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
  • 1
    Electronic Resource
    Electronic Resource
    Torsional dynamics and rigidity of fractionated poly(dGdC) (1985)
    New York : Wiley-Blackwell
    Biopolymers 24 (1985), S. 1009-1022 
    Details
    ISSN: 0006-3525
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Time-resolved fluorescence polarization anisotropy measurements were performed on two fractionated samples of duplex poly(dGdC) containing 230 (+40, -30) base pairs (bp) and 590 ± 40 bp. Deconvolution using the intermediate zone formula for the twisting correlation functions (which is not valid for such short DNAs) yields apparent torsion constants for these two samples that are disparate and, in any case, too low. By similarly deconvoluting simulated data constructed from the correct twisting correlation functions, it can be inferred that these two samples actually exhibit the same torsion constant, α = (4.0 ± 0.4) × 10-12 dyn cm. Within the experimental uncertainties, this value is the same as that reported previously from this laboratory for linear φ29 and linearized M13mp7 DNAs. The 590-bp sample exhibited a peculiar evolution of its apparent torsional rigidity from a very high initial value, \documentclass{article}\pagestyle{empty}\begin{document}$ \hat \alpha $\end{document} = (11 ± 1) × 10-12 dyn cm, to a normal value over a period of several months, during which time many very small fragments appeared to be dissociated from, or annealed out, of the predominant high-molecular-weight species. Possible interpretations of these observations are discussed.
    Additional Material: 3 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/bip.360240608
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 2
    Electronic Resource
    Electronic Resource
    Deformational dynamics and nmr relaxation of supercoiled DNAs (1985)
    New York : Wiley-Blackwell
    Biopolymers 24 (1985), S. 1023-1056 
    Details
    ISSN: 0006-3525
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The conformation and internal dynamics of supercoiled pUC 8 DNA (2717 bp) are examined by dynamic light scattering, and the magnitude and uniformity of its torsional rigidity are determined using time-resolved fluorescence polarization anisotropy of intercalated ethidium dye. Neither measurement gives any indication of an appreciably reduced bending or twisting rigidity, or anomalously rapid internal motions. For 31P, in supercoiled pUC 8, we measure T2 = (2.0 ± 0.5) × 10-3 s. This lies within the range of present theoretical estimates obtained using normal rigidities. The proton linewidths observed for pUC 8 and pBR322 (4363 bp) DNAs are within a factor of 2-3 of those similarly estimated assuming ordinary rigidities.According to Bendel, Laub and James [(1982) J. Am. Chem. Soc. 104, 6748-6754], supercoiled pIns36 DNA (7200 bp) exhibits an astonishingly long T2 = 1.17 s for 31P, a slowest rotational relaxation time, τ = 5 × 10-9 s, and an enormously reduced bending rigidity. Serious questions raised by these findings are examined here. The 5 × 10-9 s slowest rotational relaxation time is shown to be physically inadmissible.The nmr relaxation theory developed previously by Allison, Shibata, Wilcoxon, and Schurr [(1982) Biopolymers 21, 729-762], is modified to incorporate new results for deformable filaments, which directly introduce the highly nonexponential tumbling correlation function for reorientation of the local helix axis. Essential requirements for a complete calculation of R2, including estimation of the tumbling correlation function and evaluation of the still unknown DIP/CSA cross-term, are described in detail. Slow coil-deformation modes analogous to the Rouse-Zimm modes of linear DNAs are shown to make an important, if not dominant, contribution to the R2 relaxation rate. Geometrical parameters in the theory are chosen to provide good agreement with literature data for 600-bp linear DNA. Using this theory and an informed guess for the tumbling correlation function, we find that the 31P-nmr relaxation data of Bendel et al., if correct, necessarily impose on their DNA one or more extreme properties, such as enormously reduced bending or twisting rigidities. In contrast, the same theory yields reasonable agreement with the T2 reported here for 31P in supercoiled pUC 8 DNA when its rigidities are assumed to be quite ordinary.
