cometadata/datacite-rtg-text-other-reclassification-records huggingface dataset:
Reversible Bildung von Polymerketten durch Koordination von Pentaphosphaferrocen an Silber(I)-Ionen
Creators: name: Scheer, Manfred
name: Gregoriades, Laurence John
name: Virovets, Alexander V.
name: Kunz, Werner
name: Neueder, Roland
name: Krossing, Ingo
Publisher: name: Universität Regensburg
Year: 2006
Subjects: subject: Dichtefunktionalrechnungen; Koordinationspolymere; Phosphor; Silber; Strukturaufklärung
subject: 540 Chemie

description: Ein Polymer, das nicht zusammenhält: Pentaphosphaferrocen [Cp*Fe(5-P5)] reagiert mit dem AgI-Salz des schwach koordinierenden Anions [Al{OC(CF3)3}4]- zu einem Polymer, das cyclo-P5-Einheiten in einer bisher unbekannten 1,2,3-Koordinationsform enthält (siehe Bild). Analytische Daten und DFT-Rechnungen belegen die Existenz eines Monomer-Dimer-Oligomer-Gleichgewichtes in Lösung, das bei Raumtemperatur auf der Seite des Monomers liegt und sich mit sinkender Temperatur hin zu dimeren und oligomeren Spezies verschiebt.
The Unexpected Versatility of P4S3 as a Building Block in Polymeric Copper Halide Networks: 2,3-P, 1,2,3-P and all-P Coordination
Creators: name: Biegerl, Andreas
name: Brunner, Eike
name: Gröger, Christian
name: Scheer, Manfred
name: Wachter, Joachim
name: Zabel, Manfred
Publisher: name: Universität Regensburg
Year: 2007
Subjects: subject: copper halides; NMR spectroscopy; phosphorus; polymers; sulfur
subject: 540 Chemie

description: Layering solutions of P4S3 in CH2Cl2 with solutions of CuCl or CuI in CH3CN gives the coordination polymers (P4S3)3(CuCl)7 (1), (P4S3)2(CuCl)3 (2), (P4S3)(CuI) (3) and (P4S3)(CuI)3 (4), respectively, after slow diffusion. The yellow compounds were characterised by elemental analysis, 31P magic-angle spinning (MAS) NMR spectroscopy and single-crystal X-ray crystallography. The solid-state structures demonstrate the unexpected ligand versatility of the P4S3 molecule, which interacts through two, three, or even all of the phosphorus atoms with copper according to the nature of the copper halide. Compound 1 has a three-dimensional network in which linear and cylindrical infinite CuCl subunits coexist with diatomic CuCl building blocks. For the first time, all four P atoms of the P4S3 cage are involved in coordination with metal atoms. The 3D structure of 2 contains stacks of P4S3 that are interconnected by slightly undulated and planar [CuCl]n ribbons. Compound 3 is a one-dimensional polymer composed of alternating (CuI)2 rings and P4S3 bridges. The structure of 4 consists of undulated [CuI]n layers in which the P4S3 cage functions as a bridge within the layer, as well as a spacer between the layers. The 31P MAS NMR spectra obtained are in good agreement with the solid-state structures obtained crystallographically. Thus, analytically pure 3 and 4 show singlet peaks that correspond to uncoordinated P and quartets owing to coupling with 63Cu and 65Cu, respectively, whereas that of 1 contains quartets according to all-P coordination. The spectrum of 2 was obtained from a sample that still contained 40 % of 1.
A three dimensional set of limit points related to the abc Conjecture
Creators: name: Simpson, Reginald M.
Publisher: name: University of British Columbia
Year: 2017

description: We study the limit points Q' of a three-dimensional set Q which encodes the reciprocal quality of abc triples as the components of a vector of the form (log Rad a, log Rad b, log Rad c) / log c. We establish that if the abc Conjecture holds, Q' is contained in a heptahedron. Unconditionally, we establish the existence of a subset of Q' with non-zero measure. We determine the implications of previous research on related problems involving limit points of abc triples in one-dimensional sets on Q' and discuss possible avenues for future study.
Cluster Abundance in f(R) Gravity Models
Creators: name: Ferraro, Simone
name: Schmidt, Fabian
name: Hu, Wayne
Publisher: name: arXiv
Year: 2010
Subjects: subject: Cosmology and Nongalactic Astrophysics (astro-ph.CO)
subject: FOS: Physical sciences

description: As one of the most powerful probes of cosmological structure formation, the abundance of massive galaxy clusters is a sensitive probe of modifications to gravity on cosmological scales. In this paper, we present results from N-body simulations of a general class of f(R) models, which self-consistently solve the non-linear field equation for the enhanced forces. Within this class we vary the amplitude of the field, which controls the range of the enhanced gravitational forces, both at the present epoch and as a function of redshift. Most models in the literature can be mapped onto the parameter space of this class. Focusing on the abundance of massive dark matter halos, we compare the simulation results to a simple spherical collapse model. Current constraints lie in the large-field regime, where the chameleon mechanism is not important. In this regime, the spherical collapse model works equally well for a wide range of models and can serve as a model-independent tool for placing constraints on f(R) gravity from cluster abundance. Using these results, we show how constraints from the observed local abundance of X-ray clusters on a specific f(R) model can be mapped onto other members of this general class of models.
description: 8 pages, 6 figures
Main Group Lewis Acid/Base-Stabilised Phosphanylboranes
Creators: name: Adolf, Ariane
name: Zabel, Manfred
name: Scheer, Manfred
Publisher: name: Universität Regensburg
Year: 2007
Subjects: subject: Boron; Phosphorus; Hydrides; Lewis acids; Lewis bases
subject: 540 Chemie

