ALBERT — All Library Books, journals and Electronic Records Telegrafenberg

1

Digitale Medien

Premelting thermal fluctuational base pair opening probability of poly(dA) · poly(dT) as predicted by the modified self-consistent phonon theory (1991)

Chen, Y. Z. ; Feng, Y. ; Prohofsky, W.

New York : Wiley-Blackwell

Biopolymers 31 (1991), S. 139-148

zur Merkliste hinzufügen auf der Merkliste

Details

ISSN: 0006-3525

Schlagwort(e): Chemistry ; Polymer and Materials Science

Quelle: Wiley InterScience Backfile Collection 1832-2000

Thema: Chemie und Pharmazie

Notizen: We employ a mean field, modified, self-consistent phonon theory to evaluate the single base-pair opening rate and the probability of a base pair in the amino proton exchangeable state for the homopolymer poly(dA) · poly(dT) at temperatures below the helix-coil transition region. Our calculated premelting single base-pair opening probabilities are in general agreement with several available experimental estimates from imino proton exchange and formaldehyde-induced DNA melting measurements. These calculated opening probabilities, however, are in disagreement with the prediction of the helix-coil transition theory. Possible reasons for the differences are discussed, especially the possible different definition of a meaningful open state in the premelting region. The premelting open state of the modified self-consistent phonon approximation theory seems to be appropriate to describe a solvent-accessible open configuration that is sufficient to facilitate important chemical reactions such as imino proton exchange and formaldehyde reaction with the bases. This can be compared with the completely unstacked open state of the helix-coil transition theory originally defined in the helix-coil transition region. We propose that the amino proton exchangeable state is different from the open state associated with melting and only involves the breaking of the amino interbase H bond. The agreement between the calculated and experimentally estimated probability of a base pair in the amino proton exchangeable state seems to support this hypothesis.

Zusätzliches Material: 1 Ill.

Materialart: Digitale Medien

URL: http://dx.doi.org/10.1002/bip.360310202

Permalink

	Standort	Signatur	Erwartet	Verfügbarkeit

Andere fanden auch interessant ...

Artikel (Nationallizenzen)

Volltext

2

Digitale Medien

Hybrid Monte Carlo simulations theory and initial comparison with molecular dynamics (1993)

Brass, A. ; Pendleton, B. J. ; Chen, Y. ; [weitere]

New York : Wiley-Blackwell

Biopolymers 33 (1993), S. 1307-1315

zur Merkliste hinzufügen auf der Merkliste

Details

ISSN: 0006-3525

Schlagwort(e): Chemistry ; Polymer and Materials Science

Quelle: Wiley InterScience Backfile Collection 1832-2000

Thema: Chemie und Pharmazie

Notizen: A formal partially dynamical approach to ergodic sampling, hybrid Monte Carlo, has been adapted for the first time from its proven application in quantum chromodynamics to realistic molecular systems. A series of simulations of pancreatic trypsin inhibitor were run using temperature-rescaled molecular dynamics and hybrid Monte Carlo. It was found that simulations run using hybrid Monte Carlo equilibrated an order of magnitude faster than those run using temperature-rescaled molecular dynamics. Certain aspects of improved performance obtained using hybrid Monte Carlo are probably due to the increased efficiency with which this algorithm explores phase space. To discuss this we introduce the notion of “trajectory stiffness”. © 1993 John Wiley & Sons, Inc.

Zusätzliches Material: 6 Ill.

Materialart: Digitale Medien

URL: http://dx.doi.org/10.1002/bip.360330815

Permalink

	Standort	Signatur	Erwartet	Verfügbarkeit

Andere fanden auch interessant ...

Artikel (Nationallizenzen)

Volltext

3

Digitale Medien

Premelting thermal fluctuational interbase hydrogen-bond disrupted states of a B-DNA guanine-cytosine base pair: Significance for amino and imino proton exchange (1991)

Chen, Y. Z. ; Zhuang, W. ; Prohofsky, E. W.