    Additional Material: 6 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/bip.360240609
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 3
    Electronic Resource
    Electronic Resource
    Rotational dynamics of DNA from 10-10 to 10-5 seconds: Comparison of theory with optical experiments (1985)
    New York : Wiley-Blackwell
    Biopolymers 24 (1985), S. 1909-1930 
    Details
    ISSN: 0006-3525
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Optical anisotropy data spanning a very wide time range are analyzed using a recently developed theory for filamentous macromolecules that can bend, twist, and also admit overdamped local libration (or wobble) of the chromophore. A rapid relaxation in the fluorescence polarization anisotropy (FPA) near 10-10 s is fitted well by superimposing isotropic wobble of the chromophore (7° rms polar and azimuthal amplitude) on the long-wavelength twisting and bending motions that characterize the relaxation at longer times but not by the latter alone. Moreover, the decay of the FPA from 0.5 to 150 ns cannot be satisfactorily fitted by chromophore wobble in an otherwise rigid DNA and must be assigned primarily to twisting, as noted previously.Data from 26 ns to 20 μs for 600 base-pair DNA are accurately fitted with only a single adjustable scaling factor when the tumbling correlation function is taken to be the empirical electric birefringence decay function of Elias and Eden. The Barkley-Zimm (BZ) tumbling correlation for very long filaments appears to decay too rapidly and results in significant overestimation of the depolarization for t ≤ 300 ns. In the range of the FPA experiments (t ≥ 150 ns), equally good fits with equally uniform torsion constants are obtained for long DNAs, whether one assumes the BZ tumbling correlation function or neglects tumbling entirely, but the best-fit torsion constant (actually the product of the torsion constant and friction factor) is increased by the factor 1.9 when the BZ result is used with a persistence length of a = 500 Å. The BZ bending theory is compared with other experimental data, and also with a simulation at very short times with mixed results. Present uncertainties regarding the tumbling dynamics and the friction factor for azimuthal rotation allow the torsion constant to be as much as 3.8 times larger than the initial estimate of Thomas et al. Apparent torsion constants obtained from relative ligase kinetics measurements are also briefly discussed.
    Additional Material: 6 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/bip.360241006
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 4
    Electronic Resource
    Electronic Resource
    A molecular dynamics study of the effect of G · T mispairs on the conformation of DNA in solution (1991)
    New York : Wiley-Blackwell
    Biopolymers 31 (1991), S. 211-232 
    Details
    ISSN: 0006-3525
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The effect of G · T mispair incorporation into a double-helical environment was examined by molecular dynamics simulation. The 60-ps simulations performed on the two hexanucleotide duplexes d (G3C3)2 and d (G3TC2)2 included 10 Na+ counterions and first hydration shell waters. The resulting backbone torsional angle trajectories were analyzed to select time spans representative of conformational domains. The average backbone angles and helical parameters of the last time span for both duplexes are reported. During the simulation the hexamers retained B-type DNA structures that differed from typical A- or B-DNA forms. The overall helical structures for the two duplexes are vary similar. The presence of G · T mispairs did not alter the overall helical structure of the oligonucleotide duplex. Large propeller twist and buckle angles were obtained for both duplexes. The purine/pyrimidine crossover step showed a large decrease in propeller twist in the normal duplex but not in the mismatch duplex. Upon the formation of wobble mispairs in the mismatched duplex, the guanines moved into the minor groove and the thymines moved into the major groove. This helped prevent purine/purine clash and created a deformation in the relative orientation of the glycosidic bonds. It also exposed the free O4 of the thymines in the major groove and N2 of the guanines in the minor groove to interactions with solvent and counterions. These factors seemed to contribute to the apparently higher rigidity of the mismatched duplex during the simulation.
    Additional Material: 10 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/bip.360310209
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 5
    Electronic Resource
    Electronic Resource
    Macrocyclic peptides, 4.Part 3: cf.1. Preparations and enantioface-differentiating abilities of 27- and 36-membered ring peptides containing N,N′-ethylene-bridged dipeptides and glycine (1990)
    New York : Wiley-Blackwell
    Die Makromolekulare Chemie 191 (1990), S. 1261-1268 
    Details
    ISSN: 0025-116X
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: 27- and 36-membered ring peptides were prepared using glycine, (2S, 3′ S)-4-methyl-2-(2′-oxo-3′-isobutyl-1′-piperazinyl) pentanoic acid (2) and (2S,3′ S)-3-phenyl-2-(2′-oxo-3′-benzyl-1′-piperazinyl)propanoic acid as the units of peptides. The interactions of 1-phenylethylammonium (1) and p-methoxy-1-phenylethylammonium bromides (11) with these cyclic peptides were studied by 1H and 13C NMR measurements in CDCl3. It was found from these results that the peptides distinguish the enantiomers (R- and S-isomers) of the substrates. Furthermore, it was shown that the enantioface-differentiating abilities of 36-membered ring peptides are superior to those of 27-membered rings.
