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  • 1
    Electronic Resource
    Electronic Resource
    Springer
    Der Anaesthesist 47 (1998), S. 2-3 
    ISSN: 1432-055X
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Type of Medium: Electronic Resource
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  • 2
    Electronic Resource
    Electronic Resource
    College Park, Md. : American Institute of Physics (AIP)
    The Journal of Chemical Physics 111 (1999), S. 8048-8067 
    ISSN: 1089-7690
    Source: AIP Digital Archive
    Topics: Physics , Chemistry and Pharmacology
    Notes: Two-dimensional adaptive umbrella sampling with the first umbrella coordinate equal to the potential energy of the system and the second umbrella coordinate equal to a function that discriminates important folded conformations from unfolded conformations is used to determine the equilibrium properties of complex biological systems. Compared to one-dimensional adaptive umbrella sampling with the potential energy as umbrella coordinate (multicanonical sampling), more reliable results can be obtained in certain cases. The method is applied to a helical peptide (RN24) with an analytical continuum solvent potential in combination with the PARAM19 force field of CHARMM. This effective potential energy function has been shown to describe the structural preferences of solvated peptides. With the two-dimensional approach and the deviation from the helical structure as the second umbrella coordinate, a converged description of the structural properties and the thermodynamics of the peptide RN24 is obtained. In particular, we find that the formation of the helix of RN24 occurs as a transition accompanied by a characteristic peak in the heat capacity. A formalism is described that uses the weighting factors obtained from a self-consistent solution of the weighted histogram analysis method equations to combine the results from a series of simulations with different biases and calculate the ensemble average of any dynamical variable as a function of the temperature without the need for extracting the density of states from the simulations. It is shown how the formalism can be used to calculate thermodynamic properties of the system. © 1999 American Institute of Physics.
    Type of Medium: Electronic Resource
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  • 3
    Electronic Resource
    Electronic Resource
    s.l. : American Chemical Society
    The @journal of physical chemistry 〈Washington, DC〉 97 (1993), S. 8343-8360 
    Source: ACS Legacy Archives
    Topics: Chemistry and Pharmacology , Physics
    Type of Medium: Electronic Resource
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  • 4
    ISSN: 1460-9568
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Medicine
    Notes: Stress induces analgesia by mechanisms within and outside the brain. Here we show that the sympathetic nervous system is an essential trigger of intrinsic opioid analgesia within peripheral injured tissue. Noradrenaline, injected directly into inflamed hind paws of male Wistar rats, produced dose-dependent antinociception, reversible by α1-, α2- and β2-antagonists. α1-, α2- and β2-adrenergic receptors were demonstrated on β-endorphin-containing immune cells and noradrenaline induced adrenergic receptor-specific release of β-endorphin from immune cell suspensions. This antinociceptive effect of noradrenaline was reversed by µ- and δ-opioid antagonists as well as by anti-β-endorphin. Stress-induced peripheral analgesia was abolished by chemical sympathectomy and by adrenergic antagonists. These findings indicate that sympathetic neuron-derived noradrenaline stimulates adrenergic receptors on inflammatory cells to release β-endorphin, which induces analgesia via activation of peripheral opioid receptors.
    Type of Medium: Electronic Resource
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  • 5
    Electronic Resource
    Electronic Resource
    Oxford, UK : Blackwell Publishing Ltd
    Family business review 5 (1992), S. 0 
    ISSN: 1741-6248
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Sociology , Economics
    Notes: This article discusses recently altered mandates for auditors considering an entity's ability to continue as a going concern. The authors evaluate the appropriateness of these standards in engagements involving family firms and conclude that existing procedures are inadequate to assess the risks unique to family businesses. A detailed checklist of questions is proposed as warning signals in family businesses about problems affecting the going-concern status.
    Type of Medium: Electronic Resource
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  • 6
    Electronic Resource
    Electronic Resource
    [s.l.] : Nature Publishing Group
    Nature medicine 9 (2003), S. 1003-1008 
    ISSN: 1546-170X
    Source: Nature Archives 1869 - 2009
    Topics: Biology , Medicine
    Notes: [Auszug] The treatment of severe pain with opioids has thus far been limited by their unwanted central side effects. Recent research promises new approaches, including opioid analgesics acting outside the central nervous system, targeting of opioid peptide–containing immune cells to peripheral damaged ...
