Evaluation of high-resolution X-ray absorption and emission spectroscopy for the chemical speciation of binary titanium compounds.

For the chemical speciation of binary compounds of tri- and tetravalent titanium, high-resolution X-ray absorption and emission spectra were recorded in different energy regimes in order to evaluate and to qualify both near-edge X-ray absorption fine structure (NEXAFS or XANES) spectroscopy and wavelength-dispersive X-ray emission spectroscopy (WDXES) as spectroscopic methods for this analytical task. A high resolving power in the excitation channel was ensured by use of monochromatic synchrotron radiation provided by BESSY II, where the soft X-ray emission spectra were recorded as well. In the hard X-ray range, emission measurements were performed at SPring-8. For a comparison of the information gained from the various methods, the titanium compounds were classified according to the bonded titanium's oxidation state. Thus, it was possible to distinguish between inner atomic effects due to different oxidation states and external effects related to the respective ligand and the surrounding structure. It becomes evident, that certain compounds, while hardly distinguishable in their Ti-K XANES spectra, still show significant differences in their emission characteristics. On the other hand, some compounds with little difference in their emission spectra are easily distinguished by their NEXAFS structures. Only the combined use of the complementary methods both in the soft and the hard X-ray range allows for a reliable speciation of tri- and tetravalent titanium compounds.

Development and evaluation of the Parkinson Psychosis Questionnaire A screening-instrument for the early diagnosis of drug-induced psychosis in Parkinson's disease.

OBJECTIVE: Drug-induced psychosis is a frequent side-effect in the treatment of advanced Parkinson's disease (PD). We sought to develop and evaluate a brief instrument for early recognition of drug-induced psychosis in PD. METHODS: We developed the "Parkinson Psychosis Questionnaire" (PPQ), which consists of screening questions for typical early signs and psychotic symptoms in PD and which quantifies the frequency and severity of four clinical categories-sleep disturbances, hallucinations/illusions, delusions and orientation. We performed an internal validation of the PPQ in 50 unselected patients with parkinsonism. The Brief Psychiatric Rating Scale (BPRS) and the "Structurized Clinical Interview" (SCID) for DSM IV were applied to the same patients as external references. RESULTS: Of 50 subjects, 49 suffered from idiopathic PD and one from probable MSA-P. Hoehn and Yahr stages in "on" ranged from 1.5 to 4. Sensitivity of the PPQ test for drug-induced psychosis according to SCID was 100 % (95 % CI: 73.5%, 100%); while specificity was 92.1 % (95% CI: 78.6%, 98.3 %). The PPQ severity score was highly correlated with BPRS. We derived a linear prediction formula, which transformed PPQ into BPRS scores. CONCLUSION: The PPQ appears to be a suitable, and easily administered instrument for early diagnosis of drug induced psychosis in routine PD care. Whether the PPQ could also be a valuable tool for monitoring follow-up studies and therapeutic intervention trials remains to be tested.

[Differential therapy of advanced Parkinson's disease with special reference to complementary therapeutic approaches]. / Differentialtherapie im Spät- stadium der Parkinson'schen Krankheit unter spezieller Berücksichtigung adjuvanter Therapieansätze.

In Parkinson's disease advanced symptoms (fluctuation, dyskinesia) and/or psychiatric side-effects of medication require a very individual and often complicated therapeutic regime. All pharmacological groups can be useful. The adjustment of medication needs clinical control, especially when psychiatric symptoms occur. Ideally, this task should be left to specially trained medical staff. Moreover, there are a number of complementary strategies recommended by various suppliers. Physiotherapy, speech therapy and ear acupuncture have in the past been shown to be useful even in advanced cases. The German Parkinson Society (dPV) has supported clinical trials in respect of the application of ear acupuncture, Qigong and the coenzyme Q10. Positive results are expected from Q10. Acupuncture cannot be recommended, while Qigong may be helpful for some patients.

Near monochromatic X-rays for digital slot-scan mammography: initial findings.

X-ray spectra are composed of a broad bremsspectrum and anode-characteristic emission lines. In mammography typically molybdenum (Mo), rhodium (Rh) or tungsten (W) anodes are used in combination with Mo, Rh or aluminium filters. Only the photons with energies between 17 and 22 keV of the resulting spectrum are suitable for the soft tissue imaging needed for mammography. The aim of this article is to present first results obtained with a monochromator module mounted at the exit of the X-ray tube of a conventional clinical mammography unit. The experimental setup consists of a Siemens Mammomat 300, an X-ray monochromator module and a linear array detector for image acquisition. The technique is similar to the slot-scan technique known from digital mammography. The experimental machine allows to obtain images both with polychromatic and monochromatic X-rays. Initial evaluation of the system was performed by examination of a contrast-detail phantom (CD-MAM-phantom, Nijmegen, The Netherlands). Images done with the new monochromatic technique were compared to images of the phantom done with polychromatic spectra, with film-screen mammography as well as with digital mammography. The new technique with monochromatic slot-scan mammography resulted in correct identification of 93% of the phantom. Digital slot-scan mammography with polychromatic beam resulted in correct identification of 87%, digital full-field mammography in 83% and conventional film-screen mammography in 70% of the phantom. The results suggest that monochromatization has a potential for improving image quality or decreasing dose in X-ray mammography.