description: The parent compounds of phosphanylboranes of the type (LA)H2P-BH2(LB) (LA = Lewis acid, LB = Lewis base) stabilised by Lewis acid/Lewis base have been synthesised by using perfluorinated main-group Lewis acids. The Lewis acid-phosphane adducts (C6F5)3BPH3, (C6F5)3BPPhH2 and (C6F5)3GaPPhH2 (3) were used as starting materials, which upon lithiation with nBuLi react with the chlorinated Lewis base borane adduct ClBH2NMe3. The LA/LB stabilisedphosphanylboranes (C6F5)3BPH2BH2NMe3 (1), (C6F5)3BPPhHBH2NMe3 (4) and (C6F5)3GaPPhHBH2NMe3 (5), were obtained via salt elimination reactions. (C6F5)3GaPH2BH2NMe3 (2) was not accessible using this method due to the unavailability of an efficient synthetic route to (C6F5)3GaPH3. The synthesis of 2 could be achieved quantitatively via reaction of PH2BH2NMe3 with (C6F5)3Ga·Et2O. All products were comprehensively characterised by spectroscopic methods and X-ray crystallography. Additionally, the intermediate products (C6F5)3BPH2Li and (C6F5)3GaPPhH2 (3) were spectroscopically characterised.
Ringerweiterung einer Cp*-Einheit - Bildung eines 1,2-Diphosphacyclooctatetraen-Liganden [Ring Expansion of a Cp* Moiety - Formation of a 1,2-Diphosphacyclooctatetraene Ligand]
Creators: name: Scheer, Manfred
name: Himmel, Daniel
name: Johnson, Brian P.
name: Kuntz, Christian
name: Schiffer, Michael
Publisher: name: Universität Regensburg
Year: 2007
Subjects: subject: Dichtefunktionalrechnungen; Phosphaalkine; Phosphinidenkomplexe; Phosphor; Wolfram
subject: 540 Chemie

description: Gar nicht so unschuldig. Der Phosphinidenkomplex 1 reagiert mit tBuCP über ein WP-Intermediat zum Komplex 2 mit dem Diphosphabutenonyl-Liganden. Die Reaktion mit MesCP (Mes=2,4,6-Me3C6H2) führt dagegen über eine zuvor unbekannte Ringöffnung des unschuldigen Cp*-Liganden (Cp*=C5Me5) und Insertion des Phosphaalkins und des Phosphiniden-P-Atoms zum neuartigen Komplex 3 mit dem Diphosphacyclooctatetraen-Liganden.
Introducing students to the culture of physics: Explicating elements of the hidden curriculum
Creators: name: Redish, Edward F.
Publisher: name: arXiv
Year: 2010
Subjects: subject: Physics Education (physics.ed-ph)
subject: FOS: Physical sciences

description: When we teach physics to prospective scientists and engineers we are teaching more than the "facts" of physics - more, even, than the methods and concepts of physics. We are introducing them to a complex culture - a mode of thinking and the cultural code of behavior of a community of practicing scientists. This culture has components that are often part of our hidden curriculum: epistemology - how we decide that we know something; ontology - how we parse the observable world into categories, objects, and concepts; and discourse - how we hold a conversation in order to generate new knowledge and understanding. Underlying all of this is intuition - a culturally created sense of meaning. To explicitly identify teach our hidden curriculum we must pay attention to students' intuition and perception of physics, not just to their reasoning.
description: 4 pages, Physics Education Research Conference 2010 Plenary talk
A Compact Early-type Galaxy at z = 0.6 Under a Magnifying Lens: Evidence For Inside-out Growth
Creators: name: Auger, M. W.
name: Treu, T.
name: Brewer, B. J.
name: Marshall, P. J.
Publisher: name: arXiv
Year: 2010
Subjects: subject: Cosmology and Nongalactic Astrophysics (astro-ph.CO)
subject: FOS: Physical sciences

description: We use Keck laser guide star adaptive optics imaging and exploit the magnifying effects of strong gravitational lensing (the effective resolution is FWHM ~ 200 pc) to investigate the sub-kpc scale of an intermediate-redshift (z = 0.63) massive early-type galaxy being lensed by a foreground early-type galaxy; we dub this class of strong gravitational lens systems EELs, e.g., early-type/early-type lenses. We find that the background source is massive (M* = 10^{10.9} M_sun) and compact (r_e = 1.1 kpc), and a two-component fit is required to model accurately the surface brightness distribution, including an extended low-surface-brightness component. This extended component may arise from the evolution of higher-redshift `red nuggets' or may already be in place at z ~ 2 but is unobservable due to cosmological surface brightness dimming.
description: 5 pages, 4 figures; accepted to MNRAS
Ring Expansion of a Cp* Moiety: Formation of a 1,2-Diphosphacyclooctatetraene Ligand [Ringerweiterung einer Cp*-Einheit - Bildung eines 1,2-Diphosphacyclooctatetraen-Liganden]
Creators: name: Scheer, Manfred
name: Himmel, Daniel
name: Johnson, Brian P.
name: Kuntz, Christian
name: Schiffer, Michael
Publisher: name: Universität Regensburg
Year: 2007
Subjects: subject: density functional calculations, phosphaalkynes, phosphinidene complexes, phosphorus, tungsten
subject: 540 Chemie

description: Not as innocent as it looks: Reaction of the phosphinidene complex 1 with tBuCP leads, via a WP triply bound intermediate, to the diphosphabutenonyl ligand complex 2, whereas the reaction with MesCP (Mes=2,4,6-Me3C6H2) leads, through an unprecedented ring opening of the innocent Cp* ligand (Cp*=C5Me5) and insertion of the phosphaalkyne and the phosphinidene P atom, to the novel diphosphacyclooctatetraene ligand complex 3.
The surprising and stereoselective formation of P2C10 cages by the reduction of Cp*PCl2
Creators: name: Presly, C.
name: Green, Michael
name: Jeffery, John C.
name: Leiner, Eva
name: Murray, Martin
name: Russell, Christopher A.
name: Scheer, Manfred
name: Vogel, Ulf
Publisher: name: Universität Regensburg
Year: 2006
Subjects: subject: 540 Chemie

description: Reactions of Cp*PCl2 with Group 13 reducing agents result in a cascade of P–C, P–P and C–C bond forming reactions and the stereoselective formation of P2C10 cages.
An unprecedented nanoporous and fluorescent supramolecular framework with an SrAl2 topology controllably synthesized from a flexible ditopic acid
Creators: name: Wang, Su-Na
name: Yang, Yong
name: Bai, Junfeng
name: Li, Yi-Zhi
name: Scheer, Manfred
name: Pan, Yi
name: You, Xiao-Zeng
Publisher: name: Universität Regensburg
Year: 2007
Subjects: subject: 540 Chemie

