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  • Articles  (62)
  • Evolution
  • kinetics
  • Springer  (62)
  • Physics  (62)
  • 1
    Electronic Resource
    Electronic Resource
    Molecular structure of trans-[Co(NH3)4(NH2CH3)Cl](ClO4)2 (1998)
    Springer
    Journal of chemical crystallography 28 (1998), S. 69-72 
    Details
    ISSN: 1572-8854
    Keywords: Co(III) complex ; crystal structure ; kinetics ; steric effects
    Source: Springer Online Journal Archives 1860-2000
    Topics: Geosciences , Physics
    Notes: Abstract The title compound crystallizes in the orthorhombic space group Pnma, with a = 7.9209(5), b = 9.818(1), c = 16.867(2) Å, and Z = 4. The structure was solved employing 1864 independent x-ray reflections with I〉2σ(I) by Patterson and difference Fourier techniques and refined by full-matrix least-squares to R = 0.036. The trans-[CO(NH3)4(NH2CH3)Cl](ClO4)2 molecule is on a crystallographic mirror plane. The cobalt ion is in an elongated octahedral coordination with four equatorial ammonia ligands [average Co–N distance equal to 1.966(2) Å], an axial methylamine [Co–N=1.965(3)Å], and an axial chlorine ion [Co–Cl=2.2771(9)Å]. Kinetic steric effects of the complex are interpreted in terms of structural results.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1023/A:1021786804676
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  • 2
    Electronic Resource
    Electronic Resource
    Sensitivity of PSA process performance to input variables (1995)
    Springer
    Adsorption 1 (1995), S. 133-151 
    Details
    ISSN: 1572-8757
    Keywords: PSA process ; sensitivity ; equilibria ; kinetics ; heats
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Physics , Process Engineering, Biotechnology, Nutrition Technology
    Notes: Abstract Mathematical models for pressure swing adsorption (PSA) processes essentially require the simultaneous solutions of mass, heat and momentum balance equations for each step of the process using appropriate boundary conditions for the steps. The key model input variables needed for estimating the separation performance of the process are the multicomponent adsorption equilibria, kinetics and heats of adsorption for the system of interest. A very detailed model of an adiabatic Skarstrom PSA cycle for production of high purity methane from a ethylene-methane bulk mixture is developed to study the sensitivity of the process performance to the input variables. The adsorption equilibria are described by the heterogeneous Toth model which accounts for variations of isosteric heats of adsorption of the components with adsorbate loading. A linear driving force model is used to describe the kinetics. The study shows that small errors in the heats of adsorption of the components can severely alter the overall performance of the process (methane recovery and productivity). The adsorptive mass transfer coefficients of the components also must be known fairly accurately in order to obtain precise separation performance.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00705001
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  • 3
    Electronic Resource
    Electronic Resource
    Frequency response analysis of a closed diffusion cell with two resonators (1996)
    Springer
    Adsorption 2 (1996), S. 265-277 
    Details
    ISSN: 1572-8757
    Keywords: frequency response ; diffusion cell ; kinetics ; diffusion ; heat effects
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Physics , Process Engineering, Biotechnology, Nutrition Technology
    Notes: Abstract This paper deals with frequency response (FR) analysis of a closed diffusion cell system with two resonators, that is both the LHS and RHS volumes are modulated. The analysis is made for a homogeneous particle described by a single effective diffusivity as well as a biporous pellet described by macropore and micropore diffusions. It is shown that if the perturbation of the volume of the reservoir #2 is lagged behind that of the reservoir #1 by 3π/2, the pressure response in reservoir #1 is significantly enhanced with larger amplitude as well as phase angle. When the perturbations of the two reservoirs are out of phase, the heat effect is reduced and can become insignificant when the two perturbations are completely out of phase (ψ = π). Under such a condition, the pressure difference between the two reservoirs could be doubled. In the case of biporous pellets, it is shown that the FR behaviours obtained for micropore diffusion control and macropore diffusion control are well distinguished. In the former case, the FR system reduces to a traditional batch adsorber one while in the latter case, the FR behaviour is the same as for a two resonator system with homogeneous particles. This difference can be used for the discrimination of micropore and macropore diffusion processes.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00879541
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  • 4
    Electronic Resource
    Electronic Resource
    Equilibria and kinetics characterisation of two different structured nutshell-derived activated carbons (1997)
    Springer
    Adsorption 3 (1997), S. 267-275 
    Details
    ISSN: 1572-8757
    Keywords: characterisation ; equilibria ; kinetics ; micropore size distribution ; n-butane ; nutshell
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Physics , Process Engineering, Biotechnology, Nutrition Technology
    Notes: Abstract Adsorption equilibria and dynamics ofn-butane on two activated carbon samples prepared from the physical activation of nutshell are studied in this paper. The micropore size distribution (MPSD) is considered as the main source of solid heterogeneity. Lennard-Jones' potential theory and Dubinin's theory (TVFM) are used in the equilibria data to derive the MPSD, which is well fitted by a Gamma distribution function. The adsorption energy distribution derived from the MPSD is very asymmetric for both the samples studied, and this energy distribution used in the HMSD/HMSMD kinetics models for the study of adsorption dynamics ofn-butane.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01653629
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  • 5
    Electronic Resource
    Electronic Resource
    Why Does the Linear Driving Force Model for Adsorption Kinetics Work? (2000)
    Springer
    Adsorption 6 (2000), S. 137-147 
    Details
    ISSN: 1572-8757
    Keywords: adsorption ; kinetics ; linear driving force model ; process design
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Physics , Process Engineering, Biotechnology, Nutrition Technology
    Notes: Abstract The Linear Driving Force (LDF) model for gas adsorption kinetics is frequently and successfully used for analysis of adsorption column dynamic data and for adsorptive process designs because it is simple, analytic, and physically consistent. Yet, there is a substantial difference in the characteristics of isothermal batch uptake curves on adsorbent particles by the LDF and the more rigorous Fickian Diffusion (FD) model. It is demonstrated by using simple model systems that the characteristics of the adsorption kinetics at the single pore or the adsorbent particle level are lost in (a) evaluating overall uptake on a heterogeneous porous solid, (b) calculating breakthrough curves from a packed adsorbent column, and (c) establishing the efficiency of separation by an adsorptive process due to repeated averaging of the base kinetic property. That is why the LDF model works in practice.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1023/A:1008965317983
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  • 6
    Electronic Resource
    Electronic Resource
    Sorption Equilibria and Kinetics of Hydrocarbons onto Activated Carbon Samples Having Different Micropore Size Distributions (1999)
    Springer
    Adsorption 5 (1999), S. 25-37 
    Details
    ISSN: 1572-8757
    Keywords: micropore size distribution ; activated carbon ; adsorption ; desorption ; equilibrium ; kinetics
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Physics , Process Engineering, Biotechnology, Nutrition Technology
    Notes: Abstract This paper deals with the prediction of adsorption equilibrium and kinetics of hydrocarbons onto activated carbon samples having different micropore size distribution (MPSD). The microporous structure of activated carbon is characterised by the distribution of slit-shaped micropores, which is assumed to be the sole source of surface heterogeneity. The interaction between adsorbate molecule and pore walls is described by the Lennard-Jones potential theory. Different adsorbates have access to different pore size range of activated carbon due to the size exclusion, a phenomenon could have a significant influence on both multicomponent equilibria and kinetics. Activated carbons with three different MPSDs are studied with ethane and propane as the two model adsorbates. The Heterogeneous Macropore Surface Diffusion model (HMSD) is employed to simulate adsorption kinetics. The simulation results show that the MPSD is an important factor affecting both the multicomponent equilibria and kinetics.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1023/A:1026481704926
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  • 7
    Electronic Resource
    Electronic Resource
    Static and Kinetic Studies on the Adsorption Behavior of Sulfadiazene (2000)
    Springer
    Adsorption 6 (2000), S. 349-357 
    Details
    ISSN: 1572-8757
    Keywords: sulfadiazene ; adsorption ; kinetics
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Physics , Process Engineering, Biotechnology, Nutrition Technology
    Notes: Abstract To investigate the nature of interactive forces between sulfadiazene molecules and alumina surface the experiments were performed for the adsorption of sulfadiazene (SD) from its aqueous sulution onto the alumina surfaces at 25 ± 0.2°C and the influence of factors such as increasing concentration of SD (4.0–20.0 × 10−3 mol cm−3), the time required for adsorption equilibrium, pH (2.0–12.0) and temperature (5–45°C) of the adsorption medium, the presence of ions like Cl−, SO2− 4 and PO3− 4 (0.01–0.30 M) and organic solvents (5% v/v) were observed on the course of adsorption of SD. Various adsorption and kinetic parameters such as adsorption coefficient, the rate constants for adsorption and desorption were also evaluated. The results of the above cited studies facilitated to formulate the mechanisms of interaction between SD and alumina surfaces. From application view point the present work may be a potential tool for an effective chromatographic separation of sulfa drugs from industrial effluents.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1023/A:1026517117239
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  • 8
    Electronic Resource
    Electronic Resource
    Pure and Binary Gas Adsorption Equilibria and Kinetics of Methane and Nitrogen on 4A Zeolite by Isotope Exchange Technique (1999)
