Crystal Chemistry and Magnetic Properties of Gd-Substituted Aurivillius-Type Bi5FeTi3O15 Ceramics

Aurivillius-phase ferroelectrics can be turned into multiferroic materials by incorporating magnetic ions. The four-layer Aurivillius-type system Bi5FeTi3O15 is well-known to show a strong magnetoelectric effect; however, much controversy exists on its magnetic state and the possible multiferroicity at room temperature. In this paper, we report a detailed investigation on the interconnections between crystal chemistry and magnetic properties of Bi5FeTi3O15 ceramics chemically modified by the A-site gadolinium substitution. The structural studies showed that all Bi5–xGdxFeTi3O15 (0 ≤ x ≤ 1) samples adopt the polar orthorhombic space group symmetry A21am at room temperature. The unit cell volume and the orthorhombic distortion decrease alongside the reduction of octahedral tilts by increasing the amount of Gd added. The decrease in tilting distortion of the [Ti/Fe]O6 octahedra was further evidenced by the suppression of the Raman A1[111] tilt mode at 233 cm–1. By using superconducting quantum interference and vibrating sample magnetometry, it was demonstrated that all the ceramics are paramagnetic from 5 K up to 700 K. It was thus concluded that the A-site substitution of Bi5FeTi3O15 with magnetic Gd ions brings about a slight structural relaxation of the parental orthorhombic lattice, but it is not an effective way to induce multiferroic properties in the Aurivillius compound. We suggest that the room-temperature (ferri/ferro/antiferro-) magnetism in Bi5FeTi3O15 previously reported in the literature might be due to the presence of magnetic impurities or local short-range magnetic ordering formed during material processing under different conditions

Temperature influence on magnetic properties and magnetoimpedance effect of Fe-rich glass-coated microwires

Giant magnetoimpedance, GMI, effect and magnetic properties upon temperature influence of as-prepared and stress-annealed amorphous Fe75B9Si12C4 glass-coated microwires produced by the Taylor-Ulitovsky technique are analyzed. Remarkable change in the hysteresis loops and GMI effect is observed for both samples upon heating. Tuning of the stress-annealing conditions allows one to vary the temperature dependence. Furthermore, it is observed almost complete reversibility of the changes induced by the temperature. Observed dependences are explained by the heating effect on the internal stresses relaxation, by the modification of the thermal expansion coefficients of the metallic nucleus and the glass coating, and by the Hopkinson effectThis work was supported by EU under “INFINITE” (Grant No. HORIZON-CL5-2021-D5-01-06) project, by the Spanish MCIU under PGC2018-099530-B-C31 (MCIU/AEI/FEDER, UE), by the Government of the Basque Country under Grant No. PUE_2021_1_0009, Elkartek (MINERVA and ZE-KONP) projects and under the scheme of “Ayuda a Grupos Consolidados”(ref. IT1670-22), by the Diputación Foral de Gipuzkoa in the frame of Programa “Red guipuzcoana de Ciencia, Tecnología e Inno- vación 2021” under Grant No. 2021-CIEN-000007-01 project and by the University of Basque Country under Grant No. COLAB20/15 project. The authors thank for technical and human support pro- vided by SGIker of UPV/EHU (Medidas Magneticas Gipuzkoa) and European funding (ERDF and ESF). We would like to be grateful to the administration of the University of the Basque Country, which not only provides very limited funding, but even expropriates the resources received by the research group from private companies for the research activities of the group. Such interference helps keep us on our toes. The group at the Institute of Experimental Physics SAS acknowledges support of the projects VEGA 2/0171/19 and APVV-19-036

Prevalence of non-motor symptoms and their association with quality of life in cervical dystonia