description: A novel supramolecular framework was obtained from the ligand H2BDOA (benzene-1,3-dioxyacetic acid) that exhibited an SrAl2 topology with 1.7 × 1.7 nm channels formed by strong hydrogen bonds and demonstrated an interesting crystal-to-crystal transformation property.
Reversible Formation of Polymeric Chains by Coordination of Pentaphosphaferrocene with Silver(I) Cations
Creators: name: Scheer, Manfred
name: Gregoriades, Laurence John
name: Virovets, Alexander V.
name: Kunz, Werner
name: Neueder, Roland
name: Krossing, Ingo
Publisher: name: Universität Regensburg
Year: 2006
Subjects: subject: coordination polymers; density functional calculations; phosphorus; silver; structure elucidation
subject: 540 Chemie

description: A fragile coordination polymer: The pentaphosphaferrocene [Cp*Fe(5-P5)] reacts with the AgI salt of the weakly coordinating anion [Al{OC(CF3)3}4]- to yield a polymer comprising cyclo-P5 moieties in an unprecedented 1,2,3-coordination mode (see figure). Analytical data and DFT calculations support the existence of a monomer/dimer/oligomer equilibrium in solution, which is entirely in favor of the monomer at room temperature and shifts to the dimer/oligomer at reduced temperatures.
Terminally Coordinated AsS and PS Ligands
Creators: name: Balázs, Gábor
name: Green, Jennifer C.
name: Scheer, Manfred
Publisher: name: Universität Regensburg
Year: 2006
Subjects: subject: 540 Chemie

description: The terminal AsS and PS complexes [(N3N)W(ES)] (N3N=N(CH2CH2NSiMe3)3; E=P (3), As (4)) were synthesised by reaction of [(N3N)WAs] and [(N3N)WP], respectively, with cyclohexene sulfide. Both complexes present very short WE and ES bond lengths. The bonding was investigated by density functional theory (DFT) calculations using the fragment calculation method and natural bond orbital (NBO) analysis. According to the fragment analysis, in which the complexes were separated in an ES and a (N3N)W fragment, the bonding in complexes 3, 4 and [(N3N)W(SbS)] (5) is realised over a set of two (1 and 2) and two degenerate molecular orbitals (MOs) (1 and 2). The 1 MO is a bonding MO extended over the Nax-W-E-S core, whereas the 2 MO is localised mainly on the E-S fragment. The 1 set is a E-S localised bonding molecular orbital, whereas the 2 set is in phase with respect to W-E but in antiphase with respect to E-S. Both methods indicate bond orders around two for both the ES and the WE bonds. The polarity of the complexes was examined by Hirshfeld charge analysis. This shows that complexes 3 and 4 are only slightly polarised, whereas 5 is moderately polarised toward the sulphur. As suggested by the computational results, the system in complexes 3-5 is best described by two three-centre four-electron bonds.
Novel Alternating Ferro-Ferromagnetic Two-Dimensional (4,4) and Photoluminescent Three-Dimensional Interpenetrating PtS-Type Coordination Networks Constructed from a New Flexible Tripodal Ligand as a Four-Connected Node
Creators: name: Wang, Suna
name: Bai, Junfeng
name: Xing, Hang
name: Li, Yizhi
name: Song, You
name: Yi, Pan
name: Scheer, Manfred
name: You, Xiaozeng
Publisher: name: Universität Regensburg
Year: 2007
Subjects: subject: 540 Chemie

description: Two novel two-dimensional (2D) and one three-dimensional (3D) coordination polymers[Ni(HTTG)(H2O)2]n (1), [Co(HTTG)(H2O)2]n (2), and [Cd(HTTG)]n (3)have been hydrothermally synthesized by self-assembly of an unexplored tripodal ligand H3TTG (N,N‘,N‘‘-1,3,5-triazine-2,4,6-triyltris-glycine) and corresponding metal salts. X-ray diffraction analysis reveals that the three polymers exhibit novel frameworks due to diverse coordination conformations and different acid forms of the flexible tricaboxylate ligands. The isostructural complexes 1 and 2 possess 2D frameworks with M(H2O)2(CO2)2 chains bridged by the ligands, and the resulting 3D networks were extended through R22(8) hydrogen bonds between the undeprotonated carboxylate groups and the triazine rings as well as π···π interactions between the triazine rings. Complex 3 shows a 3D interpenetrating compact network with inorganic Cd2O2 chains interconnected by the flexible organic ligands. Topological analysis indicates that in all three complexes the tripodal ligand acts as a four-connected square-planar node, linking four-connected square-planar or tetrahedral-connected metal centers to form interesting two-dimensional (2D) (4,4) (in 1 and 2) and three-dimensional (3D) 2-fold interpenetrating PtS topologies (in 3), respectively. Interestingly, both 1 and 2 exhibit ferromagnetic interactions within the chains bridged by the syn−anti carboxylate groups and the water molecules alternately, and complex 3 displays strong photoluminescent properties at 413 nm due to the coordination of the ligands with the metal centers.
A New Noncentrosymmetric Superconducting Phase in the Li-Rh-B System
Creators: name: Takeya, Hiroyuki
name: Fujii, Hiroki
name: ElMassalami, Mohammed
name: Chaves, Francisco
name: Ooi, Shuuichi
name: Mochiku, Takashi
name: Takano, Yoshihiko
name: Hirata, Kazuto
name: Togano, Kazumasa
Publisher: name: arXiv
Year: 2011
Subjects: subject: Superconductivity (cond-mat.supr-con)
subject: FOS: Physical sciences

description: Superconductivity, at 2-3 K, was observed in a novel phase of the ternary Li-Rh-B system. The structural phase exhibits a large noncentrosymmetric cubic unit cell with the a-parameter being within 1.208 \leq a \leq 1.215 nm. This phase is stable over a wider compositional range of LixRhBy (0.6 < x < 2, 1 < y < 2). The superconductivity, as well as the unit cell volume, is sensitive to the Li/B content but it is manifested with Tc \geq 1.8 K over a wider compositional range: the highest Tc \approx 3 K occurs for x : y \approx 0.9:1.5 with a \approx 1.209 nm. The superconducting shielding fraction of most samples is almost 80% of that of Sn. The lower critical field, Hc1(0), is ~65 Oe while the upper one, Hc2(0) is determined from extrapolation to be higher than 14 kOe. We discuss the influence of pressure on Tc and also the influence of the lack of inversion symmetry on the superconducting properties.
description: 15 pages 6 figures
Cytotoxicity and apoptogenic properties of the standardized extract of Portulaca oleracea on glioblastoma multiforme cancer cell line (U-87): a mechanistic study
Creators: name: Baradaran Rahimi, Vafa
name: Mousavi, Seyed Hadi
name: Haghighi, Soroush
name: Soheili-Far, Sina
name: Askari, Vahid Reza
Publisher: name: IfADo - Leibniz Research Centre for Working Environment and Human Factors, Dortmund
Year: 2019
Subjects: glioblastoma multiforme (GBM)
ROS
NF-kB
U-87 cell
Portulaca oleracea
nitric oxide

