A fluorescence XAFS measurement instrument in the soft X-ray region toward observation under operando conditions.

X-ray absorption fine structure (XAFS) measurements are widely used for the analysis of electronic structure. Generally, XAFS in the soft X-ray region is measured under vacuum, but chemical structures under vacuum are typically different from those under operando conditions, where chemical species exhibit their function. Here, we developed an XAFS measurement instrument, as a step toward operando fluorescent, which yields XAFS measurement using synchrotron radiation in the soft X-ray region. We applied this method to analyze the local electronic structure of the sulfur atoms in L-cysteine in different pH solutions. In water at pH 7, the hydrogen atom does not dissociate from the thiol (-SH) group in L-cysteine, which forms a structure surrounded by and interacting with water molecules. The XAFS spectrum of L-cysteine in solution was altered by changing the pH. At pH 9, the hydrogen atom dissociated and a thiolate anion was formed. Although the -SH group was oxidized to SO4 (2-) when L-cysteine was adsorbed on a metal surface and dried, no oxidation was observed in solution. This may be because the water molecules were densely packed and protected the -SH group from oxidation. Our results show that this instrument aimed toward operando fluorescence XAFS measurements in the soft X-ray region is useful for structural analysis of sulfur atoms in organic molecules in air and in solution. The instrument will be applied to the structural analysis of materials containing elements that have absorption edges in soft X-ray region, such as phosphorus and alkali metals (potassium and cesium). It will be also particularly useful for the analysis of samples that are difficult to handle under vacuum and materials that have specific functions in solution.

Implantable telemetry capsule for monitoring arterial oxygen saturation and heartbeat.

In this study, we have developed an implantable telemetry capsule for monitoring heartbeat. The capsule has three main functions, monitoring vital signs, transmitting the vital signs, and receiving energy for driving the capsule without wires. We used two wavelengths of LEDs and a photodiode sensitive to the two wavelengths for heartbeat sensor. The arterial oxygen saturation is calculated from the amplitude of the heartbeat signal. We fabricated an FM transmitter whose carrier frequency was 80 MHz. Though the GHz range frequency is generally used in transmission, the attenuation in the human body is large. The size of a common linear antenna is about a quarter of its operating wavelength. We employed a coil-based antenna which can reduce size below the quarter of the wavelength. We fabricated a miniaturized transmitter with the coil-based antenna at lower frequency. Our capsule was driven intermittently. We used a rechargeable battery. When the battery ran down, the battery was charged by wireless using the induced electromotive force. This means that the capsule is capable of monitoring vital signs over the long term. We measured the heartbeat from the middle finger of hand in a water tank as a model of a human body.

Anticipatory postural adjustments modify the movement-related potentials of upper extremity voluntary movement.

To elucidate the effect on movement-related potentials (MRPs) of anticipatory postural adjustments (APAs) accompanied by voluntary focal movement, we examined the MRPs of shoulder flexion movement under standing and sitting postural conditions in 12 normal subjects. MRPs were evaluated based on three components: readiness potential (RP), motor potential (MP), and movement-monitoring potential. APAs were observed in the activities of postural muscles including the biceps femoris and erector spinae muscles only under standing conditions. The amplitudes of the three MRP components were larger under standing conditions than under sitting conditions for all recorded electrode positions, and the RP and MP amplitudes at the vertex position, which lies over the supplementary motor area (SMA), showed a prominent increase under standing conditions with the highest statistical significance. These results suggest that a recruited neural process of the cortical area including the SMA may be necessary to generate voluntary movement accompanied by APA.

Synaptic origin of the respiratory-modulated activity of laryngeal motoneurons.

To determine the synaptic source of the respiratory-related activity of laryngeal motoneurons, spike-triggered averaging of the membrane potentials of laryngeal motoneurons was conducted using spikes of respiratory neurons located between the Bötzinger complex and the rostral ventral respiratory group as triggers in decerebrate, paralyzed cats. We identified one excitatory and two inhibitory sources for inspiratory laryngeal motoneurons, and two inhibitory sources for expiratory laryngeal motoneurons. In inspiratory laryngeal motoneurons, monosynaptic excitatory postsynaptic potentials were evoked by spikes of inspiratory neurons with augmenting firing patterns, and monosynaptic inhibitory postsynaptic potentials (IPSPs) were evoked by spikes of expiratory neurons with decrementing firing patterns and by spikes of inspiratory neurons with decrementing firing patterns. In expiratory laryngeal motoneurons, monosynaptic IPSPs were evoked by spikes of inspiratory neurons with decrementing firing patterns and by spikes of expiratory neurons with augmenting firing patterns. We conclude that various synaptic inputs from respiratory neurons contribute to shaping the respiratory-related trajectory of membrane potential of laryngeal motoneurons.

