Characterization of the boron profile and coordination in altered glass layers by EEL spectroscopy.

Electron energy-loss spectroscopy was used to characterize the boron profile and its coordination (BIII and BIV), along the complex alteration layer of glass samples altered for 511 days at 50 °C in solution containing FeCl2, MgCl2 and/or CaCl2. To reach this goal, the impact of both TEM operating conditions and sample preparation on the determination of the boron coordination was first studied using mineralogical and pristine glasses reference samples. Then, the boron concentration profiles were characterized in the glass alteration layer. These profiles were found to be S-shaped with a thickness around forty nanometers. The proportion of BIII was found to decrease with the boron total concentration (from the pristine glass to the gel layer), which suggests a higher bonding strength for BIV bonds than that of BIII bonds under the alteration conditions. These findings are of tremendous interest to advance further in the understanding of glass alteration mechanisms.

Evaluation and application of a new scintillator-based heat-resistant back-scattered electron detector during heat treatment in the scanning electron microscope.

A new high-temperature detector dedicated to the collection of backscattered electrons is used in combination with heating stages up to 1050°C, in high-vacuum and low-vacuum modes in order to evaluate its possibilities through signal-to-noise ration measurements and different applications. Four examples of material transformations occurring at high temperature are herein reported: grain growth during annealing of a rolled platinum foil, recrystallisation of a multiphased alloy, oxidation of a Ni-based alloy and complex phase transformations occurring during the annealing of an Al-Si coated boron steel. The detector could be potentially adapted to any type of SEM and it offers good opportunities to perform high-temperature experiments in various atmospheres.

[Potentials of monocular augmented reality technology in automobile production]. / Eignung monokularer "Augmented Reality" - Technologien in der Automobilproduktion.

INTRODUCTION: Augmented reality (AR) technologies can enrich the real environment with visual data, which has potential benefits for optimising the operator's working process. It offers the possibility to provide context-sensitive information independently of the user's location and position. Data are presented to the dominant eye on a semi-transparent mirror using a head-mounted display (HMD) unit that works with retinal laser technology. In this study the potential benefits and drawbacks of this new AR technology were evaluated. MATERIALS AND METHODS: 45 participants without any visual impairment were randomly assigned to 3 groups and completed a variety of tasks during a simulated working day. Group 1 received conventional working aids (paper-based documents) to support the task processing. Group 2 additionally wore an HMD unit that was switched off. Group 3 wore a functioning HMD without any additional aids. Evaluation was carried out by means of a standardised questionnaire (BMS) and a concentration test ("d2 Aufmerksamkeits-Belastungs-Test"). RESULTS: No significant differences between the 3 groups were found in terms of mental strain, concentration-test performance and physical or mental complaints reported in a follow-up interview. Around 20 % of the subjects noticed a higher pressure and blurred vision in both eyes as well as headaches. Half of the participants complained about deficiencies concerning the ergonomic hardware design of the AR system. DISCUSSION: Changes in objective ophthalmological investigation parameters were not observed. Subjects reported reduced acceptance of the HMD based on non-ophthalmological reasons, for example, the weight of the unit or the length of the cable. However, for some specific working tasks, advantages in process optimisation and operator support were observed.

Initial experience with SPECT examinations using [123I]IBZM as a D2-dopamine receptor antagonist in Parkinson's disease.

[123I]IBZM is a new radioactive labelled ligand which has a high affinity and specificity to D2-dopamine receptors. The in vivo kinetics of [123I]IBZM were studied in patients with unilateral and bilateral accentuated idiopathic Parkinson's disease. The uptake in the basal ganglias and the imaging properties of this D2 receptor antagonist as a radiopharmaceutical for SPECT examinations had to be investigated. 5 patients, aged 42-66 years, (2 m/3 f) were examined. Each patient received 185 MBq [123I]IBZM intravenously. Blood samples were taken 0-120 min post injection (p.i.) and time activity curves were plotted. Three SPECT examinations were performed (I: 30-50 min; II: 50-70 min; and III: 70-90 min p.i.). The count rates (counts/pixel) in the basal ganglias and the cerebellum were measured for each SPECT series on transverse slices using the region-of-interest technique. The time-activity curve of [123I]IBZM shows a rapid decline in plasma during the first 10 min followed by a plateau until 120 min after injection. The SPECT examinations demonstrate the highest count rate in the basal ganglia during SPECT series III (i.e., 70-90 min p.i.). The side-to-side difference of the count rates were in the range of 3% in four patients, and 10% in one patient. The biokinetic data of [123I]IBZM make this substance capable as a radiopharmaceutical for SPECT examinations. The basal ganglia are best visualized 70-90 min p.i., thus [123I]IBZM seems to be a promising imaging agent for diseases of the D2-dopaminergic receptor system.