description: The traditional uses of Portulaca oleracea L. (PO) with anti-inflammatory and anti-cancer activity as well as antioxidants properties were expressed previously. Glioma is considered the most common primary brain tumor and its malignant form is the most lethal adult brain tumor, that glioblastoma covers about 50 % of glioma tumors. The present study was aimed to evaluate the cytotoxicity and apoptogenic effects of the hydro-ethanolic extract of PO on human glioblastoma cancer cell line (U-87) and the role of NF-kB. Cytotoxicity of the extract in the presence or absence of Vitamin C was evaluated using MTT assay, and the following hypotonic PI and SubG1 peak were performed. Moreover, the reactive oxygen species (ROS), the level of NF-kB protein and nitric oxide (NO) production were investigated. The extract had cytotoxicity and apoptogenic effects on U-87 cells in both the concentration and time-dependent manners. The mechanism of cytotoxicity and apoptosis induction of the extract at the first hours of incubation and low concentrations were dependent on ROS. However, the toxicity was replaced with NO pathway with time-lapse and higher concentrations. Results also indicated that the extract acts as an NF-kB inhibitor with concentration and time-dependent manners. The present study may suggest the anti-NF-kB activity of PO along with two upstream ROS and NO mechanisms. Furthermore, the extract as ethnobotanical may be used as adjunctive anti-cancer therapy against glioblastoma multiforme.
description: EXCLI Journal; 18:Doc165; ISSN 1611-2156
Ein ungewöhnlicher Baustein für supramolekulare Aggregate aus Elementen der Gruppe 15 und 16: der gemischte Ligandkomplex [(Cp*Mo)2(,3-P3)(,2-PS)] [An Unusual Building Block for Supramolecular Aggregates: the Mixed Group 15/16 Element Ligand Complex [(Cp*Mo)2(m,h3-P3)(m,h2-PS)]]
Creators: name: Gregoriades, Laurence John
name: Balázs, Gábor
name: Brunner, Eike
name: Gröger, Christian
name: Wachter, Joachim
name: Zabel, Manfred
name: Scheer, Manfred
Publisher: name: Universität Regensburg
Year: 2007
Subjects: subject: Molybdän; Münzmetalle; Phosphor; Schwefel; Supramolekulare Chemie
subject: 540 Chemie

description: Ein ungewöhnlicher Baustein: Der Komplex [(Cp*Mo)2(,3-P3)(,2-PS)] bildet mit CuI und Ag[Al{OC(CF3)3}4] neue lineare Koordinationspolymere (siehe die Struktur das CuI-Derivats im Kristall; Cu hellblau, I violett, Mo blau, P rosa, S gelb). Erst anhand der 31P-MAS-NMR-Spektren konnte gezeigt werden, dass in den Polymerketten die Schwefelatome nicht an die Gruppe-11-Metalle koordinieren.
A simpler and more efficient algorithm for the next-to-shortest path problem
Creators: name: Wu, Bang Ye
Publisher: name: arXiv
Year: 2011
Subjects: subject: Data Structures and Algorithms (cs.DS)
subject: FOS: Computer and information sciences

description: Given an undirected graph $G=(V,E)$ with positive edge lengths and two vertices $s$ and $t$, the next-to-shortest path problem is to find an $st$-path which length is minimum amongst all $st$-paths strictly longer than the shortest path length. In this paper we show that the problem can be solved in linear time if the distances from $s$ and $t$ to all other vertices are given. Particularly our new algorithm runs in $O(|V|\log |V|+|E|)$ time for general graphs, which improves the previous result of $O(|V|^2)$ time for sparse graphs, and takes only linear time for unweighted graphs, planar graphs, and graphs with positive integer edge lengths.
description: Partial result appeared in COCOA2010
Investigation into the Formation of Supramolecular Compounds from Mixed As/S-Ligand Complexes [(Cp*Mo)2As2S3] (Cp* = C5Me5) and Copper Halides
Creators: name: Pronold, Michael
name: Scheer, Manfred
name: Wachter, Joachim
name: Zabel, Manfred
Publisher: name: Universität Regensburg
Year: 2007
Subjects: subject: 540 Chemie

description: The coordination behavior of [(Cp*Mo)2As2S3] (3) (Cp* = C5Me5) toward Cu(I) halides was investigated. One dimensional polymers of the general formula [(Cp*Mo)2As2S3(CuHal)2]n (Hal = Cl, 4; Br, 5) and an oligomer of composition [{(Cp*Mo)2As2S3}3(CuI)7] (6) formed upon the reaction of 3 with the corresponding copper halide. All of the compounds were characterized by ESI−MS, elemental analysis, and single-crystal X-ray crystallography. The solid-state structures of 4 and 5 are isostructural and contain 1D S-shaped chains. This peculiar folding is achieved by alternating planar and folded Cu2Hal2 rings linked together by the central monosulfide bridge of the middle deck of the organometallic unit. The structure of 6 is characterized by a novel [CuI]7 aggregate, which forms a very flat Cu6I3S3 bowl along with three integrated peripheral [(Cp*Mo)2As2S3] building blocks. In contrast to earlier findings, the middle deck of the organometallic units consists in all structures of two trapezoidal AsS dumbbells and one monosulfide ligand.
Conformational Analysis of One-Dimensional Coordination Polymers Based on [Cp2Cr2(CO)4(,2-P2)] by Solid-State Multinuclear NMR Spectroscopy and Density Functional Calculations
Creators: name: Scheer, Manfred
name: Gregoriades, Laurence John
name: Zabel, Manfred
name: Sierka, Marek
name: Zhang, Long
name: Eckert, Hellmut
Publisher: name: Universität Regensburg
Year: 2007
Subjects: subject: Chromium; Copper; Halides; Density functional calculations; NMR spectroscopy; Phosphorus
subject: 540 Chemie