A dual-channel FM transmitter for acquisition of flight muscle activities from the freely flying hawkmoth, Agrius convolvuli.

Moths can perform various flight maneuvers by the contraction of some direct and indirect flight muscles. Multi-channel recording from these flight muscles and analysis of their interaction is very important for understanding insect flight motor system. In this study, we developed a dual-channel FM transmitter for acquisition of muscle potentials, with which a male hawkmoth (Agrius convolvuli) could fly freely and perform pheromone triggered zigzag flight in a wind tunnel. The transmitter weighs only 0.25 g including single battery, has a 5 m receivable range and works for more than 30 min. Doubling channels was achieved by providing two oscillators (the carrier frequencies were 82 and 85 MHz), and interference between them was overcome by buffer amplifiers and independent reference electrodes for each channel. With this transmitter, we could acquire muscle potentials from some direct and indirect muscles during free flight. Combined with simultaneous high-speed video analysis, we observed distinct changes of motor patterns during takeoff. Our radio-telemetric system allows acquisition of actual information from freely flying moths; such information will lead to further progress in the study of insect flight.

Photon-stimulated ion desorption from molybdenum oxides following Mo 2p3/2 excitation.

Photon-stimulated ion desorption from solid MoO3 following the Mo 2p3/2 resonant transition has been investigated. In the XANES spectrum, Mo 2p3/2 peak is split into two components corresponding to the excitations from Mo 2p3/2 into the t2g and e(g) orbitals. It was observed that the desorption yield of O+ ions at the Mo 2p3/2-->e(g) resonance is higher than that at the Mo 2p3/2-->t2g resonance. The Auger decay spectra reveal that there exist two kinds of spectator Auger decays. The high desorption yield at the 2p3/2-->e(g) resonance is interpreted by the fast breaking of the Mo-O bond due to the localization of the electrons in the highly antibonding e(g).

Flash-related synchronization and desynchronization revealed by a multiple band frequency analysis.

The fast Fourier transform (FFT) is a good method to estimate power spectral density (PSD), but the frequency resolution is limited to the sampling window, and thus the precise characteristics of PSD for short signals are not clear. To relax the limitation, a multiple band-pass filter was introduced to estimate the precise course of PSDs for flash visual evoked potentials (VEPs). Signals were recorded during -200 and 600 ms using balanced noncephalic electrodes, and sampled at 1,000 Hz in 12 bits. With 1 Hz and 10 ms resolutions, PSDs were estimated between 10 and 100 Hz. Background powers at the alpha- and beta-bands were high over the posterior scalp, and powers around 200 ms were evoked at the same bands over the same region, corresponding to P110 and N165 of VEPs. Normalized PSDs showed evoked powers around 200 ms and suppressed powers following the evoked powers over the posterior scalp. The evoked powers above the 20 Hz band were not statistically significant, however, the gamma band was significantly evoked intra-individually; details in the gamma bands were varied among the subjects. Details of PSDs were complicated even for a simple task such as watching flashes; both synchronization and desynchronization occurred with different distributions and different time courses.

Pseudogap formation in the intermetallic compounds (Fe1-xVx)3Al

Optical conductivity data of the intermetallic compounds (Fe1-xVx)3Al ( 0

Gastric and non-gastric signals in electrogastrography.

Electrogastrography (EGG) is the cutaneous recording of gastric myoelectrical activity, and the dominant frequency reflects the rhythm of the gastric slow wave. Ambulatory EGG is contaminated with a large amount of motion artifacts, and it is unclear how much of the signals comprising the dominant frequency originates from non-gastric sources. The aim of the present study was to evaluate the pattern of gastric and non-gastric signals in the dominant frequency histogram (DFH) obtained from long-term ambulatory EGG recordings. Ten normal controls and five post-gastrectomy patients participated in the present study. Twenty-four hour ambulatory EGG was recorded under normal daily conditions. The DFH of normal controls showed two distinctive peaks, and that of the post-gastrectomy patients, a single peak. The common peak at approximately 1.5 cpm was seen in both DFHs, and the peak at 3 cpm was seen only in the DFH of normal controls. Thus, the common peak was thought to be a product of non-gastric origin. In conclusion, the dominant frequency consists of gastric and non-gastric components which have a specific distribution pattern in the DFH. These findings quantified the contribution of gastric and non-gastric signals to the dominant frequencies in long-term ambulatory EGG.