Dicentric chromosomes in monolayers of human lymphocytes produced by monochromatized synchrotron radiation with photon energies from 1.83 keV to 17.4 keV.

A systematic approach was used to examine the induction of dicentric chromosomes in human lymphocytes irradiated in vitro with monochromatized synchrotron radiation produced with photon energies in the range from 1.83 keV to 17.4 keV. To avoid potential confounding factors that could influence the outcome of the experiments, only blood from one individual was used. Since for the irradiation experiments with these low photon energies the local dose variations would become unacceptable, monolayers of lymphocytes attached within 3 h PHA stimulation have been used. The culture conditions ensured that the chromosome analysis could be performed exclusively in metaphases of the first cell cycle in vitro. There is a strong indication for a systematic change of the alpha coefficient of the linear quadratic dose-response relationship from 1.83 keV (alpha=1.26+/-0.28) with increasing energy up to 6.9 keV (alpha=8.24+/-0.41) and a decrease with further increase of energy up to 17.4 keV (alpha=3.83+/-1.72). A tendency for a systematic change of the beta coefficient seems to be present at energies of 6.9 keV (beta=8.04+/-0.40) and 4.8 keV (beta=9.48+/-1.57) as well as at energies of 3.10 keV (beta=2.99+/-0.51) and 1.83 keV (beta=0.40+/-0.25). These results agree in essence with the previously published large data set from Sasaki's laboratory.

The maximum low-dose RBE of 17.4 and 40 keV monochromatic X rays for the induction of dicentric chromosomes in human peripheral lymphocytes.

Schmid et al. recently reported on the maximum low-dose RBE for mammography X rays (29 kV) for the induction of dicentrics in human lymphocytes. To obtain additional information on the RBE for this radiation quality, experiments with monochromatized synchrotron radiation were performed. Monochromatic 17.4 keV X rays were chosen for comparison with the diagnostic mammography X-ray spectrum to evaluate the spectral influence, while monochromatic 40 keV X rays represent a higher-energy reference radiation, within the experiment. The induction of dicentric chromosomes in human lymphocytes from one blood donor irradiated in vitro with 17.4 keV and 40 keV monochromatic X rays resulted in alpha coefficients of (3.44 +/- 0.87) x 10(-2) Gy(-1) and (2.37 +/- 0.93) x 10(-2) Gy(-1), respectively. These biological effects are only about half of the alpha coefficients reported earlier for exposure of blood from the same donor with the broad energy spectra of 29 kV X rays (mean energy of 17.4 keV) and 60 kV X rays (mean energy of 48 keV). A similar behavior is evident in terms of RBEM. Relative to weakly filtered 220 kV X rays, the RBEM for 17.4 and 40 keV monochromatic X rays is 0.86 +/- 0.23 and 0.59 +/- 0.24, respectively, which is in contrast to the RBEM of 1.64 +/- 0.27 for 29 kV X rays and 1.10 +/- 0.19 for 60 kV X rays. It is evident that the monochromatic radiations are less effective in inducing dicentric chromosomes than broad-spectrum X rays with the corresponding mean energy value. Therefore, it can be assumed that, for these X-ray qualities with broad energy spectra, a large fraction of the effects should be attributed predominantly to photons with energies well below the mean energy.

Deep-brain stimulation for Parkinson's disease.

Deep brain simulation (DBS) is a powerful new therapeutic approach for patients with Parkinson's disease. However, patient selection is critical for a valuable therapeutic result. Dopa sensitivity of the target symptoms, severe disability and low neurosurgical risks are among the major criteria for this indication. Other criteria like age or cognition must still be addressed in future prospective studies. The preferred target for DBS in PD is the subthalamic nucleus for various good reasons. However, prospective studies for this procedure are lacking and some clinical problems may be more easily solved with targeting the internal pallidum or the thalamus. Despite major progress in this field, much work remains to be done.

[Coping behaviors in Parkinson's disease]. / Krankheitsverarbeitung bei Morbus Parkinson.

