Patients with Alzheimer’s disease (AD) are often unaware of their cognitive impairment. This unawareness might have a multifactorial etiology, including impairment of cognitive domains and ...psychiatric symptoms. We conducted this study to determine the factors underlying unawareness of memory impairment (UMI) in patients with AD. In 103 patients with mild AD, the UMI was quantified as the difference between the patient’s self-rating and the rating of the patient’s caregiver on a standardized memory questionnaire system, the Everyday Memory Checklist. We then examined the relationships between UMI and memory, attention, language, visuospatial/constructive perception, frontal lobe function, and psychiatric symptoms. UMI was positively associated with memory impairment and delusions when effects of age, sex, and education were partialled out, suggesting that these symptoms are involved in the formation of UMI in the patients. Thus, existing treatments for memory impairment and delusions may be beneficial for increasing the awareness of mild AD patients of their cognitive impairment.
Alzheimer disease (AD) and vascular dementia (VaD) are the two major diseases that cause dementia, and early diagnosis is important. Single photon emission CT (SPECT) of cerebral blood flow (CBF) is ...used for the early detection of dementia and as an auxiliary method for follow-up. AD shows reduced posterior blood flow and VaD manifests reduced anterior blood flow on CBF SPECT images. We examined the usefulness of 3D fractal analysis of CBF SPECT images to objectively quantify the heterogeneity of CBF in patients with AD and VaD.
Thirty-two patients with AD and 22 with VaD based on neuropsychologic tests and imaging findings, as well as 20 age-matched control subjects underwent technetium-99m hexamethyl propyleneamine oxime CBF SPECT. We then conducted statistical image processing by 3D fractal analysis on reconstructed data. Fractal dimension, an index of heterogeneity, was then calculated for the whole brain, as well as for the anterior and posterior regions of the brain. A higher fractal dimension indicates that the CBF SPECT image is uneven. The ratio of fractal dimension of the anterior region to fractal dimension of the posterior region (A/P ratio) was calculated. Heterogeneity of CBF was compared among the AD, VaD, and control groups.
Fractal dimensions of the AD, VaD, and control groups were 1.072+/-0.179 (mean +/- SD), 1.005+/-0.156, and 0.806+/-0.06, respectively. A significant difference of fractal dimension was noted between the control group and the two types of dementia (P<.0001); however, no significant difference was noted between the AD and VaD groups. The A/P ratios of the AD and VaD groups were significantly different (0.952 and 1.163, respectively; P<.01).
Analysis of CBF SPECT images quantitatively showed that the fractal dimension was significantly higher (indicating heterogeneity) in patients with AD and VaD when compared with age-matched control subjects. Comparison of the A/P ratio on CBF SPECT images between AD and VaD groups showed that the heterogeneity of CBF was posterior-dominant for AD and anterior-dominant for VaD. Thus, 3D fractal analysis enabled a simple and objective evaluation of the heterogeneity of CBF in patients with AD and VaD.
The shikimate pathway is common to the biosynthesis of the three aromatic amino acids and that of various secondary metabolites in land plants. Shikimate kinase (SK; EC 2.7.1.71) catalyzes the ...phosphorylation of shikimate to yield shikimate 3-phosphate. In an attempt to elucidate the functional roles of enzymes that participate in the shikimate pathway in rice (Oryza sativa), we have now identified and characterized cDNAs corresponding to three SK genes-OsSK1, OsSK2, and OsSK3-in this monocotyledenous plant. These SK cDNAs encode proteins with different NH2-terminal regions and with putative mature regions that share sequence similarity with other plant and microbial SK proteins. An in vitro assay of protein import into intact chloroplasts isolated from pea (Pisum sativum) seedlings revealed that the full-length forms of the three rice SK proteins are translocated into chloroplasts and processed, consistent with the assumption that the different NH2-terminal sequences function as chloroplast transit peptides. The processed forms of all three rice proteins synthesized in vitro manifested SK catalytic activity. Northern blot analysis revealed that the expression of OsSK1 and OsSK2 was induced in rice calli by treatment with the elicitor N-acetylchitoheptaose, and that expression of OsSK1 and OsSK3 was up-regulated specifically during the heading stage of panicle development. These results suggest that differential expression of the three rice SK genes and the accompanying changes in the production of shikimate 3-phosphate may contribute to the defense response and to panicle development in rice.
