Biomedical subjects

Y Matsuda

Publications and source records attributed to Y Matsuda.

At least 19 recordsLinked to original sources

PubMed2007

Prism adaptation to optical deviation alleviates pathologic pain.

BACKGROUND: The human visual and somatosensory systems are interdependent. Using a visual subjective body-midline (SM) judgment task, we previously confirmed that pathologic pain and deafferentation can modify visuospatial perception, indicating that altered somatosensory experience can modify visual perception. Conversely, in the present study we investigated whether a change in visual experience can modify perception of pathologic pain. METHODS: We used prism adaptation (PA) to modify subjects' visual experience. Five patients with complex regional pain syndrome (CRPS) adapted to wedge prisms, producing a 20-degree visual displacement toward the unaffected side. Further, we used several types of prisms in a longitudinal single-case study. Wearing prismatic goggles, the subjects performed a target-pointing task once a day for 2 weeks. We evaluated pain intensity and visual SM judgment to measure the adaptive aftereffects at three time points: before PA (pre-test), immediately after the first PA exposure (IA-test), and after a 14-day sequence of PA exposure (post-test). RESULTS: PA toward the unaffected side alleviated pathologic pain and other CRPS pathologic features, when measured at post-test. None of the IA-test results showed an analgesic effect. In the longitudinal study, sham PA and 5-degree PA did not produce any effects, and PA toward the affected side actually exacerbated the subjective pain. CONCLUSIONS: Our findings suggest that vision can influence pathologic pain, and preliminarily suggest that prism adaptation has a direction-specific and reproducible effect on not only pathologic pain but also other CRPS pathologic features. Thus, prism adaptation may be a viable cognitive treatment for CRPS.

Adaptation, Physiological↗

PubMed2007

Pathologic pain distorts visuospatial perception.

Spatial perception is achieved by integrating multisensory information. Using visual subjective body midline (vSM) judgments in patients with unilateral limb pain (complex regional pain syndrome [CRPS]), we found that their vSM deviated toward the affected side; however, deafferentation of the affected limb caused a transient pain decrease and a transient shift of the vSM deviation toward the unaffected side. Our results indicate that the persistent pain state in CRPS distorts visuospatial perception.

Adaptation, Physiological↗

PubMed2006

Fulde-Ferrell-Larkin-Ovchinnikov state in a perpendicular field of quasi-two-dimensional CeCoIn5.

A Fulde-Ferrell-Larkin-Ovchinnkov (FFLO) state was previously reported in the quasi-2D heavy fermion CeCoIn5 when a magnetic field was applied parallel to the ab plane. Here, we conduct 115In NMR studies of this material in a perpendicular field, and provide strong evidence for FFLO in this case as well. Although the topology of the phase transition lines in the H-T phase diagram is identical for both configurations, there are several remarkable differences between them. Compared to H parallelab, the FFLO phase for H perpendicularab is confined in a much narrower region at the low-T-high-H corner in the H-T plane, and the critical field separating the FFLO and non-FFLO superconducting states almost ceases to have a temperature dependence. Moreover, directing H perpendicularab results in a notable change in the quasiparticle excitation spectrum within the planar node associated with the FFLO transition.

Journal Article↗

PubMed2006

Thermal conductivity of the pyrochlore superconductor KOs2O6: strong electron correlations and fully gapped superconductivity.

To elucidate the nature of the superconducting ground state of the geometrically frustrated pyrochlore KOs2O6 (Tc=9.6 K), the thermal conductivity was measured down to low temperatures (approximately Tc/100). We found that the quasiparticle mean free path is strikingly enhanced below a transition at Tp=7.8 K, indicating enormous electron inelastic scattering in the normal state. In magnetic fields, the conduction at T-->0 K is nearly constant up to approximately 0.4Hc2, in contrast with the rapid growth expected for superconductors with an anisotropic gap. This unambiguously indicates a fully gapped superconductivity, in contrast with previous studies. These results highlight that KOs2O6 is unique among superconductors with strong electron correlations.

Journal Article↗

PubMed2006

Evidence for a new magnetic field scale in CeCoIn5.

