Catalogue Search | MBRL
Search Results Heading
Explore the vast range of titles available.
MBRLSearchResults
-
DisciplineDiscipline
-
Is Peer ReviewedIs Peer Reviewed
-
Item TypeItem Type
-
SubjectSubject
-
YearFrom:-To:
-
More FiltersMore FiltersSourceLanguage
Done
Filters
Reset
1,268
result(s) for
"YAMAMOTO, Shin"
Sort by:
A Review of Classification Techniques of EMG Signals during Isotonic and Isometric Contractions
by
Abdul Rahman, Mohd
,
Mazlan, Saiful
,
Yamamoto, Shin-Ichiroh
in
Algorithms
,
classifications
,
Electromyography
2016
In recent years, there has been major interest in the exposure to physical therapy during rehabilitation. Several publications have demonstrated its usefulness in clinical/medical and human machine interface (HMI) applications. An automated system will guide the user to perform the training during rehabilitation independently. Advances in engineering have extended electromyography (EMG) beyond the traditional diagnostic applications to also include applications in diverse areas such as movement analysis. This paper gives an overview of the numerous methods available to recognize motion patterns of EMG signals for both isotonic and isometric contractions. Various signal analysis methods are compared by illustrating their applicability in real-time settings. This paper will be of interest to researchers who would like to select the most appropriate methodology in classifying motion patterns, especially during different types of contractions. For feature extraction, the probability density function (PDF) of EMG signals will be the main interest of this study. Following that, a brief explanation of the different methods for pre-processing, feature extraction and classifying EMG signals will be compared in terms of their performance. The crux of this paper is to review the most recent developments and research studies related to the issues mentioned above.
Journal Article
Distinct bilateral prefrontal activity patterns associated with the qualitative aspect of working memory characterized by individual sensory modality dominance
by
Yamamoto, Shin-ichiroh
,
Matsumoto, Mayuko
,
Sakurada, Takeshi
in
Activity patterns
,
Biology and Life Sciences
,
Cognitive ability
2020
In addition to quantitative individual differences in working memory (WM) capacity, qualitative aspects, such as enhanced sensory modality (modality dominance), can characterize individual WM ability. This study aimed to examine the neurological basis underlying the individual modality dominance component of WM using functional near-infrared spectroscopy (fNIRS). To quantify the degree of individual WM modality dominance, 24 participants were required to find seven hidden targets and hold their spatial location and appearance order with vibrotactile or visual stimuli aids. In this searching task, eight participants demonstrated higher performance with the tactile condition (tactile-dominant) whereas sixteen demonstrated visual dominance. We then measured prefrontal activity by fNIRS during memorization of visual stimulus numbers while finger tapping as a cognitive-motor dual-task. Individual modality dominance significantly correlated with bilateral frontopolar and dorsolateral prefrontal activity changes over repeated fNIRS sessions. In particular, individuals with stronger visual dominance showed marked decreases in prefrontal area activity. These results suggest that distinct processing patterns in the prefrontal cortex reflect an individual's qualitative WM characteristics. Considering the individual modality dominance underlying the prefrontal areas could enhance cognitive or motor performance, possibly by optimizing cognitive resources.
Journal Article
Comfortable and Convenient Turning Skill Assessment for Alpine Skiers Using IMU and Plantar Pressure Distribution Sensors
by
Matsumura, Seiji
,
Yamamoto, Shin-ichiroh
,
Kimura, Toshitaka
in
Athletic Performance
,
feature detection
,
Humans
2021
Improving ski-turn skills is of interest to both competitive and recreational skiers, but it is not easy to improve on one’s own. Although studies have reported various methods of ski-turn skill evaluation, a simple method that can be used by oneself has not yet been established. In this study, we have proposed a comfortable method to assess ski-turn skills; this method enables skiers to easily understand the relationship between body control and ski motion. One expert skier and four intermediate skiers participated in this study. Small inertial measurement units (IMUs) and mobile plantar pressure distribution sensors were used to capture data while skiing, and three ski-turn features—ski motion, waist rotation, and how load is applied to the skis—as well as their symmetry, were assessed. The results showed that the motions of skiing and the waist in the expert skier were significantly larger than those in intermediate skiers. Additionally, we found that the expert skier only slightly used the heel to apply a load to the skis (heel load ratio: approximately 60%) and made more symmetrical turns than the intermediate skiers did. This study will provide a method for recreational skiers, in particular, to conveniently and quantitatively evaluate their ski-turn skills by themselves.
