Scintillation and radioluminescence mechanism in ß-Ga2O3 semiconducting single crystals.

In this paper, we present the results of experiments on samples of ß-Ga2O3 single crystals under a project aimed at assessing and improving the scintillation performance of this material by studying scintillation and radioluminescence mechanism and its limitations. In addition to standard experiments, such as scintillation light yields and time profiles, radio-, and thermoluminescence, we developed and tested a new and promising two-beam experiment, in which a sample is excited by an X-ray beam and additionally stimulated by an IR laser diode. Fe and Mg doping compensate for the inherent n-type conductivity of ß-Ga2O3 to obtain semi-insulating single crystals for large-area substrates and wafers. At the same time, residual Fe and Ir are ubiquitous uncontrolled impurities leached from the Ir crucibles used to grow large bulk crystals by the Czochralski method. For these experiments, we selected four samples cut from the Czochralski grown 2-cm diameter ß-Ga2O3 single crystal boules; one with a reduced Fe content, two unintentionally Fe- and Ir-doped (UID) with lower and higher Fe content, and one doped with Mg. We find that steady-state radioluminescence spectra measured at temperatures between 10 and 350 K are dominated by the UV emission peaking at about 350-370 nm. Unfortunately, even for the best sample with a reduced Fe-content, the intensity of this emission drops precipitously with the temperature down to about 10 % at 300 K. From the two-beam experiments, we conclude that recombination via inadvertent Fe impurity involving three charge states (2+, 3+, and 4+) may reduce a steady-state UV emission of ß-Ga2O3 under X-ray excitation by as much as 60-70 %, one-third to one-half of which is due to the recombination (specific for Fe-doped ß-Ga2O3) involving the 4+ and 3+ charge states of Fe and the remaining 50-70 % being due to a more familiar route typical of other oxides, involving the 2+ and 3+ charge states of Fe. These losses are at higher temperatures enhanced by a thermally activated redistribution of self-trapped holes (STHs). In addition, the trapping of electrons by Fe and holes by Mg, Fe, and Ir may be responsible for scintillation light loss and reduction of the zero-time amplitude essential for the fast timing scintillation applications. Despite indirect evidence of competitive recombination in ß-Ga2O3 involving a deep Ir3+/4+ donor level, we could not quantitatively assess losses of the UV steady state radioluminescence light due to the inadvertent Ir impurity.

X-ray Scintillation in Lead Halide Perovskite Crystals.

Current technologies for X-ray detection rely on scintillation from expensive inorganic crystals grown at high-temperature, which so far has hindered the development of large-area scintillator arrays. Thanks to the presence of heavy atoms, solution-grown hybrid lead halide perovskite single crystals exhibit short X-ray absorption length and excellent detection efficiency. Here we compare X-ray scintillator characteristics of three-dimensional (3D) MAPbI3 and MAPbBr3 and two-dimensional (2D) (EDBE)PbCl4 hybrid perovskite crystals. X-ray excited thermoluminescence measurements indicate the absence of deep traps and a very small density of shallow trap states, which lessens after-glow effects. All perovskite single crystals exhibit high X-ray excited luminescence yields of >120,000 photons/MeV at low temperature. Although thermal quenching is significant at room temperature, the large exciton binding energy of 2D (EDBE)PbCl4 significantly reduces thermal effects compared to 3D perovskites, and moderate light yield of 9,000 photons/MeV can be achieved even at room temperature. This highlights the potential of 2D metal halide perovskites for large-area and low-cost scintillator devices for medical, security and scientific applications.

Clinical variability of neuroacanthocytosis syndromes-a series of six patients with long follow-up.