The Nernst coefficient of displays two distinct anomalies in magnetic field. The feature detected at Hk approximately 23 T is similar to what is observed in CeRu2Si2 at Hm = 7.8 T where a metamagnetic transition occurs. In CeCoIn5, new frequencies are observed in de Haas-van Alphen oscillations when the field exceeds 23 T where the Dingle temperature decreases by about 30%. Based on the Nernst coefficient anomalies, the magnetic phase diagram of CeCoIn5 is revised.

Journal Article↗

PubMed2006

Chromosomal assignment of LASP1 and LASP2 genes and organization of the LASP2 gene in chicken.

Lasp-1 and lasp-2 are actin-binding proteins that contain a LIM domain, two nebulin repeats and an SH3 domain with significant identity. We determined the chromosomal locations of the LASP1 and LASP2 genes in chicken by fluorescence in situ hybridization. The LASP1 gene was localized to a pair of microchromosomes and the LASP2 gene was localized to chromosome 2p3.1, indicating that the chromosomal locations of the LASP1 and LASP2 genes are highly conserved between chicken and human. The comparison of genomic and cDNA sequences of chicken lasp-2 and nebulette, a nebulin-related protein in muscle, suggested that both the corresponding mRNAs shared exons in the same manner as their human homologues. When compared with the domain structure of nebulette, another nebulin repeat was predicted for lasp-2, and all the nebulin repeats of lasp-2 were better conserved than those in nebulette. We also found the exon boundaries in nebulin repeats of lasp-2 were similar to those of other nebulin-related proteins.

Alternative Splicing↗

PubMed2006

X accumulation of LINE-1 retrotransposons in Tokudaia osimensis, a spiny rat with the karyotype XO.

The observation that LINE-1 transposable elements are enriched on the X in comparison to the autosomes led to the hypothesis that LINE-1s play a role in X chromosome inactivation. If this hypothesis is correct, loss of LINE-1 activity would be expected to result in species extinction or in an alternate pathway of dosage compensation. One such alternative pathway would be to evolve a karyotype that does not require dosage compensation between the sexes. Two of the three extant species of the Ryukyu spiny rat Tokudaia have such a karyotype; both males and females are XO. We asked whether this karyotype arose due to loss of LINE-1 activity and thus the loss of a putative component in the X inactivation pathway. Although XO Tokudaia has no need for dosage compensation, LINE-1s have been recently active in Tokudaia osimensis and show higher density on the lone X than on the autosomes.

3' Untranslated Regions↗

PubMed2005

Multiband superconductivity in the heavy fermion compound PrOs4Sb12.

The thermal conductivity of the heavy fermion superconductor Pr(Os(4)Sb(12) was measured down to T(c)/40 throughout the vortex state. At lowest temperatures and for magnetic fields H approximately 0.07H(c2), already 40% of the normal state thermal conductivity is restored. This behavior (similar to that observed in MgB2) is a clear signature of multiband superconductivity in this compound.

Journal Article↗

PubMed2005

Line nodes in the superconducting gap function of noncentrosymmetric CePt3Si.

The superconducting gap structure of recently discovered heavy fermion CePt(3)Si without spatial inversion symmetry was investigated by thermal transport measurements down to 40 mK. In zero field a residual T-linear term was clearly resolved as T --> 0, with a magnitude in good agreement with the value expected for a residual normal fluid with a nodal gap structure, together with a T2 dependence at high temperatures. With an applied magnetic field, the thermal conductivity grows rapidly, in dramatic contrast to fully gapped superconductors, and exhibits one-parameter scaling with T/sqrt[H]. These results place an important constraint on the order parameter symmetry; that is, CePt(3)Si is most likely to have line nodes.

Journal Article↗

PubMed2005

Thermal transport in the hidden-order state of URu2Si2.

We present a study of thermal conductivity in the normal state of the heavy-fermion superconductor URu2Si2. Ordering at 18 K leads to a steep increase in thermal conductivity and (in contrast with all other cases of magnetic ordering in heavy-fermion compounds) to an enhancement of the Lorenz number. By linking this observation to several other previously reported features, we conclude that most of the carriers disappear in the ordered state and this leads to a drastic increase in both the phononic and electronic mean free path.

