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  • 1
    Electronic Resource
    Electronic Resource
    College Park, Md. : American Institute of Physics (AIP)
    The Journal of Chemical Physics 113 (2000), S. 11071-11078 
    ISSN: 1089-7690
    Source: AIP Digital Archive
    Topics: Physics , Chemistry and Pharmacology
    Notes: Recent calculations on the rigid rotor surface for the LiH–He interaction [B. K. Taylor and R. J. Hinde, J. Chem. Phys. 111, 973 (1999)] surmised that the well depth and anisotropy of the new surface differ substantially from the latest valence bond calculations for the same system [F. A. Gianturco, S. Kumar, S. K. Pathak, M. Raimondi, M. Sironi, J. Gerratt, and D. L. Cooper, Chem. Phys. 215, 227 (1997)]. We examine in detail the performance of both these potential energy surfaces once employed to generate quantum observables which can be compared with experiments. Our computations clearly show that the two surfaces exhibit small differences in their short-range repulsive anisotropy and larger differences in well depths. The latter however cannot be assessed as yet from existing experiments. The different behavior of their wells in supporting van der Waals bound states is also examined and spectroscopic experiments are suggested for detecting possible transitions between such states. © 2000 American Institute of Physics.
    Type of Medium: Electronic Resource
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  • 2
    Electronic Resource
    Electronic Resource
    Oxford, UK; Malden, USA : Blackwell Publishing Ltd/Inc.
    Experimental dermatology 13 (2004), S. 0 
    ISSN: 1600-0625
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Medicine
    Notes: The hair follicle offers an exquisite model for the experimental exploration of key issues of cutaneous neuroimmunology, for example, how local, intracutaneous and systemic stress–response systems are integrated with the skin immune system and with epithelial–mesenchymal interactions (as they occur during hair follicle growth and cycling). Previously, we had shown that skin mast cells, which operate as central switchboards of inflammation and tissue remodelling, also are important regulators of hair growth in mice and that endogenous, immunomodulatory mast cell secretagogues are potent hair growth modulators. This is true both for secretagogues that are generated by the hair follicle epithelium itself (e.g. ACTH) and for mast cell-activating neuropeptides synthesized by the sensory hair follicle innervation (e.g. SP). Also, we had shown that the prototypic stress-associated neuropeptide, SP, plays a crucial role in mediating the hair growth-inhibitory, mast cell-activating, inflammation- and catagen-promoting properties of chronic psychoemotional stress on murine hair follicles. Now, we show that the immunomodulatory and mast cell-activating neurotrophin, NGF, is also crucially involved in mediating the inhibitory effects of stress on murine hair growth. Furthermore, the central, stress-related neurohormone CRH, a recognized mast cell secretagogue which is expressed by the hair follicle epithelium, also is a hair growth inhibitor and activates a fully functional peripheral equivalent of the hypothalamic-pituitary-adrenal axis within organ-cultured human scalp hair follicles, including the synthesis and secretion of cortisol as well as the induction of classical feedback loops. We also demonstrate that one of the melanocortins whose intrafollicular synthesis is stimulated by CRH (α-MSH) is a potent suppressor of MHC class I expression in situ and is thus capable of restoring the collapsed immune privilege of human anagen hair bulbs, while SP upregulates the ectopic expression of MHC class I, thus endangering the hair follicle immune privilege. Finally, we show that vanilloids long exploited as experimental tools for neuroimmunological research in the skin (capsaicin) can, in fact, directly modulate human hair growth via the stimulation of vanilloid receptors (VR1) expressed by the follicle epithelium, in addition to stimulating vanilloid expressed by skin mast cells. Therefore, the hair follicle offers an ideal, highly instructive and clinically most relevant research model for dissecting how nervous system, central and peripheral (neuro-) endocrine signalling loops and the immune system interact in order to adapt skin functions to changing environmental conditions (e.g. in response to external stressors, by alterating, e.g. keratinocyte proliferation/apoptosis, skin immune status, as well as defined cutaneous metabolic and endocrine activities).
