The constellation of signs and symptoms and neuroimaging characteristics in previous reports and the six additional cases described here with neuropathological data and findings of MR spectroscopy appears unique enough to be termed "diabetic striatopathy." This syndrome appears in poorly controlled diabetics due to obliterative vasculopathy with prominent vascular proliferation, vulnerability to which is restricted to the striatum.
The control of bistable polarization states in ferroelectrics is the underlying basis of their applications to nonvolatile memories, piezoelectric devices, and micro-electromechanical systems. The switching of the polarization states by applying an electric field is governed by the dynamics of ferroelectric domains in which spontaneous polarization (P s ) is aligned in a single direction. The polarization switching is established by nucleation of new domains followed by the movement of domain walls (DWs). The crystallography and thermodynamics of the domain structures have been extensively studied and well understood not only in bulk systems [1,2] but also in constrained films. [3,4] Recently, in perovskite ferroelectrics such as PbTiO 3 and BaTiO 3 , 90°DWs have been reported to strongly interact with charged defects such as oxygen vacancies. [5][6][7][8][9][10][11] The interaction between DWs and defects leads to a viscous movement of the DWs, and the domain structure inside ferroelectric crystals is expected to be different from that predicted by the existing theory without taking the influence of defects into account. Here, we report on the 3D domain structure in ferroelectric Bi 4 Ti 3 O 12 crystals investigated by using piezoresponse force microscopy (PFM). Energetically favorable 90°D Ws with faceted structure are established on the surface along the a-b plane, while the 90°DWs have complicated and curved surfaces along the c-axis inside the crystals. The curved 90°domain structure can be explained by the strong interaction between the local electric field near the 90°DWs and oxygen vacancies.Ferroelectric Bi 4 Ti 3 O 12 (BiT) has great potential for various applications such as nonvolatile memories and leadfree piezoelectric devices, because BiT shows a high Curie temperature (T C ) of 675°C and a large P s of more than 50 lC cm -2 . [12][13][14][15] The crystal structure of BiT is described as an alternate stacking of Bi 2 O 2 layers and perovskite Bi 2 Ti 3 O 10 layers along the c-axis. Despite having the large P s , BiT has been reported to exhibit a polarization fatigue as well as a small remanent polarization (P r ). Numerous studies [16][17][18][19][20][21][22] have been conducted to overcome these drawbacks by element substitution and/or doping. It is widely recognized that the polarization fatigue and small P r originate from domain pinning, that is, a decrease in switchable domains by applying an electric field, which is caused by the interaction between DWs and defects such as oxygen vacancies. [8][9][10][11] It is essential to understand the domain structures and the interaction between the DWs and oxygen vacancies for improving the polarization properties of BiT-based devices. Recent experimental observations have revealed that 90°DWs in SrBi 2 Nb 2 O 9[23] are irregular and highly curved due to their extremely low ferroelastic distortion of less than 0.01 %. Phase-field simulations [24] have verified that the curved 90°DWs are a result of the dominant contribution of isotropic DW energy compa...
Background: Generally, clinicians use rating scales or descriptive writing to characterize diurnal changes in motor signs and symptoms in Parkinson’s disease (PD); however, these ratings are subjective and are not easily reproducible. Objective: To examine the usefulness of actigraphy as an objective indicator of akinesia by long-term, continuous measurement of limb motor activity (MA), visualize 24-hour circadian profiles of akinesia, and quantitatively detect cabergoline (CBG) efficacy in both hospitalized patients and outpatients with Parkinson’s disease. Methods: MA was continuously recorded with a wrist-worn activity monitor (actigraph) in 29 hospitalized PD patients without tremor or abnormal involuntary movements. In another series consisting of 8 outpatients, the response duration of CBG was measured by using averaged actigraphy. Results: By averaging data gathered every 24 h over several days, it was possible to quantify the circadian patterns of akinesia. These cumulative evaluations of the patients’ motor status determined 4 types of akinesia: (1) a wearing-off pattern seen in advanced efficacy stages, (2) stable response, (3) afternoon akinesia, and (4) morning akinesia. Following CBG therapy, the MA increased significantly throughout the daytime, i.e.: by 40% in the morning (8:00 a.m. to 12:00 noon), by 60% in the afternoon (12:00 noon to 6:00 p.m.), and by 60% in the next early morning (from time to get up until 8:00 a.m.). Conclusion: In averaged motor activity, the charting of cumulative evaluations of motor status revealed the long-acting efficacy of CBG in ameliorating existing motor fluctuations throughout the daytime and even promoting sleep benefit in the next morning. Averaged actigraphy is considered to be useful in the quantitative detection of drug responses to parkinsonian akinesia and its circadian variations. This enables titration of the lowest dose of drugs needed to alleviate akinesia.
An 18-year-old man with paroxysmal kinesigenic choreoathetosis (PKC) showed rhythmic electroencephalographic (EEG) discharges of 5-Hz spikes over the entire scalp during episodes. The EEG findings in this case suggest that PKC may have an epileptogenic basis.
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