Attention changes the peak latency of the visual gamma-band oscillation of the EEG.

To investigate the physiological role of visual gamma-band oscillation (GBO), we calculated the event-related dynamics of the EEG power-spectrum for paired visual stimuli (S1 and S2) with or without attention in 12 subjects. The visual stimuli elicited transient increases in the GBO power (around 40 Hz), which were maximal over the parietal area. The peak GBO increase appeared around 300 ms after stimulus onset, but its latency was shorter after S1 and longer after S2 under the 'with attention' than under the 'without attention' condition. This transient increase in the visual GBO is thought to reflect attention and to reset the activity of the visual system in preparation for a new stimulus.

Event-related dynamics of the gamma-band oscillation in the human brain: information processing during a GO/NOGO hand movement task.

To investigate the gamma band activity relating to the discrimination process and motor behavior in the human brain, the event-related dynamics of the EEG spectrum was calculated during the visual GO/NOGO hand movement task and a control task (the visual element of the GO/NOGO task only) in eight subjects. The subjects were instructed to push (GO) or not to push (NOGO) a microswitch according to different visual stimuli and 21-channel scalp EEGs were recorded. The time courses of the power spectra after the stimuli were calculated using the fast Fourier transform for each condition (GO, NOGO and the control task), and were compared statistically between the conditions. The results suggested that a high gamma band oscillation, occurring at the frontal and left parieto-occipital areas at around 90 ms after the stimuli, relates to the discrimination process. Under the GO condition, this oscillation continued until 140 ms, and a subsequent oscillation occurred over the motor areas at around 200 ms, which seemed to be related to the motor action. On the other hand, under the NOGO condition, a low gamma band oscillation occurred in the central area at around 230 ms, which seemed to be related to the inhibition process.

The synchronization between brain areas under motor inhibition process in humans estimated by event-related EEG coherence.

To investigate the functional connection of brain areas under motor inhibition, the event-related coherence (ERCoh) of the electroencephalogram (EEG) was calculated for 10 subjects who were asked to perform a visual discrimination (GO/NO-GO) task. The subjects were instructed to push (GO) or not to push (NO-GO) a micro-switch according to different visual stimuli. Twenty-one-channel scalp EEGs were recorded and the surface Laplacians were calculated at F3, F4, C3, C4, P3 and P4 using the source derivation method. The time-courses of the inter- and intra-hemispheric coherence were calculated using the fast Fourier transform for each condition (GO or NO-GO), and were compared statistically between the two conditions. The results suggest that the ERCoh under the NO-GO condition consisted of two components; alpha band synchronization between bilateral frontal areas and theta band synchronization among bilateral frontal, central and parietal areas. It is likely that the former is related directly to the decision not to move, and the latter is related to the motor inhibition process.

Functional magnetic resonance imaging during recognition of written words: Chinese characters for concrete objects versus abstract concepts.

An attempt was made to apply functional magnetic resonance imaging (fMRI) to reveal cortical areas activated upon presentation of two groups of Chinese characters in six normal right-handed, male, Japanese subjects. Presentation of the characters representing 'abstract concepts' activated the bilateral occipital region without a significant difference between the bilateral occipital and temporal regions. Presentation of the characters representing 'concrete objects' resulted in significantly stronger activation in the left occipital and temporal regions. These results suggest that recognition of concrete characters involves a stronger initial process in the left occipital temporal cortices than recognition of abstract characters.

Differences in auditory scalp potentials evoked by meaningful words and nonlinguistic stimuli.

Differences in auditory evoked potentials with meaningful words and their reverse playback may reflect different neural processes in recognizing auditory stimuli. Auditory evoked potentials with the words and their reverse playback were analyzed for eight volunteers, and a maximal difference was observed at a latency around 400 msec. over the left middle temporal central area.

Functional magnetic resonance imaging during recognition of written words: Chinese characters for concrete objects versus abstract concepts.

An attempt was made to apply functional magnetic resonance imaging (fMRI) to reveal cortical areas activated upon presentation of two groups of Chinese characters in six normal right-handed, male, Japanese subjects. Presentation of the characters representing 'abstract concepts' activated the bilateral occipital region without a significant difference between the bilateral occipital and temporal regions. Presentation of the characters representing 'concrete objects' resulted in significantly stronger activation in the left occipital and temporal regions. These results suggest that recognition of concrete characters involves a stronger initial process in the left occipital temporal cortices than recognition of abstract characters.

Hemispheric laterality in contextual recognition.

