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  • 1
    Digitale Medien
    Digitale Medien
    Theory of emission state of tris(8-quinolinolato)aluminum and its related compounds (2001)
    [S.l.] : American Institute of Physics (AIP)
    Journal of Applied Physics 90 (2001), S. 6092-6097 
    Details
    ISSN: 1089-7550
    Quelle: AIP Digital Archive
    Thema: Physik
    Notizen: Fluorescence of fac-AlQ3 (Q=8-quinolinolato), mer-AlQ3, mer-Al(mQ)3 (mQ=4-methyl-8-quinolinolato), and BeQ2 were investigated with electronic structure calculations. The molecular structure of the first singlet excited state (the emission state) was optimized with the ab initio "configuration interaction with single excitations" (CIS) method. Ab initio CIS and semiempirical "Zerner's intermediate neglect of differential overlap" (ZINDO) methods were used to calculate the emission energies (ΔE) and also the corresponding absorption energies. Although the ab initio CIS method overestimated the experimental value of ΔE by 1.09–1.16 eV, the ZINDO method reproduced it to a reasonable accuracy (within 0.26 eV). The optimized excited-state structure has an interesting feature in that one of the equivalent ligands distorts appreciably, while the thers keep their ground-state structures. As a result the highest occupied and the lowest unoccupied molecular orbitals (HOMO and LUMO) are localized on the distorted ligand. Since the excited state is characterized as the HOMO–LUMO transition, the emission from AlQ3 (and its analogues) directly reflects that of the ligand. In order to analyze this intrigung excited-state structure, exciton transfer theory was applied, where the exciton coupling between ligands and the structural relaxation of the ligand upon excitation were taken into account. By examining these two factors for BeQ2, it is shown that the exciton localization results from weak exciton coupling and/or large structural relaxation energy. © 2001 American Institute of Physics.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1063/1.1415059
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  • 2
    Digitale Medien
    Digitale Medien
    Modulating fluorescence of 8-quinolinolato compounds by functional groups: A theoretical study (2001)
    Woodbury, NY : American Institute of Physics (AIP)
    Applied Physics Letters 79 (2001), S. 2348-2350 
    Details
    ISSN: 1077-3118
    Quelle: AIP Digital Archive
    Thema: Physik
    Notizen: Substituent dependence of a fluorescence energy of the 8-quinolinolato anion (Q−) was systematically investigated with electronic structure calculations. Large red- and blueshifts of the fluorescence were predicted for Q− with the NO2 and CN groups, respectively. For bis(8-quinolinolato)berylium with the NO2 and CN groups, the emission energies were calculated to be 1.56 eV (795 nm) and 2.66 eV (466 nm), respectively, indicating that they are potential candidates as red- and blue-light-emitting compounds. © 2001 American Institute of Physics.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1063/1.1408278
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  • 3
    Digitale Medien
    Digitale Medien
    Cloning and characterization of preferentially expressed genes in an aluminum-tolerant mutant derived from Penicillium chrysogenum IFO4626 (2004)
    Oxford, UK : Blackwell Publishing Ltd
    FEMS microbiology letters 230 (2004), S. 0 
    Details
    ISSN: 1574-6968
    Quelle: Blackwell Publishing Journal Backfiles 1879-2005
    Thema: Biologie
    Notizen: cDNAs expressed preferentially in an Al-tolerant microorganism were isolated by subtraction hybridization with cDNAs of Al-sensitive Penicillium chrysogenum IFO4626 as driver cDNA and cDNAs of the Al-tolerant mutant derived from the wild cells by UV irradiation as tester cDNA. Northern blot analysis revealed that mRNA levels of six genes were increased significantly in the Al-tolerant mutant after exposure to Al stress when compared with the wild cells. Two genes accumulated in both the presence and absence of Al stress and four genes were induced by Al stress in the Al-tolerant mutant. cDNA fragments were amplified by rapid amplification of cDNA ends and sequenced to obtain full-length cDNAs of the six genes. Two genes were novel or predicted ones and the others showed significant homology to known genes, ADP/ATP translocase, enolase, cysteine synthase, and glucoamylase, which are induced by environmental stresses in prokaryotic and eukaryotic cells. These enzyme activities increased in the Al-tolerant mutant when compared to those in the wild cells, showing that not only the levels of gene expression but also the levels of enzyme activities increased in the Al-tolerant mutant.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1016/S0378-1097(03)00886-3