    Springer
    Adsorption 5 (1999), S. 145-158 
    Details
    ISSN: 1572-8757
    Keywords: kinetics ; isotope-exchange ; nitrogen ; adsorption ; methane ; zeolite ; equilibria
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Physics , Process Engineering, Biotechnology, Nutrition Technology
    Notes: Abstract The Isotope Exchange Technique (IET) was used to simultaneously measure pure and binary gas adsorption equilibria and kinetics (self-diffusivities) of CH4 and N2 on pelletized 4A zeolite. The experiment was carried out isothermally without disturbing the adsorbed phase. CH4 was selectively adsorbed over N2 by the zeolite because of its higher polarizability. The multi-site Langmuir model described the pure gas and binary adsorption equilibria fairly well at three different temperatures. The selectivity of adsorption of CH4 over N2 increased with increasing pressure at constant gas phase composition and temperature. This curious behavior was caused by the differences in the sizes of the adsorbates. The diffusion of CH4 and N2 into the zeolite was an activated process and the Fickian diffusion model described the uptake of both pure gases and their mixtures. The self-diffusivity of N2 was an order of magnitude larger than that for CH4. The pure gas self-diffusivities for both components were constants over a large range of surface coverages (0 〈 θ 〈 0.5). The self-diffusivities of CH4 and N2 from their binary mixtures were not affected by the presence of each other, compared to their pure gas self-diffusivities at identical surface coverages.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1023/A:1008917308002
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  • 9
    Electronic Resource
    Electronic Resource
    Origin and thermal evolution of icy satellites (1995)
    Springer
    Surveys in geophysics 16 (1995), S. 533-591 
    Details
    ISSN: 1573-0956
    Keywords: Satellites ; Giant planets ; Origin ; Evolution
    Source: Springer Online Journal Archives 1860-2000
    Topics: Geosciences , Physics
    Notes: Abstract The paper reviews the problem of formation and evolution of the so-called “regular satellites “ of the giant planets, and it consists of two parts: the first describes the possible origin of the satellites, the second studies their evolution, attempting to stress the relations of the present status of the satellites with their evolutionary history. The formation of regular satellite systems around giant planets is probably related to the formation of the central planet. Some characteristics of regular satellite systems are quite similar, and suggest a common origin in a disk present around the central body. This disk can originate through different mechanisms which we will describe, paying attention to the so-called “accretion disk” model, in which the satellite-forming material is captured. The disk phase links the formation of the primary body with the formation of satellites. The subsequent stages of the disk's evolution can lead first to the formation of intermediate size bodies, and through the collisional evolution of these bodies, to the birth of satellite “embryos” able to gravitationally capture smaller bodies. Given the scenario in which icy satellites may be formed by homogeneous accretion of planetesimals made of a mixtures of ice and silicates, if no melting occurs during accretion, the satellites have a homogeneous ice-rock composition. For the smaller satellites this homogeneous structure should not be substantially modified; only sporadic local events, such as large impacts, can modify the surface structure of the smaller satellites. For the larger satellites, if some degree of melting appears during accretion, a differentiation of the silicate part occurs, the amount of differentiation and hence the core size depending on the fraction of gravitational potential energy retained during the accumulation process. Melting and differentiation soon after the accretion, for the larger satellites, could also depend on the convective evolution in presence of phase transitions and generate an intermediate rock layer, considerably denser than the underlying, still homogeneous core, and unstable to overturning on a geologic time scale. Moreover the liquid water mantle could be a transient feature because the mantle would freeze over several hundred million years. For these large bodies the stable configuration is expected to be one consisting of a silicate core and a mantle of mixed rock and ice.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00665684
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  • 10
    Electronic Resource
    Electronic Resource
    Evolution on a Smooth Landscape: The Role of Bias (1998)
    Springer
    Journal of statistical physics 90 (1998), S. 191-210 
    Details
    ISSN: 1572-9613
    Keywords: Evolution ; birth/death processes ; mean-field ; population dynamics
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Notes: Abstract The role of mutational bias in evolution on a smooth landscape is investigated. We consider both a finite-length genome where the bias increases linearly with the fitness, and an infinite genome with a fixed bias. We present simulations of finite populations in a waiting time model, showing both the nonequilibrium dynamics and the equilibrium fitness distributions that are reached. We compute the equilibrium analytically in several cases, using approximate direct solution of the master equations and truncated hierarchies.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1023/A:1023203818384
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  • 11
    Electronic Resource
    Electronic Resource
    Growth of Ordered Domains in a Computer Model Alloy with Lattice Misfit (1999)
    Springer
    Journal of statistical physics 95 (1999), S. 23-43 
    Details
    ISSN: 1572-9613
    Keywords: model alloy ; Monte Carlo ; elastic interactions ; phase separation ; kinetics
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Notes: Abstract We study via Monte Carlo simulations the influence of elastic interactions on the ordering and decomposition of a two-dimensional model binary alloy with antiferromagnetic nearest and ferromagnetic next nearest neighbor type interactions following a quench into the coexistence region. The elastic interaction leads to the development of a platelet morphology for the segregated ordered and disordered regions. A length scale characterizing the coarsening process follows a law of the type R=a+bt 1/3 with the growth b decreasing with the amount of ordered phase; this appears to be due to the presence of anti-phase boundaries between neighboring domains ordered on different sublattices which are difficult to eliminate. The application of uniaxial external stress results in “rafting” of the domains. Many of the simulation results are in agreement with experimentally observed effects in nickel-base superalloys.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1023/A:1004569209618
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  • 12
    Electronic Resource
    Electronic Resource
    Invariant kinetic approach to the description of a rock fracture process and induced seismic events (1996)
    Springer
    Pure and applied geophysics 147 (1996), S. 367-375 
    Details
    ISSN: 1420-9136
    Keywords: Induced seismicity ; kinetics ; rock fracture ; rockburst ; earthquake
    Source: Springer Online Journal Archives 1860-2000
    Topics: Geosciences , Physics
    Notes: Abstract Powerful seismic events, such as earthquakes and rockbursts, are caused by the accumulation of energy in rocks and loss of rock mass stability. Usually methods of their forecasting are based on the registration of anomalous behavior of geophysical fields. However an efficiency of this approach is low. The present paper proposes a kinetic approach to the description of rock fracture process, which can be used for the forecasting of seismic events and an investigation of structure and energy distributions in rock. 3-D and 1-D kinetic equations describing a process of cluster formation in rock were obtained. The equations are invariant to deformation conditions and to the scale level of events. They showed a good agreement with the results of field observations and laboratory experiments. It was also shown that these equations well describe the processes of earthquake, rockburst and rock sample failure preparation. Catalogues of rockbursts in mines were analyzed with the use of the kinetic equations to find out evidence of induced seismic events. The proposed approach makes it possible to reveal trends in rock behavior and thus predict the rock failure at different scale levels.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00877489
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  • 13
    Electronic Resource
    Electronic Resource
    Calcified tissues in the earliest vertebrates (1969)
    Springer
    Calcified tissue international 3 (1969), S. 107-124 
    Details
    ISSN: 1432-0827
    Keywords: Aspidin ; Bone ; Cartilage ; Dentine ; Evolution ; Fossil
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine , Physics
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF02058654
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  • 14
    Electronic Resource
    Electronic Resource
    The evolution of sweat glands (1991)
    Springer
    International journal of biometeorology 35 (1991), S. 180-186 
    Details
    ISSN: 1432-1254
    Keywords: Evolution ; Paleophysiology ; Primates ; Sweating ; Thermoregulation
    Source: Springer Online Journal Archives 1860-2000
    Topics: Geography , Physics
    Notes: Abstract Mammals have two kinds of sweat glands, apocrine and eccrine, which provide for thermal cooling. In this paper we describe the distribution and characteristics of these glands in selected mammals, especially primates, and reject the suggested development of the eccrine gland from the apocrine gland during the Tertiary geological period. The evidence strongly suggests that the two glands, depending on the presence or absence of fur, have equal and similar functions among mammals; apocrine glands are not primitive. However, there is a unique and remarkable thermal eccrine system in humans; we suggest that this system evolved in concert with bipedalism and a smooth hairless skin.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01049065
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  • 15
    Electronic Resource
    Electronic Resource
    Sequence similarities of glyceraldehyde-3-phosphate dehydrogenases, phosphoglycerate kinases, and pyruvate kinases are species optimal temperature-dependent (1998)
    Springer
    European biophysics journal 27 (1998), S. 409-410 
    Details
    ISSN: 1432-1017
    Keywords: Key words Sequence similarity ; Glyceraldehyde-3-phosphate dehydrogenase ; Phosphoglycerate kinase ; Pyruvate kinase ; Evolution ; Phylogeny
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Physics
