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  • 1
    Digitale Medien
    Digitale Medien
    Interaction of the Fe+ cation with heavy noble gas atoms (1995)
    College Park, Md. : American Institute of Physics (AIP)
    The Journal of Chemical Physics 103 (1995), S. 4551-4561 
    Details
    ISSN: 1089-7690
    Quelle: AIP Digital Archive
    Thema: Physik , Chemie und Pharmazie
    Notizen: The diatomic iron–noble gas complexes FeAr+, FeKr+, FeXe+, and FeRn+ have been theoretically investigated by means of quantum-chemical calculations including an extensive treatment of electron correlation. Potential energy curves and spectroscopic constants for the lowest 4Δ and 6Δ states are derived from an open-shell coupled-cluster approach and the relative energies of all seven low-lying electronic states are evaluated by the multireference configuration interaction method. While in FeAr+ the lowest quartet and sextet states are found to be energetically almost degenerate, the heavier Fe+–noble gas molecules are predicted to exhibit 4Φ ground states. From a qualitative point of view bonding in these species is shown to be electrostatic in origin with intrinsically higher interaction energies for the quartet as compared to the sextet states. For calibration purposes, also an accurate calculation of the 4F(4s03d7)–6D(4s13d6) energy difference in the atomic Fe+ cation is provided. © 1995 American Institute of Physics.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1063/1.470643
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  • 2
    Digitale Medien
    Digitale Medien
    A scanning force microscope with atomic resolution in ultrahigh vacuum and at low temperatures (1998)
    [S.l.] : American Institute of Physics (AIP)
    Review of Scientific Instruments 69 (1998), S. 221-225 
    Details
    ISSN: 1089-7623
    Quelle: AIP Digital Archive
    Thema: Physik , Elektrotechnik, Elektronik, Nachrichtentechnik
    Notizen: We present a new design of a scanning force microscope (SFM) for operation at low temperatures in an ultrahigh vacuum (UHV) system. The SFM features an all-fiber interferometer detection mechanism and can be used for contact as well as for noncontact measurements. Cooling is performed in a UHV compatible liquid helium bath cryostat. The design allows in situ cantilever and sample exchange at room temperature; the subsequent transport of the microscope into the cryostat is done by a specially designed transfer mechanism. Atomic resolution images acquired at various temperatures down to 10 K in contact as well as in noncontact mode are shown to demonstrate the performance of the microscope. © 1998 American Institute of Physics.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1063/1.1148499
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  • 3
    Digitale Medien
    Digitale Medien
    Generation and Structural Characterization of the Cationic Iron-Dinitrogen Complex Fe(N2)+ (1995)
    s.l. : American Chemical Society
    The @journal of physical chemistry 〈Washington, DC〉 99 (1995), S. 11405-11411 
    Details
    Quelle: ACS Legacy Archives
    Thema: Chemie und Pharmazie , Physik
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1021/j100029a017
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  • 4
    Digitale Medien
    Digitale Medien
    Pentoxifylline reduces the formation of sunburn cells (1997)
    Oxford, UK : Blackwell Publishing Ltd
    Experimental dermatology 6 (1997), S. 0 
    Details
    ISSN: 1600-0625
    Quelle: Blackwell Publishing Journal Backfiles 1879-2005
    Thema: Medizin
    Notizen: Abstract Irradiation with ultraviolet (UV) B light results in the formation of apoptotic keratinocyles called sunburn cells (SC). Although generation of SC appears to be one of the most characteristic features of UV-induced skin damage and has been a well-known phenomenon for a long time, the mechanisms involved are not quite clear. Recently, it was demonstrated that tumor necrosis factor α (TNFα) appears to be involved in the formation of SC since neutralization of TNFα both in vitro and in vivo reduced UVB-induced apoptosis of keratinocytes. Pentoxifylline is a methylxanthine derivative suppressing the release of TNFα. Therefore, we studied whether PTX is able to prevent the formation of SC. Addition of PTX to UVB-exposed HaCaT cells reduced DNA-fragmentation as examined by nick translation evaluated by floweytometry. To prove whether PTX also reduces UVB-induced apoptosis in vivo. BALB/c mice were exposed to UVB on their abdomens, skin biopsies performed 24 h later and SC counted. A single dose of 2000 J/m2 caused a significant induction of SC which were remarkably reduced when PTX was injected intraperitoneally 3 h before and 12 h after UVB exposure. In summary, the data demonstrate that PTX can reduce the formation of SC both in vitro and in vivo and thus further support that TNFα is involved in UVB-induced apoptosis of keratinocytes.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1111/j.1600-0625.1997.tb00138.x
