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  • 1
    Electronic Resource
    Electronic Resource
    Mitochondrial uncoupling agents (1975)
    Springer
    The journal of membrane biology 25 (1975), S. 361-380 
    Details
    ISSN: 1432-1424
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Chemistry and Pharmacology
    Notes: Summary Agents which uncouple oxidative phosphorylation in mitochondria were applied to identified neurons in an isolated ganglion of the marine molluscNavanax inermis. Aromatic monocarboxylic acids, acetanilides, benzamides, benzaldehydes and phenols all caused a rapid, reversible, dose-dependent increase in the membrane potential and conductance of the neurons tested. These events were due primarily to an increase in the membrane's conductance to potassium, relative to chloride. All active compounds also produced a reversible, dose-dependent decrease in the permeability of alkali-cations relative to potassium. The relative activity of congeners in each group of substances was directly correlated with the octanol-water partition coefficients of the various compounds, indicating that hydrophobicity was important in determining drug effect and suggesting that steric requirements were minimal. The results suggest that the observed changes in membrane electrical properties and cation selectivity are due to an increase in the membrane's anionic field strength caused by the hydrophobic interaction of anionic and nonionic agents with the neuronal membrane.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01868584
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  • 2
    Electronic Resource
    Electronic Resource
    Properties of Luminescent Si Nanoparticles in Sol-Gel Matrices (1998)
    Springer
    Journal of sol gel science and technology 11 (1998), S. 267-272 
    Details
    ISSN: 1573-4846
    Keywords: silicon nanoparticles ; photoluminescence ; fatty acids
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Abstract In this wor e preparation and properties of silica sol-gels incorporating luminescent Si nanocrystallites extracted from porous Si are described for the first time. These sol-gel/Si nanocrystallite composite materials are characterized by BET isotherm measurements, photoluminescence spectroscopy, and infrared spectroscopy. To stabilize the photoluminescence (PL) of Si crystallites within the silica matrix, a fatty acid (capric (C10), myristic (C14) or arachidic acid (C20)) is added as a passivation agent during the hydrolysis of tetraethoxysilane. The presence of the fatty acid is crucial to the long-term stability of the Si nanocrystallite luminescence, as the Si visible light emission remains essentially unchanged for more than a month when the fatty acid is present in the mixture but degrades quickly (within days) when absent. The thermal stability of the Si luminescence within the sol-gel is also reported. Fluorescence microscopy reveals that the light-emitting Si crystallites aggregate into micron-sized domains somewhat unevenly throughout the silica matrix. This distribution of Si crystallites can be improved by employing a surfactant, dioctyl sodium sulfosuccinate (DSS).
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1023/A:1008606312748
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  • 3
    Electronic Resource
    Electronic Resource
    Analysis of the parsley chalcone-synthase promoter in response to different light qualities (1994)
    Springer
    Planta 193 (1994), S. 275-282 
    Details
    ISSN: 1432-2048
    Keywords: Chalcone synthase ; Footprinting in vivo ; Gene expression (transient) ; Light regulation (UV-B photoreceptor, blue-light photoreceptor) ; Petroselinum
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract We examined the chalcone synthase (chs) promoter from parsley [Petroselinum crispum Miller (A.W. Hill)] for the existence of separate promoter elements responsible for transcriptional activation of the chs gene by UV-B and by blue light. A combination of in-vivo footprinting in parsley cells and light-induced transient expression assays with different chs promoter constructs in parsley protoplasts was used. Dark controls and bluelight-irradiated cells gave identical in-vivo footprints on the chs promoter. Pre-irradiation with blue light prior to a UV-B-light pulse is known to cause a shift in the timing of UV-B-light-induced increase in chs transcription rates. This shift was also manifested on the DNA template, since UV-B-light-induced in-vivo footprints in cells pretreated with blue light were detected earlier than in cells which had been irradiated with a UV-B-light pulse only. Although there was a clear shift in the timing of footprint appearance, the patterns of footprinting did not change. Light-induced transient-expression assays revealed that the shortest tested chs promoter which retained any light responsiveness, was sufficient for mediating both induction by UV light and the blue-light-mediated kinetic shift. These findings argue against a spatial separation of UV-B- and blue-light-responsive elements on the chs promoter. We interpret these data by postulating that the signal transduction pathways originating from the excitation of UV-B- and blue-light receptors merge at the chs promoter, or somewhere between light perception and protein-DNA interaction.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00192541
