The rare-earth centers in CsCdBr3

CsCdBr3 crystallizes in the quasi-linear CsNiCl3 structure. It possesses linear chains of [CdBr6]4- octahedra separated by parallel chains of Cs+. Trivalent rare-earth (RE) ions substitute for the divalent Cd ions. The need for charge compensation leads to a number of RE centers, the most prominent of which is the symmetric pair center RE3+-(Cd vacancy)-RE3+. Madelung calculations were performed for a number of different centers giving a ranking for their chance of realization. Experimental evidence from optical spectroscopy and submillimeter ESR is given for the most likely centers. The symmetric pair center is of special interest for cooperative phenomena of RE3+ ions. This includes direct ion-ion interactions and interactions with or via the electronic excitations of the host lattice. Some experiments are discussed. © 2002 Elsevier Science B.V. All rights reserved

Spectra and relaxation of electronic excitations in CsCdBr3:Yb3+ and CsCdBr3:Nd3+ monocrystals

Experimental and theoretical studies of the optical and EPR spectra, and the spin-lattice relaxation in CsCdBr3 crystals containing 0.1, 0.3 and 1.0 mol.% of impurity Yb3+ ions have been fulfilled. In the optical excitation spectrum, a broad charge transfer band has been detected in the wave-number range of 25000-35000 cm-1. The hybridization of the excited electron configuration corresponding to the charge transfer from the ligand (Br-) 4p closed shells on the ground 4f13 configuration of the ytterbium ion is considered to interpret the anomalously large crystal field splitting of the 2F5/2 multiplet. The EPR spectra with comparable intensities of the axial single-ion and symmetric dimer centres in the sample containing 0.3 mol.% of impurity Yb3+ ions were observed. Spin-lattice relaxation rates and linewidths in the EPR spectra of the single-ion and dimer centres were measured in the temperature range of 1.5 - 35 K at the frequency of 9.5 GHz at different directions of the applied magnetic field relative to the crystal symmetry axis. Experimental results are analyzed in the framework of the microscopic theory of the electron-phonon interaction with taking into account peculiarities of the phonon spectrum of the impurity CsCdBr3 lattice. High-frequency EPR spectra of dimer centres in CsCdBr3 crystals containing 0.2 and 0.5 mol.% of impurity Nd3+ ions were taken in the range of 205-250 GHz at 4.2 K in the magnetic fields up to 0.8 T parallel to the crystal symmetry axis. The crystal field splitting between the first excited and the ground Kramers doublets, and magnetic splitting factors of these doublets were determined. An estimate of the isotropic ferromagnetic exchange constant A = (2.3±0.3) 10-3 cm-1 in symmetric dimer centres formed by impurity Nd3+ ions was obtained from the zero-field splitting of the EPR signals

The psychosocial impact of home use medical devices on the lives of older people: a qualitative study

Background Increased life expectancy and the accompanying prevalence of chronic conditions have led to the focus and delivery of health care migrating from the hospital and into people’s homes. While previous studies have investigated the integration of particular types of medical devices into the home, it was our intention to describe how medical devices are integrated into the lives of older people. Methods Adopting a qualitative study design, 12 older people, who used medical devices in the home, took part in in-depth, semi structured interviews. In 7 of the interviews participants and their partners were interviewed together. These interviews were recorded, transcribed and analysed thematically. Results Two themes were constructed that describe how medical devices that are used in the home present certain challenges to older people and their partners in how the device is adopted and the personal adaptations that they are required to make. The first theme of 'self-esteem’ highlighted the psychological impact on users. The second theme of 'the social device' illustrated the social impact of these devices on the user and the people around them. Conclusions We found that these devices had both a positive and negative psychosocial impact on users’ lives. An improved understanding of these psychological and social issues may assist both designers of medical devices and the professionals who issue them to better facilitate the integration of medical devices into the homes and lives of older people

Enhanced hydrogen peroxide generation accompanies the beneficial bioenergetic effects of methylene blue in isolated brain mitochondria

The redox dye methylene blue (MB) is proven to have beneficial effects in various models of neurodegenerative diseases. Here we investigated the effects of MB (100 nM, 300 nM, and 1 μM) on key bioenergetic parameters and on H2O2 production/elimination in isolated guinea pig brain mitochondria under normal as well as respiration-impaired conditions. As measured by high-resolution Oxygraph the rate of resting oxygen consumption was increased, but the ADP-stimulated respiration was unaffected by MB with any of the substrates (glutamate malate, succinate, or α-glycerophosphate) used for supporting mitochondrial respiration. In mitochondria treated with inhibitors of complex I or complex III MB moderately but significantly increased the rate of ATP production, restored ΔΨm, and increased the rate of Ca2+ uptake. The effects of MB are consistent with transferring electrons from upstream components of the electron transport chain to cytochrome c, which is energetically favorable when the flow of electrons in the respiratory chain is compromised. On the other hand, MB significantly increased the production of H2O2 measured by Amplex UltraRed fluorimetry under all conditions, in resting, ATP-synthesizing, and respiration-impaired mitochondria, with each substrate combination supporting respiration. Furthermore, it also decreased the elimination of H2O2. Generation of H2O2 without superoxide formation, observed in the presence of MB, is interpreted as a result of reduction of molecular oxygen to H2O2 by the reduced MB. The elevated generation and impaired elimination of H2O2 should be considered for the overall oxidative state of mitochondria treated with MB