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  • 5
    Digitale Medien
    Digitale Medien
    Anthralin (dithranol) in vitro inhibits human monocytes to secrete IL-6, IL-8 and TNF-α, but not IL-1 (1997)
    Oxford, UK : Blackwell Publishing Ltd
    British journal of dermatology 136 (1997), S. 0 
    Details
    ISSN: 1365-2133
    Quelle: Blackwell Publishing Journal Backfiles 1879-2005
    Thema: Medizin
    Notizen: Anthralin is a most widely used compound for topical treatment of psoriasis. Whereas numerous studies have ascertained anthralin as a safe and effective drug its mode of action still remains unclear. Previous studies demonstrated dose-dependent inhibition of a number of pro-inflammatory functions in human enutrophils and monocytes (MO). The aim of the present study was to investigate in stimulated MO the effect of anthralin on the secretion of cytokines which are of known importance for the psoriatic tissue reaction.Highly purifies MO were incubated with anthralin (0·01–1·0μg/ml), its clinically inactive derivative danthrone (0·1 and 10 μg/ml), the solvent acetone, or medium alone. Culture supernatants were analysed for immunoreactivity for interleuking-1β, and -8 (IL-1β, IL-8), and tumour necrosis factor β (TNF-β) by specific ILISA. IL-6 bioactivity was determined using the B9-bioassay. Additionally, IL-1 bioactivity was measured by the D10[N4]M-bioassay.The results show a dose-dependent inhibition of MO IL-6, IL-8, and TNF-α release with a half- maximal inhibitory concentration of 0.25–0.6μ/ml of anthralin. There was no effect of danthrone or acetone on the secretion of these cytokines from MO. Secretion of IL-1β immunoreactivity measured by ELISA as determination of biological activity of IL-1 using the D10[N4]M- bioassay revealed a slight increase in IL-1 secretion with a maximum at an anthralin concentration of 0.1 μg/ml. Danthrone at a concentration of 10μg/ml and acetone (0.1%) similarly enhanced IL-1 secretion from human MO measured by both methods.Our results demonstrate a differential, dose-dependent inhibition of cytokine secretion from human MO by anthralin. The present data provide evidence that the anti-inflammatory and anti- proliferative activity of anthralin may at least in part be due to its inhibitory effect on pro-inflammatory cytokine secretion by MO.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1046/j.1365-2133.1997.d01-1232.x
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  • 6
    Digitale Medien
    Digitale Medien
    Effects of macrophage migration inhibitory factor and macrophage migration stimulatory factor on function and survival of foetal dopaminergic grafts in the 6-hydroxydopamine rat model of Parkinson′s disease (1998)
    Springer
    Experimental brain research 120 (1998), S. 95-103 
    Details
    ISSN: 1432-1106
    Schlagwort(e): Key words Brain transplantation ; MIF ; MSF ; 6-OHDA ; Rat
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Abstract  Activated microglia play an important role in the rejection of intracerebral grafts and the degeneration of axotomized neurones. We studied the effect of macrophage migration stimulatory factor (MSF) or macrophage migration inhibitory factor (MIF) on allogeneic foetal mesencephalic dopaminergic grafts transplanted into the striatum of 6-hydroxydopamine-lesioned rats. Rotation testing revealed a significant compensation of lesion-induced motor asymmetry 3 weeks post-grafting in animals treated with MIF and vehicle-treated controls compared with pre-graft values (Student′s t-test, P≤0.005) and MSF-treated animals (ANOVA, post hoc Fisher PLSD test, P≤0.05). The MSF group showed no significant compensation. Graft recipients with MIF application (1452.06 ± 164.32 tyrosine hydroxylase-positive ventral mesencephalic cells) and controls (1753.21 ± 165.51 tyrosine hydroxylase-positive neurones) displayed good graft survival. Animals with MSF application showed a significant reduction of tyrosine hydroxylase-positive grafted cells (MSF 570.36 ± 209.49 cells) and graft volumes compared with the MIF and the control group (ANOVA, post hoc Fisher PLSD test, P≤0.05). The propotional area of microglia was significantly reduced in MIF animals compared with control animals (ANOVA, post hoc Fisher PLSD test, P≤0.001). Activated microglia and macrophages were reduced by half in the MIF-treated group compared with MSF animals and controls. We conclude that intrastriatal injections of MSF result in impaired function and survival of allogeneic ventral mesencephalon (VM) grafts 3 weeks after transplantation. MIF can reduce the number of microglia and macrophages in allogeneic foetal VM grafts. A reduction of microglia via MIF application did not enhance graft function and survival.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/s002210050381
