown dwarf

We report on the discovery of the young, nearby, brown dwarf 2MASS J0041353$-$562112. The object has a spectral type of M7.5, it shows Li absorption and signatures of accretion, which implies that it still has a disk and suggests an age below 10 Myr. The space motion vector and position on the sky indicate that the brown dwarf is probably a member of the $\sim$20 Myr old Tuc-Hor association, or that it may be an ejected member of the $\sim$12 Myr old $\beta$ Pic association, both would imply that 2MASS J0041353$-$562112 may in fact be older than 10 Myr. No accreting star or brown dwarf was previously known in these associations. Assuming an age of 10 Myr, the brown dwarf has a mass of about 30 M$_{\rm Jup}$ and is located at 35 pc distance. The newly discovered object is the closest accreting brown dwarf known. Its membership to an association older than 10 Myr implies that either disks in brown dwarfs can survive as long as in more massive stars, perhaps even longer, or that star formation in Tuc-Hor or $\beta$ Pic occured more recently than previously thought. The history and evolution of this object can provide new fundamental insight into the formation process of stars, brown dwarfs, and planets.Comment: emulateapj version, online version at http://www.iop.org/EJ/abstract/1538-4357/702/2/L119

Challenges of temperature measurement during the friction stir welding process

The exact determination of the process zone temperature can be considered as an increasingly important role in the control and monitoring of the friction stir welding process (FSW). At present, temperature measurement is carried out with the aid of a temperature sensor integrated into the tool (usually thermocouples). Since these cannot be attached directly to the joining area, heat dissipation within the tool and to the environment cause measurement deviations as well as a time delay in the temperature measurement. The article describes a process and the challenges that arise in this process, how a direct temperature measurement during the process can be achieved by exploiting the thermoelectric effect between tool and workpiece, without changing the tool by introducing additional temperature sensors

NLO QCD and EW corrections to vector-boson scattering into ZZ at the LHC

Abstract: We present the first calculation of the full next-to-leading-order electroweak and QCD corrections for vector-boson scattering (VBS) into a pair of Z bosons at the LHC. We consider specifically the process pp → e+e−μ+μ−jj + X at orders O(α7) and O(αsα6) and take all off-shell and interference contributions into account. Owing to the presence of enhanced Sudakov logarithms, the electroweak corrections amount to −16% of the leading-order electroweak fiducial cross section and induce significant shape distortions of differential distributions. The QCD corrections on the other hand are larger (+24%) than typical QCD corrections in VBS. This originates from considering the full computation including tri-boson contributions in a rather inclusive phase space. We also provide a leading-order analysis of all contributions to the cross section for pp → e+e−μ+μ−jj + X in a realistic setup

Human intronic enhancers control distinct sub-domains of Gli3 expression during mouse CNS and limb development

<p>Abstract</p> <p>Background</p> <p>The zinc-finger transcription factor GLI3 is an important mediator of Sonic hedgehog signaling and crucial for patterning of many aspects of the vertebrate body plan. In vertebrates, the mechanism of SHH signal transduction and its action on target genes by means of activating or repressing forms of GLI3 have been studied most extensively during limb development and the specification of the central nervous system. From these studies it has emerged, that <it>Gli3 </it>expression must be subject to a tight spatiotemporal regulation. However, the genetic mechanisms and the cis-acting elements controlling the expression of <it>Gli3 </it>remained largely unknown.</p> <p>Results</p> <p>Here, we demonstrate in chicken and mouse transgenic embryos that human <it>GLI3</it>-intronic conserved non-coding sequence elements (CNEs) autonomously control individual aspects of <it>Gli3 </it>expression. Their combined action shows many aspects of a <it>Gli3</it>-specific pattern of transcriptional activity. In the mouse limb bud, different CNEs enhance <it>Gli3</it>-specific expression in evolutionary ancient stylopod and zeugopod versus modern skeletal structures of the autopod. Limb bud specificity is also found in chicken but had not been detected in zebrafish embryos. Three of these elements govern central nervous system specific gene expression during mouse embryogenesis, each targeting a subset of endogenous <it>Gli3 </it>transcription sites. Even though fish, birds, and mammals share an ancient repertoire of gene regulatory elements within <it>Gli3</it>, the functions of individual enhancers from this catalog have diverged significantly. During evolution, ancient broad-range regulatory elements within <it>Gli3 </it>attained higher specificity, critical for patterning of more specialized structures, by abolishing the potential for redundant expression control.</p> <p>Conclusion</p> <p>These results not only demonstrate the high level of complexity in the genetic mechanisms controlling <it>Gli3 </it>expression, but also reveal the evolutionary significance of <it>cis</it>-acting regulatory networks of early developmental regulators in vertebrates.</p

Alternative splicing of TGF-betas and their high-affinity receptors TβRI, TβRII and TβRIII (betaglycan) reveal new variants in human prostatic cells

<p>Abstract</p> <p>Background</p> <p>The transforming growth factors (TGF)-β, TGF-β1, TGF-β2 and TGF-β3, and their receptors [TβRI, TβRII, TβRIII (betaglycan)] elicit pleiotropic functions in the prostate. Although expression of the ligands and receptors have been investigated, the splice variants have never been analyzed. We therefore have analyzed all ligands, the receptors and the splice variants TβRIB, TβRIIB and TGF-β2B in human prostatic cells.</p> <p>Results</p> <p>Interestingly, a novel human receptor transcript TβRIIC was identified, encoding additional 36 amino acids in the extracellular domain, that is expressed in the prostatic cancer cells PC-3, stromal hPCPs, and other human tissues. Furthermore, the receptor variant TβRIB with four additional amino acids was identified also in human. Expression of the variant TβRIIB was found in all prostate cell lines studied with a preferential localization in epithelial cells in some human prostatic glands. Similarly, we observed localization of TβRIIC and TGF-β2B mainly in the epithelial cells with a preferential localization of TGF-β2B in the apical cell compartment. Whereas in the androgen-independent hPCPs and PC-3 cells all TGF-β ligands and receptors are expressed, the androgen-dependent LNCaP cells failed to express all ligands. Additionally, stimulation of PC-3 cells with TGF-β2 resulted in a significant and strong increase in secretion of plasminogen activator inhibitor-1 (PAI-1) with a major participation of TβRII.</p> <p>Conclusion</p> <p>In general, expression of the splice variants was more heterogeneous in contrast to the well-known isoforms. The identification of the splice variants TβRIB and the novel isoform TβRIIC in man clearly contributes to the growing complexity of the TGF-β family.</p