Journal Article↗

PubMed2005

Texture in the superconducting order parameter of CeCoIn5 revealed by nuclear magnetic resonance.

We present a 115In NMR study of the quasi-two-dimensional heavy-fermion superconductor CeCoIn5 believed to host a Fulde-Ferrel-Larkin-Ovchinnikov (FFLO) state. In the vicinity of the upper critical field and with a magnetic field applied parallel to the ab plane, the NMR spectrum exhibits a dramatic change below T*(H) which well coincides with the position of reported anomalies in specific heat and ultrasound velocity. We argue that our results provide the first microscopic evidence for the occurrence of a spatially modulated superconducting order parameter expected in a FFLO state. The NMR spectrum also implies an anomalous electronic structure of vortex cores.

Journal Article↗

PubMed2005

Varus-valgus balance and range of movement after total knee arthroplasty.

We performed a randomised, prospective study of 80 mobile-bearing total knee arthroplasties (80 knees) in order to measure the effects of varus-valgus laxity and balance on the range of movement (ROM) one year after operation. Forty knees had a posterior-cruciate-ligament (PCL)-retaining prosthesis and the other 40 a PCL-sacrificing prosthesis. In the balanced group (69 knees) in which the difference between varus and valgus was less than 2 degrees, the mean ROM improved significantly from 107.6 degrees to 117.7 degrees (p < 0.0001). By contrast, in the 11 knees which were unbalanced and in which the difference between varus and valgus laxity exceeded 2 degrees, the ROM decreased from a mean of 121.0 degrees to 112.7 degrees (p = 0.0061). We conclude that coronal laxity, especially balanced laxity, is important for achieving an improved ROM in mobile-bearing total knee arthroplasty.

Aged↗

PubMed2004

Flux-line lattice distortion in PrOs4Sb12.

We report that the flux-line lattice in the cubic superconductor Pr(Os4Sb12 is strongly distorted from an ideal hexagonal lattice at very low temperatures in a small applied field. We attribute this to the presence of gap nodes in the superconducting state on at least some Fermi-surface sheets.

Journal Article↗

PubMed2004

Powdery mildew pathogens can suppress the chitinase gene expression induced in detached inner epidermis of barley coleoptile.

Two-step PCR (RT-PCR and nested PCR) was used to detect gene expression in powdery mildew pathogen-infected cells of detached inner epidermis of barley coleoptiles. Cellular contents of infected cells were microscopically suctioned with a micropipette and subjected to PCR. Triosephosphate isomerase and glyceraldehyde-3-phosphate dehydrogenase genes involved in the glycolytic pathway and a stimulus-induced endochitinase gene were targeted, and their expression was determined by detecting cDNAs derived from spliced transcripts. The two gycolysis-related genes were constantly expressed in the tissue irrespective of pathogen inoculation. In contrast, chitinase gene expression was induced in non-infected inner epidermis after detachment. After inoculation, this expression was selectively suppressed in pathogen-invaded cells, in spite of continuous expression in non-invaded cells of the same epidermis. Thus, the present method enabled us to directly analyze transcripts in individual cells at the infection site and assess the capability of the pathogen to regulate host gene expression.

Biological Assay↗

PubMed2004

Giant Nernst effect in CeCoIn5.

We present a study of Nernst and Seebeck coefficients of the heavy-fermion superconductor CeCoIn5. Below 18 K, concomitant with a field-dependent Seebeck coefficient, a large sublinear Nernst signal emerges with a magnitude drastically exceeding what is expected for a multiband Fermi-liquid metal. In the mixed state, in contrast with all other superconductors studied before, this signal overwhelms the one associated with the motion of superconducting vortices. The results point to a hitherto unknown source of transverse thermoelectricity in strongly interacting electrons.

Journal Article↗

PubMed2004

On the zirconium oxide neutral cluster distribution in the gas phase: detection through 118 nm single photon, and 193 and 355 nm multiphoton, ionization.