Electroencephalographic vigilance dynamics in multiple sclerosis during an acute episode and after remission.

Twenty-three patients with multiple sclerosis were studied during an acute episode and again 4 weeks later. Whereas the patients' clinical condition improved significantly (Kurtzke DSS: from 3.9 (SD 1.4) to 3.3 (SD 1.5), P less than 0.001), the conventional power spectra of the resting EEG showed no marked changes. Following a 10-min EEG recording under resting conditions the patients performed a visuomotor tracking task, during which a further EEG recording was made. The frequency of the subvigilant non-A epochs of Loomis et al. as calculated for each minute of the resting recording was taken as the basis for evaluating the EEG dynamics of vigilance. A comparison during and after relapse showed differences in the time courses of the numbers of non-A epochs. While the non-A epochs were not time dependent in the acute phase, remission was characterized by a steady increase in non-A epochs across the 10 min of the recording period. This change in the dynamics of vigilance, which approximates a physiological pattern, was accompanied by an improvement in visuomotor tracking performance. Comparison of the power spectra of the EEG recorded during the tracking task showed a bifrontal increase in absolute alpha power during remission.

Multiple sclerosis: relations between MRI and CT findings, cerebrospinal fluid parameters and clinical features.

Cerebral MRI and CT findings were compared with various cerebrospinal fluid (CSF) parameters and clinical features in 75 patients with multiple sclerosis (MS). There were positive correlations between CSF albumin as a parameter of blood-brain barrier function and morphological parameters, namely the number of nonperiventricular foci and periventricular involvement demonstrated by MRI and ventricular enlargement as shown by CT. Apart from positive correlations between the number of nonperiventricular foci and CSF levels of IgA and IgG, including the IgG synthetic rate, no other correlations were found between CSF parameters (leucocyte count and immunoglobulin concentrations) and morphological findings. The unremitting-progressive type of MS was distinguished from the relapsing-remitting form by a lower CSF leucocyte count and a higher degree of disability, but there was no difference between the morphological findings in the two forms. Positive correlations were found between degree of disability and both periventricular involvement in the MRI and CT evidence of ventricular enlargement. In terms of correlations with the duration of disease, cerebral MRI proved to be far superior to CSF evaluations.

[Quantifying functional deficits in patients with multiple sclerosis using a computer-assisted visuomotor tracking procedure]. / Quantifizierung von Funktionsdefiziten bei Patienten mit multipler Sklerose mittels eines rechnergestützten visuomotorischen Tracking-Verfahrens.

23 Patients with multiple sclerosis were subjected to a visuomotor tracking test, consisting of subtests of different task difficulty, while being in a state of acute exacerbation and four weeks later, while exhibiting a more or less pronounced clinical remission (Kurtzke DSS 3.9 (+/- 1.4) vs. 3.3 (+/- 1.5); p less than 0.001). Corresponding to this the tracking test performances improved, the difference being significant only with the easiest test run. The tracking performances correlated with the Kurtzke scores, both for the acute state and for the remitted state, the highest correlation showing up for the easiest test run. Hence, the visuomotor tracking test seems to be suited to measure functional deficits and to evaluate the efficiency of therapeutic procedures.

Cerebral magnetic resonance imaging findings in multiple sclerosis. Relation to disturbance of affect, drive, and cognition.

Forty-six patients with multiple sclerosis were rated with respect to their psychologic symptoms, and magnetic resonance imaging was performed. A significant correlation between the cerebral multiple sclerosis manifestations and the psychologic scores was found. The periventricular and frontal lesions seem to be the most important lesions for the psychologic symptoms of patients with multiple sclerosis.

[Cortical somatosensory evoked potentials following median and tibial nerve stimulation in multiple sclerosis; relation to sensory disorders and duration of the disease]. / Kortikale somato-sensorisch evozierte Potentiale nach Medianus- und Tibialis-Stimulation bei multipler Sklerose; Beziehung zur Sensibilitätsstörung und Dauer der Erkrankung.