    Notes: Abstract Data are presented that suggest enzyme sequence similarities among species are not solely a function of their evolutionary relationship. It is demonstrated that sequence similarities of glyceraldehyde-3-phosphate dehydrogenases, phosphoglycerate kinases, and pyruvate kinases from yeast, bacteria, mammals and a bird possess a significant species optimal thriving temperature dependence that crosses through conventional phylogenetic divisions. It is therefore suggested that species which are distantly related evolutionarily may possess some degree of enzyme sequence similarity if they happen to thrive at near the same optimal temperature; conversely, organisms which are closely related evolutionarily but function at radically different temperatures will possess a sequence dissimilarity that may mask the close relatedness.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/s002490050148
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  • 16
    Electronic Resource
    Electronic Resource
    Sodium channel opening as a precursor to inactivation (1989)
    Springer
    European biophysics journal 16 (1989), S. 321-325 
    Details
    ISSN: 1432-1017
    Keywords: Sodium currents ; inactivation ; kinetics ; channel gating
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Physics
    Notes: Abstract The time constant of the process producing the delay in Na inactivation development as determined by the two pulse method (τdelay) was extracted and compared to that of the slowest Na activation process τ3 for the I Na during the conditioning pulse of that same determination. τdelay and two pulse inactivation τc values were computer generated using a nonlinear least squares algorithm. τh and single pulse inactivation τh values were independently generated for each determination also with the aid of the computer using the same non-linear least squares algorithm. In one determination at 2 mV, τc was 4.68 and τdelay 0.494 ms while τh was 4.70 and τ3 0.491 ms for a τc/τh of 0.996 and a τdelay/τ3 of 1.006. Mean τdelay/τ3 from five determinations in four axons, both Cs and K perfused, and spanning a potential range of-27 to 2mV was 1.068. The precursor process to inactivation is channel opening. Some fraction of channels presumably inactivate via another route where prior channel opening is not required.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00257880
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  • 17
    Electronic Resource
    Electronic Resource
    Dimyristoylphosphatidic acid/cholesterol bilayers (1986)
    Springer
    European biophysics journal 13 (1986), S. 343-353 
    Details
    ISSN: 1432-1017
    Keywords: Lipid/cholesterol ; phase transition ; kinetics ; second order transition ; pressure jump relaxation
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Physics
    Notes: Abstract Lipid bilayers and monolayers composed of dimyristoylphosphatidic acid (DMPA) and cholesterol were characterized by differential scanning calorimetry and film balance measurements. Increasing cholesterol content decreases the bilayer phase transition temperature and enthalpy in a manner similar to that observed before for other lipid/cholesterol systems. In monomolecular films at the air-water interface cholesterol exhibits the well known condensing effect in the liquid-expanded phase, while the liquid-condensed phase is less affected. As with the bilayer phase transition, the transition temperature and change in area at the liquid-condensed to liquid-expanded phase transition, as measured from isobars at 25 dynes/cm, decreases with increasing cholesterol content. The kinetics of the phase transition of DMPA/cholesterol bilayers were measured using the pressure jump relaxation technique with optical detection. Three relaxation times were observed. The relaxation times and amplitudes pass through maximum values at the transition midpoint. With increasing cholesterol content the maximum values of the relaxation times decrease but not in a linear fashion. The time constants display an intermediate maximum at ca. 10% to 12 mol% cholesterol. This observation is discussed in terms of a possible change in the nature of the phase transition from first-order with phase separation to a continuous second-order transition. The dependence of the relaxation amplitudes on cholesterol content gave evidence for nucleation being the rate limiting step for the transition in this particular system.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00265670
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  • 18
    Electronic Resource
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    Stellar evolution and late type stars (1995)
    Springer
    Astrophysics and space science 230 (1995), S. 169-176 
    Details
    ISSN: 1572-946X
    Keywords: Late-type Stars ; Evolution ; Carbon Stars ; RV Tauri Stars
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Notes: Abstract The M, S and C stars may be placed in an evolutionary sequence on the basis of direct observation of the spectroscopic transitions on the AGB of rich intermediate-age clusters in the Magellanic Clouds, but some S and C stars cannot be accounted for in this way. The S stars inω Centauri owe their peculiarity to a primordial enrichment in s-process elements. The J-type (13C-rich) carbon stars originate in a different way to the ordinary cool N-type carbon stars. Some of them have silicate-rich circumstellar dust, contrary to expectation. Some of the carbon-rich RV Tauri stars also have silicate-rich dust and in both cases it may be organised in a disc. Observational evidence for gas and dust ejection by ordinary N-type carbon stars has been found and may be inferred for some RV Tauri stars.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00658177
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  • 19
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    Low-mass protostars and protostellar stages (1995)
    Springer
    Astrophysics and space science 224 (1995), S. 29-42 
    Details
    ISSN: 1572-946X
    Keywords: Protostars ; Evolution ; Infall ; Jets
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Notes: Abstract The use of sensitive receivers on large ground-based radiotelescopes such as the JCMT, the IRAM 30 m MRT, and the VLA has recently yielded significant progress in our observational understanding of low-mass protostars. Submillimeter continuum observations suggest that the youngest stellar objects detected in the near-/mid-IR range -the so-called Class I sources or “infrared protostars” - have only residual amounts of circumstellar material and are thus relatively evolved. At the same time, a smaller number of colder and more obscured YSOs - designated “Class 0” - characterized by virtually no emission below 10µm but strong submillimeter emission have been identified. These Class 0 or “submillimeter protostars” have not yet assembled the bulk of their final stellar mass, and correspond to the youngest protostar stage known to date (probable age ≲ 104 yr). Direct evidence for gravitational infall has been found in some of these sources confirming their protostellar nature. However, most (if not all) Class 0 protostars already drive highly collimated CO outflows.
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    URL: http://dx.doi.org/10.1007/BF00667817
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  • 20
    Electronic Resource
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    Conformational changes of Na,K-ATPase probed with eosin Y (1996)
    Springer
    Journal of fluorescence 6 (1996), S. 165-168 
    Details
    ISSN: 1573-4994
    Keywords: Cation binding ; fluorescence decay ; kinetics ; binding constants ; Na,K-ATPase ; eosin Y
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Notes: Abstract Time-resolved fluorescence and binding studies have been carried out on Na,K-ATPase in the presence of the fluorescent dye eosin Y to obtain thermodynamic and kinetic parameters for the interaction of the enzyme with different cations. Eosin Y binding is indicated by a 3 ns fluorescence decay process and is observed only in the presence of mono- and divalent cations. This type of cation binding is interpreted as a nonselective electrostatic interaction, with negatively charged groups of the enzyme providing a high-affinity eosin Y binding site. Eosin Y binding is observed only under conditions where the enzyme exists in the conformational state F1. The kinetic parameters of eosin Y binding have been determined employing stopped-flow fluorometry.
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    URL: http://dx.doi.org/10.1007/BF00732056
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  • 21
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    Determination of the rate of rapid lipid transfer induced by poly(ethylene glycol) using the SLM Fourier transform phase and modulation spectrofluorometer (1991)
    Springer
    Journal of fluorescence 1 (1991), S. 105-112 
    Details
    ISSN: 1573-4994
    Keywords: Phase fluorometry ; lipid exchange ; membrane fusion ; kinetics ; poly(ethylene glycol) ; diphenyl hexatrient
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Notes: Abstract Rate constants were determined for the transfer of the fluorescent lipid probe 1-palmitoyl-2-[[2-[4-(6-phenyl-trans-1,3,5-hexatrienyl)phenyl]ethyl] oxy]carbonyl]-3-sn-phosphatidylcholine (DPHpPC) between large, unilamellar extrusion vesicles composed either of dipalmitoyl phosphatidylcholine (DPPC) or of DPPC mixed with a small amount (0.5 mol%) of lyso phosphatidylcholine (Lyso PC). Transfer of the lipid probe in the presence of varying concentrations of poly(ethylene glycol) (PEG) was monitored using the SLM 48000-MHF Multi-Harmonic Fourier Transform phase and modulation spectrofluorometer to collect multifrequency phase and modulation fluorescence data sets on a subsecond time scale. The unique ability of this instrument to yield accurate fluorescence lifetime data on this time scale allowed transfer to be detected in terms of a time-dependent change in the fluorescent lifetime distribution associated with the lipid-like DPHpPC probe. This probe demonstrates two short fluoresence decay times (ca. 1.1–1.4 and 4.3–4.8 ns) in a probe-rich environment but a single long lifetime (ca. 7 ns) in a probe-poor environment. A simple two-state model for initial lipid transfer was used to analyze the multifrequency data sets collected over a 4-s time frame to obtain the time rate of change of the concentrations of donor and acceptor probe populations following rapid mixing of vesicles with PEG. The ability to measure fluorescence lifetimes on this time scale has allowed us to show that the of rate of lipid transfer increased dramatically at 35% PEG in both fusing and nonfusing vesicle systems. These results are interpreted in terms of a distinct interbilayer structure associated with intimate bilayer contact induced by high and potentially fusogenic concentrations of PEG.