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  • 7
    Digitale Medien
    Digitale Medien
    Research and research impact of a technical university—A bibliometric study (1998)
    Springer
    Scientometrics 41 (1998), S. 371-388 
    Details
    ISSN: 1588-2861
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Buch- und Bibliothekswesen, Informationswissenschaft , Wissenschaftskunde und Wissenschaftsorganisation, Hochschul- und Universitätswesen, Museumswissenschaft
    Notizen: Abstract The research output of the Danish Technical University (DTUa) has been studied as an aspect of the organization's research policy and visibility in its international context. Papers published in the three-year period (1992–94) were grouped according to 20 clusters of research areas. Using citation analysis techniques, the dynamics of citation frequencies, and a number of other features of the research system, like self-citation, research collaborations, relative impact on the international literature, etc., could be studied. The methods can be used to analyze institutional and national research efforts and to monitor effects of changing policies.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF02459052
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  • 8
    Digitale Medien
    Digitale Medien
    Coordination Modes of 2,5-Di(tert-butyl)pyrrolide - Crystal Structures of HPyr*, Pyr*H·thf, (thf)2LiPyr*, and [(Me3Si)3C-Zn]2(μ-Cl)(μ-Pyr*) (Pyr* = 2,5-tBu2NC4H2) (1998)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 1998 (1998), S. 1175-1182 
    Details
    ISSN: 1434-1948
    Schlagwort(e): Hydrogen bonds ; Indium ; Lithium ; Nitrogen heterocycles ; Zinc ; Chemistry ; General Chemistry
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie
    Notizen: The lithiation of 2,5-di(tert-butyl)pyrrole (1) yields bis(tetrahydrofuran)lithium 2,5-di(tert-butyl)pyrrolide (2), which is monomeric in solution as well as in the solid state. Due to the coordination number of three for the lithium atom, short Li-O and Li-N bond lengths of 193 pm are observed. The metathesis reaction of 2 with tris(trimethylsilyl)-methylzinc chloride (3) gives colorless bis[tris(trimethyl-silyl)methylzinc] chloride 2,5-di(tert-butyl)pyrrolide (4). The pyrrolide ligand and the chlorine atom bridge the zinc atoms. One of the zinc atoms is bonded to the nitrogen atom of the pyrrolide substituent, while the other bonds to the opposite C-C bond. At 215 pm, the Zn-N bond is very long compared to those in alkylzinc amides, whereas the Zn-C distances lie in the range of Zn-C bond lengths found between zinc and η5-bonded cyclopentadienide ligands. The molecular structures of 1 and of the low-melting THF adduct 1·thf show a similar 2,5-di(tert-butyl)pyrrole molecule, but in the latter case a weak N-H···O bond is observed (N-H 97 pm, O···H 199 pm).
    Materialart: Digitale Medien
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  • 9
    Digitale Medien
    Digitale Medien
    Schwerkraft- oder Saugdrainage in der Schilddrüsenchirurgie? (1997)
    Springer
    Langenbeck's archives of surgery 382 (1997), S. 116-116 
    Details
    ISSN: 1435-2451
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/PL00008017
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  • 10
    Digitale Medien
    Digitale Medien
    Mass Spectrometric Study of [Fe,C3,H6,O]+ Isomers Relevant in the Gas-phase Oxidation of Hydrocarbons by “Bare” FeO+ (1996)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 129 (1996), S. 1463-1474 
    Details
    ISSN: 0009-2940
    Schlagwort(e): Structure determination ; Mass spectrometry ; Oxidation processes ; Ion-molecule reactions ; Chemistry ; Inorganic Chemistry
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie
    Notizen: The structures and energetics of [Fe,C3,H6,O]+ isomers are probed by mass spectrometric means. The complexes Fe-(CH3COCH3)+, Fe(CH3CH2CHO)+, Fe(CH3OCH=CH2)+, Fe(CH2O)(C2H4)+, c-(FeOCH2CH2CH2)+, Fe(CH2=CH-CH2OH)+, and Fe(OH)(C3H5)+ can be distinguished by comparing their reactivity toward benzene and their collision-induced dissociation mass spectra, respectively. These findings are used to interpret the formation of [Fe,C3,H6,O]+ in oxidation reactions of hydrocarbons by the highly reactive FeO+ cation. For example, in the reactions of FeO+ with norbornane and pentanol Fe(OH)(C3H5)+ is produced, while the reaction of FeO+ with norbornane to yield [Fe,C3,H6,O]+ is one of the rare cases of initial C—C bond activation by a “bare” transition-metal oxide. The reaction of FeO+ with propene involves formation of metalla oxetanes as primary products. In general, “bare” FeO+ is not selective and allylic C—H bond activation of propene competes efficiently, thus pointing to a potentially rich chemistry.
    Zusätzliches Material: 4 Ill.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1002/cber.19961291211
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