description: Reaction of the complex [Cp2Cr2(CO)4(,2-P2)] (2) with copper(I) halides leads to the quantitative formation of the new one-dimensional (1D) linear polymers [CuX{Cp2Cr2(CO)4(,2:1:1-P2)}]n [X = Cl (3), Br (4), I (5)]. Polymers 3-5 are the first examples of supramolecular aggregates incorporating 2 as a connecting moiety. The solid-state structures of 3-5 are compared and their remarkable influence on the respective solid-state 31P magic angle spinning (MAS) NMR spectra is interpreted with the help of density functional theory (DFT) calculations, which suggest that the 31P chemical shifts are extremely sensitive to the position of the phosphorus atoms with respect to the cones of anisotropy of the carbonyl ligands.
Ungewöhnliches Koordinationsverhalten von Pn-Ligandkomplexen gegenüber Tl+ [Unusual Coordination Behaviour of Pn-Ligand Complexes with Tl+]
Creators: name: Welsch, Stefan
name: Gregoriades, Laurence John
name: Sierka, Marek
name: Zabel, Manfred
name: Virovets, Alexander
name: Scheer, Manfred
Publisher: name: Universität Regensburg
Year: 2007
Subjects: subject: Wechselwirkungen; Koordinationspolymere; Phosphor; Schwach koordinierende Anionen; Thallium
subject: 540 Chemie

description: Pentaphosphaferrocen koordiniert als -Ligand an das große Kation Tl+. Zusätzlich bindet ein Phosphoratom jeder cyclo-P5-Einheit zum benachbarten Tl+-Ion, sodass ein eindimensionales Koordinationspolymer entsteht. In Lösung und im Festkörper wird auch bei tiefen Temperaturen eine schnelle Rotation der P5-Ringe beobachtet.
The Complexed Triphosphaallyl Radical, Cation, and Anion Family [Eine Familie mit komplexiertem Triphosphaallyl-Radikal, -Kation und -Anion]
Creators: name: Scheer, Manfred
name: Kuntz, Christian
name: Stubenhofer, Markus
name: Linseis, Michael
name: Winter, Rainer F.
name: Sierka, Marek
Publisher: name: Universität Regensburg
Year: 2009
Subjects: subject: allyl ligands; DFT calculationsM; phosphinidines; phosphorus; radicals
subject: 540 Chemie

description: Radically complex: The photolytic reaction of [Cp*P{W(CO)5}2] (Cp*=C5Me5) with a diphosphene produces, via a radical intermediate, an air-stable complexed triphosphaallyl radical, in which the unpaired electron is evenly distributed over both terminal P atoms. Oxidation of the radical leads to a triphosphaallyl cation, which is only stable at low temperatures in solution, whereas the stable triphosphaallyl anion is formed by reduction (see picture, Mes*=2,4,6-tri-tert-butylphenyl).
Phase diagrams for the spatial public goods game with pool-punishment
Creators: name: Szolnoki, Attila
name: Szabo, Gyorgy
name: Perc, Matjaz
Publisher: name: arXiv
Year: 2011
Subjects: subject: Physics and Society (physics.soc-ph)
subject: Statistical Mechanics (cond-mat.stat-mech)
subject: Biological Physics (physics.bio-ph)
subject: Populations and Evolution (q-bio.PE)
subject: FOS: Physical sciences
subject: FOS: Biological sciences

description: The efficiency of institutionalized punishment is studied by evaluating the stationary states in the spatial public goods game comprising unconditional defectors, cooperators, and cooperating pool-punishers as the three competing strategies. Fine and cost of pool-punishment are considered as the two main parameters determining the stationary distributions of strategies on the square lattice. Each player collects its payoff from five five-person public goods games, and the evolution of strategies is subsequently governed by imitation based on pairwise comparisons at a low level of noise. The impact of pool-punishment on the evolution of cooperation in structured populations is significantly different from that reported previously for peer-punishment. Representative phase diagrams reveal remarkably rich behavior, depending also on the value of the synergy factor that characterizes the efficiency of investments payed into the common pool. Besides traditional single and two-strategy stationary states, a rock-paper-scissors type cyclic dominance can emerge in strikingly different ways.
description: 11 two-column pages, 12 figures; accepted for publication in Physical Review E
Self-Assemblies Based on [Cp2Mo2(CO)4(,2-P2)] - Solid-State Structure and Dynamic Behaviour in Solution
Creators: name: Scheer, Manfred
name: Gregoriades, Laurence John
name: Zabel, Manfred
name: Bai, Junfeng
name: Krossing, Kai
name: Brunklaus, Gunther
name: Eckert, Hellmut
Publisher: name: Universität Regensburg
Year: 2008
Subjects: subject: density functional calculations; group 11 metals; molybdenum; NMR spectroscopy; phosphorus
subject: 540 Chemie