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    DEDO: A specific, fluorescent inhibitor for spectroscopic investigations of Na,K-ATPase (1994)
    Springer
    Journal of fluorescence 4 (1994), S. 287-290 
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    ISSN: 1573-4994
    Keywords: Na,K-ATPase ; fluorescent inhibitor ; kinetics ; energy transfer
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Notes: Abstract The interaction between the fluorescent ouabain derivative DEDO and purified renal Na,K-ATPase (isolated from different animal species) is investigated. Equilibrium binding studies provide a pK value of about 7.5 and a stoichoimetric coefficient of 1. Nonmodified ouabain exhibits the same affinity to the rabbit enzyme; the enzyme originating from the other sources binds DEDO 10 times less strongly than ouabain. Kinetic studies indicate that this is the consequence of a 10 times higher dissociation rate constant of the complexes formed with DEDO. The fluorescence emission intensity of DEDO is enhanced, being dependent on the enzyme source. The single decay time of DEDO is 3 ns in the absence and 21 ns in the presence of the rabbit enzyme and 14 ns in the presence of the pig renal enzyme. This result suggests that the fluorophore of DEDO is bound to a very hydrophobic environment of the enzyme. Further characterization of the static fluorescence spectra provides evidence for energy transfer between Trp residues of the enzyme and DEDO. Distance estimations suggest that one or two Trp residues are likely to be located in the proximity of the fluorophore.
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    URL: http://dx.doi.org/10.1007/BF01881441
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    Stopped-flow fluorescence studies of the interaction of a mutant form of cytochrome b5 with lipid vesicles (1994)
    Springer
    Journal of fluorescence 4 (1994), S. 227-233 
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    ISSN: 1573-4994
    Keywords: Cytochrome b5 ; site-directed mutagenesis ; kinetics ; fluorescence ; membrane-binding
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Notes: Abstract Cytochrome b5 binds spontaneously to lipid vescles and also self-associates in aqueous solution. Two mutant proteins have been generated, one has a self-association constant which is less than that of the native protein, while the other has a larger self-association constant. All three proteins have Trp in the membrane-binding domain but as aqueous solutions of these proteins contain differing amounts of monomeric protein, the kinetics of fluorescence enhancement, when the proteins are mixed with lipid vesicles, are complex. Similar complex kinetics are seen when the Trp are quenched by the addition of bromolipid vesicles. The mutant which has Trp 108 and 112 both replaced by Leu does not self-associate and shows monoexponential stopped-flow fluorescence kinetics. Identical rate constants are seen with this mutant for fluorescence enhancement by POPC and fluorescence quenching by three bromolipids with bromines at the 6,7-, 9,10-, and 11,12-positions of thesn-2 acyl chain. This rate constant is only 1% of the calculated collisional rate constant and it is suggested that the reduced rate is caused by a reduction in the number of productive collisions rather than by a slow rate of penetration of the membrane-binding domain into the bilayer.
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    URL: http://dx.doi.org/10.1007/BF01878455
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    Global view of microstructural evolution: Energetics, kinetics and dynamical systems (1996)
    Springer
    Acta mechanica Sinica 12 (1996), S. 144-157 
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    ISSN: 1614-3116
    Keywords: microstructural evolution ; energetics ; kinetics ; dynamic system
    Source: Springer Online Journal Archives 1860-2000
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: Abstract An evolving material structure is in a non-equilibrium state, with free energy expressed by the generalized coordinates. A global approach leads to robust computations for the generalized thermodynamic forces. Those forces drive various kinetic processes, causing dissipation at spots, along curves, surfaces and interfaces, and within volumetric regions. The actual evolution path, and therefore the final equilibrium state, is determined by the energetics and kinetics. A virtual work principle links the free energy landscape and the kinetic processes, and assigns a viscous environment to every point on the landscape. The approach leads to a dynamical system that governs the evolution of generalized coordinates. The microstructural evolution is globally characterized by a basin map in the coordinate space; and by a diversity map and a variety map in the parameter space. The control of basin boundaries raises the issue of energetic and kinetic bifurcations. The variation of basin boundaries under different sets of controlling parameters provides an analytical way to plot the diversity maps of structural evolution.
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    Muonic atoms and muon-catalyzed fusion in inhomogeneous mixtures of hydrogen isotopes (1996)
    Springer
    Hyperfine interactions 101-102 (1996), S. 155-162 
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    ISSN: 1572-9540
    Keywords: muon ; muonic hydrogen ; muonic molecule ; deuterium ; tritium ; fusion ; solid target ; kinetics
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Notes: Abstract The emission of µd and µt atoms from multilayer solid targets consisting of the mixtures of hydrogen isotopes has been investigated with a kinetics model. The methods to study the elastic scattering of muonic atoms, muon transfer, and molecular formation reactions with µ-atomic beams are discussed.
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    URL: http://dx.doi.org/10.1007/BF02227617
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    Kinetics of muonic hydrogen drift in axial symmetric geometry (1996)
    Springer
    Hyperfine interactions 101-102 (1996), S. 163-167 
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    ISSN: 1572-9540
    Keywords: muon ; muonic hydrogen ; energy distribution ; kinetics
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Notes: Abstract The kinetics of muonic atoms of hydrogen isotopes in an axially symmetric trap is studied. The problem of the determination of the initial kinetic energy distribution of µp and µd atoms from time-of-flight spectra is discussed. The effects of the scattering of muonic atoms from gas and of the stopping distribution are evaluated. When the collision length is much larger than the target radius, the moments of the kinetic energy distribution are shown to be determined by the time-of-flight spectrum in a model-independent way.
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    Statistical Properties of Stimulated Raman Scattering in a Nonlinear Regime (2000)
    Springer
    Journal of applied spectroscopy 67 (2000), S. 981-989 
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    ISSN: 1573-8647
    Keywords: nonlinear regime of stimulated Raman scattering ; fluctuation ; Stokes radiation ; kinetics ; spectrum ; distribution function
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Notes: Abstract Statistical properties of the Raman scattering of an intense step pulse are investigated by numerical solution of the equations of a semi-classical theory with assignment of a random Gaussian distribution of the initial polarization over the sample. The probability density functions of the intensity, energy, delay time, and width of a Stokes pulse and also of the position, height, and width of the spectral peaks of the first incidental Stokes component with the preservation of the phase memory of scattering centers are calculated. The influence of collisional dephasing on the fluctuation of these characteristics is considered.
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    URL: http://dx.doi.org/10.1023/A:1004120404710
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    Cytochromec oxidase ofEuglena gracilis: Purification, characterization, and identification of mitochondrially synthesized subunits (1989)
    Springer
    Journal of bioenergetics and biomembranes 21 (1989), S. 359-373 
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    ISSN: 1573-6881
    Keywords: Cyrochromec oxidase ; kinetics ; subunit composition ; mitochondrially synthesized polypeptides ; Euglena gracilis
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Chemistry and Pharmacology , Physics
    Notes: Abstract Cytochromec oxidase was purified from mitochondria ofEuglena gracilis and separated into 15 different polypeptide subunits by polyacrylamide gel electrophoresis. All 15 subunits copurify through various purification procedures, and the subunit composition of the isolated enzyme is identical to that of the immunoprecipitated one. Therefore, the 15 protein subunits represent integral components of theEuglena oxidase. In anin vitro protein-synthesizing system using isolated mitochondria, polypeptides 1–3 were radioactive labeled in the presence of [35S]methionine. This further identifies these polypeptides with the three largest subunits of cytochromec oxidse encoded by mitochondrial DNA in other eukaryotic organisms. By subtraction, the other 12 subunits can be assigned to nuclear genes. The isolatedEuglena oxidase was highly active withEuglena cytochromec 558 and has monophasic kinetics. Using horse cytochromec 550 as a substrate, activity of the isolated oxidase was rather low. These findings correlate with the oxidase activity of mitochondrial membranes. Again, reactivity was low with cytochromec 550 and 35-fold higher with theEuglena cytochromec 558. The data show that the cytochromec oxidase of the protistEuglena is different from other eukaryotic cytochromec oxidases in number and size of subunits, and also with regard to kinetic properties and substrate specificity.
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    Functional properties of purified and reconstituted mitochondrial metabolite carriers (1993)
    Springer
    Journal of bioenergetics and biomembranes 25 (1993), S. 525-535 
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    ISSN: 1573-6881
    Keywords: Mitochondria ; transport ; carrier proteins ; reconstitution ; kinetics ; liposomes
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Chemistry and Pharmacology , Physics
    Notes: Abstract Eight mitochondrial carrier proteins were solubilized and purified in the authors' laboratories using variations of a general procedure based on hydroxyapatite and Celite chromatography. The molecular mass of all the carriers ranges between 28 and 34 kDa on SDS-PAGE. The purified carrier proteins were reconstituted into liposomes mainly by using a method of detergent removal by hydrophobic chromatography on polystyrene beads. The various carriers were identified in the reconstituted state by their kinetic properties. A complete set of basic kinetic data including substrate specificity, affinity, interaction with inhibitors, and activation energy was obtained. These data closely resemble those of intact mitochondria, as far as they are available from the intact organelle. Mainly on the basis of kinetic data, the asymmetric orientation of most of the reconstituted carrier proteins were established. Several of their functional properties are significantly affected by the type of phospholipids used for reconstitution. All carriers which have been investigated in proteoliposomes function according to a simultaneous (sequential) mechanism of transport; i.e., a ternary complex, made up of two substrates and the carrier protein, is involved in the catalytic cycle. The only exception was the carnitine carrier, where a ping-pong mechanism of transport was found. By reaction of particular cysteine residues with mercurial reagents, several carriers could be reversibly converted to a functional state different from the various physiological transport modes. This “unphysiological” transport mode is characterized by a combination of channel-type and carrier-type properties.
