| 1. |
- Boström, Mathias, et al.
(författare)
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Casimir attractive-repulsive transition in MEMS
- 2012
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Ingår i: European Physical Journal B. - : Springer Science and Business Media LLC. - 1434-6028 .- 1434-6036. ; 85:11, s. 377-
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Tidskriftsartikel (refereegranskat)abstract
- Unwanted stiction in micro-and nanomechanical (NEMS/MEMS) systems due to dispersion (van der Waals, or Casimir) forces is a significant hurdle in the fabrication of systems with moving parts on these length scales. Introducing a suitably dielectric liquid in the interspace between bodies has previously been demonstrated to render dispersion forces repulsive, or even to switch sign as a function of separation. Making use of recently available permittivity data calculated by us we show that such a remarkable nonmonotonic Casimir force, changing from attractive to repulsive as separation increases, can in fact be observed in systems where constituent materials are in standard NEMS/MEMS use requiring no special or exotic materials. No such nonmonotonic behaviour has been measured to date. We calculate the force between a silica sphere and a flat surface of either zinc oxide or hafnia, two materials which are among the most prominent for practical microelectrical and microoptical devices. Our results explicate the need for highly accurate permittivity functions of the materials involved for frequencies from optical to far-infrared frequencies. A careful analysis of the Casimir interaction is presented, and we show how the change in the sign of the interaction can be understood as a result of multiple crossings of the dielectric functions of the three media involved in a given set-up.
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| 2. |
- Boström, Mathias, et al.
(författare)
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Casimir force between atomically thin gold films
- 2013
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Ingår i: European Physical Journal B. - : Springer Science and Business Media LLC. - 1434-6028 .- 1434-6036. ; 86:2, s. 43-
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Tidskriftsartikel (refereegranskat)abstract
- We have used density functional theory to calculate the anisotropic dielectric functions for ultrathin gold sheets (composed of 1, 3, 6, and 15 atomic layers). Such films are important components in nano-electromechanical systems. When using correct dielectric functions rather than bulk gold dielectric functions we predict an enhanced attractive Casimir-Lifshitz force (at most around 20%) between two atomically thin gold sheets. For thicker sheets the dielectric properties and the corresponding Casimir forces approach those of gold half-spaces. The magnitude of the corrections that we predict should, within the today's level of accuracy in Casimir force measurements, be clearly detectable.
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| 3. |
- Larsson, Helen, 1982, et al.
(författare)
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Dysphagia and health-related of life in patients with eosinophilic esophagitis: a long-term follow-up.
- 2015
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Ingår i: European archives of oto-rhino-laryngology : official journal of the European Federation of Oto-Rhino-Laryngological Societies (EUFOS) : affiliated with the German Society for Oto-Rhino-Laryngology - Head and Neck Surgery. - : Springer Science and Business Media LLC. - 1434-4726. ; 272:12, s. 3833-3839
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Tidskriftsartikel (refereegranskat)abstract
- Eosinophilic esophagitis (EoE) is a chronic immune/antigen-mediated disease, with dysphagia as the main symptom. The aim of this study was to survey symptoms and health-related quality of life in adult patients with EoE at least 1year after diagnosis and a 2-month course of topical corticosteroids. Forty-seven consecutive patients [79% males, mean age 49years (range 18-90years)] were evaluated using three different questionnaires at three different occasions: the Watson Dysphagia Scale (WDS), the European Organization for Research and Treatment of Cancer Quality of Life Questionnaire-Oesophageal Module 18 (EORTC QLQ-OES18) and the Short Form-36 (SF-36). The median time from diagnosis to the long-term follow-up was 23months (range 12-34months). The WDS scores and the EORTC QLQ-OES18 Dysphagia and Eating scale scores were improved after 2months of treatment (p=0.00007, p=0.01, p=0.004, respectively), as were the long-term follow-up scores (p=0.01, p=0.03, p=0.005, respectively), relative to the scores at diagnosis. In addition, the EORTC QLQ-OES18 Choking scores were improved after the steroid course (p=0.003) but not after the long-term follow-up. No significant differences were detected with respect to the SF-36 scores. In summary, EoE seems to be associated with a substantial burden of symptoms that improve significantly after treatment. A partial remission persists more than 1year after diagnosis and the discontinuation of medication. The WDS and the EORTC QLQ-OES18 appear to be sensitive instruments appropriate for surveillance in these patients.
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| 4. |
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| 5. |
- Sheikh, Sanea, et al.
