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  • Polymer and Materials Science  (34)
  • Fluorescence
  • Invertebrate neurobiology
  • 1
    Electronic Resource
    Electronic Resource
    Photopigment and receptor properties in Drosophila compound eye and ocellar receptors (1979)
    Springer
    European biophysics journal 5 (1979), S. 197-209 
    Details
    ISSN: 1432-1017
    Keywords: Visual pigments ; Invertebrate neurobiology ; Membrane biophysics ; Retina
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Physics
    Notes: Abstract A review of the spectral sensitivity and the rhodopsin and metarhodopsin characteristics in three compound eye receptor types (R1–6, R7, and R8) and ocellar receptors is presented (Fig. 1). Photopigment properties were determined from measures of conversion efficiency. The photopigments of R1–6 were studied using in vivo microspectrophotometry in the deep pseudopupil of white-eyed flies. These studies yielded a refined estimate of the R1–6 metarhodopsin spectrum (Fig. 2). The quantum efficiency relative to the spectral sensitivity estimate of the rhodopsin spectrum was factored out. The quantum efficiency of rhodopsin is about 1.75 times that of metarhodopsin. The peak absorbance of metarhodopsin was estimated to be about 2.6 times that of rhodopsin. The mechanism of the two-peaked R1–6 spectral sensitivity and metarhodopsin spectrum is discussed in terms of evidence that there is only one rhodopsin in R1–6 and that vitamin A deprivation preferentially lowers ultraviolet sensitivity. The prolonged depolarizing afterpotential is reviewed from the standpoint of the internal transmitter hypothesis of visual excitation. A careful comparison of the intensity-responsivity for photopigment conversion and its adaptional consequences is made (Fig. 3).
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00535448
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  • 2
    Electronic Resource
    Electronic Resource
    Optical and electrical studies on dansyllysine-valinomycin in thin lipid membranes (1976)
    Springer
    European biophysics journal 2 (1976), S. 119-137 
    Details
    ISSN: 1432-1017
    Keywords: Valinomycin ; Lipid membranes ; Fluorescence ; Relaxation methods
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Physics
    Notes: Summary Dansyllysine-valinomycin, a fluorescent analogue of the ionophore valinomycin was synthesized and incorporated into black lipid membranes. Its concentration inside the membrane was measured fluorometrically and was also determined from electrical relaxation experiments, which were analyzed on the basis of a previously proposed carrier model. The results of both methods agreed within less than one order of magnitude. This appears satisfactory in view of the sources of error inherent in both procedures. A conductance increment per carrier molecule of about 3 · 10−17 Ω−1 was obtained for dansyllysine-valinomycin in diphytanoyllecithin membranes at 25
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00863705
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  • 3
    Electronic Resource
    Electronic Resource
    Hydroxyl-modified epoxy resins: Some technical and analytical aspectsDedicated to Professor Dr. H. Batzer in honour of his 60th birthday (1980)
    New York : Wiley-Blackwell
    Die Makromolekulare Chemie 181 (1980), S. 1-17 
    Details
    ISSN: 0025-116X
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: The modification of epoxy resins by reactions involving their hydroxyl groups is described. For example, reactions with enol ethers, acrylonitrile, ethyl acetoacetate and certain other carboxylic esters, or triethyl orthoformate, gave products which had reduced reactivities towards various hardeners, and which therefore gave lower peak temperatures on cure and/or longer usable lives. Suitable modification of epoxy resins with various other reagents(certain acid anhydrides, epichlorohydrin, or N-hydroxymethylacrylamide) introduces additional useful functional groups. The uses of a diisocyanate and of α-naphthyl isocyanate to modify epoxy resins or their mixtures prior to GPC analysis are also mentioned.