description: Reaction of complex [Cp2Mo2(CO)4(,2-P2)] (Cp=C5H5 (1)) with CuPF6, AgX (X=BF4, ClO4, PF6, SbF6, Al{OC(CF3)3}4) and [(Ph3P)Au(THF)][PF6] (THF=tetrahydrofuran), respectively, results in the facile formation of the dimers 3 b-h of the general formula [M2({Cp2Mo2 (CO)4(,2:2-P2)}2)({Cp2Mo2(CO)4 (,2:1:1-P2)}2)][X]2 (M=Cu, Ag, Au; X=BF4, ClO4, PF6, SbF6, Al{OC(CF3)3}4). As revealed by X-ray crystallography, all these dimers comprise dicationic moieties that are well-separated from the weakly coordinating anions in the solid state. If 1 is allowed to react with AgNO2 and LAuCl (L=CO or tetrahydrothiophene), respectively, the dimer [Ag2{Cp2Mo2 (CO)4(,2:1:1-P2)}2(2-NO2)2] (5) and the complex [AuCl{Cp2Mo2(CO)4(,2:1-P2)}] (6) are formed, which have also been characterised by X-ray crystallography. In compounds 5 and 6, the anions remain coordinated to the Group 11 metal centres. Spectroscopic data suggest that the dimers 3 b-h display dynamic behaviour in solution and this is discussed by using the comprehensive results obtained for 3 g (M=Ag; X=Al{OC(CF3)3}4) as a basis. The interpretation of the experimental results is facilitated by density functional theory (DFT) calculations on 3 g (structures, energetics, NMR shielding tensors). The 31P magic angle spinning (MAS) NMR spectra recorded for the dimers 3 b (M=Cu; X=PF6) and 3c (M=Ag; X=BF4) as well as that of the previously reported one-dimensional (1 D) polymer [Ag2{Cp2Mo2(CO)4(,2:1:1-P2)}3(,1:1-NO3)]n[NO3]n (4) are also discussed herein and the strong dependence of the chemical shift of the phosphorus atoms within each compound on subtle structural differences in the solid state is demonstrated. Furthermore, the X-ray crystallographic and 31P MAS NMR spectroscopic characterisation of a new polymorph of 1 is reported.
Synthesis and unprecedented coordination behaviour of a novel 1,2,3-triphosphaferrocene complex
Creators: name: Deng, Shining
name: Schwarzmaier, Christoph
name: Eichhorn, Christiane
name: Scherer, Otto
name: Wolmershäuser, Gotthelf
name: Zabel, Manfred
name: Scheer, Manfred
Publisher: name: Universität Regensburg
Year: 2008
Subjects: subject: 540 Chemie

description: A novel 1,2,3-triphosphaferrocene has been synthesised, which reacts with CuBr to give a 2D polymer, revealing an unprecedented -stacking of the triphospholyl moieties.
Stationary state solutions for a gently stochastic nonlinear wave equation with ultraviolet cutoffs
Creators: name: Wang, Yao
name: Thomas, Lawrence E.
Publisher: name: arXiv
Year: 2010
Subjects: subject: Mathematical Physics (math-ph)
subject: FOS: Physical sciences
subject: 82C05, 60H15

description: We consider a non-linear, one-dimensional wave equation system with finite-dimensional stochastic driving terms and with weak dissipation. A stationary process that solves the system is used to model steady-state non-equilibrium heat flow through a non-linear medium. We show existence and uniqueness of invariant measures for the system modified with ultraviolet cutoffs, and we obtain estimates for the field covariances with respect to these measures, estimates that are uniform in the cutoffs. Finally, we discuss the limit of these measures as the ultraviolet cutoffs are removed.
description: 19 pages
Development of novel concatemer technology using potassium channel (Kv1.1) homotetramer as a framework
Creators: name: Ray, Arnab
Publisher: name: University of British Columbia
Year: 2017

description: Voltage gated potassium channels (Kv) belong to a larger family of proteins called ion channels. Kv channels occur ubiquitously in the body and play a range of essential roles in cellular processes such as signal propagation and cellular excitability. Kv are made up of four subunits, each of which is translated individually, followed by assembly and expression on the cell surface. Kv1.1 is a Kv family member capable of assembling as either a homotetramer or a heterotetramer. In particular, when Kv1.1 subunits assemble with other Kv1.x subunits, the former shape the activation threshold and kinetics of macroscopic current of a channel, and play an important role in the trafficking and surface expression of other Kv1.4 channels. Dysfunction of Kv1.1 has been linked to an autosomal dominant neurological disorder, episodic ataxia (EA-1), that affects both the central nervous system and peripheral nervous system. Patients with EA-1 are 10 times more likely to develop epilepsy than normal individuals. Kv1.1 channels have also been implicated in sudden unexpected death in epilepsy (SUDEP) and Alzheimer’s disease. Dysfunction of Kv1.1 channels has been characterized by studying specific mutations in KCNA1 genes. Current techniques for generating Kv1.1 channels in heterologous expression systems for subsequent biophysical characterizations include coexpression and dimer construction methods, and the creation of tandem dimer-linked concatemers. The latter provides the greatest control over stoichiometry and arrangement of subunits; however, generation of each concatemer is extremely labour- and time-intensive. This thesis focuses on the development of a new concatemer system built on an inhouse plasmid (pICDNA), with an intentionally designed linker sequence that physically concatenates four Kcna1 genes. The Kv1.1 homotetramer concatemer system has been developed to permit flexibility, such that each gene (or multiple genes) in the concatemer can be targets for future cloning. The development of the Kv1.1 homotetramer system will facilitate the examination of the role Kv1.1 channels play, independently of its main partners, Kv1.2 and Kv1.4. The Kv1.1 concatemer platform can be used in the future as a backbone upon which future Kv1.x heterotetramers can be developed more easily.
4U 1210−64: a new member of the rare intermediate-mass X-ray binary subclass
Creators: name: Monageng, I. M.
name: McBride, V. A.
name: Alfonso-Garzon, J.
name: Townsend, L. J.
name: Coley, J. B.
name: Montesinos, B.
name: Corbet, R. H. D.
name: Pottschmidt, Katja
Publisher: name: Oxford University Press
Year: 2024

description: 4U 1210−64 is a peculiar X-ray binary that was first discovered in 1978 by the Uhuru satellite. The analysis of the X-ray data revealed a 6.7-d orbital period and an additional long-term modulation that is manifested as low- and high-flux states. Based on the previous classification of the donor star from the analysis of its optical spectra, the system has been suggested to be a high-mass X-ray binary. We revisit the optical classification where, based on the spectra from the Southern African Large Telescope (SALT), we conclude that the donor star is of spectral class A8 III–IV, making it a member of the rare intermediate-mass X-ray binaries. We perform radial velocity analysis using the SALT spectra where we consider circular and eccentric orbits. From the mass function derived and the mass constraints of the donor star, we demonstrate that a neutron star is favoured as the compact object in the binary system. We show, for the first time, the folded optical light curves, whose shape is interpreted to be due to a combination of ellipsoidal variations, irradiation of the donor star, and mutual eclipses of the star and accretion disc.
Test of Lorentz Symmetry by using a 3He/129Xe Co-Magnetometer
Creators: name: Tullney, K.
name: Gemmel, C.
name: Heil, W.
name: Karpuk, S.
name: Lenz, K.
name: Sobolev, Yu.
name: Burghoff, M.
name: Kilian, W.
name: Knappe-Grüneberg, S.
name: Müller, W.
name: Schnabel, A.
name: Seifert, F.
name: Trahms, L.
name: Schmidt, U.
Publisher: name: arXiv
Year: 2010
Subjects: subject: High Energy Physics - Phenomenology (hep-ph)
subject: FOS: Physical sciences