New York : Wiley-Blackwell

Biopolymers 31 (1991), S. 1273-1281

zur Merkliste hinzufügen auf der Merkliste

Details

ISSN: 0006-3525

Schlagwort(e): Chemistry ; Polymer and Materials Science

Quelle: Wiley InterScience Backfile Collection 1832-2000

Thema: Chemie und Pharmazie

Notizen: Modified self-consistent phonon theory when applied to the DNA double helix indicates the existence of fairly long-lived states in which single interbase H bonds are disrupted. One can then postulate a number of situations in which particular disrupted H bonds can enhance particular proton exchange. In this paper we postulate a number of such partially open states for a B-conformation GC base pair and calculate the probability of each of these states for a B-conformation poly(dG) · poly(dC). We compare these probabilities to those probabilities needed to explain various observed proton exchange rates. We propose that, for a GC base pair in B conformation, there are two amino proton exchangeable states - a cytosine amino proton exchangeable state and a guanine amino proton exchangeable state; both require the disruption of only the corresponding inter base H bond. The imino proton exchange, however, requires the disruption of all three inter base H bonds and this defines a third open state. Our calculated probabilities for a GC base pair in these three states are in fair agreement with available experimental estimates from measurements of amino and imino proton exchange.

Zusätzliches Material: 1 Ill.

Materialart: Digitale Medien

URL: http://dx.doi.org/10.1002/bip.360311105

Permalink

	Standort	Signatur	Erwartet	Verfügbarkeit

Andere fanden auch interessant ...

Artikel (Nationallizenzen)

Volltext

4

Digitale Medien

A histological study of the “stomach” and caecum in the genus Pheretima (Oligochaeta) (1941)

Chen, Y. ; Puh, Y. Chiung

New York, NY : Wiley-Blackwell

Journal of Morphology 68 (1941), S. 507-517

zur Merkliste hinzufügen auf der Merkliste

Details

ISSN: 0362-2525

Schlagwort(e): Life and Medical Sciences ; Cell & Developmental Biology

Quelle: Wiley InterScience Backfile Collection 1832-2000

Thema: Biologie , Medizin

Materialart: Digitale Medien

URL: http://dx.doi.org/10.1002/jmor.1050680305

Permalink

	Standort	Signatur	Erwartet	Verfügbarkeit

Andere fanden auch interessant ...

Artikel (Nationallizenzen)

Volltext

5

Digitale Medien

Diffusion of oxygen, nitrogen and their mixtures in carbon molecular sieve (1994)

Chen, Y. D. ; Yang, R. T. ; Uawithya, P.

Hoboken, NJ : Wiley-Blackwell

AIChE Journal 40 (1994), S. 577-585

zur Merkliste hinzufügen auf der Merkliste

Details

ISSN: 0001-1541

Schlagwort(e): Chemistry ; Chemical Engineering

Quelle: Wiley InterScience Backfile Collection 1832-2000

Thema: Chemie und Pharmazie , Werkstoffwissenschaften, Fertigungsverfahren, Fertigung

Notizen: Diffusivities of oxygen, nitrogen and their mixtures in carbon molecular sieve are measured under conditions used for kinetic separation of air by adsorption (elevated pressures). In binary diffusion, codiffusion enhances fluxes for both components, whereas counterdiffusion has the opposite effects; for both cases, the effects are significantly more pronounced for the fast diffusing component. The multicomponent diffusion theory developed earlier in this laboratory for surface diffusion is reformulated for diffusion in molecular sieves. Multicomponent diffusivities can be predicted from the following pure-component information: concentration-dependent diffusivities and diffusional activation energies. Predicted binary diffusion results agree fairly with the experimental data for oxygen and nitrogen in carbon molecular sieve.

Zusätzliches Material: 15 Ill.

Materialart: Digitale Medien

URL: http://dx.doi.org/10.1002/aic.690400402

Permalink

	Standort	Signatur	Erwartet	Verfügbarkeit

Andere fanden auch interessant ...