OBJECTIVE: To provide clinical clues to differential diagnosis in patients with chorea and other movement disorders with blood acanthocytes. METHODS: We present a long-term video accompanied follow-up of six Caucasian patients with neuroacanthocytosis from several centers, three diagnosed with chorea-acanthocytosis (ChAc): 34-y.o.(no.1), 36-y.o.(no.2), 43-y.o.(no.3), two diagnosed with McLeod Syndrome (MLS): 52-y.o.(no.4), 61-y.o.(no.5) and one 63-y.o.(no.6), a brother of no.5, with clinical suspicion of MLS. Additionally we report pathological findings of the mother of two brothers with MLS reported in our series with acanthocytes on peripheral blood smear RESULTS: The patients had an unremarkable family history and were asymptomatic until adulthood. Patients no. 1,2,4,5,6 developed generalized chorea and patient no. 3 had predominant bradykinesia. Patients no. 1,2,3 had phonic and motor tics, additionally patients no. 1 and 2 exhibited peculiar oromandibular dystonia with tongue thrusting. In patients no. 2 and 3 dystonic supination of feet was observed, patient no. 3 subsequently developed bilateral foot drop. Patients no. 2 and 4 had signs of muscle atrophy. Tendon reflexes were decreased or absent and electroneurography demonstrated sensorimotor neuropathy in patients no. 1,2,3,4,5, except no. 6. Generalized seizures were seen in patients no. 2,3,5,6 and myoclonic jerks in patient no. 1. Cognitive deterioration was reported in patients no. 1,2,3,5,6. Serum creatine kinase levels were elevated in all six patients. CONCLUSION: We highlight the variability of clinical presentation of neuroacanthocytosis syndromes and the long time from the onset to diagnosis with the need to screen the blood smears in uncertain cases, however, as in one of our cases acanthocytes may even be not found. Based on our observations and data from the literature we propose several red flags that should raise the suspicion of an NA syndrome in a patient with a movement disorder: severe orofacial dyskinesia with tongue and lip-biting (typical of ChAc), feeding dystonia, psychiatric and cognitive disturbances, seizures, peripheral neuropathy, elevation of creatine kinase, elevation of transaminases, hepatosplenomegaly, cardiomyopathy and arrhythmias, and an X-linked pattern of inheritance (McLeod Syndrome, MLS).

Gelsolin concentration in cerebrospinal fluid from patients with multiple sclerosis and other neurological disorders.

BACKGROUND: Gelsolin is a highly conserved intracellular actin-binding protein with an extracellular isoform, plasma gelsolin, for which there is not yet a clearly defined function. MATERIALS AND METHODS: In this study, we determined gelsolin concentrations in blood and cerebrospinal fluid (CSF) obtained from 25 subjects using immunoblotting and a functional assay that quantifies gelsolin's ability to accelerate actin polymerization. RESULTS: The gelsolin concentration in CSF, determined by quantitative immunoblotting was 1.2-15.9 microg/ml (average 5.9 +/- 3.8 mug/ml). In samples obtained from patients diagnosed with conditions that do not alter standard CSF clinical tests [(idiopathic cephalgia, ischialgia due to discopathy, and idiopathic (Bell's) facial nerve palsy or entrapment radial neuropathy)], the average gelsolin concentration was 7.2 +/- 4.3 microg/ml. In contrast, the gelsolin concentration in samples obtained from patients diagnosed with multiple sclerosis was 2.1 +/- 0.7 microg/ml, and a similar low concentration was found in a patient recovering from a subarachnoid hemorrhage. The range of CSF gelsolin concentrations determined by the actin polymerization assay was 0.61-9.97 microg/ml (average 3.6 +/- 2.2 microg/ml). These lower values compared with those obtained from immunoblotting analysis suggest that CSF gelsolin may bind other CSF molecules leading to a reduction of its actin-binding activity. CONCLUSIONS: The results presented here show that CSF gelsolin concentration is significantly altered in certain neurological conditions, including multiple sclerosis, indicating the possible utility of CSF gelsolin levels for diagnostic purposes.

Metabolite Profile in Pyramidal Tracts after Ischemic Brain Stroke Assessed by 1H MRS. A Multicenter Study.

The magnitude of the motor deficit in patients with stroke depends not only on the size and location of the destroyed brain tissue, but also on axonal injury in the descending motor pathways which appears after stroke. After cerebral ischemia, there are no visible abnormalities in conventional MRI in the intact pyramidal tracts despite the process of neuronal destruction by Wallerian degeneration. Conventional MRI is not a sensitive test for Wallerian degeneration in the acute or subacute time period as it shows no changes within the first four weeks. Magnetic resonance spectroscopy (MRS) has been used for better quantification of the extent or severity of fibre damage by evaluating metabolite alterations in normal-appearing corticospinal and corticopontal tracts. This study assessed the role of 1H MRS in the detection of changes in cerebral metabolite levels in pyramidal tracts after cortical/ subcortical infarction and to compare metabolite alterations to clinical outcome (assessed by Barthel index, Scandinavian Stroke Scale). The study included 31 patients who had suffered an ischemic cortical/subcortical stroke involving the motor cortex or the descending fibers. Ratios of NAA/Cr, Cho/Cr, lip/Cr and Lac/Cr from internal capsules and cerebral peduncles were measured and compared with clinical status assessed by Barthel index and Scandinavian Stroke Scale (SSS). The ratio of NAA/Cr was significantly decreased (p<0.001) in the normal-appearing ipsilateral internal capsule in comparison with the control group. Cho/Cr and lac/Cr ratios were increased compared to the control group (p=0.019). Decrease of NAA/Cr ratio correlated with clinical status assessed by Barthel index and there was a correlation between clinical improvement (assessed by SSS) and lac/Cr ratio. Tissue metabolite concentrations distant from the infarcted region correlated with the clinical course and had predictive value. Proton MRS is very useful tool for evaluating major changes in metabolite levels in pyramidal tracts after brain stroke.