Hemispheric dominance in contextual recognition is now under discussion. Auditory event-related potentials (ERPs) with a contextual decision task were recorded to study hemispheric dominance by using the wave energy and amplitudes of N400 for eight native volunteers. Two types of 80 sentences with four clauses were used as the structure: [subject] + [object or complement] + [object] + [two-syllable verb]. One type was congruent and the other deviated at the terminal clause as an incongruent sentence. Twenty-one channel ERPs were triggered at the verbs and recorded during -200 and 1,000 ms, with a noncephalic reference from 0.05 to 30 Hz. The wave energy was calculated as mean square potentials and was normalized with the background activity (pretrigger 200 ms). The amplitudes of N400 showed significant differences between the incongruent and congruent sentences, but the hemispheric dominance for the amplitudes of N400 was not significant between the incongruent and congruent sentences. Reaction times with the index finger to respond to the deviated verbs were 470.0 (mean) +/- 42.5 (SD) ms. The maximum normalized wave energy within the mean reaction time showed significant differences between the incongruent and congruent sentences, and the left hemispheric energy was shown to be significantly higher than the right one.

Binocular interactions in visual evoked cortical potentials with two light-emitting-diodes.

Binocular interaction for a central field was studied with transient scalp visual evoked cortical potentials (VECPs) using two light-emitting-diodes. VECPs were obtained for binocular and monocular visions with dominant and non-dominant eyes, and arithmetical sums of monocular VECPs with dominant and non-dominant eyes were calculated. Amplitude and latency of remarkable initial three peaks were tested with the multivariate analysis of variance. Significant differences were noted among the four VECPs. Pairwise comparisons showed that (1) the amplitude of the first peak for the binocular VECPs was larger than that for the monocular VECPs but smaller than that for the sum-VECPs; the latency of the first peaks for the binocular VECPs were earlier than that for the monocular VECPs with the non-dominant eye; (2) the amplitude of the first negative peak for the sum-VECPs was larger than that for the binocular VECPs, and the peak latency for the sum-VECPs showed later than that for the binocular VECPs; (3) the amplitude of the second positive peak for the binocular VECPs and monocular VECPs with the dominant eye was larger than that with the non-dominant eye, but smaller for the binocular VECPS than that for the sum-VECPs; the latency for the binocular VECPs showed earlier than that for the monocular VECPs with the dominant eye and for the sum-VECPs. Binocular suppression was noted in amplitude for the three peaks and binocular facilitation was noted in latency for the latter two peaks.

Reconstruction of BL7B for UV, VIS and IR spectroscopy with a 3 m normal-incidence monochromator.

The beamline BL7B at the UVSOR facility for solid-state spectroscopy is currently under reconstruction. This reconstruction mainly involves the replacement of the 1 m Seya-Namioka-type monochromator (50-600 nm) with a 3 m NIM (modified version of McPherson model 2253), which covers the 50-1000 nm range with three gratings. The deviation angle of the gratings is 15 degrees. For linear and circular polarization experiments, the beamline optics consist of a two-grazing-incidence (87.5 degrees ) pre-mirror system and a normal-incidence (15 degrees ) post-mirror.

X-ray absorption of bromonaphthalene dissolved in supercritical fluid xenon.

The results of Br K-edge X-ray absorption measurements of 1-bromonaphthalene dissolved in supercritical fluid Xe are reported. As the pressure of Xe confined in a high-pressure cell is increased, the absorption spectrum of bromonaphthalene gradually appears, showing that Xe in the supercritical fluid state solvates the bromonaphthalene molecule. The spectrum of the dissolved sample shows a remarkable difference from that of the pure liquid sample in the near-edge region of the X-ray absorption spectrum, reflecting the interaction of the solute material with solvent Xe. Ab initio full multiple-scattering calculations can reproduce the spectral features qualitatively. A large value of the Debye-Waller factor must be introduced to give the best fit, corresponding to a large degree of spatial disorder and violent thermal vibration of the Xe atoms around the Br atom.

The time course of interhemispheric EEG coherence during a GO/NO-GO task in humans.

Event-related coherence of the EEG was calculated for 10 subjects performing a visual discrimination GO/NO-GO task. The subjects were instructed to push (GO) or not to push (NO-GO) a button according to visual stimuli. Twenty-one-channel scalp EEGs were recorded and the surface Laplacian was calculated using the source derivation method. The time courses of the coherence between F3 and F4, C3 and C4, and P3 and P4 were calculated using the fast Fourier transform for each task and were compared between conditions. Statistical analysis showed that coherence in the NO-GO condition became significantly higher than that in the GO condition between F3 and F4. The synchronization between bilateral dorsolateral frontal areas might therefore play an important role in the motor inhibition process.