Artikel (Nationallizenzen)

Volltext

6

Digitale Medien

Surface diffusion of multilayer adsorbed species (1993)

Chen, Y. D. ; Yang, R. T.

Hoboken, NJ : Wiley-Blackwell

AIChE Journal 39 (1993), S. 599-606

zur Merkliste hinzufügen auf der Merkliste

Details

ISSN: 0001-1541

Schlagwort(e): Chemistry ; Chemical Engineering

Quelle: Wiley InterScience Backfile Collection 1832-2000

Thema: Chemie und Pharmazie , Werkstoffwissenschaften, Fertigungsverfahren, Fertigung

Notizen: A model based on kinetic theory is derived for surface diffusion of multilayer adsorbed species on a homogeneous surface. A simple solution is obtained for expressing the concentration dependence of surface diffusivity. For monolayer adsorbate, the solution is reduced to the classical HIO model. This solution, in principle, requires no fitting parameters and is capable of predicting the unique concentration dependent behavior exhibited by multilayer surface diffusion, where the diffusivity first increases with surface concentration to a maximum followed by a decrease. Seventeen sets of experimental data from the literature are used to test the model, with fair results. It is also shown that heats of adsorption can be calculated from multilayer surface diffusivity data by using this model.

Zusätzliches Material: 7 Ill.

Materialart: Digitale Medien

URL: http://dx.doi.org/10.1002/aic.690390408

Permalink

	Standort	Signatur	Erwartet	Verfügbarkeit

Andere fanden auch interessant ...

Artikel (Nationallizenzen)

Volltext

7

Digitale Medien

Wrong-way behavior of packed-bed reactors: Influence of interphase transport (1989)

Chen, Y. C. ; Luss, Dan

Hoboken, NJ : Wiley-Blackwell

AIChE Journal 35 (1989), S. 1148-1156

zur Merkliste hinzufügen auf der Merkliste

Details

ISSN: 0001-1541

Schlagwort(e): Chemistry ; Chemical Engineering

Quelle: Wiley InterScience Backfile Collection 1832-2000

Thema: Chemie und Pharmazie , Werkstoffwissenschaften, Fertigungsverfahren, Fertigung

Notizen: Large transient temperature excursions may be caused by a sudden reduction in the feed temperature to a packed-bed reactor operating at an intermediate conversion. When a unique steady state exists for all feed temperatures, the magnitude of the wrong-way behavior predicted by a two-phase model is very close to that predicted by a pseudohomogeneous model if PeH is equal to the dimensionless heat transfer coefficient H. The two-phase model enables a more efficient numerical simulation in such cases. The predictions of these two models may be rather different when steady-state multiplicity exists for some feed temperatures. In such cases, a two-phase model, which accounts for the axial dispersion of heat, should be used to simulate the transient behavior. The wrong-way behavior may lead to an ignition of a low-temperature state or an upstream propagation of a transient temperature wave.

Zusätzliches Material: 13 Ill.

Materialart: Digitale Medien

URL: http://dx.doi.org/10.1002/aic.690350710

Permalink

	Standort	Signatur	Erwartet	Verfügbarkeit

Andere fanden auch interessant ...

Artikel (Nationallizenzen)

Volltext

8

Digitale Medien

Concentration dependence of surface diffusion and zeolitic diffusion (1991)

Chen, Y. D. ; Yang, R. T.

Hoboken, NJ : Wiley-Blackwell

AIChE Journal 37 (1991), S. 1579-1582

zur Merkliste hinzufügen auf der Merkliste

Details

ISSN: 0001-1541

Schlagwort(e): Chemistry ; Chemical Engineering

Quelle: Wiley InterScience Backfile Collection 1832-2000

Thema: Chemie und Pharmazie , Werkstoffwissenschaften, Fertigungsverfahren, Fertigung

Zusätzliches Material: 3 Ill.

Materialart: Digitale Medien

URL: http://dx.doi.org/10.1002/aic.690371015

Permalink

	Standort	Signatur	Erwartet	Verfügbarkeit

Andere fanden auch interessant ...