In 40 patients with multiple sclerosis, 11 of whom presented with their first disease manifestation, cortical somatosensory evoked potentials following median and tibial nerve stimulation were examined. 45 percent of the patients with first manifestation had at least one pathological SEP, while 79 percent of the patients with longer course of the illness showed pathological SEPs. The group of patients with first manifestation differs significantly in this aspect from the group of those patients with longer duration of the illness. The occurrence of pathological SEPs was associated significantly more often with impairment of joint position and vibration sense, than with nonspecific sensory disturbances. Not only in some patients with first manifestation, but also in some patients with long, but mild courses, there were nonspecific sensory disturbances in association with normal SEPs. One should not underestimate the complaints in such cases.

[Cortical SEP of early and intermediate latency following stimulation of the median and tibial nerves in disseminated encephalomyelitis--relation to findings in cerebral nuclear magnetic resonance tomography]. / Kortikale SEP früher und mittlerer Latenz nach Medianus-und Tibialisstimulation bei Encephalomyelitis disseminata--Beziehung zu Befunden der zerebralen Magnetischen Resonanztomographie.

Cortical somatosensory evoked potentials following median and tibial nerve stimulation were compared with the findings in nuclear magnetic resonance imaging in 23 patients with multiple sclerosis, 11 of whom presented with their first disease manifestation. Pathological SEP's were found in 55 percent of patients presenting with first manifestation and in 83 percent of those with a longer duration of illness. Except for one patient with spinal cord involvement only, in whom no cerebral lesions were seen, all patients showed periventricular lesions in NMR. Between 1 and 16 (4.7 +/- 3.5) non-periventricular isolated lesions were found per patient. Cortical SEP's are affected differently by lesions within the thalamocortical system: Plaques within the internal capsule may result in SEP-changes as seen in other causes of damage to this region. However, lesions in this strategic area may also remain clinically and electrophysiologically silent. Nevertheless, the size of the lesion seen in NMR is not relevant, as observed in one case of an extensive plaque within the centrum semiovale. Correlations between the lesions near the parietal cortex or within the parietal white matter and SEP-component alterations of intermediate latency (N55, N75) remained insignificant.

[Initial manifestation of disseminated encephalomyelitis: MRT comparative study with established disseminated encephalomyelitis]. / Erstmanifestation der Encephalomyelitis disseminata: MRT-Vergleichsstudie gegenüber gesicherter Encephalomyelitis disseminata.

40 patients with a definite diagnosis and 16 patients with an initial manifestation of multiple sclerosis were investigated by cerebral nuclear magnetic resonance imaging (NMR) and compared. The initial manifestation is predominantly characterized in the NMR by significantly less periventricular involvement, especially within the region of the occipital horns, by significantly rarer appearance of confluent, periventricular lesions within the region of the pars centralis and the temporal horns of the lateral ventricles and by significantly rarer appearance of circumscribed non-periventricular lesions. Unlike those in definite multiple sclerosis, the morphology and distribution of the initial lesions do not show a stereotypical and diagnostically characteristic pattern. The importance of the cerebral NMR for the early diagnosis of multiple sclerosis lies primarily in the indication of disseminated lesions.

[EEG changes in disseminated encephalomyelitis in comparison with the findings of cerebral magnetic resonance tomography]. / EEG-Veränderungen bei Encephalomyelitis disseminata im Vergleich mit den Befunden der zerebralen magnetischen Resonanztomographie.

The electroencephalograms of 40 patients with acute symptoms of multiple sclerosis, 10 of whom presented with primary manifestation, were compared with the findings in cerebral nuclear magnetic resonance imaging. 32.5% of the patients EEGs showed abnormalities. Considering borderline findings the percentage of remarkable EEGs mounted to 60%. All of the patients presented periventricular lesions in NMR. In addition to the periventricular abnormalities between 1 and 26 district lesions per patient were found (mean = 6.5; Median = 5). In the patients group with five and more non-periventricular lesions, there were significantly more pathologic EEG-findings (p less than 0.05) than in the group with fewer lesions. Statistical correlations between EEG-abnormalities and the extent of functional deficit could not be substantiated. Neither could type and locality of EEG-changes be correlated to non-periventricular lesions in NMR.