(författare)
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A New Classification of the Dictyostelids
- 2018
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Ingår i: Protist. - : Elsevier BV. - 1434-4610 .- 1618-0941. ; 169:1, s. 1-28
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Tidskriftsartikel (refereegranskat)abstract
- Traditional morphology-based taxonomy of dictyostelids is rejected by molecular phylogeny. A new classification is presented based on monophyletic entities with consistent and strong molecular phylogenetic support and that are, as far as possible, morphologically recognizable. All newly named clades are diagnosed with small subunit ribosomal RNA (18S rRNA) sequence signatures plus morphological synapomorphies where possible. The two major molecular clades are given the rank of order, as Acytosteliales ord. nov. and Dictyosteliales. The two major clades within each of these orders are recognized and given the rank of family as, respectively, Acytosteliaceae and Cavenderiaceae fam. nov. in Acytosteliales, and Dictyosteliaceae and Raperosteliaceae fam. nov. in Dictyosteliales. Twelve genera are recognized: Cavenderia gen. nov. in Cavenderiaceae, Acytostelium, Rostrostelium gen. nov. and Heterostelium gen. nov. in Acytosteliaceae, Tieghemostelium gen. nov., Hagiwaraea gen. nov., Raperostelium gen. nov. and Speleostelium gen. nov. in Raperosteliaceae, and Dictyostelium and Polysphondylium in Dictyosteliaceae. The “polycephalum” complex is treated as Coremiostelium gen. nov. (not assigned to family) and the “polycarpum” complex as Synstelium gen. nov. (not assigned to order and family). Coenonia, which may not be a dictyostelid, is treated as a genus incertae sedis. Eighty-eight new combinations are made at species and variety level, and Dictyostelium ammophilum is validated.
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| 6. |
- Algarra, Andres G.
(författare)
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Computational Insights into the Isomerism of Hexacoordinate Metal-Sarcophagine Complexes : The Relationship between Structure and Stability
- 2015
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Ingår i: European Journal of Inorganic Chemistry. - : Wiley. - 1434-1948 .- 1099-1948 .- 1099-0682. ; :3, s. 503-511
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Tidskriftsartikel (refereegranskat)abstract
- The hexacoordinate complexes that the macrobicyclic ligands {(NH3)(2)sar)(2+) and {NMe3)(2)sar}(2+) (sar = 3,6,10,13,16,19-hexaazabicyclo[6.6.6]icosane) form with transition metals such as Co-III, Co-II and Cu-II can adopt several isomeric structures. In this article, we have firstly employed DFT methods lo compute the relative stability of their Delta-ob(3), Delta-ob(2)lel, Delta-lel(2)ob and Delta-lel(3) isomers, as well as the activation barriers for their interconversion. In agreement with the experimental data, the results show that, in general, the different isomers of the Co-III and Co-II complexes present similar free energies, whereas the Cu-II complexes show a strong tendency towards the lel(3) form. In addition, the interplay between the structure and stability of these species has been studied by combining shape maps with a distortion/interaction energy analysis. In contrast to the geometries close to the ideal octahedron that all the studied Co complexes present, the le)3 structures of [Cu{(NH3)(2)sar}](4+) and [Cu{(NMe3)(2)sar](4+) are better described. as trigonal prisms. In such structures the ligand adopts a conformation significantly more stable than in the other isomers, and this drives the formation of lel(3)-[Cu{(NH3)(2)sar}](4+) and lel(3)-[Cu{(NNe3)(2)sar}](4+). Overall, the results show a clear relationship between the stability of a given isomer and its degree of distortion with respect to the ideal octahedron (or trigonal prism), with the latter being ultimately dependent on the transition metal and its radius.
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| 7. |
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| 8. |
- Ali, Sk Imran, et al.
(författare)
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Synthesis and Magnetic Properties of the Ternary Oxofluoride Fe3Sb4O6F6
- 2020
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Ingår i: European Journal of Inorganic Chemistry. - : Wiley. - 1434-1948 .- 1099-1948 .- 1099-0682. ; 2020:39, s. 3746-3752
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Tidskriftsartikel (refereegranskat)abstract
- The new compound Fe(3)Sb(4)O(6)F(6)was prepared by hydrothermal synthesis and its crystal structure was determined from single-crystal X-ray diffraction data. The synthesis was made under slightly basic conditions to prevent oxidation of Fe(2+)to Fe3+. The compound crystallizes in the cubic space groupI-43mwith separate crystallographic sites for Fe(2+)and Sb3+. Fe(3)Sb(4)O(6)F(6)is isostructural with M3Sb4O6F6(M = Co, Ni, Zn). The crystal structure is comprising distorted [FeO2F4] octahedra connected via corner sharing at F-atoms and [SbO3] trigonal pyramids that form [Sb4O6] units that connect via O-atoms to the Fe-atoms. Mossbauer spectroscopy measurements on the hydrothermal synthesis products prove the majority phase contains Fe in the oxidation state +2. Powder X-ray diffraction suggests that an additional phase of the Mossbauer sample containing Fe(3+)can be attributed to FeSbO(2)F(2)as secondary phase. Fe(3)Sb(4)O(6)F(6)exhibits antiferromagnetic order below ca. 72 K succeeded by a second magnetic phase transition at ca. 30 K. Strong antiferromagnetic spin-exchange interaction is attributed to 180 degrees Fe-F-Fe superexchange pathways identified in the crystal structure.