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    Temperature dependence of mitochondrial oligomycin-sensitive proton transport ATPase (1984)
    Springer
    Journal of bioenergetics and biomembranes 16 (1984), S. 391-406 
    Details
    ISSN: 1573-6881
    Keywords: OS-ATPase ; temperature effect ; kinetics ; lipid role ; membrane enzyme ; protein-lipid interaction (bovine mitochondria)
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Chemistry and Pharmacology , Physics
    Notes: Abstract The temperature dependence of the oligomycin-sensitive ATPase (complex V) kinetic parameters has been investigated in enzyme preparations of different phospholipid composition. In submitochondrial particles, isolated complex V, and complex V reconstituted in dimirystoyl lecithin vesicles, the Arrhenius plots show discontinuities in the range 18–28°C, while no discontinuity is detected with dioleoyl lecithin recombinant. Van't Hoff plots ofK m also show breaks in the same temperature interval, with the exception of the dioleoylenzyme vesicles, whereK m is unchanged. Thermodynamic analysis of the ATPase reaction shows that DMPC-complex V has rather larger values of activation enthalpy and activation entropy below the transition temperature (24°C) than those of the other preparations, while all enzyme preparations show similar free energies of activation (14.3–18.5 kcal/mol). The results indicate that temperature and lipid composition influence to a different extent both kinetic and thermodynamic parameters of ATP hydrolysis catalyzed by the mitochondrial ATPase.
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    Electron transfer from cytochromeb 5 to cytochromec (1995)
    Springer
    Journal of bioenergetics and biomembranes 27 (1995), S. 331-340 
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    ISSN: 1573-6881
    Keywords: Cytochromeb 5 ; cytochromec ; electron transfer ; kinetics ; ruthenium
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Chemistry and Pharmacology , Physics
    Notes: Abstract The reaction of cytochromeb 5 with cytochromec has become a very prominent system for investigating fundamental questions regarding interprotein electron transfer. One of the first computer modeling studies of electron transfer and protein/protein interaction was reported using this system. Subsequently, numerous studies focused on the experimental determination of the features which control protein/protein interactions. Kinetic measurements of the intracomplex electron transfer reaction have only appeared in the last 10 years. The current review will provide a summary of the kinetic measurements and a critical assessment of the interpretation of these experiments.
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    Kinetics of the Reconstituted Tricarboxylate Carrier from Eel Liver Mitochondria (1998)
    Springer
    Journal of bioenergetics and biomembranes 30 (1998), S. 555-563 
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    ISSN: 1573-6881
    Keywords: Tricarboxylate carrier ; mitochondria ; transport ; liposomes ; kinetics ; reconstitution ; eel
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Chemistry and Pharmacology , Physics
    Notes: Abstract The tricarboxylate carrier from eel liver mitochondria was purified by chromatography on hydroxyapatite and Matrix Gel Blue B and reconstituted into liposomes by removal of the detergent with Amberlite. Optimal transport activity was obtained by using a phospholipid concentration of 11.5 mg/ml, a Triton X-114/phospholipid ratio of 0.9, and ten passages through the same Amberlite column. The activity of the carrier was influenced by the phospholipid composition of the liposomes, being increased by cardiolipin and phosphatidylethanolamine and decreased by phosphatidylinositol. The reconstituted tricarboxylate carrier catalyzed a first-order reaction of citrate/citrate or citrate/malate exchange. The maximum transport rate of external [14C]citrate was 9.0 mmol/min per g of tricarboxylate carrier protein at 25°C and this value was virtually independent of the type of substrate present in the external or internal space of the liposomes. The half-saturation constant (K m) was 62 μM for citrate and 541 μM for malate. The activation energy of the citrate/citrate exchange reaction was 74 kJ/mol from 5 to 19°C and 31 kJ/mol from 19 to 35°C. The rate of the exchange had an external pH optimum of 8.
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    Transport of calcium by mitochondria (1994)
    Springer
    Journal of bioenergetics and biomembranes 26 (1994), S. 471-485 
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    ISSN: 1573-6881
    Keywords: Mitochondria ; transport ; calcium ; metabolic mediator ; kinetics ; calcium pulses
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Chemistry and Pharmacology , Physics
    Notes: Abstract The identification of intramitochondrial free calcium ([Ca2+ m) as a primary metabolic mediator [see Hansford (this volume) and Gunter, T. E., Gunter, K. K., Sheu, S.-S., and Gavin, C. E. (1994)Am. J. Physiol. 267, C313–C339, for reviews] has emphasized the importance of understanding the characteristics of those mechanisms that control [Ca2+]m. In this review, we attempt to update the descriptions of the mechanisms that mediate the transport of Ca2+ across the mitochondrial inner membrane, emphasizing the energetics of each mechanism. New concepts within this field are reviewed and some older concepts are discussed more completely than in earlier reviews. The mathematical forms of the membrane potential dependence and concentration dependence of the uniporter are interpolated in such a way as to display the convenience of consideringV max to be an explicit function of the membrane potential. Recent evidence for a transient rapid conductance state of the uniporter is discussed. New evidence concerning the energetics and stoichiometries of both Na+-dependent and Na+-independent efflux mechanisms is reviewed. Explicit mathematical expressions are used to describe the energetics of the system and the kinetics of transport via each Ca2+ transport mechanism.
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    Control of mitochondrial and cellular respiration by oxygen (1995)
    Springer
    Journal of bioenergetics and biomembranes 27 (1995), S. 583-596 
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    ISSN: 1573-6881
    Keywords: Oxygen limitation ; p 50 ; critical oxygen pressure ; respirometry ; polarographic oxygen sensor ; human endothelial cells ; rat liver mitochondria ; intracellular $$p_{O_2 } $$ ; oxygen gradients ; kinetics ; nonequilibrium thermodynamics
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Chemistry and Pharmacology , Physics
    Notes: Abstract Control and regulation of mitochondrial and cellular respiration by oxygen is discussed with three aims: (1) A review of intracellular oxygen levels and gradients, particularly in heart, emphasizes the dominance of extracellular oxygen gradients. Intracellular oxygen pressure, $$p_{O_2 } $$ , is low, typically one to two orders of magnitude below incubation conditions used routinely for the study of respiratory control in isolated mitochondria. The $$p_{O_2 } $$ range of respiratory control by oxygen overlaps with cellular oxygen profiles, indicating the significance of $$p_{O_2 } $$ in actual metabolic regulation. (2) A methodologically detailed discussion of high-resolution respirometry is necessary for the controversial topic of respiratory control by oxygen, since the risk of methodological artefact is closely connected with far-reaching theoretical implications. Instrumental and analytical errors may mask effects of energetic state and partially explain the divergent views on the regulatory role of intracellular $$p_{O_2 } $$ . Oxygen pressure for half-maximum respiration,p 50, in isolated mitochondria at state 4 was 0.025 kPa (0.2 Torr; 0.3 ΜM O2), whereasp 50 in endothelial cells was 0.06–0.08 kPa (0.5 Torr). (3) A model derived from the thermodynamics of irreversible processes was developed which quantitatively accounts for near-hyperbolic flux/ $$p_{O_2 } $$ relations in isolated mitochondria. The apparentp 50 is a function of redox potential and protonmotive force. The protonmotive force collapses after uncoupling and consequently causes a decrease inp 50. Whereas it is becoming accepted that flux control is shared by several enzymes, insufficient attention is paid to the notion of complementary kinetic and thermodynamic flux control mechanisms.