A prospective study of the financial costs of multiple sclerosis at different stages of the disease.

The aim of our study was to estimate the costs of multiple sclerosis (MS) in Poland according to severity of disease. Total, direct and indirect costs were compared in 148 patients divided into three groups categorized by disease severity: stage I Expanded Disability Status Scale (EDSS <3.5), stage II (EDSS 4.0-6.0) and stage III (EDSS >6.5). Cost evaluation was performed from the societal perspective and covered the 5-month period. Simple sensitivity analysis was performed by varying the tariffs and valuing caregiving at 40% of the average wage. The mean total cost/patient for 5 months was estimated at 10,955, 15, 603 and 18, 464 PLN for stage I, II and III, respectively [exchange rate: 4 PLN=1 EUR; purchasing power pariety: 1 EUR=2.05 PLN] (P <0.0001). Regardless of EDSS stage indirect costs exceeded direct costs. Both direct and indirect costs increased with MS progression. For indirect cost the main item was productivity loss. This study confirms that MS represents a high economic burden, with indirect costs greatly exceeding direct costs. As costs increase with disease progression, treatment efforts should focus on patients in the early stages of MS.

[Idiopathic autonomic neuropathy (pandysautonomia)]. / Samoistna neuropatia autonomiczna (pandysautonomia).

On the basis of current literature, clinical and neuropathologic features of idiopathic autonomic neuropathy is presented. Idiopathic autonomic neuropathy is a disease characterized by acute or subacute onset, monophasic course over a period of several years, it is often preceded by an infection. The spectrum of autonomic changes ranges from cholinergic or adrenergic dysfunction to pandysautonomia, leading to heterogeneity of its clinical features. Possible sympathetic system abnormalities found in autonomic neuropathy are: poor pupillary response to light in darkness, orthostatic hypotension leading to syncope, hypotension without compensatory tachycardia, ejaculation disturbances and vasomotor instability. Possible parasympathetic dysfunctions are: salivation and lacrimation disturbances, absent pupillary constriction to light and near gaze, gastrointestinal tract immobility and impairment of gastrointestinal function, atonic bladder with large residual volume, erectile impotence. Pandysautonomia is thought to result from an immune mediated mechanism and responds well to plasmaferesis and intravenous immunoglobin therapy leading to gradual, sometimes not full, recovery. Moreover in this article we pay attention to the clinical value of many tests like cardiovascular or pharmacological studies in the diagnosis of pandysautonomia and in differentiation of pre- and postganglionic changes. In order to diagnose idiopathic autonomic neuropathy one has to rule out a large number of diseases with autonomic dysfunction e.g.: diabetes, malignant neoplasms, acute intermittent porphyria, Shy-Drager syndrome, Riley-Day's dysautonomia, Parkinson's disease, amyloidosis and others.

[Emotional disorders in patients with multiple sclerosis]. / Zaburzenia emocjonalne u chorych na stwardnienie rozsiane.

Multiple sclerosis (MS) is the most common demyelinating disease of the central nervous system, especially young adults. Although MS is usually looked on as a disorder of the sensory and motor systems it can also be associated with emotional dysfunctions and changes in personality. The depression, bipolar disorders, euphoria, and pathological laughing and crying are most frequently associated with the disease. Authors present a review of current opinions on pathogenesis, diagnostic criteria and treatment of emotional problems in MS patients.

[Frontotemporal dementias]. / Demencje czolowo-skroniowe.

Frontotemporal dementias are the second largest degenerative dementia group after Alzheimer's disease. It is a clinical syndrome corresponding to at least three histological entities: Pick's disease, non-specific frontotemporal degeneration, frontal lobe abnormalities associated with motor neuron disease. There are four group of symptoms in the clinical description of FTD: behavioural disorder, affective symptoms, speech disorders, neurological signs. FTD is associated with primary degeneration of the frontal and temporal lobes. Histologically there was neuronal loss, microvacuolation, tau- and ubiquitin-immunoreactive inclusions. The ballooned cortical neurons and tau- and ubiquitin-immunoreactive, argyrophilic inclusions have been called Pick-type histology. There are many descriptions of association of FTD and Pick's disease with motor neuron disease and amyotrophic lateral sclerosis. Histological changes were similar to cortical ones. In this study, we described clinical characteristic features of frontotemporal dementia and difficulties in its identification. The distinctive histopathological pattern in the FTD patients and its value to differentiate frontotemporal degeneration from other degenerative dementias is discussed.

