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
    Stages of emerging life —Five principles of early organization (1982)
    Springer
    Journal of molecular evolution 19 (1982), S. 47-61 
    Details
    ISSN: 1432-1432
    Keywords: Prebiotic evolution ; Polynucleotide replication ; Quasispecies ; Hypercycles ; Compartmentalization
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary Five principles underly the evolution of the genetic language: formation of stereoregular heteropolymers, selection through self-replication, evolution of quasispecies towards optimal structures, regulated cooperation between competitors through catalytic hypercycles and evaluation of translation products through compartmentalization. These principles are formulated and illustrated by means of experimental results
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF02100223
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 2
    Electronic Resource
    Electronic Resource
    Proton transfer reactions in aqueous solutions of pyridoxamine phosphate (1988)
    Springer
    European biophysics journal 16 (1988), S. 219-229 
    Details
    ISSN: 1432-1017
    Keywords: Relaxation kinetics ; ultrasound absorption ; temperature jump ; proton transfer ; vitamin B 6
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Physics
    Notes: Abstract UV-visible and 13C NMR measurements described in the literature and our 31P NMR measurements support the following mechanism of proton transfer reactions in aqueous solutions of pyridoxamine phosphate: Only the tautomeric equilibrium between neutral form, A N, and zwitterion, A Z, which is analogous to the tautomeric equilibrium of 3-hydroxypyridine in aqueous solution, is important, and that equilibrium does not change upon the dissociation of the second phosphate proton. With these simplifying assumption, we have simulated the relaxation spectrum of the proton transfer reactions of pyridoxamine phosphate in water using parameters from analogous reactions and compared it with our ultrasound and temperature jump measurements. We have found that the relaxation process measured by the temperature jump experiment is mainly caused by the overall reaction A N=A Z (or A N - =A Z - ) and the ultrasound absorption at the isoelectric point between pK2 and pK3 is mainly caused by the overall reaction $$A^{\text{ + }} + {\text{x}} A_N^ - + \left( {1 - {\text{x}}} \right)A_Z^ - = {\text{y}}A_N + \left( {2 - {\text{y}}} \right)A_Z , 0 \leqq {\text{x}} \leqq {\text{1,}} {\text{0}} \leqq {\text{y}} \leqq 2$$ .
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00261264
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 3
    Electronic Resource
    Electronic Resource
    RNA multi-structure landscapes (1993)
    Springer
    European biophysics journal 22 (1993), S. 13-24 
    Details
    ISSN: 1432-1017
    Keywords: Fitness landscapes ; Partition function ; Quasispecies ; RNA secondary structures
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Physics
    Notes: Abstract Statistical properties of RNA folding landscapes obtained by the partition function algorithm (McCaskill 1990) are investigated in detail. The pair correlation of free energies as a function of the Hamming distance is used as a measure for the ruggedness of the landscape. The calculation of the partition function contains information about the entire ensemble of secondary structures as a function of temperature and opens the door to all quantities of thermodynamic interest, in contrast with the conventional minimal free energy approach. A metric distance of structure ensembles is introduced and pair correlations at the level of the structures themselves are computed. Just as with landscapes based on most stable secondary structure prediction, the landscapes defined on the full biophysical GCAU alphabet are much smoother than the landscapes restricted to pure GC sequences and the correlation lengths are almost constant fractions of the chain lengths. Correlation functions for multi-structure landscapes exhibit an increased correlation length, especially near the melting temperature. However, the main effect on evolution is rather an effective increase in sampling for finite populations where each sequence explores multiple structures.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00205808
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 4
    Electronic Resource
    Electronic Resource
    Algorithm independent properties of RNA secondary structure predictions (1996)
    Springer
    European biophysics journal 25 (1996), S. 115-130 
    Details
    ISSN: 1432-1017
    Keywords: Key words Kinetic folding ; Minimun free energy structures ; RNA secondary structures ; Sequence structure relations
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Physics
    Notes: Abstract Algorithms predicting RNA secondary structures based on different folding criteria – minimum free energies (mfe), kinetic folding (kin), maximum matching (mm) – and different parameter sets are studied systematically. Two base pairing alphabets were used: the binary GC and the natural four-letter AUGC alphabet. Computed structures and free energies depend strongly on both the algorithm and the parameter set. Statistical properties, such as mean number of base pairs, mean numbers of stacks, mean loop sizes, etc., are much less sensitive to the choice of parameter set and even of algorithm. Some features of RNA secondary structures, such as structure correlation functions, shape space covering and neutral networks, seem to depend only on the base pairing logic (GC or AUGC alphabet).
