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.

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.

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).

[Bilateral ptosis in right hemisphere strokes]. / Obustronna ptoza w prawostronnych udarach mózgu.

Two patients with rare symptom of bilateral ptosis after ischaemic strokes of the right hemisphere are reported. It may be explained by loss of supranuclear function regulation of the nucleus of bilateral levator palpebrae.

[Evaluation of the amplitude and frequency of F wave in healthy persons]. / Ocena amplitudy i czestotliwosci wystepowania fali F u osób zdrowych.

The mean amplitude an frequency of the F wave were assessed in the median and peroneal nerves in 32 healthy subjects. A high variability of this response was noted with constant stimulation parameters, but without relation to age, sex and laterality of the nerve. Statistically significant differences were noted only between the median nerves and the peroneal nerves.

[Evaluation of the status of peripheral nerves in patients on long-term treatment with anticonvulsants based on a study of H-reflex and F wave]. / Ocena nerwów obwodowych u pacjentów przewlekle leczonych srodkami przeciwpadaczkowymi przy pomocy odruchu H i fali F.

In 30 patients with chronic epilepsy treated mainly with diphenyl hydantoin the routine examination of motor conduction velocity and the H reflex and F wave were used for assessment of the state of the ulnar-median peroneal and tibial nerves. Slight abnormalities were found in the orthodromic motor impulse conduction and much greater and more frequent abnormalities in the conduction of late responses. These results confirm the opinions of a part of the authors on a neurotoxic effect on the peripheral nerves of long-term treatment with anticonvulsants.

[Hoffmann's reflex in the evaluation of peripheral nerve fibers in alcoholism with early neurological changes]. / Odruch Hoffmanana w ocenie obwodowych wlókien nerwowych w alkoholizmie w okresie wczesnych zmian neurologicznych.

Motor nerve conduction was assessed in the tibial nerve and the conduction of H reflex was studied from the gastrocnemius muscle in a group of 30 healthy controls and 30 alcoholics without evident signs of neuropathy. Significantly greater abnormalities were found in the analysed parameters of Hoffmann's reflex-latency, conduction velocity and index than in orthodromic motor nerve conduction. The obtained results suggest the usefulness of H reflex examination for the evaluation of the state of nerve fibres, especially at the time of early changes in the peripheral nerves and their proximal location.

[The assessment of amplitude and occurrence of F waves in hemiparetic patients]. / Ocena amplitudy i czestosci wystepowania fali F w niedowladach polowiczych.

An analysis of occurrence of F response in a group of 40 patients with vascular unilateral hemiplegia was conducted. In trains of 100 supramaximal stimuli, the frequency and amplitude of the F wave was estimated bilaterally in the median and peroneal nerves. Differences in the appearance of those responses in groups with different muscular tone, were shown. Small changes were also observed contralaterally to the hemiparetic side. In 2 cases instead of F wave H reflex was recorded from the abductor pollicic brevis muscle.

[Evaluation of the peripheral nervous system by studying the F wave in patients with lung and brain tumors]. / Ocena obwodowego ukladu nerwowego przy pomocy fali F u chorych z nowotworami pluc i mózgu.

In 50 patients with various tumours: 25 with pulmonary cancer and 25 with brain tumours, the peripheral nervous system was studied carefully, both clinically and electrophysiologically, with evaluation of orthodromic conduction in motor fibres and F wave. Evidence of peripheral nerve damage was found by physical examination in 4% of pulmonary cancer cases and in 8% of these cases by analysis of orthodromic motor nerve conduction and in about 16% of cases by the method of F wave conduction. The size of the deviations was significantly greater also in the F wave responses. In patients with brain tumours no significant abnormalities were found in nerve conduction.

[Use of the F wave for detection of preclinical changes in the peripheral nerves in alcoholics]. / Zastosowanie badania fali F w wykrywaniu przedklinicznych zmian nerwów obwodowych u osób naduzywajacych alkoholu.

Orthodromic conduction in motor fibres and F wave were analysed in the median, ulnar, peroneal and tibial nerves in groups of 30 subjects: one control and one comprising patients with chronic alcoholism without detectable clinically damage to the peripheral nervous system. Abnormalities were demonstrated in both these analysed parameters, but they were more pronounced and were present in a greater proportion of cases in the assessment of the F wave. In the light of these results the determination of this response may be a useful supplementary method in the investigation of peripheral nerves, especially in the stage of preclinical lesions.

[Rheoencephalographic examination of patients with stroke in Trendelenburg's position]. / Badanie reoencefalograficzne w ulozeniu Trendelenburga u chorych z niedokrwiennymi udarami mozgu.

Typical rheoencephalographic investigations were done and repeated in Trendelenburg's position in 91 subjects including 40 healthy ones and 51 patients with ischaemic strokes. The test produced haemodynamic changes in the arterial and venous systems. The arterial changes manifested themselves as bilateral increase in blood flow, more pronounced on the side of the lesion, and bilateral increase in the vascular tonus more on the side contralateral to the focus. As a rule changes were observed in the shape of rheoencephalographic waves. Venous changes included mainly increased number of venous waves, more frequent in the patients, especially on the side contralateral to the lesion. The results of the observations are interpreted in confrontation with literature data.

