Virtual depth-electrode measurement using MEG eigenspace beamformer Sekihara, K.; Poeppel, D.; Miyashita, Y.
Proceedings of the First Joint BMES/EMBS Conference : serving humanity advancing technology, Oct. 13-16, 99, Atlanta, GA, USA,
1999, Letnik:
1
Conference Proceeding, Journal Article
We have developed a method that can estimate the time course of a neural activity at a predetermined location with a high signal-to-noise ratio. Using this method, an MEG sensor array can perform ...like a virtual depth electrode in vivo. The developed method consists of two steps: the first step estimating the orientation of a neural source and the second step estimating its activity time course. The second step uses the eigenspace beamformer, which is known to give the signal-to-noise ratio higher than that from the conventional minimum-variance beamformer.
The low-lying states in ¹⁰⁶Zr and ¹⁰⁸Zr have been investigated by means of β-γ and isomer spectroscopy at the radioactive isotope beam factory (RIBF), respectively. A new isomer with a half-life of ...620 ± 150 ns has been identified in ¹⁰⁸Zr. For the sequence of even-even Zr isotopes, the excitation energies of the first 2⁺ states reach a minimum at N = 64 and gradually increase as the neutron number increases up to N = 68, suggesting a deformed subshell closure at N = 64. The deformed ground state of ¹⁰⁸Zr indicates that a spherical subshell gap predicted at N = 70 is not large enough to change the ground state of ¹⁰⁸Zr to the spherical shape. The possibility of a tetrahedral shape isomer in ¹⁰⁸Zr is also discussed.
In order to obtain the age distribution of normal values of the effects of topical tyramine or cocaine on the pupil, we measured the pupillary light reflexes of 50 normal volunteers before and 45 ...minutes (tyramine) or 90 minutes (cocaine) after the topical instillation in right eyes. Left eyes were used as controls. An infrared videopupillogram (HTV-C301) was used. Topical tyramine as well as cocaine caused mydriasis, increase of maximum %-velocity of dilatation (%-VDmax), reduction of %-amplitude of constriction (%-A) and decrease of maximum %-velocity of constriction (%-VCmax). These alternations of pupillary parameters coincided with the changes induced by topical epinephrine. The effects of tyramine or cocaine significantly increased as the age of the subjects increased, though the increase of %-VDmax caused by cocaine was only related to age. Age-related augmentation of pupillary changes were also been observed in a previous study using topical epinephrine or topical pilocarpine which concluded that the effects of any topical autonomics were increased by aging. No physiological senile Horner's syndrome was detected. It was concluded that the age-related augmentation of pupillary changes caused by topical autonomics probably resulted from the increment of corneal permeability in the aged which was confirmed in the previous fluorophotometric study by the authors following topical fluorescein administration. It is possible to assess the pupillary sensitivity to topical adrenergics of the patients with bilateral Horner's syndrome by comparing the age-related normal values obtained in this study.
Cellulose/poly(
N-vinylpyrrolidone-
co-glycidyl methacrylate) (CELL/P(VP-
co-GMA)) composites were synthesized via photopolymerization in the gel state of cellulose swollen in a mixture of VP and GMA ...monomers as reactive impregnant. The cellulose gels were formed from homogeneous solutions in N,N-dimethylacetamide/lithium chloride by coagulation in ethanol, followed by exchange of the coagulant for the monomer mixture. The thermal transition behaviour and phase construction of the (CELL/P(VP-
co-GMA) composites obtained in film form over a wide composition range were investigated. For compositions containing less than 20 wt% CELL, it was reasonably assumed that the original network structure of cellulose gels was sufficiently perpetuated into the polymerized bulk. Dynamic mechanical analysis revealed that the lowering of the storage modulus (
E′) of the copolymer-rich composites in the glass transition temperature (
T
g) region was extremely suppressed, compared with the corresponding
E′ drop observed for plain P(VP-
co-GMA) samples. The additional treatment of as-polymerized composites with aqueous formic acid or sodium hydroxide solution gave rise to a marked elevation of their
T
g values, due to a certain crosslinking reaction in the copolymer constituent. A similar
T
g elevation phenomenon was noted in the case where CELL/P(VP-
co-GMA) samples were subjected to a prolonged heat treatment at temperatures higher than ca. 175°C. This may be ascribed to the prominence of crosslinking between the cellulose and copolymer components through reaction of GMA epoxides with cellulose hydroxyls.