[Significance of magnetic resonance tomography in disseminated encephalomyelitis]. / Zur Bedeutung der Magnetischen Resonanz-Tomographie bei Encephalomyelitis disseminata.

23 out of 24 patients with multiple sclerosis showed multiple, distinct lesions on investigation with cerebral nuclear magnetic resonance imaging (NMR). Arguments for the specific relationship of these lesions to demyelinating foci are: 1. Morphology and pattern of distribution agree to the known pathological observations. 2. Single lesions shown by computerized tomography (CT) were similarly located to lesions shown by NMR. The morphology and distribution of the lesions in the NMR show a common pattern largely independent of the individual neurological deficits. The nuclear magnetic resonance imaging is a method of high sensitivity and specificity for the diagnosis of multiple sclerosis. It offers valuable additional information in particular for early diagnosis and in cases of diagnostic uncertainty.

[Extracranial aneurysms of the internal carotid artery proximal to the skull base. A case report]. / Extrakranielles schädelbasisnahes Aneurysma der A. carotis interna. Ein kasuistischer Beitrag.

Extracranial aneurysms of the internal carotid artery are considered to be relatively rare. The main causes are constitutional vessel weakness arteriosclerosis and trauma. Neurological complications can sometimes give rise to confusing symptoms. Most important are transitory ischaemic attacks. Apart from these, damage by compression of the lower cranial and sympathetic nerves may occur. A case is reported in which the symptoms led to the topological diagnosis. The method of treatment used was that of delayed carotis ligature as described by van Dongen.

[EEG findings in patients with aortocoronary bypass--a visual-morphologic analysis in comparison with clinical data]. / EEG-Befunde bei Patienten mit aorto-koronarem Bypass--Eine visuell-morphologische Analyse im Vergleich mit klinischen Daten.

In course of a catamnesis during a period of 1,5 up to 5 years after operation we made electroencephalographic examinations in 140 patients submitted to an aorto-coronary-veins-bypass (ACVB). Compared with a control group of corresponding age we observed a significant frequency of focal disturbances, being interpreted as expression of an increased functional lability due to vascular effects. 14 percent of these patients showed evident signs of cerebrovascular insufficiency. 33 percent suffered from symptoms of the unspecific pseudoneurasthenic syndrome, often to be found in the preliminary region of cerebrovascular insufficiency. Compared with the control group we found among the EEG of alpha-type within the ACVB-group a significantly increased number of subvigilant patterns. There were no relations between the extent of these patterns and the clinical syndromes of cerebrovascular insufficiency and pseudoneurasthenia. The increased appearance of fluctuations of vigilance within the group showing a higher vascular morbidity can be regarded as a first step of limited regulative dynamics. The results of this study confirm the necessity of an interdisciplinary medical treatment of patients suffering from arteriosclerosis.

[Relationships between effects and plasma levels of clozapine (author's transl)]. / Beziehungen zwischen Wirkungen und Plasmaspiegeln von Clozapin.

Relations between clozapine plasma levels and effects were investigated in 32 hospitalized patients. Clozapine dosage and plasma levels correlate linearly. The clinical improvement due to clozapine treatment was significant. A relationship between the rate of improvement and the plasma levels could be seen on the third day of treatment only. Of the side effects, body temperature elevation and orthostatic disregulation temporarily correlated with the plasma levels. Development of tolerance was seen with regard to the sedative effect and orthostatic disregulation. Linear correlations between pulse frequency as well as dopamine-beta-hydroxylase activity in serum and clinical improvement were observed during the second half of the 30-day treatment period.

[Antipsychotic efficacy in relation to plasma levels of clozapine (author's transl)]. / Antipsychotische Wirksamkeit im Verhältnis zum Plasmaspiegel von Clozapin

The relationship between antipsychotic effect and side effects and plasma levels of clozapine were investigated in 26 patients. A significant linear correlation was found between dosage and plasma levels of clozapine. All patients were clearly improved. The degree of improvement was independent of the plasma levels in an average range of plasma levels (100 ng/ml-800 ng/ml). Sedation and orthostatic dysregulation occurred most pronounced on the third day of treatment. There was no relationship between plasma levels and these symptoms. After prolonged treatment the degree of both symptoms diminished. The development of tolerance of symptoms is concluded.