description: To test Lorentz symmetry we used a 3He/129Xe co-magnetometer. We will give a short summary of our experimental setup and the results of our latest measurements. We obtained preliminary results for the equatorial component of the background field interacting with the spin of the bound neutron: b_n < 3.72 x 10^(-32) GeV (95 C.L.).
description: Presented at the Fifth Meeting on CPT and Lorentz Symmetry, Bloomington, Indiana, June 28 - July 2, 2010
N-Heterocyclic Carbenes in Lewis Acid/Base Stabilised Phosphanylboranes
Creators: name: Adolf, Ariane
name: Vogel, Ulf
name: Zabel, Manfred
name: Timoshkin, Alexey Y.
name: Scheer, Manfred
Publisher: name: Universität Regensburg
Year: 2008
Subjects: subject: Boron; Phosphorus; Gallium; Carbenes; Lewis acids; Lewis bases
subject: 540 Chemie

description: The reactions of 2-borane-1,3,4,5-tetramethylimidazoline (BH3·NHCMe) with selected phosphane adducts of the Lewis acids B(C6F5)3 and Ga(C6F5)3 are studied. Among others, adducts (C6F5)3Ga·PH2Cp* (1a) and (C6F5)3B·PH2Cp* (2) are used as starting materials. When the (C6F5)3Ga-phosphane adducts 1a and (C6F5)3Ga·PPhH2 are treated with BH3·NHCMe, the Lewis acid/base stabilised phosphanylboranes (C6F5)3Ga·P(Cp*)HBH2·NHCMe (3a) and (C6F5)3Ga·P(Ph)HBH2·NHCMe (3b) are formed, respectively, by a hydrogen elimination reaction. In contrast, the reaction of BH3·NHCMe with the (C6F5)3B-phosphane adducts (C6F5)3B·PH2R [R = H, R = Cp* (2) and R = Ph] in CH2Cl2 at room temperature leads to the formation of a salt with the general formula [(C6F5)3BH][RPH2·BH2·NHCMe] (4a: R = H, 4b: R = Cp*, 4c: R = Ph). To synthesise the Lewis acid/base stabilised phosphanylborane with (C6F5)3B as a Lewis acid and 1,3,4,5-tetramethylimidazolylidene (NHCMe) as a Lewis base, a different synthetic pathway was applied: the replacement reaction of the Lewis base. At room temperature, NHCMe displaced the amine in (C6F5)3B·P(Ph)HBH2·NMe3 to yield (C6F5)3B·P(Ph)HBH2·NHCMe (5). All compounds were comprehensively characterised by spectroscopic methods. Compounds 1a, 1b, 2, 3a, 3b and 5 were additionally characterised by X-ray crystallographic analysis.
Superorbital Modulation in the High-mass X-Ray Binary 4U 1538–52 and Possible Modulation in IGR J16393–4643
Creators: name: Corbet, Robin
name: Coley, Joel B.
name: Krimm, Hans A.
name: Pottschmidt, Katja
name: Roche, Paul
Publisher: name: AAS
Year: 2020

description: Hard X-ray observations with the Neil Gehrels Swift Observatory Burst Alert Telescope (BAT) reveal superorbital modulation in the wind-accreting supergiant high-mass X-ray binary (HMXB) 4U 1538−52 at a period of 14.9130 ± 0.0026 days that is consistent with four times the 3.73 day orbital period. These periods agree with a previously suggested correlation between superorbital and orbital periods in similar HMXBs. During the ∼14 yr of observations the superorbital modulation changes amplitude, and since ∼MJD 57,650 it was no longer detected in the power spectrum, although a peak near the second harmonic of this was present for some time. Measurements of the spin period of the neutron star in the system with the Fermi Gamma-ray Burst Monitor show a long-term spin-down trend, which halted toward the end of the light curve, suggesting a connection between and superorbital modulation, as proposed for 2S 0114+650. However, an earlier torque reversal from INTEGRAL observations was not associated with superorbital modulation changes. B- and V-band photometry from the Las Cumbres Observatory reveals orbital ellipsoidal photometric variability, but no superorbital optical modulation. However the photometry was obtained when the 14.9130 day period was no longer detected in the BAT power spectrum. We revisit possible superorbital modulation in BAT observations of IGR J16393−4643 but cannot conclusively determine whether this is present, although it is not persistent. We consider superorbital modulation mechanisms, and suggest that the corotating interaction region model, with small deviations from orbital synchronization, appears promising.
SUPPLEMENTARY MATERIALS from Ancient insect vision tuned for flight among rocks and plants underpins natural flower colour diversity
Creators: name: Dorin, Alan
name: Shrestha, Mani
name: Garcia, Jair E.
name: Burd, Martin
name: Dyer, Adrian G.
Publisher: name: The Royal Society
Year: 2023
Subjects: classificationCode: 310399
subject: Ecology not elsewhere classified
classificationCode: 310899
subject: Plant biology not elsewhere classified
classificationCode: 310901
subject: Animal behaviour

description: Understanding the origins of flower colour signalling to pollinators is fundamental to evolutionary biology and ecology. Flower colour evolves under pressure from visual systems of pollinators, like birds and insects, to establish global signatures among flowers with similar pollinators. However, an understanding of the ancient origins of this relationship remains elusive. Here, we employ computer simulations to generate artificial flower backgrounds assembled from real material sample spectra of rocks, leaves and dead plant materials, against which to test flowers' visibility to birds and bees. Our results indicate how flower colours differ from their backgrounds in strength, and the distributions of salient reflectance features when perceived by these key pollinators, to reveal the possible origins of their colours. Since Hymenopteran visual perception evolved before flowers, the terrestrial chromatic context for its evolution to facilitate flight and orientation consisted of rocks, leaves, sticks and bark. Flowers exploited these pre-evolved visual capacities of their visitors, in response evolving chromatic features to signal to bees, and differently to birds, against a backdrop of other natural materials. Consequently, it appears that today's flower colours may be an evolutionary response to the vision of diurnal pollinators navigating their world millennia prior to the first flowers.
High pressure synthesis of FeO-ZnO solid solutions with rock salt structure: in situ X-ray diffraction studies
Creators: name: Sokolov, P. S.
name: Baranov, A. N.
name: Lathe, C.
name: Solozhenko, V. L.
Publisher: name: arXiv
Year: 2011
Subjects: subject: Materials Science (cond-mat.mtrl-sci)
subject: FOS: Physical sciences

