| 1. |
- Björneholm, O., et al.
(author)
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Doppler splitting of in-flight auger decay of dissociating oxygen molecules : The localization of delocalized core holes
- 2000
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In: Physical Review Letters. - : AMERICAN PHYSICAL SOC. - 0031-9007 .- 1079-7114. ; 84:13, s. 2826-2829
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Journal article (peer-reviewed)abstract
- By exploiting the core-excitation-induced dissociation of O-2, we find that the Auger emission exhibits a Doppler-like energy shift. We show this to be a manifestation of localization of the core hole and propose that the problem of core-hole localization versus delocalization in core-hole spectroscopies may be resolved by considering the nature of the measurement.
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| 2. |
- Friedlein, Rainer, et al.
(author)
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Role of electronic localization and charge-vibrational coupling in resonant photoelectron spectra of polymers : Application to poly(para-phenylenevinylene)
- 2004
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In: Physical Review B. Condensed Matter and Materials Physics. - 1098-0121 .- 1550-235X. ; 69:12
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Journal article (peer-reviewed)abstract
- A combination of x-ray absorption and resonant photoemission (RPE) spectroscopy has been used to study the electronic structure of the one-dimensional conjugated polymer poly (para-phenylenevinylene) in nonordered (as prepared) thin films. The dispersion of RPE features for the decay to localized and delocalized bands are qualitatively different. A theory for band dispersion of RPE in polymers is given, showing the important roles of electronic state localization and vibrational (phonon) excitations for the character of the dispersion.
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| 3. |
- Kvikliene, Adriana, et al.
(author)
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Modelling of nonlinear effects and the response of ultrasound contrast micro bubbles : simulation and experiment
- 2004
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In: Ultrasonics. - : Elsevier BV. - 0041-624X .- 1874-9968. ; 42:01-Sep, s. 301-307
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Journal article (peer-reviewed)abstract
- The propagation of diagnostic ultrasonic imaging pulses in tissue and their interaction with contrast micro bubbles is a very complex physical process, which we assumed to be separable into three stages: pulse propagation in tissue, the interaction of the pulse with the contrast bubble, and the propagation of the scattered echo. The model driven approach is used to gain better knowledge of the complex processes involved. A simplified way of field simulation is chosen due to the complexity of the task and the necessity to estimate comparative contributions of each component of the process. Simulations are targeted at myocardial perfusion estimation. A modified method for spatial superposition of attenuated waves enables simulations of low intensity pulse pressure fields from weakly focused transducers in a nonlinear, attenuating, and liquid-like biological medium. These assumptions enable the use of quasi-linear calculations of the acoustic field. The simulations of acoustic bubble response are carried out with the Rayleigh-Plesset equation with the addition of radiation damping. Theoretical simulations with synthesised and experimentally sampled pulses show that the interaction of the excitation pulses with the contrast bubbles is the main cause of nonlinear scattering, and a 2-3 dB increase of second harmonic amplitude depends on nonlinear distortions of the incident pulse. (C) 2004 Elsevier B.V. All rights reserved.
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| 4. |
- Minkov, Ivaylo, et al.
(author)
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Core-excitations of naphthalene : Vibrational structure versus chemical shifts
- 2004
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In: Journal of Chemical Physics. - : AIP Publishing. - 0021-9606 .- 1089-7690. ; 121:12, s. 5733-5739
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Journal article (peer-reviewed)abstract
- The initial state chemical shifts and vibrational fine structure of core excitations of naphthalene were analyzed using high-resolution x-ray photoelectron emission (XPS) and near-edge x-ray absorption fine structure (NEXAFS) spectra. The carbon atoms at peripheral sites were found to experience a small chemical shift and exhibit similar charge-vibrational coupling. The C-H stretching modes provide significant contributions to overall shape of spectra in the XPS spectra. The results show that vibrational fine structure dominates by particular C-C stretching modes, and in XPS of C2 and C3 sites also by high-energy C-H stretching modes.
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| 5. |
- Rosendahl, Lars, 1971-, et al.
(author)
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Increase in muscle nociceptive substances and anaerobic metabolism in patients with trapezius myalgia : microdialysis in rest and during exercise
- 2004
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In: Pain. - : Ovid Technologies (Wolters Kluwer Health). - 0304-3959 .- 1872-6623. ; 112:3, s. 324-334
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Journal article (peer-reviewed)abstract
- Local metabolic changes are suggested to be involved in muscle pain development in humans. Nineteen women with chronic work-related trapezius myalgia (TM) and 20 healthy female controls (CON) were studied during baseline rest, 20 min repetitive low-force exercise, and 120 min recovery. Interstitial serotonin (5-HT), glutamate, lactate, pyruvate, and blood flow were determined by microdialysis in the trapezius muscle. Baseline pressure pain threshold (PPT) was lower (143+/-18 (TM) vs. 269+/-17 (CON) kPa) (mean +/- SEM), pain intensity (visual analogue scale, VAS) higher (33+/-5 vs. 2+/-1 mm), muscle 5-HT higher (22.9+/-6.7 vs. 3.8+/-1.3 nmol/l), and glutamate higher (47+/-3 vs. 36+/-4 mumol/l) in TM than in CON (all P<0.05), whereas muscle blood flow was similar in groups. Furthermore, muscle pyruvate was higher (180+/-15 vs. 135+/-12 mumol/l) and lactate higher (4.4+/-0.3 vs. 3.1+/-0.3 mmol/l) in TM than in CON (P<0.001). In response to exercise, VAS and glutamate increased in both TM and CON (all P<0.05). In TM only, lactate and pyruvate increased significantly (P<0.02), whereas blood flow increased to similar levels in both groups. During the initial 20 min recovery period, blood flow remained increased in TM (P<0.005) whereas it decreased to baseline levels in CON. In conclusion, patients with chronic work-related TM have increased levels of muscle 5-HT and glutamate that were correlated to pain intensity (r=0.55, P<0.001) and PPT (r=-0.47, P<0.001), respectively. In addition, TM was associated with increased anaerobic metabolism, whereas a normal rise in blood flow was seen with exercise. These findings indicate that peripheral nociceptive processes are active in work-related TM.
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