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/s002490050023
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 5
    Electronic Resource
    Electronic Resource
    Spin-resolved electronic band structure of fct-cobalt (100) (abstract) : 35th annual conference on magnetism and magnetic materials (1991)
    [S.l.] : American Institute of Physics (AIP)
    Journal of Applied Physics 69 (1991), S. 5003-5003 
    Details
    ISSN: 1089-7550
    Source: AIP Digital Archive
    Topics: Physics
    Notes: The spin-polarized electronic structure of the fcc high-temperature modification of cobalt has not been investigated yet, because of the experimental difficulties of photoemission at high temperature. We stabilized fcc Co by molecular-beam epitaxy on a Cu(100) substrate with large, atomically flat terasses (0.5–1 μm wide) as revealed by STM. The structure of the layers was studied by LEED and MEED, showing a tetragonal distortion of the fcc lattice perpendicular to the (100) surface plane. The dispersion of the exchange split bands perpendicular to the surface was determined for a 5-monolayer-thick sample (tetragonal distortion on average 4%–5%) by spin- and momentum-resolved photoemission. The results are compared to two relativistic spin-polarized band-structure calculations for fcc cobalt. Somewhat surprisingly, even a 5-ML-thick sample shows three-dimensional dispersion in good agreement with the calculations, as far as the average exchange splitting (1.2±0.2 eV), and the symmetry character of the bands is concerned. There are, however, some systematic deviations of minority bands near the Fermi energy which are attributed to the tetragonal compression.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.348153
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 6
    Electronic Resource
    Electronic Resource
    Dynamical systems under constant organization I. Topological analysis of a family of non-linear differential equations —A model for catalytic hypercycles (1978)
    Springer
    Bulletin of mathematical biology 40 (1978), S. 743-769 
    Details
    ISSN: 1522-9602
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Mathematics
    Notes: Abstract The paper presents a qualitative analysis of the following systems ofn differential equations: $$\dot x_i = x_i x_j - x_i \sum\nolimits_r^n { = 1} x_r x_s {\mathbf{ }}(j = i - 1 + n\delta _{i1} {\mathbf{ }}and{\mathbf{ }}s = r - 1 + n\delta _{r1} )$$ , which show cyclic symmetry. These dynamical systems are of particular interest in the theory of selforganization and biological evolution as well as for application to other fields.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF02460605
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 7
    Electronic Resource
    Electronic Resource
    Semiempirische LCAO-MO-SCF-Rechnungen zur Konformation und konformativen Beweglichkeit von 1,3-Dioxan-4,6-dionen (1972)
    Springer
    Monatshefte für Chemie 103 (1972), S. 1483-1495 
    Details
    ISSN: 1434-4475
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Zusammenfassung Die Energien und Dipolmomente mehrerer Konformationen von 2,2-Dimethyl-1,3-dioxan-4,6-dion (Meldrumsäure) wurden mit Hilfe der semiempirischenLCAO-MO-SCF-Methode vonPople berechnet. Die Ergebnisse werden mit den experimentellen Dipolmomenten einiger Derivate von 1,3-Dioxan-4,6-dion verglichen. Die Unterschiede zwischen den experimentellen Dipolmomenten dieser Verbindungen können durch Annahme unterschiedlicher Konformerengleichgewichte erklärt werden. Die berechnete Protonenaffinität desMeldrumsäureanions läßt sich in eine Reihe von Aciditäten verschiedenartiger Säuren in Übereinstimmung mit den experimentellen Werten einordnen.