In 45 patients with Parkinson's disease, we investigated coping behavior and its correlations to demographic and disease-related data, locus of control, depression, and psychosocial adaptation. Active, problem oriented, and self-reorganizing strategies were predominantly used and regarded as especially helpful by the 27 men and 18 women (age: 56 years; duration of illness: 9 years). While age and sex were not associated with coping, external locus of control correlated positively to "depressive coping" and duration of illness correlated negatively to "distraction and self-affirmation." Coping strategies regarded as maladaptive and a small degree of internal locus of control correlated to unfavourable results for depression and satisfaction.

Workshop IV: drug treatment guidelines for the long-term management of Parkinson's disease.

An attempt was made to establish a decision algorithm for the treatment of idiopathic Parkinson's disease at various stages and in different subgroups such as akinetic-rigid or tremor dominance type. We suggest treating young patients with selegiline and a dopamine agonist. In the tremor dominance type we use either budipine or a dopamine agonist. Due to levodopa-induced dyskinesia, we try to avoid levodopa in the early stages of the disease and use it only later in more advanced situations in a combination therapy with dopamine agonists. Since IPS is not only based upon dopamine deficiency but also on resulting glutamatergic overstimulation, we advocate the use of a glutamate antagonist such as amantadine or budipine. Catechol-O-methyl inhibitors are very helpful when wearing-off occurs. Anticholinergics are only used in the early stages of tremor-dominant IPS because we fear enhancing the risk of dementia.

Carbon/Titanium multilayers as soft-x-ray mirrors for the water window.

C/Ti multilayers with a period thickness of 2.1-2.7 nm were produced by electron-beam evaporation in ultrahigh vacuum as soft-x-ray mirrors in the water window (lambda = 2.3-4.4 nm). For smoothing the individual interfaces and thus enhancing the total reflectance, each layer was ion polished with an Ar(+) ion beam after deposition. For a multilayer of 85 bilayers, a reflectance of approximately 11% at an angle of incidence of 59 degrees (with respect to the surface normal) by use of s-polarized radiation at a wavelength of 2.77 nm was achieved.

Measurement of the electron energy and energy spread at the electron storage ring BESSY I.

Knowledge of the electron energy with a small uncertainty is necessary for the Physikalisch-Technische Bundesanstalt (PTB) to operate the electron storage ring BESSY I, and the future BESSY II, as a primary radiation source standard of calculable synchrotron radiation. At BESSY I the electron energy can now be measured either by the long-established method of resonant spin depolarization or by the newly set up method of Compton backscattering (CBS) of laser photons (CO(2) laser, lambda = 10.6 micro m). Results obtained at different electron energies by these two independent methods are presented. They agree within a relative uncertainty of better than 10(-4). The advantages and disadvantages of these two complementary techniques are described and applications of CBS for the measurement of other storage-ring parameters, e.g. the electron energy spread, are given.

The PTB electromagnetic undulator for BESSY II.

The Physikalisch-Technische Bundesanstalt (PTB) will operate an electromagnetic undulator designed for radiometry at the BESSY II storage ring. The undulator has a period length of 180 mm, 21 full periods and a maximum magnetic induction of 0.46 T, resulting in a tuning range of the first harmonic from 5 to 150 eV at 1.7 GeV electron energy. Moreover, the electromagnetic design allows the undulator to be operated in a special mode with the period length doubled to 360 mm, thus accordingly shifting the tuning range to lower energies. The main design parameters of the undulator for radiometric applications, as well as measured magnetic field data, are presented.

A plane-grating monochromator beamline for the PTB undulators at BESSY II.

At the BESSY II storage ring, the Physikalisch-Technische Bundesanstalt (PTB) will operate insertion devices dedicated to radiometric use. One branch of the appendant beamline system will be equipped with a grazing-incidence monochromator, described here. The monochromator concept is based on a plane grating operated in parallel light; therefore exact focusing is maintained for all photon energies irrespective of the angular setting at the grating. The monochromator has been optimized for small higher-order transmittance and high power throughput, as required by radiometric applications in the wide photon energy range from 20 eV to 1900 eV.

Components for the X-ray radiometry beamline at BESSY II.

Optical components for the X-ray radiometry beamline of the Physikalisch-Technische Bundesanstalt at BESSY II were investigated at BESSY I. Reflectometry measurements on different mirror coatings were used to calculate their capability to suppress higher-order radiation. An MgF(2) coating proved to be best suited for photon energies below 4 keV. The reflectance of silicon (111) monochromator crystals at low photon energies around 2 keV was homogeneous within +/-1%. In a test at a superconducting wavelength shifter the cooling system for the first crystal was shown to cope with the absorbed power of 14 W.

High-accuracy detector calibration in the 3-1500 eV spectral range at the PTB radiometry laboratory.

