ALBERT

All Library Books, journals and Electronic Records Telegrafenberg

X
feed icon rss

Your email was sent successfully. Check your inbox.

An error occurred while sending the email. Please try again.

Proceed reservation?

Export
Filter
  • Wiley-Blackwell  (8)
  • Oxford University Press  (6)
  • American Chemical Society (ACS)
  • 1990-1994  (14)
  • 1993  (14)
  • 1
    Electronic Resource
    Electronic Resource
    Regulation of polyamine transport by polyamines and polyamine analogs (1993)
    New York, NY [u.a.] : Wiley-Blackwell
    Journal of Cellular Physiology 155 (1993), S. 399-407 
    Details
    ISSN: 0021-9541
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: Regulation of polyamine transport in murine L1210 leukemia cells was characterized in order to better understand its relationship to specific intracellular polyamines and their analogs and to quantitate the sensitivity by which it is controlled. Up-regulation of polyamine uptake was evaluated following a 48-hr treatment with a combination of biosynthetic enzyme inhibitors to deplete intracellular polyamine pools. The latter declined gradually over 48 hr and was accompanied by a steady increase in spermidine (SPD) and spermine (SPM) transport as indicated by rises in Vmax to levels ∼4.5 times higher than control values. Restoration of individual polyamine pools during a 6-hr period following inhibitor treatment revealed that SPD and SPM uptake could not be selectively affected by specific pool changes. The effectiveness of individual polyamines in reversing inhibitor-induced stimulation of uptake was as follows: putrescine 〈 SPD 〈 SPM = the SPM analog, N1, N12-bis(ethyl)spermine (BESPM). In contrast to stimulation of transport, down-regulation by exogenous polyamines or analogs occurred rapidly and in response to subtle increases in intracellular pools. Following a 1-hr exposure to 10 μM BESPM, Vmax values for SPD and SPM fell by 70%, whereas the analog pool increased to only 400-500 pmol/106 cells - about 15-20% of the total polyamine pool (∼2.8 nmol/106 cells). SPM produced nearly identical regulatory effects on transport kinetics. Both BESPM and SPM were even more effective at down-regulating transport that had been previously stimulated four to fivefold by polyamine depletion achieved with enzyme inhibitors. A dose response with BESPM at 48 hr revealed a biphasic effect on uptake whereby concentrations of analog 〈 3 μM produced an increase in SPD and SPM Vmax values, whereas concentrations 3 μM and higher produced a marked suppression of these values. Cells treated with 3 μM BESPM for 2 hr and placed in analog-free medium recovered transport capability in only 3 hr. Thus, whereas stimulation of polyamine transport is a relatively insensitive and slowly responsive process that tends to parallel polyamine depletion, down-regulation of polyamine transport by exogenous polyamines and analogs and its reversal are rapidly responsive events that correlate with relatively small (i.e., 15-20%) changes in intracellular polyamine pools.
    Additional Material: 5 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/jcp.1041550222
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 2
    Electronic Resource
    Electronic Resource
    Trapping efficiencies of various collection solvents after supercritical fluid extraction (1993)
    Weinheim : Wiley-Blackwell
    Journal of High Resolution Chromatography 16 (1993), S. 713-716 
    Details
    ISSN: 0935-6304
    Keywords: SFE ; Supercritical carbon dioxide ; Sand ; Test mixture ; Solvent trapping ; Solvent mixtures ; Trapping efficiency ; Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: A polarity test mix consisting of acetophenone, N, N-dimethylaniline, naphthalene, decanoic acid, 2-naphthol, and n-tetracosane was spiked onto sand, and extracted with supercritical carbon dioxide, to evaluate the collection efficiency of various solvents and solvent mixtures. Nine single collection solvent systems and four mixed collection solvent systems were studied. When one-component collection solvents were employed, quantitative (above 90%) recovery of all analytes was not possible. With mixed collection solvents, recoveries of 90% or better with all analytes studied were possible.
    Additional Material: 4 Tab.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/jhrc.1240161208
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 3
    Electronic Resource
    Electronic Resource
    An expanded nomenclature scheme for labeling peptide fragmentations and its use with ‘AMASS’, a computer program for generating all possible fragment ion structures from known precursors (1993)
    Chichester : Wiley-Blackwell
    Biological Mass Spectrometry 22 (1993), S. 31-44 
    Details
    ISSN: 1052-9306