description: X-ray diffraction with synchrotron radiation has been used for the first time to study chemical interaction in the FeO-ZnO system at 4.8 GPa and temperatures up to 1300 K. Above 750 K, the chemical reaction between FeO and ZnO has been observed that resulted in the formation of rock salt (rs) Fe1-xZnxO solid solutions (0.3 \leq x \leq 0.85). The lattice parameters of these solid solutions have been in situ measured as a function of temperature under pressure, and corresponding thermal expansion coefficients have been calculated.
description: 9 pages, 2 figures, 1 table
Selective halogenation at the pnictogen atom in Lewis-acid/base-stabilised phosphanylboranes and arsanylboranes
Creators: name: Schwan, Karl-Christian
name: Adolf, Ariane
name: Vogel, Ulf
name: Thoms, Christine
name: Zabel, Manfred
name: Timoshkin, Alexey Y.
name: Scheer, Manfred
Publisher: name: Universität Regensburg
Year: 2008
Subjects: subject: 540 Chemie

description: The halogenation of Lewis-acid/base-stabilised phosphanylboranes ( 1a) and arsanylboranes ( 1b) with CX4 (X = Cl, Br) leads selectively to the substitution of both protons at the pentel atom and the new compounds [(CO)5W(X2PBH2·NMe3)] ( 2a: X = Cl, 2b: X = Br) and [(CO)5W(X2AsBH2·NMe3)] ( 3a: X = Cl, 3b: X = Br), respectively, are obtained. The new products were comprehensively characterised by spectroscopic methods and by X-ray crystallography. While compounds 2a and 2b show an antiperiplanar arrangement of the Lewis acid (W(CO)5) and the Lewis base (NMe3) in the solid state, a synclinal arrangement in 3a and 3b, respectively, was observed. Computational calculations of the optimised antiperiplanar and synclinal geometries of the compounds 2 and 3 in the gas phase slightly favour the antiperiplanar arrangement of the Lewis acid and the Lewis base for both compounds.
title: Wärmepotentiale von Biomasse und Müllverbrennung für Nürnberg
Creators: name: Metzger, Mario
Publisher: name: Technische Hochschule Nürnberg Georg Simon Ohm
Year: 2024
Subjects: subject: 62 Ingenieurwissenschaften

description: Diese Arbeit begrenzt sich auf die regenerative Wärmeversorgung der Stadt Nürnberg im Jahr 2035. Sie untersucht die Forschungsfrage, ob die intensivere Nutzung von Holzhackschnitzeln zur Energiegewinnung im Anlieferumkreis von kleiner gleich 80 km um Nürnberg möglich ist, ohne dabei zusätzliche Flächen der Futtermittelproduktion zu verwenden. Dabei wird konkret ermittelt wie viel Fläche zusätzlich benötigt wird, um den Rohstoff bereit zu stellen. Ergänzend bräuchte man ab 2035 ein Gebiet, der Größe von Nürnberg selbst, um insgesamt 15% des Wärmebedarfs aus Biomasse abdecken zu können. Ein weiterer Teil dieser Arbeit beschäftigt sich mit der Fragestellung, welche Potentiale zur Energiegewinnung Haus- und/oder Gewerbeabfälle, welche aus dem europäischen Ausland importiert werden, bieten. Hierzu wird einen Massenberechnung durchgeführt, die zu dem Ergebnis kommt, dass Tschechien die notwendig Menge Müll deponiert, um 100% der Wärmenachfrage Nürnbergs abdecken zu können,
Ergänzend zu den ersten beiden Forschungsfragen lautet die Dritte: Wie viel Prozent können die Sekundärenergieträger Hackschnitzel und Müll wirtschaftlich vom Gesamtwärmebedarf abdecken? Die Rentabilität nimmt bei der Ausarbeitung eine bedeutende Rolle ein. Es wird beispielsweise geprüft, ob es aus finanzieller Sicht Sinn macht, auf Feldern Bäume zu pflanzen und diese später als Hackgut zu verkaufen.
Die Arbeit bringt konkrete Ergebnisse hervor, welche als unterstützendes Material für die Planung zukünftiger Projekte im Nürnberger Energiesektor herangezogen werden können.
description: Projekt Regenerative Energieversorgung (SoSe 2024); 3
Comparison of GFED3, QFED2 and FEER1 Biomass Burning Emissions Datasets in a Global Model
Creators: name: Pan, Xiaohua
name: Ichoku, Charles
name: Bian, Huisheng
name: Chin, Mian
name: Ellison, Luke
name: Da Silva, Arlindo
name: Darmenov, Anton
Publisher: name: Maryland Shared Open Access Repository
Year: 2015
Subjects: Environment Pollution

description: AeroCom Workshop, Frascati, Italy, October 5-9, 2015
description: Biomass burning contributes about 40% of the global loading of carbonaceous aerosols, significantly affecting air quality and the climate system by modulating solar radiation and cloud properties. However, fire emissions are poorly constrained in models on global and regional levels. In this study, we investigate 3 global biomass burning emission datasets in NASA GEOS5, namely: (1) GFEDv3.1 (Global Fire Emissions Database version 3.1); (2) QFEDv2.4 (Quick Fire Emissions Dataset version 2.4); (3) FEERv1 (Fire Energetics and Emissions Research version 1.0). The simulated aerosol optical depth (AOD), absorption AOD (AAOD), angstrom exponent and surface concentrations of aerosol plumes dominated by fire emissions are evaluated and compared to MODIS, OMI, AERONET, and IMPROVE data over different regions. In general, the spatial patterns of biomass burning emissions from these inventories are similar, although the strength of the emissions can be noticeably different. The emissions estimates from QFED are generally larger than those of FEER, which are in turn larger than those of GFED. AOD simulated with all these 3 databases are lower than the corresponding observations in Southern Africa and South America, two of the major biomass burning regions in the world.