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  • 1
    Electronic Resource
    Electronic Resource
    Photoionization studies of metal carbonyls. I. Ionization potentials and the bonding in Group VI metal hexacarbonyls and in mononuclear carbonyls and nitrosyl carbonyls of iron, cobalt, and nickel (1969)
    s.l. : American Chemical Society
    Inorganic chemistry 8 (1969), S. 2544-2555 
    Details
    ISSN: 1520-510X
    Source: ACS Legacy Archives
    Topics: Chemistry and Pharmacology
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1021/ic50082a003
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  • 2
    Electronic Resource
    Electronic Resource
    Evolution of the core and unoccupied orbitals of biphenyl and bithiophene on Cs doping (1992)
    College Park, Md. : American Institute of Physics (AIP)
    The Journal of Chemical Physics 97 (1992), S. 4489-4495 
    Details
    ISSN: 1089-7690
    Source: AIP Digital Archive
    Topics: Physics , Chemistry and Pharmacology
    Notes: X-ray photoelectron spectroscopy (XPS) and near-edge x-ray absorption fine structure (NEXAFS) have been used to study the core and unoccupied orbitals of condensed multilayers of biphenyl and bithiophene on Cs dosing. The CK XPS shifts, observed on dosing are understandable in terms of repositioning of the Fermi level due to creation of states in the band gap, and at higher Cs concentrations to the high polarizability of the charge transfer complexes formed. The behavior of the CK XPS satellites on increasing Cs exposure are related to changes observed in the electron energy loss spectra (EELS). The CK NEXAFS of biphenyl and the SL23 NEXAFS of bithiophene indicate that an unoccupied molecular orbital is filled by charge transfer from Cs. In the case of bithiophene, both the SL23 XPS and NEXAFS features shift by 2 eV to lower binding and adsorption energy, respectively. This strong chemical shift suggests significant localization of the transferred charge on the S sites. Comparison of the SL23 NEXAFS of doped and undoped bithiophene allows the identification of the unoccupied orbital with S character and leads to a reassignment for the NEXAFS features of thiophene and its oligomers.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.463892
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  • 3
    Electronic Resource
    Electronic Resource
    Core excitation, decay, and fragmentation in solid benzene as studied by x-ray absorption, resonant Auger, and photon stimulated desorption (1992)
    College Park, Md. : American Institute of Physics (AIP)
    The Journal of Chemical Physics 96 (1992), S. 1724-1734 
    Details
    ISSN: 1089-7690
    Source: AIP Digital Archive
    Topics: Physics , Chemistry and Pharmacology
    Notes: For condensed benzene ice layers, core photoabsorption near edge structure (x-ray absorption; recorded by Auger electron yield measurements), decay electron spectra for resonant and nonresonant excitation, and fragmentation as evident in yields of hydrogen and other ions, have been measured in the C1s region. The absorption spectrum is better resolved than most previously published spectra, exhibits some new features, and shows a high degree of parallelity to the spectrum of isolated molecules. Interestingly, the hydrogen ion yield indicates a particular dissociativeness of a certain core excitation resonance, X, which in the molecule has previously been assigned to a Rydberg state. This selective dissociation suggests that the responsible excitation is strongly antibonding for the carbon–hydrogen bond, while the degenerate Rydberg states broaden into a conduction band in the solid; and that the bond breaking probably occurs or at least starts in the core-excited state, thus proceeding on an extremely short time scale, similarly to observations for other hydrogen-containing molecules. The decay spectra are analyzed in terms of autoionization vs normal Auger decay and indicate that, apart from the first strong π resonance (which leads to pure autoionization) and the X resonance, the core resonances partly or fully ionize before core decay takes place. For the X resonance, the decay spectrum contains a contribution which cannot be assigned to intact benzene; this is taken as additional evidence for ultrafast dissociation, i.e., competitive with core decay. We use these results for a discussion of the influence of condensation on excitation, decay, and fragmentation.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.462127
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  • 4
    Electronic Resource
    Electronic Resource
    Immunoglobulin-degrading enzymes in localized juvenile periodontitis (1992)
    Oxford, UK : Blackwell Publishing Ltd
    Journal of periodontal research 27 (1992), S. 0 
    Details
    ISSN: 1600-0765
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Medicine