    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: A nomenclature scheme for exhaustively labeling peptide fragment ions is proposed. The scheme is based on IUPAC nomenclature1-3 and the previously proposed Roepstorff nomenclature scheme4 used to label fragment ions in linear peptides. The descriptor used is specifically defined in order to increase the number of peptide and side chain linkages to which the nomenclature scheme can be applied compared with the Roepstorff scheme. The proposed descriptor can be used unambiguously to assign all possible fragments from linear, cyclized, branched, extended (i.e. β-amino acids) and retro inverso peptides. A significant advantage of the proposed scheme is its simple interface with the currently accepted Roepstorff scheme. This nomenclature scheme is able to label all theoretical fragments generated by the computer program ‘AMASS’. AMASS is proposed as a means of systematically calculating the mass of all possible fragment ions from known precursor structures. The program can help determine whether a peptide fragment was derived from an internal sequence fragment or a combination of side chain and backbone cleavages. The program AMASS and the proposed nomenclature scheme are used to illustrate a procedure for identifying fragment ions in the metastable product ion spectrum of somatostatin-14. We envisage that this procedure will be useful for identifying fragment ions which are characteristic of particular structural arrangements in dicyclic and polycyclic peptides.
    Additional Material: 8 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/bms.1200220105
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 4
    Electronic Resource
    Electronic Resource
    Thermal analyses of graft copolymers of poly (methyl methacrylate) main chain with poly (propylene oxide-b-ethylene oxide) graft chain (1993)
    New York, NY [u.a.] : Wiley-Blackwell
    Journal of Applied Polymer Science 49 (1993), S. 1211-1222 
    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: Poly(methyl methacrylate-g-(propylene oxide-b-ethylene oxide)) and poly (methyl methacrylate-g-(ethylene oxide-b-propylene oxide)), comprising chemically dissimilar sequences, exhibit intramolecular phase separation. These compositions have applications in coatings and as surface-tension modifiers. This paper presents the thermal behavior of these graft copolymers: separate samples of the homopolymer and of the grafts were also analyzed to provide comparisons. The phase behavior has been analyzed by differential scanning calorimetry and by dynamic-mechanical thermal measurements. Two glass transitions (Tg) are observed, caused by the partial incompatibility within the copolymers. The activation energy of the Tg relaxation process of the main chain is decreased by the graft chain. The influence of poly(propylene oxide-b-ethylene oxide) grafts on the thermal degradation of the poly(methyl methacrylate) (PMMA) main chain was studied by using thermogravimetric analysis. Prolysis of the graft copolymers occurs in three stages and begins on the graft chain and at a lower temperature than the pyrolysis of pure PMMA. Both the phase behavior and the thermal stability are found to depend sensitively on the composition of the copolymer. © 1993 John Wiley & Sons, Inc.
    Additional Material: 9 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/app.1993.070490710
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 5
    Electronic Resource
    Electronic Resource
    A macromolecular deformation model to estimate viscoelastic flow effects in polymer melts (1993)
    Stamford, Conn. [u.a.] : Wiley-Blackwell
    Polymer Engineering and Science 33 (1993), S. 437-444 
    Details
    ISSN: 0032-3888
    Keywords: Chemistry ; Chemical Engineering
    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 elastic deformation of polymer macromolecules in a shear field is used as the basis for quantitative predictions of viscoelastic flow effects in a polymer melt. Non-Newtonian viscosity, capillary end correction factor, maximum die swell, and die swell profile of a polymer melt are predicted by the model. All these effects can be reduced to generic master curves, which are independent of polymer type. Macromolecular deformation also influences the brittle failure strength of a processed polymer glass. The model gives simple and accurate estimates of practically important processing effects, and uses fitting parameters with the clear physical identity of viscoelastic constants, which follow well established trends with respect to changes in polymer composition or processing conditions.
    Additional Material: 11 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pen.760330710
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 6
    Electronic Resource
    Electronic Resource
    Miscibility of a polyarylate with a liquid crystalline copolyester (1993)
    Bognor Regis [u.a.] : Wiley-Blackwell
    Journal of Polymer Science Part B: Polymer Physics 31 (1993), S. 1067-1073 
    Details
    ISSN: 0887-6266