A novel capacitive tactile sensor using a gelled polyurethane thin film is proposed in this paper. In previous studies, capacitive tactile sensors have an air gap between two electrodes in order to ...enhance sensitivity of the sensors. On the other hand, there is only polyurethane thin film between the electrodes in this study. However, sensitivity of this sensor is higher than the established capacitive tactile sensors because the polyurethane is vey flexible elastomer and the polyurethane film is very thin (about 1 ¿m). The polyurethane film is formed by spin-coating and etched back from 6 ¿m to 1 ¿m by using 48% sulfuric acid. As a result of evaluation of the tactile sensor, it is found that its sensitivity to the applied compressive pressure is about 0.8 nF/N and Young's modulus of the polyurethane is about 20 kPa.
To investigate the neural substrate underlying the mechanisms of Kanji and Kana writing, we conducted a PET activation study during mental writing task in eight right-handed normal Japanese subjects. ...During scans subjects were required to mentally write a Kanji or three Kana letters with their right hand, for each stimulant word presented auditorily. The direct comparisons between Kanji writing and Kana writing revealed that the left posterior inferior temporal gyrus was activated in Kanji writing while the left angular gyrus was activated in Kana writing. In addition, more extensive areas were activated in Kanji writing compared with Kana writing. These results suggest that different respective neural substrates are involved in Kanji and Kana writing respectively.
In patients with post‐traumatic stress disorder (PTSD), re‐experiencing the trauma is often induced by external cues in the environment. The cues, which were emotionally neutral for the patients ...before the traumatic event, become fearful ones after the event. This phenomenon is considered to be associated with fear conditioning. The paradigm was set up so that the emotionality changes in the patients with PTSD would be reproduced, and the regional cerebral blood flow (rCBF) measured with positron emission tomography (PET) was compared during exposure to the same stimuli before and after acquisition of fear conditioning. Ten healthy male subjects were asked to look at some emotionally neutral photos, then to watch a video with fearful content that also contained images similar to that presented in the photos, and afterwards to look at the photos again. Five of the 10 subjects felt that the object in the photos was more fearful after watching the video than before, and they were considered to have acquired fear conditioning. In those five subjects, the rCBF in the right amygdala and the left posterior cingulate gyrus after acquisition of fear conditioning significantly increased relative to the rCBF before conditioning. Thus, these regions seem to have a critical role in fear conditioning.
Recently multi-legged walking robots are widely developed. For these robots to walk safely, a sole sensor with high performance is desired. In the present paper, an arrayed type tactile sensor made ...of flexible silicone rubber, which is based on micro-electro-mechanical-systems (MEMS) technology, was developed. This sensor was applied as a sole sensor of a legged mobile robot. By processing the force data from many sensing elements using neural networks, information of contact force, i.e., three dimensional x, y, and z components of force vector, was able to be detected, which was confirmed by both simulation and experiment.
It is widely accepted that strong and variable radiation detected over all accessible energy bands in a number of active galaxies arises from a relativistic, Doppler-boosted jet pointing close to our ...line of sight1. Furthermore, the size of the emitting zone and the location of this region relative to the central supermassive black hole are, however, poorly known, with estimates ranging from light-hours to a light-year or more. We report the coincidence of a gamma (γ)-ray flare with a dramatic change of optical polarization angle. This provides evidence for co-spatiality of optical and γ-ray emission regions and indicates a highly ordered jet magnetic field. Our results also require a non-axisymmetric structure of the emission zone, implying a curved trajectory for the emitting material within the jet, with the dissipation region located at a considerable distance from the black hole, at about 105 gravitational radii.
Celotno besedilo
Dostopno za:
DOBA, IJS, IZUM, KILJ, NUK, PILJ, PNG, SAZU, SIK, UILJ, UKNU, UL, UM, UPUK
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