Objectives Non-motor symptoms (NMS) are commonly present along with motor impairment in patients with cervical dystonia (CD) and have a significant impact on health-related quality of life (HRQoL). However, the prevalence of NMS and their association with dystonia are still unclear. The aim of our study was to assess the prevalence of depression, anxiety, fatigue, apathy, pain, sleep problems, and excessive daytime sleepiness (EDS) in CD using different evaluation approaches and to explore their association with HRQoL relative to that of motor symptoms. Materials and Methods We enrolled 102 Slovak patients with CD. The severity of both motor and non-motor symptoms was assessed using validated scales. HRQoL was determined by the 36-item Short Form Health Survey (SF-36). Association of NMS with poor HRQoL was assessed using multiple regressions. Results The most frequent NMS in our sample were sleep impairment (67.3%), anxiety (65.5%), general and physical fatigue (57.5% and 52.9%, respectively), depression (47.1%), mental fatigue (31.4%), apathy (30.4%), reduced activity (29.4%), EDS (20.2%), and reduced motivation (18.6%). Univariate analysis showed that NMS, but not motor symptoms, were significantly linked to poor HRQoL, with EDS being most commonly associated with poor HRQoL, followed by disrupted sleep, depression, and fatigue. Conclusions The prevalence of NMS among patients with CD is high, and some NMS are strongly associated with poor HRQoL, while motor impairment was not associated with the severity of NMS or poor HRQoL. Actively diagnosing and treating NMS should therefore be a routine part of the clinical management of patients with CD

Terbium-induced phase transitions and weak ferromagnetism in multiferroic bismuth ferrite ceramics

The increasing addition of Tb in the system Bi1−xTbxFeO3 produces a progressive modification of the crystal structure from rhombohedral R3c to orthorhombic Pnma which results in the appearance and enhancement of the net magnetization, with the composition x ≈ 0.15–0.20 being a promising candidate for magnetoelectric applications.</p

Assessment of ataxia rating scales and cerebellar functional tests : critique and recommendations

Background: We assessed the clinimetric properties of ataxia rating scales and functional tests, and made recommendations regarding their use. Methods: A systematic literature search was conducted to identify the instruments used to rate ataxia symptoms. The identified rating scales and functional ability tests were reviewed and ranked by the panel as "recommended," "suggested," or "listed" for the assessment of patients with discrete cerebellar disorders, using previously established criteria. Results: We reviewed 14 instruments (9 rating scales and 5 functional tests). "Recommended" rating scales for the assessment of symptoms severity were: for Friedreich's ataxia, the Friedreich's Ataxia Rating Scale, the International Cooperative Ataxia Rating Scale (ICARS), and the Scale for the Assessment and Rating of Ataxia (SARA); for spinocerebellar ataxias, ICARS and SARA; for ataxia telangiectasia: ICARS and SARA; for brain tumors, SARA; for congenital disorder of glycosylation-phosphomannomutase-2 deficiency, ICARS; for cerebellar symptoms in multiple sclerosis, ICARS; for cerebellar symptoms in multiple system atrophy: Unified Multiple System Atrophy Rating Scale and ICARS; and for fragile X-associated tremor ataxia syndrome, ICARS. "Recommended" functional tests were: for Friedreich's ataxia, Ataxia Functional Composite Score and Composite Cerebellar Functional Severity Score; and for spinocerebellar ataxias, Ataxia Functional Composite Score, Composite Cerebellar Functional Severity Score, and SCA Functional Index. Conclusions: We identified some "recommended" scales and functional tests for the assessment of patients with major hereditary ataxias and other cerebellar disorders. The main limitations of these instruments include the limited assessment of patients in the more severe end of the spectrum and children. Further research in these populations is warranted

Prevalence of Fabry Disease among Patients with Parkinson's Disease

BACKGROUND: An increased prevalence of Parkinson’s disease (PD) disease has been previously reported in subjects with Fabry disease (FD) carrying alpha-galactosidase (GLA) mutations and their first-line relatives. Moreover, decreased alpha-galactosidase A (AGLA) enzymatic activity has been reported among cases with PD compared to controls. OBJECTIVE: The aim of our study was to determine the prevalence of FD among patients with PD. METHODS: We recruited 236 consecutive patients with PD from February 2018 to December 2020. Clinical and sociodemographic data, including the MDS-UPDRS-III scores and HY stage (the Hoehn and Yahr scale), were collected, and in-depth phenotyping was performed in subjects with identified GLA variants. A multistep approach, including standard determination of AGLA activity and LysoGb3 in males, and next-generation based GLA sequencing in all females and males with abnormal AGLA levels was performed in a routine diagnostic setting. RESULTS: The mean age of our patients was 68.9 ± 8.9 years, 130 were men (55.1%), and the mean disease duration was 7.77 ± 5.35 years. Among 130 men, AGLA levels were low in 20 patients (15%), and subsequent Lyso-Gb3 testing showed values within the reference range for all tested subjects. In 126 subsequently genetically tested patients, four heterozygous p.(Asp313Tyr) GLA variants (3.2%, MAF 0.016) were identified; all were females. None of the 4 GLA variant carriers identified had any clinical manifestation suggestive of FD. CONCLUSIONS: The results of this study suggest a possible relationship between FD and PD in a small proportion of cases. Nevertheless, the GLA variant found in our cohort is classified as a variant of unknown significance. Therefore, its pathogenic causative role in the context of PD needs further elucidation, and these findings should be interpreted with caution