    Additional Material: 5 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/macp.1980.021810101
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  • 4
    Electronic Resource
    Electronic Resource
    Factors influencing izod impact properties of thermoplastics measured with the autographic impact test (1964)
    New York, NY [u.a.] : Wiley-Blackwell
    Journal of Applied Polymer Science 8 (1964), S. 119-140 
    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 standardization of notched Izod impact test data to normalized values of foot pounds per inch of notch is based on the assumption of a 1:1 increase in breaking strength with increasing notch width. This assumed relation is not supported by experimental tests on commercial thermoplastics. As notch width was increased from 1/8 to 1/4 to 3/8 to 1/2 in., nine of ten thermoplastics tested showed a decrease in normalized impact strength. Each material appears to show a characteristic loss in breaking strengths as the notch width increases. A technique developed for calibration of pendulum impact testers has been used to examine the variation of impact breaking strength in relation to the total kinetic energy of the hammer. Experimental tests show practically no change in impact strengths up to values that take 2/3 of the available hammer energy. Experimental work on the comparison of the impulse transferred by the hammer during breaking with impulse curves photographed by the Autographic Impact test show very good agreement for catastrophic breaks and fair agreement for plastic type breaks. The reduction in recorded impulse is attributed to the degrading of the sample during the plastic portion of the breaking cycle. The peak force of thermoplastics as measured by the Autographic Impact test increases as the temperature decreases from 100°C. or above to 0°C. Over the same temperature range flexural tests on small cantilever samples of these thermoplastics show the same thermal dependence for the flexural yield or permanent distortion stress. Plots of the impact peak forces and flexural yield stress at corresponding temperatures give a linear correlation. Each thermoplastic material exhibits a unique relation for this correlation between impact yielding and flexural yielding. This correlation between the impact and flexural tests over the range of temperatures is the first known experimental indication of a direct relation between impact properties and standard physical tests.
    Additional Material: 11 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/app.1964.070080109
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  • 5
    Electronic Resource
    Electronic Resource
    Swelling characteristics of gel fractions of formaldehyde-modified cotton cellulosesPresented in part at the Spring Meeting of The Fiber Society at Williamsburg, Va., May 1966. (1966)
    New York, NY [u.a.] : Wiley-Blackwell
    Journal of Applied Polymer Science 10 (1966), S. 1777-1786 
    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: A method for assessing extent of swelling of the gel fraction of formaldehyde-modified cottons, employing cupriethylenediamine hydroxide as the swelling agent, is described. Substantial differences in apparent specific volumes of swollen gel fractions are observed for cottons crosslinked by different processes to the same level of agent. The apparent crosslink density measured by the swelling of gel fraction increases with formaldehyde content of the cotton; at 0.20% formaldehyde the order of increasing crosslink density in the various processes of reaction is as follows: nonaqueous system (forms D and D′) 〈 aqueous system (forms W and W′) 〈swelling system (form F) 〈 vapor system (form V) 〈 bake-cure system (form C).
    Additional Material: 4 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/app.1966.070101115
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  • 6
    Electronic Resource
    Electronic Resource
    Direct observation of cell wall glucans in whole cells of Saccharomyces cerevisiae by magic-angle spinning 13C-nmr (1994)
    New York : Wiley-Blackwell
    Biopolymers 34 (1994), S. 1627-1635 
    Details
    ISSN: 0006-3525
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Intact cells of Saccharomyces cerevisiae were examined as an aqueous paste by 13C-nmr spectroscopy with direct polarization and magic-angle spinning. The spectra obtained were highly resolved, showing numerous resonances in the 60-105 ppm range that were assigned to carbons of a liquid-like domain of the cell wall glucan. Assignments were confirmed by running the spectrum of S. cerevisiae in which the cell wall glucans were labeled with [13C] by feeding the cell [13C ] galactose. The spectra indicate that the glucan in the cell wall of intact S. cerevisiae assumes a helical conformation and suggest that strain 17A fed with galactose preferentially incorporates the resulting glucose into β(1 → 3)-linkages. © 1994 John Wiley & Sons, Inc.
    Additional Material: 5 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/bip.360341207
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  • 7
    Electronic Resource
    Electronic Resource
    Analysis of resorcinol-phenol-formaldehyde resins by NMR spectroscopy (1972)
    Weinheim : Wiley-Blackwell
    Angewandte Makromolekulare Chemie 26 (1972), S. 171-176 
    Details
    ISSN: 0003-3146
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Description / Table of Contents: Es wird eine NMR-Methode zur Bestimmung der ungefähren Verhältnisse zwischen aus Phenolkernen, Resorcinkernen und Formaldehyd gebildeten Gruppenin Kondensationsprodukten aus Phenol, Resorcin und Formaldehyd beschrieben.
    Notes: A method is reported, based on NMR spectroscopy, for approximate determination of the component ratios of resins formed by condensation of resorcinol, phenol and formaldehyde.