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  • 4
    Electronic Resource
    Electronic Resource
    Porosified Silicon Wafer Structures Impregnated With Platinum Anti-Tumor Compounds: Fabrication, Characterization, and Diffusion Studies (2000)
    Springer
    Biomedical microdevices 2 (2000), S. 265-272 
    Details
    ISSN: 1572-8781
    Keywords: porous silicon ; cis-platin ; drug delivery ; calcium phosphate ; carbo-platin
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine , Technology
    Notes: Abstract In this work, the incorporation and characterization of cis-platin (cis-diammine dichloroplatinum(II)), carbo-platin [cis-diammine(cyclobutane-1,1-dicarboxylato] platinum(II)), and Pt(en)Cl2 (ethylenediamminedichloro platinum(II)) within layers of calcium phosphate on porous Si/Si substrates are described. These materials have been characterized by scanning electron microscopy, secondary ion mass spectrometry, and X-ray energy dispersive spectroscopy. The diffusion of platinum species from the doped calcium phosphate layers has also been investigated by UV-visible absorption spectrometry and inductively-coupled plasma spectroscopy. The influence of initial platinum concentration, the impact of thermal annealing of the calcium phosphate/porous Si/Si matrix, as well as the effect of varying the ligand coordination sphere of the Pt complex on its ability to be delivered to the surroundings have also been analyzed. For the case of cis-platin, it is found that increasing the concentration of platinum complex in the electrolyte during cathodic growth of calcium phosphate results in a relatively greater concentration of Pt incorporated into the calcium phosphate layers and a larger amount of Pt which subsequently can be delivered to the surrounding medium upon exposure to solvent.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1023/A:1009951121205
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  • 5
    Electronic Resource
    Electronic Resource
    Approaches for Generating Mesoscale Patterns of Semiconductor Nanoclusters (1997)
    Springer
    Journal of cluster science 8 (1997), S. 159-178 
    Details
    ISSN: 1572-8862
    Keywords: Mesoscale patterns ; cadmium selenide
    Source: Springer Online Journal Archives 1860-2000
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: Abstract In this review, existing approaches for the manipulation and/or construction of isolated semiconductor nanoclusters into deliberate, patterned arrays are described. Diverse examples of different strategies from solid state, solution, and hybrid combinations are described as well as successes achieved to date. The approaches to be discussed include conventional solid state lithography, volumetric constriction of monodisperse nanoclusters deposited from solution, and the use of anchored macromolecular templates to direct semiconductor nanocluster assembly.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1023/A:1022679923799
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  • 6
    Electronic Resource
    Electronic Resource
    Thermochemical Passivation of DNA-Stabilized Q-Cadmium Sulfide Nanoparticles (2000)
    Springer
    Journal of cluster science 11 (2000), S. 359-372 
    Details
    ISSN: 1572-8862
    Keywords: cadmium sulfide ; quantum dots ; DNA stabilized
    Source: Springer Online Journal Archives 1860-2000
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: Abstract In this work, the conditions required to transform quantum-confined cadmium sulfide (Q-CdS) nanoparticles stabilized by calf thymus deoxyribonucleic acid from deep trap photoluminescent states to “band edge”-type luminescence are probed. The presence of fivefold excess sulfide relative to cadmium concentration during cluster synthesis, followed by mild heating at 80°C, results in the desired transformation of the Q-CdS emission spectrum. We also indirectly analyze the accompanying structural changes in the polymeric stabilizer, accomplished in this case by use of well-known spectrofluorometric methods with the dyes ethidium bromide and trisphenanthroline ruthenium(II).