Journal Article
Effects of molecular weight on the optical and electrochemical properties of EDOT-based π-conjugated polymers
by
Hayashi, Shotaro
,
Yamamoto, Shin-ichi
,
Koizumi, Toshio
in
639/638/455/954
,
639/638/549/941
,
Absorptiometry
2017
Absolute molecular weight values obtained by gel permeation chromatography with multi angle light scattering of
PEDOTF8
were approximately 65% of the relative molecular weight values obtained by gel permeation chromatography using polystyrene standards. Both light absorption and molecular weight measurements showed the effective conjugation lengths (absolute molecular weight <2600, relative molecular weight <4000, number of EDOT-F8 units:
n
< ca. 5 unit). The low molecular weight polymers showed higher energy absorption and fluorescence bands. Molecular weight also affected the electrochemical process of the polymer films. The high molecular weight
PEDOTF8
(number average molecular weight >70000) showed a higher redox stability than the low molecular weight one. The two polymers with number average molecular weights of 70200 and 40000 retained 65% and 25% of the charge storage capacity after 100 electrochemical scans, respectively. Square-wave potential step absorptiometry measurements of the polymers with number average molecular weights of 70200 and 40000 showed that the optical contrasts remain stable after ca. 55 and three cycles, respectively. The high molecular weight polymer has a high electrochemical stability and would be a good material for optoelectronic devices.
Journal Article
Characteristics of the gait adaptation process due to split-belt treadmill walking under a wide range of right-left speed ratios in humans
by
Nakazawa, Kimitaka
,
Yokoyama, Hikaru
,
Kawashima, Noritaka
in
Adaptability
,
Adaptation
,
Biology and Life Sciences
2018
The adaptability of human bipedal locomotion has been studied using split-belt treadmill walking. Most of previous studies utilized experimental protocol under remarkably different split ratios (e.g. 1:2, 1:3, or 1:4). While, there is limited research with regard to adaptive process under the small speed ratios. It is important to know the nature of adaptive process under ratio smaller than 1:2, because systematic evaluation of the gait adaptation under small to moderate split ratios would enable us to examine relative contribution of two forms of adaptation (reactive feedback and predictive feedforward control) on gait adaptation. We therefore examined a gait behavior due to on split-belt treadmill adaptation under five belt speed difference conditions (from 1:1.2 to 1:2). Gait parameters related to reactive control (stance time) showed quick adjustments immediately after imposing the split-belt walking in all five speed ratios. Meanwhile, parameters related to predictive control (step length and anterior force) showed a clear pattern of adaptation and subsequent aftereffects except for the 1:1.2 adaptation. Additionally, the 1:1.2 ratio was distinguished from other ratios by cluster analysis based on the relationship between the size of adaptation and the aftereffect. Our findings indicate that the reactive feedback control was involved in all the speed ratios tested and that the extent of reaction was proportionally dependent on the speed ratio of the split-belt. On the contrary, predictive feedforward control was necessary when the ratio of the split-belt was greater. These results enable us to consider how a given split-belt training condition would affect the relative contribution of the two strategies on gait adaptation, which must be considered when developing rehabilitation interventions for stroke patients.
Journal Article
Modulation of corticospinal excitability related to the forearm muscle during robot-assisted stepping in humans
2023
In recent years, the neural control mechanisms of the arms and legs during human bipedal walking have been clarified. Rhythmic leg stepping leads to suppression of monosynaptic reflex excitability in forearm muscles. However, it is unknown whether and how corticospinal excitability of the forearm muscle is modulated during leg stepping. The purpose of the present study was to investigate the excitability of the corticospinal tract in the forearm muscle during passive and voluntary stepping. To compare the neural effects on corticospinal excitability to those on monosynaptic reflex excitability, the present study also assessed the excitability of the H-reflex in the forearm muscle during both types of stepping. A robotic gait orthosis was used to produce leg stepping movements similar to those of normal walking. Motor evoked potentials (MEPs) and H-reflexes were evoked in the flexor carpi radialis (FCR) muscle during passive and voluntary stepping. The results showed that FCR MEP amplitudes were significantly enhanced during the mid-stance and terminal-swing phases of voluntary stepping, while there was no significant difference between the phases during passive stepping. Conversely, the FCR H-reflex was suppressed during both voluntary and passive stepping, compared to the standing condition. The present results demonstrated that voluntary commands to leg muscles, combined with somatosensory inputs, may facilitate corticospinal excitability in the forearm muscle, and that somatosensory inputs during walking play a major role in monosynaptic reflex suppression in forearm muscle.
Journal Article
Natural Variation of the RICE FLOWERING LOCUS T 1 Contributes to Flowering Time Divergence in Rice
by
Fujisawa, Hiroko
,
Yano, Masahiro
,
Ando, Tsuyu
in
Amino Acid Sequence
,
Amino Acid Substitution
,
Amino acids
2013
In rice (Oryza sativa L.), there is a diversity in flowering time that is strictly genetically regulated. Some indica cultivars show extremely late flowering under long-day conditions, but little is known about the gene(s) involved. Here, we demonstrate that functional defects in the florigen gene RFT1 are the main cause of late flowering in an indica cultivar, Nona Bokra. Mapping and complementation studies revealed that sequence polymorphisms in the RFT1 regulatory and coding regions are likely to cause late flowering under long-day conditions. We detected polymorphisms in the promoter region that lead to reduced expression levels of RFT1. We also identified an amino acid substitution (E105K) that leads to a functional defect in Nona Bokra RFT1. Sequencing of the RFT1 region in rice accessions from a global collection showed that the E105K mutation is found only in indica, and indicated a strong association between the RFT1 haplotype and extremely late flowering in a functional Hd1 background. Furthermore, SNPs in the regulatory region of RFT1 and the E105K substitution in 1,397 accessions show strong linkage disequilibrium with a flowering time-associated SNP. Although the defective E105K allele of RFT1 (but not of another florigen gene, Hd3a) is found in many cultivars, relative rate tests revealed no evidence for differential rate of evolution of these genes. The ratios of nonsynonymous to synonymous substitutions suggest that the E105K mutation resulting in the defect in RFT1 occurred relatively recently. These findings indicate that natural mutations in RFT1 provide flowering time divergence under long-day conditions.