    Type of Medium: Electronic Resource
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  • 7
    ISSN: 1476-4687
    Source: Nature Archives 1869 - 2009
    Topics: Biology , Chemistry and Pharmacology , Medicine , Natural Sciences in General , Physics
    Notes: [Auszug] Eukaryotic cells respond to many hormones and neurotransmitters with increased activity of the enzyme phospholipase C and a subsequent rise in the concentration of intracellular free calcium ([Ca2+]i). The increase in [Ca2+]i occurs ...
    Type of Medium: Electronic Resource
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  • 8
    Electronic Resource
    Electronic Resource
    Springer
    European archives of psychiatry and clinical neuroscience 243 (1994), S. 328-339 
    ISSN: 1433-8491
    Keywords: Typus melancholicus ; Typus migraenicus-Fixation on tidiness and orderliness ; Premorbid personality ; Unipolar depression ; Migraine ; Personality inventories ; Comparative class type
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary The present study tests the hypothesis that persons suffering from migraine show personality traits of the “typus melancholicus” (melancholy type, Tellenbach). Ninety-six migraineurs were compared to 115 normal subjects, 36 neurotics, 38 psychosomatic patients, 52 patients suffering from other pain disorders and 38 unipolar depressives, matched for sex, age and social status. Several already standardized personality inventories were used (MP-T, D-S, FAPK, IAF, GT-S), as well as a questionnaire constructed especially to record typus-melancholicus traits in migraineurs. The results of univariate and multivariate methods of comparison clearly confirmed the hypothesis. In contrast to normal subjects, neurotic, psychosomatic and pain patients, migraineurs showed significantly higher levels of typus-melancholicus traits, whereas they did not differ from the unipolar depressives in this respect.
    Type of Medium: Electronic Resource
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  • 9
    ISSN: 1432-2234
    Keywords: Key words: Helical peptide ; β-Hairpin ; Random coil ; Umbrella sampling ; Multicanonical sampling
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Abstract. To compare different implicit solvent potentials, the folding thermodynamics of the helical peptide RN24 and the β-hairpin peptide BH8 are studied by molecular dynamics simulation with adaptive umbrella sampling. As the potential energy functions, the analytical continuum solvent (ACS) potential and three simplified variants, termed EPSR1, EPSR4, and EPSR10, are used. The ACS potential is a combination of the standard CHARMM force field for the internal energy (bonds, angles, dihedrals) and the van der Waals energy with the analytical continuum electrostatic (ACE) potential and a non-polar solvation potential. The EPSR potentials differ from the ACS potential by the use of Coulomb's law with a distance-dependent dielectric function to calculate the electrostatic energy. With the ACS potential, quantitative agreement with experiment is obtained for the helix propensity (RN24: 62% calculated vs 50–60% experiment) and the β-hairpin propensity (BH8: 33% calculated vs 19–37% experiment) of the peptides. During the simulations with the EPSR potentials, no significant formation of secondary structure is observed. It is shown that the preference for coil conformations over conformations with secondary structure by the EPSR potentials is due to an overestimation of the energy of salt bridge formation, independent of the magnitude of the Coulomb energy relative to the other energy terms. Possible improvements of the distance-dependent dielectric functions which may permit their application to the simulation of peptide folding, are discussed.
    Type of Medium: Electronic Resource
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  • 10
    ISSN: 1432-2234
    Keywords: Key words: Adaptive umbrella sampling ; Multicanonical sampling ; Helical peptide ; β-hairpin
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Abstract. Adaptive umbrella sampling of the potential energy is used as a search method to determine the structures and thermodynamics of peptides in solution. It leads to uniform sampling of the potential energy, so as to combine sampling of low-energy conformations that dominate the properties of the system at room temperature with sampling of high-energy conformations that are important for transitions between different minima. A modification of the procedure for updating the umbrella potential is introduced to increase the number of transitions between folded and unfolded conformations. The method does not depend on assumptions about the geometry of the native state. Two peptides with 12 and 13 residues, respectively, are studied using the CHARMM polar-hydrogen energy function and the analytical continuum solvent potential for treatment of solvation. In the original adaptive umbrella sampling simulations of the two peptides, two and six transitions occur between folded and unfolded conformations, respectively, over a simulation time of 10 ns. The modification increases the number of transitions to 6 and 12, respectively, in the same simulation time. The precision of estimates of the average effective energy of the system as a function of temperature and of the contributions to the average effective energy of folded conformations obtained with the adaptive methods is discussed.
    Type of Medium: Electronic Resource
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