    Additional Material: 2 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/macp.1990.021910605
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 6
    Electronic Resource
    Electronic Resource
    Development of nondestructive technique for measuring carburization thickness and of A new carburization-resistant alloyLecture, held at ACHEMA '85, Frankfurt/M, June 9-15, 1985. (1986)
    Weinheim [u.a.] : Wiley-Blackwell
    Materials and Corrosion/Werkstoffe und Korrosion 37 (1986), S. 410-418 
    Details
    ISSN: 0947-5117
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Description / Table of Contents: Entwicklung einer zerstörungsfreien Meßtechnik für die Aufkohlungsdicke und einer neuen, gegen Aufkohlung beständigen LegierungDie zerstörungsfreie Messung der Aufkohlung von Crack-Öfen und die Auswahl von aufkohlungsbeständigen Legierungen sind von großer Bedeutung für die Konstruktion und Instandhaltung von Anlagen, wie z.B. Ethylen-Crack-Öfen. In dieser Arbeit wird zum ersten Mal eine neuentwickelte Technik zur Messung der Aufkohlung beschrieben und über eine neue aufkohlungsbeständige Legierung berichtet, die sich auch im Hinblick auf die Verzögerung der Kohleablagerung aus Kohlenwasserstoffen als vorteilhaft erwiesen hat. Die Verfasser haben die Einflüsse des Reaktormetalls auf die Kohleablagerung unter simulierten Ethylen-Crack-Bedingungen untersucht, wobei das Ziel in der Verhinderung der Aufkohlung bestand. Sie sind zu dem Schluß gekommen, daß die abgelagerte Koksmenge mit dem Nickelgehalt in den Legierungen stetig ansteigen. Aufgrund dieser Ergebnisse wurde ein neuer Röhrenreaktor für Crackverfahren (CORET-Rohr) entwikkelt, bei dem Rohre aus HP innen mit Fe25Cr9Mn3Ni plattiert sind; das ganze wird durch Schleuderguß hergestellt. Diese Röhren wurden in technischen Ethylen-Crack-Öfen auf ihre Aufkohlungsbeständigkeit und mechanische Festigkeit sowie das Betriebsverhalten untersucht. Bei diesem mehr als drei Jahre dauernden Betriebsversuch wurden die folgenden Ergebnisse erhalten: 1. Das CORET-Rohr ist für den technischen Einsatz aufgrund seiner Aufkohlungsbeständigkeit und seinen mechanischen Eigenschaften geeignet. 2. Die vorläufigen Betriebsergebnisse deuten darauf hin, daß die Koksablagerung in diesen Röhren im Vergleich zu Röhren aus HP etwas verzögert ist. 3. Beim Betrieb unter strengen Bedingungen ist aufgrund der Betriebsergebnisse auch eine gewisse Erhöhung der Olefinausbeute zu erwarten.
    Notes: Nondestructive measurement of carburization of cracking tube and selecting carburization-resistant alloys have been of much importance in design and maintenance of such equipment as ethylene cracking heater.In this paper, the authors firstly describe the newly developed manner of measuring carburization and then report a new carburization resistant alloy which is also proved to retard coke deposition from hydrocarbon stream on tube surface.The authors studied the effects of tube metallurgy on coke deposition under the conditions simulated to ethylene cracking tube with the aim of preventing carburization and concluded that the coke deposition amount increases consistantly with increase of nickel content of alloys. Based on the above results, the authors developed a new cracking tube designated as CORET tube which has inner layer of Fe-25Cr-9Mn-3Ni alloy clad to HP tubes by centrifugal double layer casting. Those tubes were installed in commercial ethylene cracking heaters and tested for their carburization resistance, mechanical stability and process performances. The results of the field test lasting for more than three years are as follows: 1. The CORET tube proved to be carburization resistant and mechanically reliable enough for actual use. 2. Preliminary process performance data suggest some degree of coking retardation in the CORET tubes when compared with HP tubes; both operating at approximately the same conditions. 3. These data also indicate some degree of enhancement in the olefins yield, when operating at or near high severity conditions.