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    The role of the adenine nucleotide translocator in oxidative phosphorylation. A theoretical investigation on the basis of a comprehensive rate law of the translocator (1982)
    Springer
    Journal of bioenergetics and biomembranes 14 (1982), S. 45-61 
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    ISSN: 1573-6881
    Keywords: Mitochondria ; adenine nucleotide translocator ; kinetics ; metabolic control ; oxidative phosphorylation
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Chemistry and Pharmacology , Physics
    Notes: Abstract A minimum model of adenine nucleotide exchange through the inner membrane of mitochondria is presented. The model is based on a sequential mechanism, which presumes ternary complexes formed by binding of metabolites from both sides of the membrane. The model explains the asymmetric kinetics of ADP-ATP exchange as a consequence of its electrogenic character. In energized mitochondria, a part of the membrane potential suppresses the binding of extramitochondrial ATP in competition with ADP. The remaining part of the potential difference inhibits the back exchange of internal ADP for external ATP. The assumption of particular energy-dependent conformational states of the translocator is not necessary. The model is not only compatible with the kinetic properties reported in the literature about the adenine nucleotide exchange, but it also correctly describes the response of mitochondrial respiration to the extramitochondrial ATP/ADP ratio under different conditions. The model computations reveal that the translocation step requires some loss of free energy as driving force. The size of the driving force depends on the flux rate as well as on the extra- and intramitochondrial ATP/ADP quotients. By both quotients the translocator controls the export of ATP formed by oxidative phosphorylation in mitochondria.
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    Effect of trypsin on the kinetic properties of reconstituted beef heart cytochromec oxidase (1985)
    Springer
    Journal of bioenergetics and biomembranes 17 (1985), S. 375-384 
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    ISSN: 1573-6881
    Keywords: Cytochromec oxidase ; kinetics ; trypsin digestion ; reconstitution ; proteoliposomes
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Chemistry and Pharmacology , Physics
    Notes: Abstract Isolated beef heart cytochromec oxidase was reconstituted in liposomes by the cholate dialysis method with 85% of the binding site for cytochromec oriented to the outside. Trypsin cleaved specifically subunit VIa and half of subunit IV from the reconstituted enzyme. The kinetic properties of the reconstituted enzyme were changed by trypsin treatment if measured by the spectrophotometric assay but not by the polarographic assay. It is concluded that subunit VIa and/or subunit IV participate in the electron transport activity of cytochromec oxidase.
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    The effect of cAMP-dependent protein kinase phosphorylation on the external Ca2+ binding sites of cardiac sarcoplasmic reticulum (1983)
    Springer
    Journal of bioenergetics and biomembranes 15 (1983), S. 179-194 
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    ISSN: 1573-6881
    Keywords: Ca2+ binding ; Ca2+-Mg2+-ATPase ; sarcoplasmic reticulum ; cAMP ; protein kinase ; cooperativity ; cardiac muscle ; membrane protein ; kinetics
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Chemistry and Pharmacology , Physics
    Notes: Abstract Canine cardiac sarcoplasmic reticulum (SR) is known to be phosphorylated by adenosine 3′,5′-monophosphate (cAMP)-dependent protein kinase on a 22,000-dalton protein, Phosphorylation is associated with an increase in both the initial rate of Ca2+ uptake and the Ca2+-ATPase activity which is partially due to an increase in the affinity of the Ca2+-Mg2+-ATPase (E) of sarcoplasmic reticulum for calcium. In this study, the effect of cAMP-dependent protein kinase phosphorylation on the binding of calcium to the SR and on the dissociation of calcium from the SR was examined. The rate of dissociation of the E·Ca2 was measured directly and was not found to be significantly altered by cAMP-dependent protein kinase phosphorylation. Since the affinity of the enzyme for Ca2+ is equal to the ratio of the on and off rates of calcium, these results demonstrate that the observed change in affinity must be due to an increase in the rate of calcium binding to the Ca2+-Mg2+-ATPase of SR. In addition, an increase in the degree of positive cooperativity between the two calcium binding sites was associated with protein kinase phosphorylation.
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    Kinetic and regulatory aspects of the function of the alternative oxidase in plant respiration (1995)
    Springer
    Journal of bioenergetics and biomembranes 27 (1995), S. 387-396 
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    ISSN: 1573-6881
    Keywords: Plant mitochondria ; alternative oxidase ; kinetics ; regulation
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Chemistry and Pharmacology , Physics
    Notes: Abstract The kinetic modelling of the respiratory network in plant mitochondria is discussed, with emphasis on the importance of the choice of boundary conditions, and of modelling of both quinol-oxidising and quinone-reducing pathways. This allows quantitative understanding of the interplay between the different pathways, and of the functioning of the plant respiratory network in terms of the kinetic properties of its component parts. The effects of activation of especially succinate dehydrogenase and the cyanide-insensitive alternative oxidase are discussed. Phenomena, such as respiratory control ratios depending on the substrate, shortcomings of the Bahr and Bonner model for electron distribution between the oxidases and reversed respiratory control, are explained. The relation to metabolic control analysis of the respiratory network is discussed in terms of top-down analysis.
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    “Exchange diffusion”: Rate equations for the influx of α-aminoisobutyric acid into mouse cerebrum slices containing this amino acid (1985)
    Springer
    Journal of bioenergetics and biomembranes 17 (1985), S. 305-326 
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    ISSN: 1573-6881
    Keywords: α-Aminoisobutyric acid ; amino acids ; brain slices ; exchange diffusion ; kinetics ; membrane transitions ; rate equations ; transport
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Chemistry and Pharmacology , Physics
    Notes: Abstract Rate equations for the gross influx of α-aminoisobutyric acid (AIB) into mouse cerebrum slices containing AIB have a first-order term for unsaturable concentrative influx, identical to the corresponding term for unloaded slices, and a modified Michaelis-Menten term,V′max/(1+K t /S), for saturable concentrative influx. [V′max ≡v′ L (1+K t /S), wherev′ L =saturable component of influx,S=AIB concentration in medium, andK t =Michaelis constant for unloaded slices.] Below a tissue AIB (T) of 19 µmol/g final wet weight,V′max increases linearly followingV′max=V 1+m 1 T; above that value,V max is virtually constant. The transition is sharp. This equation is consistent with a carrier model for active transport. At the transition, intracellular AIB is about 1 molecule for every 70 amino acid residues of tissue protein, vastly more than could be accommodated by AIB-binding sites in cell membranes. The transition may come from a slow process that does not fill all sites when the tissue AIB is below the transition concentration, or from an AIB-induced phase transition in the membrane.
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    Phospholipid transfer proteins: Mechanism of action (1986)
    Springer
    Journal of bioenergetics and biomembranes 18 (1986), S. 71-91 
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    ISSN: 1573-6881
    Keywords: Phospholipid transfer protein ; phosphatidylcholine ; phosphatidyllinositol ; exchange ; net transfer ; lipid-protein interactions ; kinetics
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Chemistry and Pharmacology , Physics
    Notes: Abstract Phospholipid transfer proteins are generally localized in the cytosolic fraction of cells and are capable of catalyzing the flux of phospholipid molecules among membranes. Artificial membranes also participate in protein-catalyzed phospholipid movements. In this review the major phospholipid transfer proteins are discussed with respect to their phospholipid substrate specificity and the contributions of membrane physical properties to this process. The phenomenon of net transfer of phospholipids is described. The use of various kinetic approaches to the study of these catalysts is reviewed. A detailed consideration of the distinct phospholipid binding and membrane interaction domains of one phospholipid transfer protein is presented. Finally, some recent applications of phospholipid transfer proteins to the examination of membrane structure and function and further directions for the continued research activity with this class of proteins are summarized.
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    Control of the Mitochondrial Permeability Transition Pore by High-Affinity ADP Binding at the ADP/ATP Translocase in Permeabilized Mitochondria (2000)
    Springer
    Journal of bioenergetics and biomembranes 32 (2000), S. 91-96 
    Details
    ISSN: 1573-6881
    Keywords: Permeability transition ; ADP/ATP translocase ; kinetics ; adenosine diphosphate ; carboxya tractyloside ; bongkekic acid ; mitochondria
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Chemistry and Pharmacology , Physics
    Notes: Abstract Low levels of ADP binding at the ADP/ATP translocase caused inhibition of the Ca2+-inducedpermeability transition of the mitochondrial inner membrane, when measured using the shrinkage assay on mitochondria, which have already undergone a transition. Inhibition was preventedby carboxyatractyloside, but potentiated by bongkrekic acid, which increased the affinity forinhibition by ADP. This suggests that inhibition was related to the conformation of thetranslocase. Ca2+ addition was calculated to remove most of the free ADP. Ca2+ added after ADPinduced a slow decay of the inhibition, which probably reflected the dissociation of ADP fromthe translocator. We conclude that the probability of forming a permeability transition pore(PTP) is much greater when the translocase is in the CAT conformation than in the BKAconformation, and, in the absence of CAT and BKA, the translocator is shifted between theBKA and CAT conformations by ADP binding and removal, even in deenergized mitochondria with no nucleotide gradients.