    Additional Material: 1 Tab.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/apmc.1972.050260113
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  • 8
    Electronic Resource
    Electronic Resource
    Organo-metal carbonyl compounds of iron, molybdenum, and manganese as photosensitisers of the anhydride cure of epoxy resins (1976)
    Weinheim : Wiley-Blackwell
    Angewandte Makromolekulare Chemie 50 (1976), S. 9-14 
    Details
    ISSN: 0003-3146
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Description / Table of Contents: Verbindungen der Strukturformeln [π-C5H5M(CO)nX] (M = Fe, n = 2; M = Mo, n = 3; X = CH3, CH2C6H5, CH2Si(CH3)3, CH2OCH3, Sn(C6H5)3, SnCl3, HgCl, I), [Mn(CO)5CH3], und [(π-CH3C5H4)Mn(CO)3] wurden als Katalysatoren für die Härtung von Epoxidharzen unter verschiedenen Bedingungen geprüft. Es wurde gefunden, daß die Verbindungen [π-C5H5Fe(CO)2R] (R = CH3, CH2C6H5) und [π-C5H5Mo(CO)3CH3] wirksame lichtempfindliche Beschleuniger für die Anhydridhärtung von Expoxidharzen sind. Der Aktivierungsmechanismus wird diskutiert.
    Notes: Compounds of the types [π-C5H5M(CO)nX] (M = Fe, n = 2; M = Mo, n = 3; X = CH3, CH2C6H5, CH2Si(CH3)3, CH2OCH3, Sn(C6H5)3, SnCl3, HgCl, I), [Mn(CO)5CH3], and [(π-CH3C5H4)Mn(CO)3] have been examined as catalysts for the cure of epoxy resins under various conditions. It was found that the compounds [π-C5H5Fe(CO)2R] (R = CH3, CH2C6H5) and [π-C5H5Mo(CO)3CH3] are active photosensitizing agents for the anhydride cure of certain epoxy resins. The mechanism of the process is discussed.
    Additional Material: 1 Tab.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/apmc.1976.050500102
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  • 9
    Electronic Resource
    Electronic Resource
    Paramagnetic shifts induced by europium and praseodymium chelates in the NMR spectrum of bisphenol a diglycidyl ether (1972)
    Weinheim : Wiley-Blackwell
    Angewandte Makromolekulare Chemie 27 (1972), S. 159-164 
    Details
    ISSN: 0003-3146
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Description / Table of Contents: Es wurde eine Voruntersuchung des Einflusses unternommen, den die Verschiebereagenzien Tris-(dipivaloylmethano)-europium uncl Tris-(dipivaloylmethano)-pra-seodym auf das NMR-Spektrum des Diglyzidyläthers des Bisphenol A ausüben. Es ergab sich, daß die Signale der am Epoxidring anliegenden Protonen durch den Zusatz dieser Chelate weit mehr als die Signale der exozyklischen -OCH2-Gruppen verschoben werden. Die Verschiebung kann man durch den Zusatz eines Alkohols rückgängig machen, der vorzugsweise mit dem Verschiebemittel reagiert.
    Notes: A preliminary study has been made of the effects of the shift reagents Eu (DPM)3 and Pr(DPM)3 on the NMR spectrum of Bisphenol A diglycidyl ether (I). Protons attached to the epoxy ring were observed to shift appreciably more than protons of the exocyclic —OCH2— group, on addition of these chelates. The shifts could be reversed by addition of an alcohol, which interacted preferentially with the shift reagent.
    Additional Material: 4 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/apmc.1972.050270111
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  • 10
    Electronic Resource
    Electronic Resource
    Paramagnetic shifts induced by europium and praseodymium complexes in the NMR spectra of some substituted phenols (1972)
    Weinheim : Wiley-Blackwell
    Angewandte Makromolekulare Chemie 27 (1972), S. 151-157 
    Details
    ISSN: 0003-3146
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Description / Table of Contents: Es wurden die Verschiebungen untersucht, die durch Tris-(dipivaloylmethano)-europium und Tris-(dipivaloylmethano)-praseodym im NMR- Spektrum versehiedener Derivate substituierter Phenole hervorgerufen werden. Der Zweck dieser Arbeiten war, die Möglichkeiten zu erfassen, die diese Verschiebereagenzien als Hilfsmittel in der NMR-Analyse von Phenolharzen bieten, und Information über Verschiebungen bei Molekülen zu gewinnen, die mehr als eine Koordinationsposition besitzen.
    Notes: An investigation into the shifts induced in the NMR spectra of some derivatives of substituted phenols by tris(dipivalomethanato)europium and tris(dipivalomethanato)praseodymium is reported. The phenol derivatives were studied to ascertain the possible utility of the shift reagents as an aid in the analysis of phenolformaldehyde resins by NMR spectroscopy, and to gain information on induced shifts with molecules having more than one possible co-ordination site.
    Additional Material: 1 Tab.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/apmc.1972.050270110
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