    Additional Material: 16 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/maco.19860370707
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 7
    Electronic Resource
    Electronic Resource
    Evidence of three distinct conformations - single chain, single helix, and triple helix - of (1 → 3)-β-D-xylan in the solid and intact frond of green algae as studied by 13C-nmr spectroscopy (1991)
    New York : Wiley-Blackwell
    Biopolymers 31 (1991), S. 933-940 
    Details
    ISSN: 0006-3525
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: High-resolution solid-state 13C-nmr spectra of (1 → 3) -β-D-xylan from Bryopsis maxima and Caulerpa brachypus were recorded for various preparations from intact through dried frond to anhydrous and hydrated xylan, to gain insight into their secondary structures as compared with those of (1 → 3)-β-D-glucans. It turned out that 13C-nmr peaks of intact or dried frond were mainly ascribed to the peaks from (1 → 3)-β-D-linked xylose residue, although some peaks were seen at the carbonyl and aliphatic regions. Dehydration of frond by either air drying or ethanol, and extraction of xylan with acid, did not result in substantial spectral change, although extraction with saturated ZnCl2 solution caused appreciable displacements of the C-3 as well as C-2 and C-5 peaks. This means that no major conformational change was induced during the above-mentioned processes of the dehydration and the extraction with acid. The extraction with ZnCl2 solution, however, induced major conformational change. Thus, we found that the above-mentioned three distinct conformations-triple helix, single helix, and single chain-are also present in (1 → 3)-β-D-xylan, as judged from the conformation-dependent displacements of 13C chemical shifts, hydration/dehydration-induced spectral change, and the x-ray diffraction data on Penicillus dumetosus by Atkins et al. In particular, we found that all the preparations except for the extraction with ZnCl2 solution retain the triple helix form, whereas the anhydrous and hydrate samples of the latter preparations take the single-chain and single-helix form, respectively. Further, we measured the 13C spin-lattice relaxation times of laboratory frame of the xylan to gain insight into better understanding of the role of the hydroxymethyl group as an efficient relaxation pathway in (1 → 3)-β-D-glucan.
    Additional Material: 3 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/bip.360310803
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 8
    Electronic Resource
    Electronic Resource
    A molecular dynamics simulation of the (dG)6·(dC)6 minihelix including counterions and water (1990)
    New York : Wiley-Blackwell
    Biopolymers 29 (1990), S. 1027-1044 
    Details
    ISSN: 0006-3525
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The results of a 60 ps molecular dynamics (MD) simulation of (dG)6·(dC)6 including 10 Na+ counterions and 292 water molecules are presented. All backbone angles and helix parameters for the hexamer are reported in this paper along with trajectory plots of selected angles. Hydrogen bonding between the bases along the helical axis was observed to flucturate with time, showing the dynamic nature of the base-pairing interaction. These fluctuations gave rise to unusual hydrogen-bonding patterns. Good intrastrad base stacking and no interstrand base stacking were also observed. The hexamer minihelix retains an essentially B-DNA conformation throughout the entire simulation even though some helix parameters and backbone angles do not have strict B-DNA values. The most striking feature obtained from the simulation was a high propeller twist, which resulted in a narrow minor groove for the minihelix. It is proposed that (dG)n·(dC)n sequences are resistant to DNAase I because of this narrow minor groove in dilute aqueous solution.
    Additional Material: 7 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/bip.360290614
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 9
    Electronic Resource
    Electronic Resource
    Synthesis of polymer analogues of triphenylselenonium chloride as phase-transfer catalysts (1994)
    Weinheim : Wiley-Blackwell
    Macromolecular Rapid Communications 15 (1994), S. 291-294 
    Details
    ISSN: 1022-1336
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Additional Material: 3 Tab.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/marc.1994.030150317
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 10
    Electronic Resource
    Electronic Resource
    Formation of polyelectrolyte complexes between cellulose derivatives and their blood compatibility (1986)
    New York, NY [u.a.] : Wiley-Blackwell
    Journal of Applied Polymer Science 31 (1986), S. 2491-2500 
    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: Formation of polyelectrolyte complexes (PECs) between cellulose derivatives in aqueous solution and their blood compatibility were examined. To this end, two types of quaternary ammonium cellulose derivatives, Q-Cell and Q-HEC, were prepared by treating cellulose and hydroxyethyl cellulose (HEC), respectively, with glycidyl trimethylammonium chloride. Anionic derivatives were carboxymethyl cellulose (CMC) with different degrees of substitution (DS) and cellulose sulfate (CS). In vivo blood tests were made by a method of peripheral vein indwelling suture. The results showed that the complex formation of Q-Cell did not follow a stoichiometric reaction, but Q-HEC reacted stoichiometrically with CMC and CS. It was also found that water-insoluble cellulosic PECs are soluble in formic acid, showing that the cellulosic PEC films can be prepared from formic acid solutions. The blood tests revealed that by the criteria of the test method employed in this work, cellulosic PECs had a good blood compatibility.
    Additional Material: 8 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/app.1986.070310810
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
Close ⊗
This website uses cookies and the analysis tool Matomo. More information can be found here...