Zirconium oxide clusters are generated in the gas phase by laser ablation of the metal into a flow of ca. 5% O2/95% He at 100 psig and supersonic expansion into a vacuum chamber. Mass spectra of neutral gas phase zirconium oxide clusters are obtained through photoionization at three different laser wavelengths: 118, 193, and 355 nm. Ionization of the clusters with 118 nm laser radiation is through a single photon ionization mechanism, while ionization by 193 and 355 nm laser radiation is through a multiphoton (three or more photon) mechanism. Fragment ion features are observed in the mass spectra of ZrmOn+ for only the 193 nm and 355 nm ionization schemes. The true neutral ZrmOn cluster distribution is obtained only through 118 nm single photon ionization, as verified by mass spectral peak linewidths and calculations of the cluster binding energies, ionization energies, and fragmentation rates. The neutral cluster distribution consists mainly of the series ZrmO2m and ZrmO(2m+1) for m = 1,..., approximately 30.

Journal Article↗

PubMed2004

On the iron oxide neutral cluster distribution in the gas phase. I. Detection through 193 nm multiphoton ionization.

Iron oxide (FemOn) neutral clusters are generated in the gas phase through laser ablation of the metal and reaction with various concentrations of O2 in He. The mixture of expansion gas and neutral FemOn cluster species is expanded through a supersonic nozzle into a vacuum system, in which the clusters are ionized by an ArF excimer laser at 193 nm, and the ions are detected and identified in a time-of-flight mass spectrometer. In this report, the experimental parameters that influence the observed cluster distributions, such as ablation laser power, expansion pressure, vacuum system pressure, and 193 nm ArF ionization laser power, are explored. In the second paper in this series, the effect of the ionization laser wavelength (355 nm, 193 nm, 118 nm) on the observed cluster ion distribution is explored. The cluster ion distribution observed employing 193 nm laser ionization, is sensitive to the neutral cluster distribution as evidenced by the change in the observed time-of-flight mass spectra with changes in laser power, growth conditions, and expansion conditions. The thermodynamically stable neutral clusters for saturated O2 growth conditions are suggested to be of the forms FemOm, FemO(m+1), and FemO(m+2); which one of these series of neutral clusters is most stable depends on the size of the cluster. For m < 10, FemOm is the most stable neutral cluster series, for 10 < or = m < or = 20, FemO(m+1) is the most stable neutral cluster series, and for 21 < or = m < = 30, FemO(m+2) is the most stable neutral cluster series. Some neutral cluster fragmentation is clearly present for 193 nm ionization due to multiphoton absorption in both the neutral and ionic cluster species.

Journal Article↗

PubMed2004

On the iron oxide neutral cluster distribution in the gas phase. II. Detection through 118 nm single photon ionization.

Neutral clusters of iron oxide are created by laser ablation of iron metal and subsequent reaction of the gas phase metal atoms, ions, clusters, etc., with an O2/He mixture. The FemOn clusters are cooled in a supersonic expansion and detected and identified in a time-of-flight mass spectrometer following laser ionization at 118 nm (10.5 eV), 193 nm (6.4 eV), or 355 nm (3.53 eV) photons. With 118 nm radiation, the neutral clusters do not fragment because single photon absorption is sufficient to ionize all the clusters and the energy/pulse is approximately 1 microJ. Comparison of the mass spectra obtained at 118 nm ionization (single photon) with those obtained at 193 nm and 355 nm ionization (through multiphoton processes), with regard to intensities and linewidths, leads to an understanding of the multiphoton neutral cluster fragmentation pathways. The multiphoton fragmentation mechanism for neutral iron oxide clusters during the ionization process that seems most consistent with all the data is the loss of one or two oxygen atoms. In all instances of ionization by laser photons, the most intense features are of the forms FemOm+, FemO(m+1)+, and FemO(m+2)+, and this strongly suggests that, for a given m, the most prevalent neutral clusters are of the forms FemOm, FemO(m+1), and FemO(m+2). As the value of m increases, the more oxygen rich neutral clusters appear to increase in stability.

Journal Article↗