Dystonia Linked to EIF4A2 Haploinsufficiency: A Disorder of Protein Translation Dysfunction

Background: Protein synthesis is a tightly controlled process, involving a host of translation-initiation factors and microRNA-associated repressors. Variants in the translational regulator EIF2AK2 were first linked to neurodevelopmental-delay phenotypes, followed by their implication in dystonia. Recently, de novo variants in EIF4A2, encoding eukaryotic translation initiation factor 4A isoform 2 (eIF4A2), have been described in pediatric cases with developmental delay and intellectual disability. Objective: We sought to characterize the role of EIF4A2 variants in dystonic conditions. Methods: We undertook an unbiased search for likely deleterious variants in mutation-constrained genes among 1100 families studied with dystonia. Independent cohorts were screened for EIF4A2 variants. Western blotting and immunocytochemical studies were performed in patient-derived fibroblasts. Results: We report the discovery of a novel heterozygous EIF4A2 frameshift deletion (c.896_897del) in seven patients from two unrelated families. The disease was characterized by adolescence- to adulthood-onset dystonia with tremor. In patient-derived fibroblasts, eIF4A2 production amounted to only 50% of the normal quantity. Reduction of eIF4A2 was associated with abnormally increased levels of IMP1, a target of Ccr4-Not, the complex that interacts with eIF4A2 to mediate microRNA-dependent translational repression. By complementing the analyses with fibroblasts bearing EIF4A2 biallelic mutations, we established a correlation between IMP1 expression alterations and eIF4A2 functional dosage. Moreover, eIF4A2 and Ccr4-Not displayed significantly diminished colocalization in dystonia patient cells. Review of international databases identified EIF4A2 deletion variants (c.470_472del, c.1144_1145del) in another two dystonia-affected pedigrees. Conclusions: Our findings demonstrate that EIF4A2 haploinsufficiency underlies a previously unrecognized dominant dystonia-tremor syndrome. The data imply that translational deregulation is more broadly linked to both early neurodevelopmental phenotypes and later-onset dystonic conditions. © 2023 The Authors. Movement Disorders published by Wiley Periodicals LLC on behalf of International Parkinson and Movement Disorder Society

Lack of Accredited Clinical Training in Movement Disorders in Europe, Egypt, and Tunisia

Background: Little information is available on the official postgraduate and subspecialty training programs in movement disorders (MD) in Europe and North Africa. Objective: To survey the accessible MD clinical training in these regions. Methods: We designed a survey on clinical training in MD in different medical fields, at postgraduate and specialized levels. We assessed the characteristics of the participants and the facilities for MD care in their respective countries. We examined whether there are structured, or even accredited postgraduate, or subspecialty MD training programs in neurology, neurosurgery, internal medicine, geriatrics, neuroradiology, neuropediatrics, and general practice. Participants also shared their suggestions and needs. Results: The survey was completed in 31/49 countries. Structured postgraduate MD programs in neurology exist in 20 countries; structured neurology subspecialty training exists in 14 countries and is being developed in two additional countries. Certified neurology subspecialty training was reported to exist in 7 countries. Recommended reading lists, printed books, and other materials are the most popular educational tools, while courses, lectures, webinars, and case presentations are the most popular learning formats. Mandatory activities and skills to be certified were not defined in 15/31 countries. Most participants expressed their need for a mandatory postgraduate MD program and for certified MD sub-specialization programs in neurology. Conclusion: Certified postgraduate and subspecialty training exists only in a minority of European countries and was not found in the surveyed Egypt and Tunisia. MD training should be improved in many countries.Peer reviewe