We examined the expression of the inducible transcription factors Zif268 and c-Fos in the inferior olive during the behavioural recovery following unilateral labyrinthectomy known as vestibular ...compensation. These transcription factors were differentially induced in the two subnuclei of the inferior olive. In the beta nucleus, c-Fos induction was restricted to the side contralateral to the lesion whereas Zif268 was induced on both the ipsilateral and contralateral side. In the dorsal cap, both proteins were expressed mostly on the contralateral side. In addition to this spatial difference, the expression of Zif268 attenuated faster than that of c-Fos. The present data suggest a functional difference between these two subnuclei of the inferior olive at the level of gene expression in vestibular compensation.
Rolling contact fatigue tests of sintered alloy were carried out under two cylinder contacts. Damage of the specimen was detected by using acceleration sensor before occurrence of final failure, ...namely spalling failure. In order to study the damage process of contact fatigue of sintered alloy, surfaces and cross sections of the specimens were observed after contact fatigue test. Damage on the specimen surface such as pitting mode of failure was not observed, while subsurface crack initiation and propagation were dominantly observed. Subsurface crack length increased with increasing number of cycles. Crack initiation and propagation in the subsurface of the specimen will be followed by a spalling mode of fracture. Stress distribution near the contact region was estimated by FEM (Finite Element Method) analysis. The location of the maximum shear stress range estimated by FEM analysis coincided with the depth of the crack initiation point observed in experiment. The position at the maximum shear stress range approaches to the specimen surface with an increase in tangential force. Subsurface crack growth behavior was controlled by the shear stress intensity factor range, ΔKII.
Chitin/poly(2-hydroxyethyl methacrylate) (PHEMA) composites were synthesized via photo-polymerization in a gel state of chitin swollen with HEMA monomer as reactive impregnant. The transition ...behavior and phase structure of the chitin/PHEMA composites were characterized by differential scanning calorimetry, dynamic viscoelastic analysis, and solid-state
13C NMR spectroscopy. For compositions containing ≲ 20wt% chitin, it was reasonably assumed that an original network structure of chitin gels was sufficiently perpetuated into the cross-linked PHEMA matrix, resulting in the formation of an interpenetrating polymer network (IPN) type organization. Owing to this IPN effect, the lowering of the dynamic modulus
E
́
of the composites in the glass transition temperature region was extremely suppressed, compared with the corresponding
É-drop observed for plain PHEMA samples. From measurements of the proton spin-lattice relaxation times
t
1
ρ
h
in the NMR study, the IPN-like composites were estimated to be homogeneous on a scale of less than ~2.4nm.
2-0-(beta-D-Glucopyranosyl)ascorbic acid (AA2 beta G) isolated from a popular traditional Chinese food (Lycium fruit) was synthesized using cellulase derived from Trichoderma sp. with cellobiose as a ...glucose donor. 6-0-(P-D-Glucopyranosyl)ascorbic acid as well as AA2 beta G, was also synthesized in this reaction. The vitamin C activity of AA2 beta G was also evaluated using inherently scorbutic (osteogenic disorder Shionogi ODS) rats. The rats were fed vitamin C-deficient food and water containing AA2 beta G for 21. AA2 beta G(. supported their growth and the level of vitamin C in tissues was moderately maintained. The vitamin C level in some tissues depended on the hydrolytic activity of AA2 beta G (beta-glucosidase activity) although the correlation was not statistically significant (P=0.08). The results indicate that AA2 beta G. has pro-vitamin C activity.
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