[Neurologic and psychiatric sequelae of carbon monoxide poisoning]. / Neurologiczne i psychiatryczne nastepstwa zatrucia tlenkiem wegla.

Carbon monoxide intoxication may result in neuropsychiatric abnormalities that can be overlooked or not fully appreciated. The authors describe two female patients who developed troublesome cognitive and emotional problems following carbon monoxide poisoning and stress the value of the precise neuropsychological testing and prolonged clinical observation in such cases.

[Cortico-basal degeneration]. / Zwyrodnienie korowo-podstawne.

Cortico-basal degeneration (CBD) or cortico-basal ganglionic degeneration is a condition characterised by selective cortical atrophy of parietal and in a lesser extent, frontal lobe associated with dysfunction of the basal ganglia. The clinical symptoms of CBD, predominantly extrapyramidal signs (bradykinesia and rigidity) and apraxia, affect often only one body side in the onset phase, with the left one being more frequent. Neuropathological studies reveal neuronal loss, gliosis, and achromasia chiefly in frontal and parietal cortex, as well as in basal ganglia and substantia nigra. Functional investigations, such as SPECT, disclose similar distribution of abnormalities (hypometabolism). The aetiology and causative treatment of CBD are unknown. The authors highlight the diagnostic difficulties in CBD including a necessity of a prolonged patient's observation in order to ascertain the differential diagnosis of other neurodegenerative disorders, in particular progressive supranuclear palsy, Alzheimer's disease and Parkinson's disease.

[Knowledge of stroke problems among adults in Poland]. / Znajomosc problematyki udarowej wsród osób doroslych w Polsce.

An inquiry questionnaire was given to 180 adults without a history of stroke. The questions concerned the problem of stroke. The responders were aged from 15 to 82 years (mean 48 years). They were asked about risk factors for stroke, symptoms preceding stroke, behaviour of stroke witnesses. A correct definition of stroke was given by 86.7% of the responders. Only a small proportion of them knew risk factors for stroke (27.8% knew that one of them was hypertension, 6.1% gave smoking, 4.4% diabetes as risk factors). Although 93.9% knew that in face of stroke physician or ambulance service should be called, 6.1% thought that it would be sufficient to lie down or take paracetamol. The inquiry showed that the knowledge of risk factors for stroke is insufficient in the Polish adult population who not yet had cerebrovascular disturbances. It seems advisable to deliver an education programme in mass media on stroke prevention and its management in case of its development.

[Sensory neuronopathy]. / Neuronopatie czuciowe.

The authors present the question of sensory neuronopathy which are disorders affecting intervertebral ganglia. The neuropathological background and clinical symptoms of sensory neuronopathy are emphasised, as well as diagnostic difficulties resulting from a variety of ethiological conditions: toxic, inflammatory, and autoimmunological ones, and from lack of unequivocal clinical criteria enabling a difference diagnosis along with neuropathy and radiculopathy, which in turn requires a broad spectrum of diagnostic tests and prolonged observation of patients. The authors discuss also the clinical outcome, prognosis, and current therapeutic possibilities focusing on intensive immunosuppressive management.

[Subcortical infarcts (caudate nucleus) in a case of bilateral anterior cerebral artery occlusion]. / Zawaly podkorowe (jadra ogoniastego) w przypadku obustronnej niedroznosci tetnic mózgu przednich.

The authors describe a patient with bilateral anterior cerebral artery (ACA) occlusion. CT and MRI revealed bilateral encephalomalacia in the regions supplied by Heubner arteries and/or by perforating branches of ACA. The patient presented mainly with frontal symptomatology resulting from caudate nuclei lesion. Frontal symptomatology due to caudate impairment is discussed in the sense of frontal-subcortical circuits: lateral orbitofrontal and anterior cingulate ones. We emphasise a similarity of behavioural and cognitive disorders in early Huntington's disease and in frontal lobe lesion.

[A sporadic case of Creutzfeldt-Jakob disease with peculiar neuropathological lesions]. / Sporadyczny przypadek choroby Creutzfeldta-Jakoba o szczególnym obrazie neuropatologicznym.