Panayiotopoulos syndrome: video-EEG illustration of a typical seizure

Panayiotopoulos syndrome (PS) is a form of idiopathic, partial epilepsy of childhood with a high prevalence rate, but with poor clinical recognition, possibly due to the characteristics of the seizure, which not infrequently lack common epileptic motor and/or sensory phenomena. Instead, autonomic symptoms such as retching and vomiting, predominate. Semiological knowledge of the seizures in PS depends mainly on parental observations, but not enough ictal-EEG data are available, possibly due to the rarity of seizures. In addition to previous knowledge regarding the occipital onset of seizures in PS, it has been recognized that other areas, mainly the frontal regions, may be involved. The present report demonstrates the video-EEG findings of a seizure in a patient with PS. Subclinical ictal EEG discharges with occipital onset precede the clinical autonomic symptoms; eye deviation which is typical of occipital involvement, appears in later sequences. These findings suggest that at least for certain seizures an occipital origin may be considered, even in seizures without the early manifestations typical of this region. (Published with videosequences)

Benign rolandic epilepsy: neuropsychological findings

Benign rolandic epilepsy (BRE) is a partial idiopathic epilepsy of childhood presenting with a nocturnal seizure and with a typical EEG showing centrotemporal spike and multifocal or generalized sharp slow waves. Although normal neurological and intellectual development are expected in BRE, it is not infrequent to detect subtle defects in neuropsychological functions and neuromotor development. This study included 20 cases of BRE diagnosed according to the criteria of ILAE. The patients underwent several tests of neuropsychological functions as well as detailed neurological examination and the results were compared statistically to normal controls. In the patient group, a family history of language delay or learning disability (P < 0.005), presence of consanguinity (P < 0.05), dyspraxia in the lower extremities (to imitation) (P < 0.05), difficulties in go-no-go test(P < 0.001), as well as some problems related to language such as dysprosody (P = 0.05), minor motor deficits in the left (P < 0.05) and right upper extremity (P < 0.05) were significantly more frequent compared to the control group. One should be rather guarded against the prognosis in BRE with respect to the higher cortical functions and neurodevelopmental problems

The rare-earth centers in CsCdBr3

CsCdBr3 crystallizes in the quasi-linear CsNiCl3 structure. It possesses linear chains of [CdBr6]4- octahedra separated by parallel chains of Cs+. Trivalent rare-earth (RE) ions substitute for the divalent Cd ions. The need for charge compensation leads to a number of RE centers, the most prominent of which is the symmetric pair center RE3+-(Cd vacancy)-RE3+. Madelung calculations were performed for a number of different centers giving a ranking for their chance of realization. Experimental evidence from optical spectroscopy and submillimeter ESR is given for the most likely centers. The symmetric pair center is of special interest for cooperative phenomena of RE3+ ions. This includes direct ion-ion interactions and interactions with or via the electronic excitations of the host lattice. Some experiments are discussed. © 2002 Elsevier Science B.V. All rights reserved

Variations of IL2, IL6, TNF alpha plasmatic levels in relapsing remitting multiple sclerosis

We performed a longitudinal analysis of serum IL2, IL6 and TNF alpha concentrations in 40 relapsing remitting MS patients and 20 healthy subjects. Disease activity was quantified by Minimal Record of Disease (M. R. D.) for MS, every 2 or 3 months. IL2, IL6, TNF alpha production was analysed without and with PHA stimulation of whole blood for 2 hours at 37 degrees C. No significant change in IL2 level was found in MS serum. Individual TNF alpha production was significantly increased (P < 0.007) during relapses. The global spontaneous IL6 production was markedly higher in the relapse group than in the control group (p < 0.01) and than in the remission group (P < 0.002) without significant individual variations of cytokine levels regarding the disease activity. Productions of cytokines were enhanced by PHA stimulation, a condition that however suppressed the differences observed without mitogen stimulation. Our data suggest that TNF alpha could be a marker for relapses while IL6 might reflect the global activity of the immune system in MS

A clinical and EEG study on idiopathic partial epilepsies with evolution into ESES spectrum disorders

Purpose: Questioning the presence of any possible prognostic predictors, this study includes a long-term follow-up of clinical and EEG characteristics of 16 patients with idiopathic partial epilepsy (IPE) who subsequently developed epilepsy with electrical status epilepticus during slow sleep (ESES) spectrum disorders