    Notes: Abstract The total energies and dipole moments of some conformations of 2.2-dimethyl-1,3-dioxane-4,6-dione (Meldrum's acid) were calculated withPople's semiempiricalLCAO-MO-SCF-procedure (CNDO). The results are compared with the experimental dipole moments of 2.2-dimethyl-1.3-dioxane-4.6-dione and its alkyl derivatives. The unusual high differences in the experimental dipole moments of this series of compounds are explained by the assumption of different conformational equilibria. The proton affinity ofMeldrum's acid anion fits well into a series of calculated proton affinities of otherBrønsted acids.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00904532
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 8
    Electronic Resource
    Electronic Resource
    1,2-Dimethyl-3,5-dioxopyrazolidin und seine Kondensations-produkte mit Aldehyden (1968)
    Springer
    Monatshefte für Chemie 99 (1968), S. 601-605 
    Details
    ISSN: 1434-4475
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Zusammenfassung 1,2-Dimethyl-3,5-dioxopyrazolidin wird durch direkte Umsetzung von Malonsäuredimethylester und sym-Dimethylhydrazin erhalten. Kondensation dieser Verbindung mit aliphatischen und aromatischen Aldehyden liefert elektrisch neutrale organische Lewissäuren, die in bezug auf die UV-Absorption weitestgehend den entsprechenden cyclischen Isopropylidenacylalen von Alkylund Aryl-methylenmalonsäuren gleichen. 1,2-Dimethyl-3,5-pyrazolidinedione obtained directly from dimethyl malonate and sym.-dimethylhydrazine. Condensation with aliphatic and aromatic aldehydes leads to electrically neutral organic Lewis acids. Their UV-spectra are similar to those of the corresponding cyclic isopropylidene acylals of substituted malonic acids.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00901209
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 9
    Electronic Resource
    Electronic Resource
    Zur Kenntnis cyclischer Acylale, 18. Mitt.: Über die Einwirkung von Diazomethan auf substituierte Benzylidenmeldrumsäuren und ähnliche Verbindungen (1967)
    Springer
    Monatshefte für Chemie 98 (1967), S. 1772-1782 
    Details
    ISSN: 1434-4475
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Abstract The reaction is described of the condensation products ofMeldrum's acid with aldehydes1–3 2 with diazomethane in methanol/ether, which leads to the cyclopropane compounds1 b-3 b. This is a known mode of reaction and is predicted by quantum chemical calculations ofP. Schuster. A reaction hitherto unobserved was found in the case of the compound4. The reaction with CH2N2 in methanol/ether at various temperatures yields the compound4 c as well as4 a and4 b. In CHCl3 the reactions yields only4 b in addition to many other high molecular weight products.
    Notes: Zusammenfassung Es wird die Reaktion der Kondensationsprodukte (1–3) vonMeldrumsäuren mit Diazomethan in Methanol/Äther beschrieben, die zu den Cyclopropanverbindungen1 b-3 b führt. Diese Reaktionsweise ist bekannt und auch nach quantenchemischen Berechnungen des einen von uns (P. Schuster) zu erwarten. Eine neue, bisher nicht beobachtete Reaktion wurde bei der Verbindung4 gefunden. Bei verschiedenen Temperaturen führt die Reaktion mit CH2N2 in Methanol/Äther (außer zu den Verbindungen4 a und4 b) zu4 c. In CHCl3 entsteht nur4 b neben viel allem Anschein nach hochmolekularen Produkten.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01167135
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 10
    Electronic Resource
    Electronic Resource
    Competition and cooperation in catalytic selfreplication (1981)
    Springer
    Journal of mathematical biology 11 (1981), S. 155-168 
    Details
    ISSN: 1432-1416
    Keywords: Catalytic selfreplication ; Concentration simplex ; Dynamical systems ; Flow reactor ; Hypercycle
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Mathematics
    Notes: Abstract It is shown that in a flow reactor, hypercyclic coupling of self-reproducing macromolecular species leads to cooperation, i.e. none of the concentrations will vanish. On the other hand, autocatalytic selfreproducing macromolecules usually compete, and the number of surving species increases with the total concentration. Both results are proved under very general assumptions concerning the growth rates.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00275439
    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...