    Notes: Previous reports have indicated the association of periodontal diseases with elevated levels of serum immunoglobulin G (IgG) antibodies to periodontally relevant bacteria. Recent results from this laboratory suggest that enzymes proteolytic for immunoglobulins are important virulence factors of several periodontal bacteria. Specifically, enzymes from Porphyromonas (Bacteroides) gingivalis culture supernatant fluid (SF) cleaved human IgG (4 subclasses), IgAl and IgA2, IgM, IgD and IgE. Proteolytic enzymes from Actinobacillus actinomycetemcomitans culture SF cleaved IgG, IgA and IgM. An enriched Ig proteolytic preparation from Capnocytophaga ochracea culture SF was shown to extensively cleave all 4 subclasses of human IgG. Extensive degradation of IgG and IgA in crevicular fluid samples on SDS-PAGE from periodontal disease sites of localized juvenile periodontitis (LJP) patients in comparison to little degradation in healthy sites indicated the potential role the proteolytic enzymes from periodontopathogenic bacteria may play in situ. Treatment of IgG with P. gingivalis, A. actinomycetemcomitans and C. ochracea SF resulted in similar patterns of degradation. LJP patients had significantly higher levels of IgG and IgA proteolytic activity in whole saliva than age, sex, and race-matched periodontal disease-free controls. However, not all of the proteolytic activity could be ascribed to Bacteriol proteases since neutrophils are also present in large numbers at diseased sites. Using similar techniques, lysates of neutrophils from healthy controls cleaved IgG, IgA and IgM. The observation of enhanced Ig cleavage activity in crevicular fluid and saliva in LJP patients suggest a role for Ig proteolytic enzymes in LJP.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1111/j.1600-0765.1992.tb01666.x
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  • 5
    Electronic Resource
    Electronic Resource
    Cold fusion ideas (1989)
    [s.l.] : Nature Publishing Group
    Nature 340 (1989), S. 105-106 
    Details
    ISSN: 1476-4687
    Source: Nature Archives 1869 - 2009
    Topics: Biology , Chemistry and Pharmacology , Medicine , Natural Sciences in General , Physics
    Notes: [Auszug] SIR-In the excitement about the possibi-lity of chemically induced nuclear fusion12, there is a danger that observations may be considered indicative of fusion when more conventional explanations from cognate fields are overlooked3. We wish to draw attention to two such cases. First, ...
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1038/340105b0
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  • 6
    Electronic Resource
    Electronic Resource
    Excited band densities, surface resonances, and overlayer Umklapp processes observed in secondary electron emission from Ir(111) and Ir(111)(2×1)O surfaces (1986)
    Springer
    The European physical journal 63 (1986), S. 97-108 
    Details
    ISSN: 1434-6036
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Notes: Abstract The Ir(111) surface shows well-defined structural features in the angle-resolved low energy secondary electron spectrum, and the angular dispersions of these features have been measured for the three principal azimuths. The spectra are interpreted principally as emission from excited bulk bands; the correlation with calculations by Noffke and Fritsche [10] is excellent. Features in the symmetric ΓLW azimuth can be interpreted simply in terms of densities of states, but in the asymmetric pair of azimuths ΓLU, ΓLK there are substantial asymmetries in the secondary electron spectra although the densities of states are symmetric; it is proposed that the asymmetry is due to group velocity effects. Some additional features are interpreted as surface resonances. The Ir(111)(2×1)O surface shows additional low energy features which are interpreted as surface Umklapp of bulk state emission and as folding back of a surface resonance at the new surface zone boundary.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01312584
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  • 7
    Electronic Resource
    Electronic Resource
    A rapid method for evaluation of cell number and viability by flow cytometry (1997)
    Springer
    Cytotechnology 24 (1997), S. 161-168 
    Details
    ISSN: 1573-0778
    Keywords: cell number ; flow cytometry ; proliferationassay ; viability
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine , Process Engineering, Biotechnology, Nutrition Technology
    Notes: Abstract A simple, rapid and reliable method has been developed for assessing the number and viability of cells, as well as cell size, in suspension culture by the use of flow cytometry. Propidium iodide exclusion is used for viability determination and fluorescent beads serve as an internal standard for cell enumeration. The main advantages of this method are its ability to handle a large number of samples with a high degree of precision and its specificity in detecting viable cells quantitatively in a heterogeneous culture of living and dead cells and debris. The method shows only a fraction of the variation found in the haemacytometer/trypan blue counting method due to its very low operator dependence. CHO - Chinese hamster ovary; FCS - Foetal calf serum; FS - Forward scatter light; MTT - 3-(4,5-dimethylthiazolyl-2)-2,5-diphenyltetrazolium bromide; NCS - newborn calf serum; PBS - Phosphate buffered saline; PI - Propidium iodide; SS - Side scatter light.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1023/A:1007910920355