State-of-the-art detector calibration in the UV/VUV and soft X-ray spectral ranges at the Physikalisch-Technische Bundesanstalt (PTB) is based on the primary detector standard SYRES, a cryogenic electrical substitution radiometer capable of measuring radiant power of a few micro W. At the PTB radiometry laboratory at the synchrotron radiation facility BESSY, two dedicated beamlines are operated, providing monochromatic radiation of high spectral purity, high radiant power and tunable photon energy in the 3-1500 eV range. The spectral responsivity of detectors, e.g. photodiodes, can be measured with a relative uncertainty of about 1% by direct comparison with SYRES, as will be demonstrated for PtSi/Si and GaAsP/Au Schottky and silicon n-on-p photodiodes. The calibration of photon-counting detectors traceable to SYRES can by accomplished by exploiting the unique capability to scale the spectral photon flux over several orders of magnitude by changing the stored electron current. Calibrations of CCDs and photomultipliers are presented as examples.

Synchrotron-radiation-operated cryogenic electrical-substitution radiometer as the high-accuracy primary detector standard in the ultraviolet, vacuum-ultraviolet, and soft-x-ray spectral ranges.

The accuracy of detector calibration in the UV, vacuum-ultraviolet, and soft-x-ray spectral ranges could be significantly improved by the use of the synchrotron radiation electrical substitution radiometer (SYRES) as the primary detector standard. The SYRES radiometer is optimized for use with spectrally dispersed synchrotron radiation as supplied by two monochromator beam lines in the radiometry laboratory of the Physikalisch-Technische Bundesanstalt at the Berlin electron-storage ring (BESSY). Wavelength ranges from 0.8 to 25 nm and from 35 to 400 nm are covered. The typically available radiant power of approximately 1-10 microW can be measured with the SYRES radiometer with a standard relative uncertainty of less than 0.2%. The spectral responsivity of qualified photodiodes for use as secondary detector standards is determined by direct comparison with the primary detector standard at an arbitrary wavelength. At present, the scale of spectral responsivity is realized with a standard relative uncertainty of well below 1% in the spectral ranges 0.8-3.5 nm, 5-25 nm, and 120-400 nm. We provide a comprehensive description of the SYRES radiometer and of the two facilities for detector calibration in the UV and vacuum-ultraviolet spectral ranges and in the soft-x-ray spectral range, respectively, and we discuss the achievable uncertainties in the calibration of detectors.

Smoking and Parkinson's disease: a case-control study in Germany.

BACKGROUND: In a hospital based case-control study, we investigated the role of environmental factors in the aetiology of Parkinson's disease. This paper describes our results on smoking habits. METHODS: The smoking histories of 380 Parkinson's disease (PD) patients recruited from nine German clinics were compared to those of age- and sex-matched control subjects (379 neighbourhood controls and 376 controls from the same region). Detailed information on smoking behaviour was collected in structured personal interviews in order to calculate the number of pack-years smoked up to the time of diagnosis. Conditional logistic regression was used to calculate odds ratios (OR) and control for potential confounders. RESULTS: Among PD patients, 44% had ever smoked, as compared to 59% in both control groups. Among ever-smoking patients, 74% quit prior to the date of diagnosis, as compared to roughly 45% of the ever-smoking control subjects. The OR for ever having smoked was 0.5 (95% confidence interval [CI]: 0.3-0.7), P trend < 0.00005). CONCLUSIONS: The results are considered in terms of criteria for causality. Plausible explanations for the observed inverse association between smoking and PD include: 1. A genetic predisposition that increases the risk for PD (such as defective detoxification enzymes) simultaneously decreases the likelihood of smoking. 2. Inherently lower dopamine levels in predestined PD patients cause them to be less prone to addiction. 3. Smoking is neuroprotective.

Remote memory in Parkinson's disease and senile dementia.

Remote memory for public events was investigated in 14 demented patients with Parkinson's disease (PD), 14 non-demented PD patients, and 14 controls. These groups were compared with 16 demented patients with dementia that was due to Alzheimer or was of vascular origin (SDAVT), and with a group of elderly controls. The two demented groups were of a different age but displayed a comparable degree of dementia. Remote memory was assessed using a 'famous events' questionnaire with items both of comparable salience and difficulty. Results showed severely impaired retrograde memory functions in the two demented groups for both recall and recognition with non-demented PD patients performing similar to the controls. Remote memory impairments extended 30-40 years without any temporal graded memory losses. Non-demented PD patients and controls showed an inferior free recall performance, especially for the remote past. The two PD groups benefited from recognition to the same extent as the controls, whereas the improvement for SDAVT patients was inferior when compared to their elderly controls. In contrast to SDAVT patients, anterograde memory was associated with remote memory for specific decades in demented PD patients. The results are interpreted with respect to an underlying retrieval deficit with a superimposed anterograde impairment common to both types of dementia and an additional loss of storage sites in SDAVT patients.