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    URL: http://dx.doi.org/10.1023/A:1005568630151
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    Rate of opening of a population of Na channels in frog skeletal muscle fibers (1989)
    Springer
    Journal of biological physics 17 (1989), S. 75-94 
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    ISSN: 1573-0689
    Keywords: Na channels ; skeletal muscle ; kinetics
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Physics
    Notes: Abstract Linear Systems convolution analysis of muscle sodium currents was used to predict the opening rate of sodium channels as a function of time during voltage clamp pulses. If open sodium channel lifetimes are exponentially distributed, the channel opening rate corresponding to a sodium current obtained at any particular voltage, can be analytically obtained using a simple equation, given single channel information about the mean open-channel lifetime and current. Predictions of channel opening rate during voltage clamp pulses show that sodium channel inactivation arises coincident with a decline in channel opening rate. Sodium currents pharmacologically modified with Chloramine-T treatment so that they do not inactivate, show a predicted sustained channel opening rate. Large depolarizing voltage clamp pulses produce channel opening rate functions that resemble gating currents. The predicted channel opening rate functions are best described by kinetic models for Na channels which confer most of the charge movement to transitions between closed states. Comparisons of channel opening rate functions with gating currents suggests that there may be subtypes of Na channel with some contributing more charge movement per channel opening than others. Na channels open on average, only once during the transient period of Na activation and inactivation. After transiently opening during the activation period and then closing by entering the inactivated state, Na channels reopen if the voltage pulse is long enough and contribute to steady-state currents. The convolution model overestimates the opening rate of channels contributing to the steady-state currents that remain after the transient early Na current has subsided.
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    Evolution of the cometary cloud under the action of stellar perturbations (1996)
    Springer
    Earth, moon and planets 72 (1996), S. 31-34 
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    ISSN: 1573-0794
    Keywords: Oort Cloud ; Evolution ; Close Encounters
    Source: Springer Online Journal Archives 1860-2000
    Topics: Geosciences , Physics
    Notes: Abstract The probability of variation of the integrals of the orbit as a result of an encounter was found for a two dimensional system. A method of solution of the Kolmogorov-Feller's equation is obtained using this probability function as a kernel, and it allows us to obtain the distribution of the integrals of the orbit as a function of time. The method is applied to the investigation of the evolution of orbits in the outer cometary cloud under the action of galactic stars. We consider the variations of orbits as a purely discontinuous random process, so we take into account not only distant but also close interactions.
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    A simplified cooperative model of stress relaxation and other consolidation processes in solids (1992)
    Springer
    Rheologica acta 31 (1992), S. 390-398 
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    ISSN: 1435-1528
    Keywords: Bose-Einstein statistics ; relaxation ; aging ; kinetics ; relaxation time ; spectrum
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: Abstract This paper explores the properties of a relaxation function derived from a differential equation mimicking the distribution mechanism of Bose-Einstein statistics in the time domain. Within a significant portion of the process, the relaxation quantity n decreases linearly with log time. The relation between dn/dt and n is an exponential one. In this respect, the present approach produces results largely equivalent to those obtained using the hypothesis of stress-dependent thermal activation or a box-like spectrum of relaxation times, τ. The τ spectrum of the model proposed here is discrete, with integer valued fractions of a characteristic -centering the equations.
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    Evolution of massive close binaries (1993)
    Springer
    Space science reviews 66 (1993), S. 327-347 
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    ISSN: 1572-9672
    Keywords: Evolution ; Binaries
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Notes: Abstract This paper briefly reviews the competition between massive single star and massive close binary evolution the last two decades. The status of the binary evolutionary model is summarized, the assumptions and simplifications are critically discussed. Using all computations performed since 1970, general conclusions are drawn and a comparison with massive single star evolution is presented. Special attention is given at the assumptions behind the commonly accepted model for the mass gainer and a new accretion model is proposed. The binary results in combinarion with single star evolution are compared with observations of massive stars with emphasis on the HR diagram, star number counts, WR stars, SN 1987A, OBN and OBC stars.
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    Non-standard mixing in stars (1995)
    Springer
    Space science reviews 74 (1995), S. 363-367 
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    ISSN: 1572-9672
    Keywords: Stars ; Abundances ; Evolution ; Rotation ; Mixing
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Notes: Abstract One of the most powerful tests of the stellar evolution theory is analysis of stars' atmospheric chemical composition. It has shown that some non-standard mixing different from ordinary convection, semiconvection and convective overshooting seems to occur in stellar interiors. In the present study Zahn's rotationally induced turbulent diffusion is assumed to be responsible for such kind of mixing. We compare results of our evolutionary calculations with available observational data for massive main-sequence stars and red giants in globular clusters.
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    Double-zone model with diffusive mixing and the mass and helium discrepancies in OB-stars (1993)
    Springer
    Space science reviews 66 (1993), S. 405-408 
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    ISSN: 1572-9672
    Keywords: Early-Type Stars ; Abundances ; Evolution ; Rotation ; Mixing
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Notes: Abstract A model for massive main sequence (MS) stars is proposed that quantitatively accounts for the mass and helium discrepancies in luminous OB stars. The radiative envelope of the model consists of two zones being mixed by rotationally induced turbulent diffusion during the star's evolution on the MS. The rate of the mixing in the outer zone is assumed to be substantially lower than that in the inner zone. Both, the mass and helium discrepancy, are shown to be due to helium enrichment in the envelope produced by turbulent diffusion. Some arguments to support this double-zone stellar model are given.
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    Evolution of structure, order and complexity in biological systems: Part III of a general theory (1989)
    Springer
    Journal of biological physics 17 (1989), S. 109-125 
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    ISSN: 1573-0689
    Keywords: Evolution ; order ; complexity ; biological systems
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Physics
    Notes: Abstract In this, Part III of a general theory, the large-scale features of evolution of structure, order, and complexity are considered as characteristic features of the biological state of matter. This starts with a rigorous formal definition of structure, classes of structural order, complexity, measures of complexity, and how these arise through evolution by a cumulative process of storing information in memory systems. Three such memory systems have evolved: the genetic memory, the immune memory, and the memories of the nervous system. The evolution, characteristic parameters and the limitations of these memory systems are explored. From these considerations emerge the large-scale features of the evolutionary pathways of biological structure, function, and complexity.
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    Kinetic evidence for two Na channels in frog skeletal muscle (1990)
    Springer
    Journal of biological physics 17 (1990), S. 193-211 
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    ISSN: 1573-0689
    Keywords: Na channels ; skeletal muscle ; kinetics
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Physics
    Notes: Abstract The kinetics of voltage-clamped sodium currents were studied in frog skeletal muscle. Sodium currents in frog skeletal muscle activate and inactivate following an initial delay in response to a depolarizing voltage pulse. Inactivation occurs via a double exponential decay exhibiting fast and slow components for virtually all depolarizing pulses used. The deactivation of Na currents exhibits two exponential components, one decaying rapidly, while the other decays slowly in time; the relative amplitude of the two components changes with the duration of the activating pulse. The two deactivation phases remain after pharmacological elimination of inactivation. In individual fibers, the percent amplitude of the slow inactivation component correlates with the percent amplitude of the slow deactivation component. Tetrodotoxin differentially blocks the slow deactivation component. These observations are interpreted as the activation, inactivation and deactivation of two subtypes (fast and slow) of Na channels. Studies of the slow deactivation phase magnitude vs the duration of the eliciting pulse provide a way to determine the kinetics of the slow Na channel in muscle. Ammonium substitution for Na in the Ringer produces a voltage dependent activation and inactivation of current which exhibits only one decay phase, and eliminates the slow decay phase of current, suggesting that adjustments of the ionic environment of the channels can mask the presence of one of the channel subtypes.
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    Culture and evolution on populations of neural networks (1992)
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    Journal of statistical physics 69 (1992), S. 1137-1149 
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    ISSN: 1572-9613
    Keywords: Evolution ; neural networks ; self-organizing criticality
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Notes: Abstract Although acquired characteristics are not incorporated into the genotype, some works have pointed to the influence of learning in evolution. We present a dynamic model of neural networks presenting evolutive features, even without modification in genotype, due to the introduction of culture. Our model presents other features that seem to reproduce some aspects of real world populations.
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    Kinetics of Phase Ordering on Curved Surfaces (1999)
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    Journal of statistical physics 95 (1999), S. 949-979 
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    ISSN: 1572-9613
    Keywords: numerical simulations ; interface description ; kinetics ; phase ordering ; relaxation ; dynamical scaling ; model A ; curved surface ; lipid bilayer ; dominant length scale
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Notes: Abstract An interface description and numerical simulations of model A kinetics are used for the first time to investigate the intrasurface kinetics of phase ordering on corrugated surfaces. Geometrical dynamical equations are derived for the domain interfaces. The dynamics is shown to depend strongly on the local Gaussian curvature of the surface, and can be fundamentally different from that in flat systems: dynamical scaling breaks down despite the persistence of the dominant interfacial undulation mode; growth laws are slower than t 1/2 and even logarithmic; a new very-late-stage regime appears characterized by extremely slow interface motion; finally, the zero-temperature fixed point no longer exists, leading to metastable states. Criteria for the existence of the latter are derived and discussed in the context of more complex systems.
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    URL: http://dx.doi.org/10.1023/A:1004502500899
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    Quantum field methods in the theory of diffusion-controlled reactions (1985)
    Springer
    Journal of statistical physics 38 (1985), S. 347-359 
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    ISSN: 1572-9613
    Keywords: Diffusion ; reaction ; kinetics ; master equation ; perturbation methods
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Notes: Abstract The diagrammatic perturbation technique for the kinetic theory of classical reacting systems with diffusion is developed. It is further applied to investigation of recombination-type reactions in media of one, two, and three dimensions. The effective rates of this reaction are calculated, covering the whole range from the slow to the fast (diffusion-controlled) regimes.