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  • 8
    Electronic Resource
    Electronic Resource
    Synthesis and characterization of sulfonated poly(acrylene ether sulfones)This paper is dedicated to Professor V. T. Stannett on the occasion of his 65th birthday. (1984)
    New York : Wiley-Blackwell
    Journal of Polymer Science: Polymer Chemistry Edition 22 (1984), S. 721-737 
    Details
    ISSN: 0360-6376
    Keywords: Physics ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Ionic groups incorporated into a polymer have a decided effect on its physical properties. A number of ionomers and polyelectrolytes have been widely applied. In particular, sulfonated bisphenol-A polysulfone (SPSF) has been used as a composite or single-component membrane for the desalination of water. In this article, the synthesis and physical characteristics of sulfonated polysulfone are addressed. A detailed synthesis route is provided and methods that yield determinable levels of sulfonation are described. These ion-containing polymers retain an excessive amount of residual salts, which, of course, are impurities to the system. Therefore, before any analyses were made the polymers were subjected to a thorough soxhlet extraction process with boiling water, which appeared to be quite effective. The degree of sulfonation was assessed by several methods such as 1H NMR and FT-IR. A new 1H NMR method was derived because the method cited in the literature proved to be too inconsistent for our work. The new 1H NMR method used a quaternary ammonium counterion [N(CH3)4]. These methyl protons are easily measured and may be ratioed against the isopropylidene protons in the polymer backbone that act as an internal standard. Characterization of the physical properties of SPSF consisted of water uptake, differential scanning calorimetry (DSC), thermomechanical analysis (TMA), and solubility studies. Its physical appearance and mechanical behavior were improved by the solution procedure. Also addressed were the effects of different counterions (Na+ & Mg++) with SPSFs of low levels of sulfonation. The variation in physical properties between the divalent and monovalent counterions is dramatic, especially when observed by TMA in the rubber plateau above the apparent glass temperature.
    Additional Material: 12 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pol.1984.170220320
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  • 9
    Electronic Resource
    Electronic Resource
    Ionically crosslinked poly(acrylic acid) membranes. III. Reverse osmosis results for dry cast membranes (1979)
    New York, NY [u.a.] : Wiley-Blackwell
    Journal of Applied Polymer Science 24 (1979), S. 1341-1351 
    Details
    ISSN: 0021-8995
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: The reverse osmosis properties of ionically crosslinked polyacrylic acid membranes were investigated in terms of the salt separation of a 0.1% NaCl solution and water flux. The membranes were synthesized and crosslinked with the metal ion Al3+ via the dry casting technique described in a previous paper. The effect of such variables as the polymer concentration in the casting solution, the ratios of solvents used (DMF/H2O), the ratio of monomer to the crosslinking agent (AA/Al), the evaporation time and temperature, and the nonsolvent nature and treatment times were studied in some detail. The most important variable was found to be the length and nature of the treatment in the nonsolvents acetone and methanol. In the best series of the membranes that were synthesized, fluxes of more than 3.0 gfd, with salt separations at the 80%-85% level, were obtained.
    Additional Material: 8 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/app.1979.070240518
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  • 10
    Electronic Resource
    Electronic Resource
    Investigations on nylon 4 membranes. Synthesis and transport properties. I. Synthesis of nylon 4 polymerPresented at the IUPAC 26th International Symposium on Macromolecules, Mainz, West Germany, September 17-21, 1979. (1981)
    New York, NY [u.a.] : Wiley-Blackwell
    Journal of Applied Polymer Science 26 (1981), S. 1135-1142 
    Details
    ISSN: 0021-8995
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: The synthesis of nylon 4 (polypyrrolidone) by the anionic polymerization of 2-pyrrolidone through the use of the CO2/potassium pyrrolidonate catalyst system for use in preparing polymer membranes for separation purposes was investigated in detail. The effects of the quantity of CO2, the potassium pyrrolidonate catalyst, and the reaction temperature on the yield and molecular weights of the nylon 4 were studied. At reaction temperatures of 50°C and a reaction time of 120 hr, a yield of 50.9% with intrinsic viscosity of 4.42 (corresponding to Mn of 108,200 and Mw of 135,850) was obtained. The molecular weight distributions of the nylon 4 were determined by gel permeation chromatography (GPC) using m-cresol as the eluting solvent and were found to have a relatively narrow distribution.
    Additional Material: 3 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/app.1981.070260407
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