    Keywords: polyarylate ; copolyester ; liquid crystal ; transesterfication ; Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: The miscibility has been investigated for binary blends of a polyarylate (PAr) with a liquid crystalline copolyester of p-hydroxybenzoate and ethylene terephthalate units in a 6/4 molar ratio (PET/PHB). The binary blends were prepared by solution precipitation. The transitions of the PET/PHB have been measured with a rheometrics dynamic spectrometer. The phases in blends have been studied with a differential scanning calorimeter, by ther-mogravimetry and with a polarizing optical microscope. The blends exhibit two glass transitions (Tgs) over the composition range 10-90 wt %. The amorphous PET phase from the PET-PHB is found to be partially miscible with PAr, which leads to a decrease of the PAr Tg. The amount of this partially miscible portion of PET has been estimated by the Couch-man equation. On heat treatment of the blends at 250 to 300°C, transesterficiation takes place, as judged by the shift of the higher of the two Tgs. © 1993 John Wiley & Sons, Inc.
    Additional Material: 7 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/polb.1993.090310901
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 7
    Electronic Resource
    Electronic Resource
    Miscible blends of modified poly(aryl ether ketones) with aromatic polyimides (1993)
    Bognor Regis [u.a.] : Wiley-Blackwell
    Journal of Polymer Science Part B: Polymer Physics 31 (1993), S. 821-830 
    Details
    ISSN: 0887-6266
    Keywords: blends of modified PEEK with aromatic polyimides ; miscibility of blends of modified PEEK with aromatic polyimides ; Spectra, IR and UV, of blends of modified PEEK with aromatic polyimides ; Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: The phase behavior of binary blends of poly(ether ether ketone) (PEEK), sulfonated PEEK, and sulfamidated PEEK with aromatic polyimides is reported. PEEK was determined to be immiscible with a poly(amide imide) (TORLON 4000T). Blends of sulfonated and sulfamidated PEEK with this poly(amide imide), however, are reported here to be miscible in all proportions. Blends of sulfonated PEEK and a poly(ether imide) (ULTEM 1000) are also reported to be miscible. Spectroscopic investigations of the intermolecular interactions suggest that formation of electron donoracceptor complexes between the sulfonated/sulfamidated phenylene rings of the PEEKs and the n-phenylene units of the polyimides are responsible for this miscibility. © 1993 John Wiley & Sons, Inc.
    Additional Material: 9 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/polb.1993.090310710
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 8
    Electronic Resource
    Electronic Resource
    Melting behavior of poly(ether ether ketone) in its blends with poly(ether imide) (1993)
    Bognor Regis [u.a.] : Wiley-Blackwell
    Journal of Polymer Science Part B: Polymer Physics 31 (1993), S. 1845-1850 
    Details
    ISSN: 0887-6266
    Keywords: melting behavior of PEEK/PEI blends ; equilibrium melting point ; crystal reorganization ; interlamellar segregation ; melting point depression ; interaction parameter ; Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: We detail the melting behavior of poly(ether ether ketone) (PEEK) and investigate its melting behavior in miscible blends with poly(ether imide) (PEI). The determination of the equilibrium melting point (Tm0) of PEEK is discussed by considering its inhomogeneous morphology. Tm0 is obtained by a long extrapolation of a Hoffman-Weeks plot to 384°C. Hindrance of PEEK crystal reorganization induced by PEI during heating is observed over the blend composition investigated (20-75 wt % PEEK). This behavior is correlated with the incorporation of PEI in the interlamellar zones of PEEK crystals. The interaction parameter χ of PEEK/PEI blends is estimated by the equilibrium melting point depression. This gives the interaction density B = -1.2 cal/cm3, and x = -0.40 at 400°C. © 1993 John Wiley & Sons, Inc.
    Additional Material: 6 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/polb.1993.090311217
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 9
    facet.materialart.
    Unknown
    The interleukin-2 receptor γ chain maps to Xq13.1 and is mutated in X-linked severe combined immunodeficiency, SCIDX1 (1993)
    Oxford University Press
    Details
    Publication Date: 1993-01-01
    Print ISSN: 0964-6906
    Electronic ISSN: 1460-2083
    Topics: Biology , Medicine
    Published by Oxford University Press
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    PAPER CURRENT
  • 10
    facet.materialart.
    Unknown
    The re-iterated Galerkin method (1993)
    Oxford University Press
    Details
    Publication Date: 1993-01-01
    Print ISSN: 0272-4979
    Electronic ISSN: 1464-3642
    Topics: Mathematics
    Published by Oxford University Press on behalf of Institute of Mathematics and its Applications.
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    PAPER CURRENT
Close ⊗
This website uses cookies and the analysis tool Matomo. More information can be found here...