[Spontaneous dissection of cerebral arteries. I. Carotid arteries and their branches]. / Samoistne rozwarstwienia tetnic domózgowych. I. Tetnice szyjne i ich rozgalezienia.

Artery dissection means tearing apart of its layers by blood coming inside after endothelial damage. The authors describe the prevalence of that pathology of carotid, arteries (diagnosed rarely so far), pointing to early onset age and to its multifactorial aetiology and pathogenesis. They also outline the pathomechanism of the neurological symptoms and emphasize the variety of the clinical manifestations. The diagnostic possibilities of artery dissection are also presented.

[Assessment of blink reflex in hemiparetic patients after stroke]. / Ocena odruchu mrugania u pacjentów z niedowladem polowiczym po udarach mózgu.

Blink reflex (BR) was evaluated in a group of 50 hemiparetic patients after stroke with lesions localized in cerebral hemispheres and in a group of 12 healthy controls. The response was examined and compared, after stimulation of the supraorbital nerve, on both paretic and "healthy" side in affected patients. Abnormalities of BR were observed in late response only. The damage of one hemisphere affects the BR bilaterally. We found prolongation of latency and decrease of amplitude of late responses bilaterally when stimulating the supraorbital nerve of the paretic side. On the contrary, stimulation of the "healthy" side evoked similar abnormalities mainly contralaterally.

[Spontaneous dissection of carotid and vertebral arteries. II. Vertebral arteries and their branches]. / Samoistne rozwarstwienia tetnic domózgowych. II. Tetnice kregowe i ich rozgalezienia.

Dissection of the extra- and ntracranial portions of vertebral arteries, as well as basilar artery and their branches are discussed based on the up-to-date literature. Formerly, arterial dissections were found exclusively at necropsy, yet they have currently arisen to the field of interest of not only neurologists but also radiologists, neurosurgeons, and vascular surgeons. Ischemic strokes frequently result from arterial dissection, in particular subintimal dissection (most often in the extracranial portion of vertebral artery), by formation of emboli or reduced perfusion. Conversely, subadventitial and transmedial dissections produce aneurysms (most often in the intracranial portion of vertebral arteries and basilar artery) which may result in subarachnoid or intracerebral hemorrhages. The other possible mechanism of focal lesions is the compression of adjacent structures by dissected artery, most frequently by dolichoectasia of basilar artery which originates from its multiple intramural lesions. The dissections may present with cranial nerve palsies, symptoms of ischemia of cervical spine, cerebellum, and cerebral trunk, as well as occipital lobe syndromes. Arterial dissection may occur in adolescents and young adults. The clinical symptom that should be stressed is headache which precedes the occurrence of stroke for several days. The right diagnosis gives a chance for proper treatment, including operative procedures, and improved prognosis.

[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.

[Paroxysmal dyskinesis and epilepsy]. / Dyskinezy napadowe a padaczka.

Based on the available literature, we outline the classification criteria of paroxysmal involuntary movements with instant onset and termination. Four types of those movements are currently distinguished: dystonic Mount-Reback paroxysmal choreoathetosis, kinesigenic paroxysmal choreoathetosis, exercise-induced paroxysmal dystonia, and hypnogenic paroxysmal dystonia. We present the clinical characteristics of those entities, as well as diagnostic and therapeutic aspects. An association with epilepsy is emphasised, which seems to predominantly apply to hypnogenic dystonia and kinesigenic paroxysmal choreoathetosis.

[Electroneurographic and electromyographic assessment of rat skeletal muscle reinnervation after microsurgical implantation of nerve into muscle venter]. / Elektroneurograficzna i elektromiograficzna ocena reinerwacji miesni szkieletowych szczura po mikrochirurgicznej implantacji nerwu w brzusiec miesnia.

The purpose of the study was an assessment of the reinnervation of paralysed rat muscles after implantation of nerve into muscle venter (neurotization). The study was carried out in three groups of rats, with neurotization performed in two groups, the third group served as control. Reinnervation was assessed by means of electroneurography (eng) and electromyography (emg) during electrostimulation of the implanted nerve. Latency and amplitude of M response were evaluated quantitatively. The study demonstrated that functional reinnervation of muscle after nerve implantation into its venter was possible, and the process of reinnervation developed at the highest rate within 16 weeks after neurotization. The use of nerve graft bridging the distance between the stump of the severed nerve and the denervated muscle had no unfavourable effect on the end-result of neurotization.

[Peripheral nerve regeneration by autografts in rats. II. Electrophysiological assessment]. / Regeneracja nerwów obwodowych szczura po rekonstrukcji ubytku wlasnopochodnym przeszczepem miesnia. II. Ocena elektrofizjologiczna.

Peripheral nerves repairing using freeze-thawed skeletal muscle autografts were compared to conventional nerve grafts with respect to their electrical properties. It was found that the amplitude and distal latency of action potentials in both groups were not significantly different 3 and 6 months after the operation. These observations support the thesis that peripheral nerve repair by freeze-thawed autogenous muscle grafts may have a significant role in the reconstruction of injured nerves.

[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.