Journal Article
Development of – 80 °C storage for Allium shoot tips using D cryo-plate method
by
Yamamoto Shin-ich
,
Sakuma Yoshinori
,
Valle Arizaga Miriam
in
Air temperature
,
Alginic acid
,
Allium
2021
D cryo-plate method was successfully adapted for storage at – 80 °C and – 196 °C of Allium shoot tips. The optimal D cryo-plate method using garlic shoot tips for the storage at – 80 °C and – 196 °C includes preculture of shoot tips for 2 days at 25 °C on solidified 1/2 MS medium containing 0.3 M sucrose, then placing them in wells on an aluminum cryo-plate, embedded in calcium alginate gel. Osmoprotection was performed by immersing the cryo-plates with shoot tips for 30 min at 25 °C in 2.0 M glycerol and 1.0 M sucrose. The optimal dehydration time of shoot tips was for 30 to 180 min at 25 °C. Cooling was performed by transferring the samples on the cryo-plate into 2 ml cryotubes, then cooling into a deep freezer at – 80 °C for 14 days or directly plunging into liquid nitrogen (− 196 °C) for 60 min. The regrowth rate of shoot tips stored both at – 80 °C and – 196 °C was almost 100%. This optimized procedure was applied to seven Allium spp. The average regrowth rates after cooling at – 80 °C and – 196 °C were 95.3 and 94.0%, respectively. Thus, the storage of shoot tips at – 80 °C using D cryo-plate method is considered to be efficiently applicable for practical genebank storage.Key messageD cryo-plate method was successfully adapted for storage at – 80 °C of Allium shoot tips. Grass transition temperature of shoot tips after air desiccation were − 39.4 °C.
Journal Article
Influence of Yb doping on optical and upconversion photoluminescence properties of Yb-, Er-co-doped Y2O3 transparent ceramics prepared by SPS
by
Kawaguchi, Noriaki
,
Kato, Takumi
,
Nakauchi, Daisuke
in
Ceramics
,
Characterization and Evaluation of Materials
,
Chemistry and Materials Science
2021
x
% Yb-, 0.5% Er-co-doped Y
2
O
3
transparent ceramics (
x
= 0, 0.1, 0.5, 1.0, 5.0 and 10) were prepared by the spark plasma sintering, and then we evaluated the effect of Yb doping on optical and upconversion (UC) photoluminescence (PL) properties. Under an excitation at 380 nm, the sharp emission peaks appeared around 550 and 660 nm, and the quantum yield was approximately 2%. The PL decay curves monitoring around 550 nm were fitted by a single exponential decay function. The decay time constants were 0.03–0.11 ms, and the values were typical for the 4f → 4f transitions of Er
3+
. Regarding the UC PL properties, the sharp UC emission peaks around 550 and 660 nm were observed, and the UC emission intensity of 5.0% Yb-, 0.5% Er-co-doped Y
2
O
3
transparent ceramic sample was the highest among the prepared samples. With increasing
x
, the chromaticity of UC emission color was tuned from green to red region. Regarding the UC PL decay curves, the rise time became slower as increasing
x
. This behavior is one of the evidence of energy transfer from Yb
3+
to Er
3+
.
Journal Article
Multiple functional polymorphisms in a single disease resistance gene in rice enhance durable resistance to blast
2014
The improvement of resistance to blast, a devastating fungal disease of rice, would support the sustainable production of one of the world's staple foods, yet the identification of genes for durable resistance in rice is a challenge owing to their complicated genetic control. Here we show that map-based cloning of
Pi35
identifies multiple functional polymorphisms that allow effective control of the disease and that
Pi35
is allelic to
Pish
, which mediates race-specific resistance to blast and encodes a protein containing a nucleotide-binding site (NBS) and leucine-rich repeats (LRRs). Analysis using
Pish
–
Pi35
chimeric genes demonstrated that multiple functional polymorphisms cumulatively enhance resistance and that an amino acid residue in a LRR of
Pi35
is strongly associated with the gene's mediation of quantitative but consistent resistance to pathogen isolates in Japan, in contrast to
Pish
, which mediates resistance to only a single isolate. Our results reinforce the substantial importance of mining allelic variation for crop breeding.
Journal Article