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  • 4
    Digitale Medien
    Digitale Medien
    Gauge-invariant basis sets for magnetic property calculations (1995)
    College Park, Md. : American Institute of Physics (AIP)
    The Journal of Chemical Physics 102 (1995), S. 285-293 
    Details
    ISSN: 1089-7690
    Quelle: AIP Digital Archive
    Thema: Physik , Chemie und Pharmazie
    Notizen: The use of augmented basis sets of the form, {χ, rtχ, rtruχ, ...} (rt, ru=x, y, z), is proposed for calculating magnetic properties which are almost gauge-origin independent. It is derived from Epstein's theorem which states the sufficient condition for unitary invariance. Test calculations using the coupled-Hartree–Fock/finite perturbation method show that the augmented sets correctly reduce the origin dependence of magnetic shielding constants, and that the results agree well with the experiment. Through systematic modifications of the basis set, a practical procedure in choosing basis functions to be added is suggested. © 1995 American Institute of Physics.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1063/1.469401
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  • 5
    Digitale Medien
    Digitale Medien
    Theoretical study on metal NMR chemical shifts: niobium complexes (1992)
    s.l. : American Chemical Society
    The @journal of physical chemistry 〈Washington, DC〉 96 (1992), S. 4375-4381 
    Details
    Quelle: ACS Legacy Archives
    Thema: Chemie und Pharmazie , Physik
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1021/j100190a048
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  • 6
    Digitale Medien
    Digitale Medien
    Theoretical study on metal NMR chemical shifts. Gallium compounds, GaCl4-nBrn- (n = 0-4) (1993)
    s.l. : American Chemical Society
    The @journal of physical chemistry 〈Washington, DC〉 97 (1993), S. 5868-5874 
    Details
    Quelle: ACS Legacy Archives
    Thema: Chemie und Pharmazie , Physik
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1021/j100124a015
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  • 7
    Digitale Medien
    Digitale Medien
    Screening and characterization of trehalose-oleate hydrolyzing lipase (2001)
    Oxford, UK : Blackwell Publishing Ltd
    FEMS microbiology letters 195 (2001), S. 0 
    Details
    ISSN: 1574-6968
    Quelle: Blackwell Publishing Journal Backfiles 1879-2005
    Thema: Biologie
    Notizen: Various soil samples were collected to screen the presence of microorganisms which have ability to degrade TOE. One strain (AKU-883) with good TOE degrading activity was isolated and identified as Burkholderia cepacia and the extracellular enzyme was purified to homogeneity. The purification was achieved by ultrafiltration, Super Q anion-exchange chromatography and Superdex 200HR gel-filtration in the presence of Triton X. The enzyme was purified to 85-fold, and specific activity of 4.910 kU mg protein−1. The peak preparation on gel filtration showed a single band of 34 kDa on SDS-PAGE and native PAGE which indicate the monomeric nature of the enzyme. The pI of the enzyme was 6.3. The enzyme showed the maximum activity at pH 9 and 65°C, and was stable in the range of pH 5–10 and up to 60°C. Almost all the activity (92%) was kept after incubation for more than 1 week at 50°C (pH 7.3). High activities remained even in water-miscible solvents such as ethanol, dimethyl formamide, diisopropyl ether, and dioxane. The N-terminal 16 amino acid residues were determined as A-N-G-Y-A-A-T-R-Y-P-I-I-L-V-G-G, which showed a consensus sequence for lipases from Burkholderia species. Thus the enzyme was concluded to be a kind of lipase.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1111/j.1574-6968.2001.tb10526.x
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  • 8
    Digitale Medien
    Digitale Medien
    Isolation and characterization of acid- and Al-tolerant microorganisms (2000)
    Oxford, UK : Blackwell Publishing Ltd
    FEMS microbiology letters 189 (2000), S. 0 
    Details
    ISSN: 1574-6968
    Quelle: Blackwell Publishing Journal Backfiles 1879-2005
    Thema: Biologie