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1023/A:1009049823345
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  • 7
    Electronic Resource
    Electronic Resource
    The one-to-one shortest-path problem: An empirical analysis with the two-tree Dijkstra algorithm (1993)
    Springer
    Computational optimization and applications 2 (1993), S. 47-75 
    Details
    ISSN: 1573-2894
    Keywords: Shortest-paths ; parallel algorithms
    Source: Springer Online Journal Archives 1860-2000
    Topics: Computer Science
    Notes: Abstract Four new shortest-path algorithms, two sequential and two parallel, for the source-to-sink shortest-path problem are presented and empirically compared with five algorithms previously discussed in the literature. The new algorithm, S22, combines the highly effective data structure of the S2 algorithm of Dial et al., with the idea of simultaneously building shortest-path trees from both source and sink nodes, and was found to be the fastest sequential shortest-path algorithm. The new parallel algorithm, PS22, is based on S22 and is the best of the parallel algorithms. We also present results for three new S22-type shortest-path heuristics. These heuristics find very good (often optimal) paths much faster than the best shortest-path algorithm.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01299142
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  • 8
    Electronic Resource
    Electronic Resource
    The singly constrained assignment problem: A Lagrangian relaxation heuristic algorithm (1994)
    Springer
    Computational optimization and applications 3 (1994), S. 7-26 
    Details
    ISSN: 1573-2894
    Keywords: network programming ; assignment ; integer programming
    Source: Springer Online Journal Archives 1860-2000
    Topics: Computer Science
    Notes: Abstract This manuscript presents a new heuristic algorithm to find near optimal integer solutions for the singly constrained assignment problem. The method is based on Lagrangian duality theory and involves solving a series of pure assignment problems. The software implementation of this heuristic, ASSIGN+1, successfully solved problems having one-half million binary variables (assignment arcs) in less than 17 minutes of wall clock time on a Sequent Symmetry S81 using a single processor. In computational comparisons with MPSX and OSL on an IBM 3081D, the specialized software was from 100 to 1,000 times faster. In computational comparisons with the specialized code of Mazzola and Neebe, we found that ASSIGN+1 was 40 times faster. In computational comparisons with our best alternating path specialized code, we found that ASSIGN+1 was more than three times faster than that code. This new software proved to be very robust as well as fast. The robustness is due to an elaborate scheme used to update the Lagrangean multipliers and the speed is due to the fine code used to solve the pure assignment problems. We also present a modification of the algorithm for the case in which the number of jobs exceeds the number of men along with an empirical analysis of the modified software.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01299389
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  • 9
    Electronic Resource
    Electronic Resource
    Foreword (1989)
    Springer
    Annals of operations research 20 (1989), S. XIII 
    Details
    ISSN: 1572-9338
    Source: Springer Online Journal Archives 1860-2000
    Topics: Mathematics , Economics
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF02216921
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  • 10
    Electronic Resource
    Electronic Resource
    The singly constrained assignment problem: An AP basis algorithm (1995)
    Springer
    Computational optimization and applications 4 (1995), S. 347-374 
    Details
    ISSN: 1573-2894
    Keywords: mathematical programming ; assignment ; networks
    Source: Springer Online Journal Archives 1860-2000
    Topics: Computer Science
    Notes: Abstract This manuscript presents a specialized primal simplex algorithm to obtain near optimal integer solutions for the singly constrained assignment problem. An optimal solution for the continuous relaxation of the problem is obtained by generalizing the alternating basis algorithm of Barr, Glover, and Klingman for the pure assignment problem. Near optimal integer solutions are obtained by pivoting into the optimal basis the slack variable associated with the side constraint. Our empirical analysis indicated that for our test problems the soft-ware implementation of this algorithm was six times faster than CPLEX and four times faster than NETSIDE (a specialized code for network problems with side constraints). The integer solutions obtained in our tests were typically within 2% of the optimum of the continuous relaxation.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01300862
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