Artikel (Nationallizenzen)

Volltext

9

Digitale Medien

Wrong-way behavior of packed-bed reactors: II. Impact of thermal dispersion (1988)

Pinjala, V. ; Chen, Y. C. ; Luss, D.

Hoboken, NJ : Wiley-Blackwell

AIChE Journal 34 (1988), S. 1663-1672

zur Merkliste hinzufügen auf der Merkliste

Details

ISSN: 0001-1541

Schlagwort(e): Chemistry ; Chemical Engineering

Quelle: Wiley InterScience Backfile Collection 1832-2000

Thema: Chemie und Pharmazie , Werkstoffwissenschaften, Fertigungsverfahren, Fertigung

Notizen: A sudden reduction in the feed temperature of a packed-bed reactor may lead to a transient temperature rise, referred to as a wrong-way behavior. As expected, the axial dispersion of heat decreases the magnitude of the temperature excursion and prolongs the transient shift to a new steady state. In addition, the thermal dispersion may enable the wrong-way behavior to ignite a low-temperature steady state leading to a disastrous runaway of the reactor. Moreover, it may create a transient high-temperature wave, which moves initially in the upstream direction. The axial dispersion of heat can lead to some behavioral features which are qualitatively different from those of a model which ignores it. The transient temperature excursion does not exceed a value, which can be estimated by a simple analytical expression.

Zusätzliches Material: 19 Ill.

Materialart: Digitale Medien

URL: http://dx.doi.org/10.1002/aic.690341010

Permalink

	Standort	Signatur	Erwartet	Verfügbarkeit

Andere fanden auch interessant ...

Artikel (Nationallizenzen)

Volltext

10

Digitale Medien

Siderophore-Mediated microbial iron(III) uptake: An exercise in chiral recognition (1993)

Shanzer, A. ; Libman, J. ; Yakirevitch, P. ; [weitere]

New York, NY [u.a.] : Wiley-Blackwell

Chirality 5 (1993), S. 359-365

zur Merkliste hinzufügen auf der Merkliste

Details

ISSN: 0899-0042

Schlagwort(e): synthetic siderophore analogs ; hydroxamates ; ferrichrome ; ferrioxamine ; coprogen ; Pseudomonas putida ; membrane receptors ; transport proteins ; growth promotion ; growth inhibition ; Chemistry ; Organic Chemistry

Quelle: Wiley InterScience Backfile Collection 1832-2000

Thema: Chemie und Pharmazie

Notizen: Molecular recognition by microbial receptors for siderophores [natural iron(III) carriers] is examined with synthetic iron(III) carriers as structural probes. The iron(III) carriers have been designed to reproduce the two essential features of the natural siderophores: the capability to form octahedral iron(III) binding cavities and to fit specific membrane receptors. Specifically, analogs of tripodal ferrichrome and linear ferrioxamines have been prepared and examined. The ferrichrome analogs rely on C3-symmetric binders that are assembled from triscarboxylates as anchors, amino acids as bridges, and terminal hydroxamate groups as binding sites. The ferrioxamine analogs are based on linear assemblies of three identical monomers, each derived from a chiral amino acid. The deliberate use of animo acid residues as variable building blocks enables us to systematically modify the molecules' envelopes and the preferred absolute configuration of the iron(III) complexes until optimal performance is reached. Examination of the synthetic analogs in Pseudomonas putida demonstrates that the domains around the iron(III) center and their chiral sense dictate the extent of recognition by the membrane receptors. It is also shown that the synthetic siderophore analogs may be designed to either exert a broader, or a more narrow range of microbial activity than the natural siderophores. The implications of these findings are discussed in relation to the possible design of species-specific antimicrobial agents. © 1993 Wiley-Liss, Inc.

Zusätzliches Material: 9 Ill.

Materialart: Digitale Medien

URL: http://dx.doi.org/10.1002/chir.530050516

Permalink

	Standort	Signatur	Erwartet	Verfügbarkeit

Andere fanden auch interessant ...

Artikel (Nationallizenzen)

Volltext