    Type of Medium: Electronic Resource
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  • 3
    Electronic Resource
    Electronic Resource
    Oxford, UK : Blackwell Publishing Ltd
    Journal of interventional cardiology 13 (2000), S. 0 
    ISSN: 1540-8183
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Medicine
    Notes: Early diagnosis and risk stratification of patients presenting to the emergency room for a suspected acute coronary syndrome is an emerging problem. In general, diagnosis is based on an ECG, clinical presentation, and elevated cardiac markers. In the past decade cardiac troponins and myoglobin have been identified as important markers for the global assessment and treatment of patients with acute coronary syndromes. Recent studies have identified patients with increased troponin I and T levels as a high risk population gaining benefit from the adjunctive treatment with glycoprotein (GP) IIb/IIIa receptor antagonists or low molecular weight heparin. Myoglobin was introduced as a sensitive marker of successful or failed reperfusion following thrombolytic therapy. These studies indicate that cardiac markers are important tools in the risk stratification of patients with acute coronary syndromes allowing adequate treatment decisions. However, certain limitations of cardiac markers have to be considered. These limitations mainly refer to the delay in time from presentation to the emergency room to the availability of the results of the blood sample. Thus, in the individual case, especially if an ECG and clinical presentation are unspecific or there is doubt concerning the success of thrombolytic therapy, early angiography remains the gold standard for diagnosis and establishment of adequate therapy. In this setting, early reperfusion by percutaneous coronary interventions will increase myocardial salvage, and therefore, should be preferred to the delayed confirmation of the diagnosis by repeated determination of cardiac markers.
    Type of Medium: Electronic Resource
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  • 4
    Electronic Resource
    Electronic Resource
    Oxford, UK : Blackwell Publishing Ltd
    Pacing and clinical electrophysiology 23 (2000), S. 0 
    ISSN: 1540-8159
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Medicine
    Notes: The analysis oft wave alternans (TWA) was introduced to identify patients with an increased risk of ventricular tachyarrhythmias. The inducibility of ventricular tach-yarrhythmias and the spontaneous arrhythmic events are correlated with a positive TWA in patients with a reduced left ventricular ejection fraction and survived myocardial infarction. In contrast, this study is the first to investigate the correlation of a survived sudden cardiac death and TWA in patients without coronary heart disease and only slightly decreased left ventricular function. Sixty patients were included in the study. The TWA analysis was performed using the Cambridge Heart system (CH2000). Patients were sitting on a bicycle ergometer and exercised with a gradual increase of workload to maintain a heart rate of at least 105 beats/min. The exercise test was stopped after recording 254 consecutive low noise level heart beats. The electrocardiographic signals were digitally processed using a spectral analysis method. The magnitude of TWA was measured at a frequency of 0.5 cycles/beat. A TWA was defined as positive if the ratio between TWA and noise level was 〉 3.0 and the amplitude of the TWA was 〉 1.8 μV. Twelve (20%) of the included 60 patients showed a positive TWA. The sensitivity concerning a previous arrhythmic event amounted to 65%, the specificity up to 98%, respectively. The alternans ratio was significantly higher in patients with a previous event (30.3 ± 53.2 vs 2.9 ± 5.9, P 〈 0.001) and cumulative alternans voltage (4.67 ± 3.55 vs 1.75 ± 1.88 μV, P 〈 0.001). In 19 patients, invasively investigated by an electro-physiological study, a significant correlation between inducibility of tachyarrhythmias and a positive TWA result was found (Spearman R = 0.51, P = 0.01). In conclusion, the TWA analysis seems to identify patients with nonischemic Cardiomyopathy who are at an increased risk of ventricular tachyarrhythmias.