The authors report a case of Creutzfeldt-Jakob disease in a man aged 60 years from a family without a history of similar disease. The disease extended over 11 months. In the clinical picture initially equilibrium disturbances and dementia with psychotic symptoms predominated, EEG pattern was not typical of CJD. Neuropathological examination revealed extensive spongiform lesions in the cortex of all cerebral lobes, in striatum and substantia nigra, moreover a considerable number of kuru plaques was found in cerebellar cortex. The authors consider that the case meets the criteria accepted for the sporadic form of CJD but believe that the final differentiation from the Gerstmann-Streussler-Scheinker syndrome should be based on genetic studies.

[Empty sella syndrome]. / Zespól pustego siodla.

The authors present two middle-aged female patients with empty sella revealed at imaging studies (CT, MRI). Their main complaint was severe fronto-parietal and fronto-temporal headache. Physical examination showed obesity, hypertension, and local hypersensitivity on deep palpation and percussion in the above-mentioned regions, in both cases. Endocrine function of pituitary gland, visual fields and fundi were normal as was EEG. The CSF composition and pressure also showed no abnormalities. The diagnostic and therapeutic problems of empty sella syndrome are discussed.

Effects of clobazam and vitamin E on the lipid peroxidation in the rat brain after electroconvulsive shock.

The effect of vitamin E and clobazam on lipid peroxides [LP] in the rat brain and the pattern of electroshock-induced seizures were assessed. Significant increase in the concentration of brain LP at the peak of seizures was found. Both vitamin E and clobazam reduced the levels of LP in the rat brain after electroshock. Clobazam combined with vitamin E inhibited markedly formation of LP in the rats with electroshock-induced seizures. Vitamin E augmented anticonvulsant effect of clobazam though itself it had not exhibited any anticonvulsant effect in this model of seizures. The action of two drugs combined resulted in reducing the intensity and the duration of seizures, and only minimal seizures were observed. In our opinion the obtained results possess some interesting clinical aspect They suggest that the combined treatment with clobazam and vitamin E of epileptic patient may decrease the intensity of epileptic seizures due to inhibition of LP formation.

[Empty sella syndrome--diagnostic difficulties]. / Zespól pustego siodla--trudnosci diagnostyczne.

The authors present three middle-aged patients (1 male, 2 females) presenting with empty sella on magnetic resonance or computed tomography imaging. Their main complaints were severe headache and dizziness. Neurological examination showed no abnormalities, except for local tenderness on palpation and percussion in the fronto-parietal or fronto-temporal regions. Endocrine evaluation showed no functional deficit of the pituitary gland. Visual fields, fundi and EEG records were normal as were the CSF composition and pressure, a skull X-ray radiograms showed an enlarged sella with thinned floor and blurred posterior oblique processes. MRI revealed a liquid space below the plane of the sellar diaphragm which pressed on the pituitary gland. The diagnostic and therapeutic problems of empty sella syndrome are briefly discussed.

[Post lumbar puncture syndrome and the manner of needle insertion]. / Zespól popunkcyjny a sposób wprowadzenia igly punkcyjnej.

We have analysed the correlation between the direction of needle bevel insertion and the occurrence of post-puncture syndrome appearing after diagnostic lumbar puncture. Post-puncture headache was observed in 38 of 380 patients (13.6%). The syndrome occurred in 11 patients (7.9%) in whom the needle bevel had been inserted parallel to the patient's backbone and in 27 patients (19.3%) in whom the needle bevel had been inserted perpendicularly to the backbone. The complications after lumbar puncture could be reduced by inserting the needle bevel parallel to the patient's backbone.

[Seasonal variations in stroke incidence in North-Eastern Poland]. / Sezonowosc wystepowania udarów niedokrwiennych mózgu w Polsce pólnocno-wschodniej.

The authors analysed seasonal and monthly incidence of and mortality from ischaemic stroke (IS) in the region of Bialystok (North-Eastern Poland). 839 cases of IS (437 men and 402 women), aged 22 to 94 years, were hospitalised in the Department of Neurology, Medical Academy in Bialystok during the analysed period (1990-1997). Significant seasonality in IS incidence was observed in both sex groups, with a nadir in summer. The lowest occurrence of infarcts was observed in August in women, and in June in men. The peak month for IS, independently of sex, was January. 240 patients (28.6%) died of stroke or its complications during the analysed period. The occurrence of fatal IS followed also a clear seasonal pattern with peak in autumn. The authors attempt to explain this seasonal incidence and mortality pattern of IS in relation to variation in temperature, diet, way of life (holidays in summer), and biochemical blood changes, which occur in different seasons of the year.