    Notizen: Acid- and aluminum (Al)-tolerant microorganisms were isolated from tea fields, from which six strains were selected and identified as Cryptococcus humicola, Rhodotorula glutinis, Aspergillus flavus Link, Penicillium sp., Penicillium janthinellum Biourge and Trichoderma asperellum. They were tolerant to Al up to 100–200 mM and could grow at low pH, 2.5–2.2. In a glucose medium (pH 3.5) the pH of the spent medium decreased to below 3.0. The toxic inorganic monomeric Al in the spent medium decreased with three strains (A. flavus F-6b, Penicillium sp. F-8b and P. janthinellum F-13), but the total Al remained constant for all strains. In a soil extract medium (pH 3.5), the pH of the spent medium of all strains increased to around 6.0–7.2 and total Al in the spent medium was removed by precipitation due to pH increase. Thus, different tolerance mechanisms were suggested in glucose and soil extract media.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1111/j.1574-6968.2000.tb09220.x
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  • 9
    Digitale Medien
    Digitale Medien
    Establishment by the rat lymph node method of epitope-defined monoclonal antibodies recognizing the six different α chains of human type IV collagen (1995)
    Springer
    Histochemistry and cell biology 104 (1995), S. 267-275 
    Details
    ISSN: 1432-119X
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Medizin
    Notizen: Abstract A group of rat monoclonal antibodies recognizing the six different α chains of human type IV collagen have been established by our novel method. The method is designated the rat lymph node method in which enlarged medial iliac lymph nodes of a rat injected with an antigen emulsion via hind footpads are used as a source of B cells for cell fusion to produce hybridomas. The immunogens used were synthetic peptides having non-consensus amino acid sequences near the carboxyl termini of type IV collagen α chains. Hybridomas were screened both by ELISA with synthetic peptides and by indirect immunofluorescence with cryostat sections of human kidneys. Because the epitopes of all antibodies were determined by multipin-peptide scanning, they were confirmed to be isoform-specific. They are useful for identification of α chains of type IV collagen at the protein level in normal and abnormal conditions. The combined use of synthetic peptides as immunogens, the rat lymph node method as making monoclonal antibodies, and the multipin-peptide scanning as epitope mapping is found to be a strong tool for identification of peptides and proteins whose amino acid sequences are known or have been deduced.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF01464322
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  • 10
    Digitale Medien
    Digitale Medien
    Acetylene-insertion reactions into Pt(II)–H and Pt(II)–SiH3 bonds. An ab initio MO study and analysis based on the vibronic coupling model (1999)
    Springer
    Theoretical chemistry accounts 102 (1999), S. 377-384 
    Details
    ISSN: 1432-2234
    Schlagwort(e): Key words: Ab initio molecular orbital methods ; Acetylene insertion ; Platinum hydride ; Platinum silyl ; Vibronic coupling ; Hydrosilylation
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Chemie und Pharmazie
    Notizen: Abstract. Acetylene insertion into Pt(II)–H and Pt(II)SiH3 bonds of PtH(SiH3)(PH3) was investigated using ab initio molecular orbital and Møller-Plesset perturbation theory methods. The insertion into PtH was predicted to proceed with a smaller activation energy (E a =12.8 kcal/mol) than that into PtSiH3 (E a =20.9 kcal/mol). The reaction energy (ΔE) of the insertion into PtH is 10 kcal/mol smaller than that for the insertion into PtSiH3, which reflects differences in bond energies between CH and CSi and between PtH and PtSiH3. A comparison with ethylene insertion revealed that the acetylene insertion occurs more easily, and the latter reaction is more exothermic. A simple vibronic coupling model combined with Toyozawa's interaction mode analysis was used to examine interesting differences in E a and ΔE between insertions into PtH and PtSiH3, and between acetylene and ethylene insertions. This analysis suggests that the factors determining E a are the stiffness of the PtH and PtSiH3 bonds and the vibronic coupling strength of acetylene and ethylene.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/s002140050509
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