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    Diffusion-annihilation and the kinetics of the Ising model in one dimension (1991)
    Springer
    Journal of statistical physics 65 (1991), S. 1235-1246 
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    ISSN: 1572-9613
    Keywords: Diffusion-annihilation ; Ising model ; kinetics
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Notes: Abstract The relationship between the one-dimensional kinetic Ising model at zero temperature and diffusion-annihilation in one dimension is studied. Explicit asymptotic results for the average domain size, average magnetization squared, and pair-correlation function are derived for the Ising model, for arbitrary initial magnetization. For the case of zero initial magnetization (m 0=0, a number of recent exact results for diffusion-annihilation with random initial conditions are obtained. However, for the casem 0 not equal to zero, the asymptotic behavior turns out to be different from diffusion-annihilation with random initial conditions and at a finite density. In addition, in contrast to the case of diffusion-annihilation, the domain-size distribution scaling functionh(x) is found to depend nontrivially on the initial magnetization. The origin of these differences is clarified and the existence of nontrivial correlations in the initial wall distribution for finite initial magnetization is found to be responsible for these differences. Results of Monte Carlo simulations for the domain size distribution function for different initial magnetizations are also presented.
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    Evolution on a smooth landscape (1997)
    Springer
    Journal of statistical physics 87 (1997), S. 519-544 
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    ISSN: 1572-9613
    Keywords: Evolution ; birth/death processes ; mean-field ; population dynamics
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Notes: Abstract We study in detail a recently proposed simple discrete model for evolution on smooth landscapes. An asymptotic solution of this model for long times is constructed. We find that the dynamics of the population is governed by correlation functions that although being formally down by powers ofN (the population size), nonetheless control the evolution process after a very short transient. The long-time behavior can be found analytically since only one of these higher order correlators (the two-point function) is relevant. We compare and contrast the exact findings derived herein with a previously proposed phenomenological treatment employing mean-field theory supplemented with a cutoff at small population density. Finally, we relate our results to the recently studied case of mutation on a totally flat landscape.
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    Cascade in muonic and pionic atoms with Z = 1 (1999)
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    Hyperfine interactions 119 (1999), S. 11-21 
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    ISSN: 1572-9540
    Keywords: exotic atom ; muonic hydrogen ; pionic hydrogen ; cascade ; kinetics
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Notes: Abstract Recent theoretical and experimental studies of the exotic atoms with Z = 1 are reviewed. An interplay between the atomic internal and external degrees of freedom is essential for a good description of the atomic cascade. The perspective of ab initio cascade calculations is outlined.
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    URL: http://dx.doi.org/10.1023/A:1012642215730
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    Efficiency of the muon catalyzed fusion in triple H/D/T mixtures (2000)
    Springer
    Hyperfine interactions 128 (2000), S. 481-493 
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    ISSN: 1572-9540
    Keywords: muon catalyzed fusion ; triple mixture ; kinetics
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Notes: Abstract In this paper, we solve numerically kinetic equations for the chain reactions of μCF in triple H/D/T mixture. Regarding the computational results, we show that μCF efficiency decreases by adding hydrogen H to D/T mixture. This is in contradiction to the usual belief which expects the increase of μCF efficiency in H/D/T mixture. Our results are confirmed by the first and recent experiment on μdt cycling rate in the triple mixture.
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    Solute segregation at grain boundaries (1996)
    Springer
    Interface science 3 (1996), S. 241-267 
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    ISSN: 1573-2746
    Keywords: grain boundary segregation ; grain boundary cohesion ; fracture ; kinetics ; equilibrium ; anisotropy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: Abstract This feature article summarizes the present art and science of grain boundary segregation from the viewpoint of the authors activities in this field. In the part on equilibrium segregation, fundamental effects on grain boundary segregation are discussed such as the nature of the solute/matrix binary system, presence of additional elements, temperature, grain boundary orientation and type of interface. In addition, the predictive capabilities of grain boundary segregation diagrams are outlined. The present models of segregation kinetics are reviewed and discussed in connection with recent experiments. The last part of the paper is focussed on the most important consequences of grain boundary segregation, i.e., grain boundary cohesion and fracture.
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    Grain Boundary Migration in Solid State Discontinuous Reactions (1998)
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    Interface science 6 (1998), S. 113-131 
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    ISSN: 1573-2746
    Keywords: discontinuous reactions ; discontinuous precipitation ; discontinuous coarsening ; discontinuous dissolution ; grain boundary ; migration ; diffusion ; kinetics ; mechanism
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: Abstract Discontinuous reactions are a special class of solid state moving boundary reactions characterized by a discontinuous change in orientation and composition across the migrating reaction front that provides a short circuit path of solute transport. Grain boundary migration in discontinuous reactions is both of technological as well as fundamental interest. In this paper, the initiation/growth mechanism, product morphology, driving force, reaction kinetics, and effect of external parameters on the major discontinuous reactions, namely, discontinuous precipitation, coarsening, dissolution, and diffusion induced grain boundary migration have been discussed. In addition, a number of interesting features about boundary migration in discontinuous reactions has been analyzed. Finally, the scope and necessity of continued research attention in this area have been highlighted.
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    The Compensation Effect in Thermally Activated Interface Processes (1998)
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    Interface science 6 (1998), S. 267-278 
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    ISSN: 1573-2746
    Keywords: grain boundaries ; kinetics ; thermal activation ; activation entropy ; activation enthalpy ; compensation effect ; interfaces
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: Abstract Extensive experimental evidence is provided for the occurrence of the compensation effect, i.e., the linear dependence of the activation energy on the logarithm of the preexponential factor in interface kinetics, primarily grain boundary migration. It is proposed to attribute the compensation effect to a first order phase transition from the ground state to the activated state during thermal activation. The model is in line with the thermodynamic principles of phase transitions as well as the fundamentals of irreversible thermodynamics. It is capable of accounting for important phenomenological relations of interface kinetics.
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    Viscosity of Strain Gradient Effects on the Kinetics of Propagating Phase Boundaries in Solids (1997)
    Springer
    Journal of elasticity 46 (1997), S. 53-90 
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    ISSN: 1573-2681
    Keywords: phase transitions ; kinetics ; traveling waves
    Source: Springer Online Journal Archives 1860-2000
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: Abstract The theory of thermoelastic materials undergoing solid-solid phase transformations requires constitutive information that governs the evolution of a phase boundary. This is known as a kinetic relation which relates a driving traction to the speed of propagation of a phase boundary. The kinetic relation is prescribed in the theory from the onset. Here, though, a special kinetic relation is derived from an augmented theory that includes viscous, strain gradient and heat conduction effects. Based on a special class of solutions, namely travelling waves, the kinetic relation is inherited from the augmented theory as the viscosity, strain gradient and heat conductivity are removed by a suitable limit process.
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    A consideration of curved interfaces in stress-assisted martensite formation (1996)
    Springer
    Journal of elasticity 44 (1996), S. 271-284 
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    ISSN: 1573-2681
    Keywords: martensite ; kinetics ; driving traction
    Source: Springer Online Journal Archives 1860-2000
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: Abstract A purely mechanical, sharp interface model is developed to consider curved interfaces that have been observed between martensite phase variants. The approach is based on a theory of small strains as distinct from small displacement gradients. It admits a realistic characterization of each phase with standard elasticity tensors and allows for inhomogeneous states of strain within each phase including inhomogeneous, finite rotations. The model indicates that any signficant interface curvature must be due to material rotation because interfaces cannot be finitely curved with respect to the material lattice. It is also found that the interface driving traction is not influenced by local lattice rotations unless inertia affects the reaction.
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    Electrochemical and Adsorption Studies on the Formation of Poly-8-Hydroxyquinaldine Thin Films at Glassy Carbon/Electrolyte Interface (2000)
    Springer
    Interface science 8 (2000), S. 111-121 
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    ISSN: 1573-2746
    Keywords: 8-hydroxyquinaldine ; electropolymerization ; adsorption ; glassy carbon ; kinetics
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: Abstract The kinetics and thermodynamics of the electropolymerization of the chelating agent 8-hydroxyquinaldine on GCE's (Glassy Carbon Electrodes') surface from aqueous phosphate buffers are reported. Thermodynamic functions related to the adsorption of the monomer on the GCE's surfaces were determinated. No contribution from GCE surface's functional group to the electropolymerization reactions was reported. The effects of monomer concentration, pH, and temperature on the electrochemical growth of poly 8-hydroxyquinaldine were investigated. The results suggest that the propagation of the electropolymerization process takes place via a free radical chain reactions. Furthermore, the results indicate that the electrochemical growth of the polymeric films is dictated by pre-polymerization adsorption on the electrode surface.
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    URL: http://dx.doi.org/10.1023/A:1008799724511
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