    Type of Medium: Electronic Resource
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  • 5
    ISSN: 1540-8159
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Medicine
    Notes: For evaluation of patients with an increased risk of sudden cardiac death, the analyses of ventricular late potentials, heart rate variability, and baroreflexsensitivity are helpful. But so far, the prediction of a malignant arrhythmic event is not possible with sufficient accuracy, For a better risk stratification other methods are necessary. In this study the importance of the ChRS for the identification of patients at risk for ventricular tachyarrhythmic events should be investigated. Of 41 patients included in the study, 26 were survivors of sudden cardiac arrest. Fifteen patients were not resuscitated, of whom 6 patients had documented monomorphic ventricular tachycardia and 9 had no ventricular tachyarrhythmias in their prior history. All patients had a history of an old myocardial infarction (〉 1 year ago). For determination of the ChRS the ratio between the difference of the RR intervals in the ECG and the venous pO2 before and after a 5-minute oxygen inhalation via a nose mask was measured (ms/mmHg). The 26 patients with survived sudden cardiac death showed a significantly decreased ChRS compared to those patients without a tachyarrhythmic event (1.74 ± 1.02 vs 6.97 ± 7.14 ms/mmHg, P 〈 0.0001). The sensitivity concerning a survived sudden cardiac death amounted to 88% for a ChRS below 3.0 ms/mmHg. During a 12-month follow-up period, the ChRS was significantly different between patients with and without an arrhythmic event (1.64 ± 1.06 vs 4.82 ± 5.83 ms/mmHg, P 〈 0.01). As a further method for evaluation of patients with increased risk of sudden cardiac death after myocardial infarction the analysis of ChRS seems to be suitable and predicts arrhythmias possibly more sensitive than other tests of neurovegetative imbalance. The predictive importance has to be examined by prospective investigations in larger patient populations.
    Type of Medium: Electronic Resource
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  • 6
    ISSN: 1600-0625
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Medicine
    Notes: The functional role of VR1, which we and others have recently identified on several epithelial and mesenchymal human skin cell populations, was investigated in the human hair follicle (HF), as a prototypic epithelial–mesenchymal interaction system. VR1 immunoreactivity was confined to distinct epithelial compartments of HFs in anagen and catagen, while dermal papilla fibroblasts and HF melanocytes were VR1 negative. In organ culture, VR1 activation by capsaicin resulted in a dose-dependent and VR1-specific inhibition of hair shaft elongation, suppression of proliferation, promotion of apoptosis, and induction of catagen transformation, possibly due to upregulation of a potent hair growth inhibitor TGFβ2. Cultured outer root sheath (ORS), as well as HaCaT, keratinocytes also expressed functional VR1, whose stimulation inhibited proliferation, induced apoptosis, and elevated intracellular calcium concentration. Finally, VR1 stimulation of cultured ORS keratinocytes upregulated the expression of recognized endogenous hair growth inhibitors (IL-1β and TGFβ2) and downregulated the expression of stimulators (HGF, IGF-1, and SCF), while key differentiation markers (CK17, CK14, filaggrin, and involucrin) remained unaffected. In conclusion, VR1 is a significant novel player in human hair growth control underscoring that its physiological functions in human skin far extend beyond sensory neuron-coupled nociception.
    Type of Medium: Electronic Resource
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  • 7
    Electronic Resource
    Electronic Resource
    Springer
    The European physical journal 15 (2001), S. 321-329 
    ISSN: 1434-6079
    Keywords: PACS. 34.20.-b Interatomic and intermolecular potentials and forces, potential energy surfaces for collisions – 34.20.Gj Intermolecular and atom-molecule potentials and forces – 34.50.-s Scattering of atoms and molecules
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Notes: Abstract: The interaction between LiH and H has been calculated using a Coupled Cluster approach in view of examining the strength of the coupling between the impinging atom and the rovibrational LiH states in low energy collision regimes. The potential energy surface was thus obtained by considering not only the angular anisotropy but also the dependence of the interaction energy on the vibrational motion of the LiH molecule, hence producing the strength of the vibrational coupling. The main objective is that of gaining a realistic description of the interaction in the sub-reactive region. The results of our calculations show here that this interaction should be used in conjunction with that of the reactive configurational space because of the strong coupling between the non-reactive and the reactive channels in the present system makes the full reactive scattering calculations a more reliable way to obtain realistic cross-sections also for inelastic relaxation and excitation processes.
    Type of Medium: Electronic Resource
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  • 8
    ISSN: 1434-6079
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Notes: Abstract. The quantum treatment of the collisional excitation of rotations in H2 and N2 gases as test molecules is carried out within a space-fixed frame of reference by solving the multichannel close-coupled equations using an approach newly developed in our group, i.e. the modified variable phase approximation (MVPA). The interaction potentials contain the static, exchange and correlation-polarisation contributions and are obtained via a local, multipolar expansion formulation from ab initio data. The results are compared with existing experiments and produce numerically converged rotationally inelastic cross-sections obtained from an exact molecular-frame treatment of the problem.
    Type of Medium: Electronic Resource
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