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| 9. |
- Anderlund, Magnus F., et al.
(författare)
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Redox chemistry of a dimanganese(II,III) complex with an unsymmetric ligand : Water binding, deprotonation and accumulative light-induced oxidation
- 2006
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Ingår i: European Journal of Inorganic Chemistry. - : Wiley. - 1434-1948 .- 1099-1948 .- 1099-0682. ; :24, s. 5033-5047
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Tidskriftsartikel (refereegranskat)abstract
- A dinuclear manganese complex {[(Mn2L)-L-II,IIII(mu-OAc)(2)]-ClO4} has been synthesised, where L is the dianion of 2-{[bis-(pyrid-2-ylmethyl)amino]methyl}-6-{[(3,5-di-tert-butyl-2- hydroxybenzyl)(pyrid-2-ylmethyl)amino]methyl)-4-methylphenol, an unsymmetric binucleating ligand with two coordinating phenol groups. The two manganese ions, with a Mn-Mn distance of 3.498 angstrom, are bridged by the two bidentate acetate ligands and the 4-methylphenolate group of the ligand, resulting in a N3O3 and N2O4 donor set of Mn-II and Mn-II, respectively. Electrochemically [Mn2(II,III)L(mu-OAc)(2)](+) is reduced to [(Mn2L)-L-II,II(mu-OAc)(2)] at E-1/2(1)=-0.53 V versus Fc(+/0) and oxidised to [(Mn2L)-L-III,III(mu-OAC)(2)](2+) at E-1/2(2)=0.38 V versus Fc(+/0). All three redox states have been characterised by EPR, IR and UV/Vis spectroscopy. Subsequent oxidation of [(Mn2L)-L-II,III(mu-OAc)(2)](2+) [E-1/2(3)=0.75 V vs. Fc(+/0)] in dry acetonitrile results in an unstable primary product with a lifetime of about 100 ins. At high scan rates quasireversible voltammetric behaviour is found for all three electrode processes, with particularly slow electron transfer for the II,III/II,II [k(o)(1) = 0.002 cms(-1) and III,III/II,III [k(o)(2) = 0.005 cms(-1)] couples, which can be rationalised in terms of major distortions of the Mn-II centres. In aqueous media the bridging acetates are replaced by water-derived ligands. Deprotonation of these stabilises higher valence states, and photo-induced oxidation of the manganese complex results in a (Mn2L)-L-IlI,IV complex with oxo or hydroxo bridging ligands, which is further oxidised to an EPR-silent product. These results demonstrate that a larger number of metal-centred oxidations can be compressed in a narrow potential range if build up of charge is avoided by charge-compensating reactions.
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| 10. |
- Andersson, Claes-Henrik, et al.
(författare)
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Synthesis and IR Spectroelectrochemical Studies of a [60]Fulleropyrrolidine-(tricarbonyl)chromium Complex : Probing C-60 Redox States by IR Spectroscopy
- 2011
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Ingår i: European Journal of Inorganic Chemistry. - : John Wiley & Sons. - 1434-1948 .- 1099-1948 .- 1099-0682. ; :11, s. 1744-1749
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Tidskriftsartikel (refereegranskat)abstract
- The synthesis of a new fulleropyrrolidine-(tricarbonyl)chromium complex: 1-methyl-2-(4-methoxyphenyl)-3,4-[60]fulleropyrrolidine-(tricarbonyl)chromium is described together with its characterization by IR, NMR and cyclic voltammetry. IR spectro-electrochemistry has been used to probe the redox level of the fullerene derivative via the relative position of the vibrational bands of the CO ligands, which are sensitive to the electronic state of the complex. Other strategies to incorporate a tricarbonylchromium moiety to fullerene C60 are also briefly discussed and evaluated.
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