Magnetic-field-induced shape recovery by reverse phase transformation

Large magnetic-field-induced strains have been observed in Heusler alloys with a body-centred cubic ordered structure and have been explained by the rearrangement of martensite structural variants due to an external magnetic field. These materials have attracted considerable attention as potential magnetic actuator materials. Here we report the magnetic-field-induced shape recovery of a compressively deformed NiCoMnIn alloy. Stresses of over 100 MPa are generated in the material on the application of a magnetic field of 70 kOe; such stress levels are approximately 50 times larger than that generated in a previous ferromagnetic shape-memory alloy. We observed 3 per cent deformation and almost full recovery of the original shape of the alloy. We attribute this deformation behaviour to a reverse transformation from the antiferromagnetic (or paramagnetic) martensitic to the ferromagnetic parent phase at 298 K in the Ni45Co5Mn36.7In13.3 single crystal.

Metamagnetic quantum criticality revealed by 17O-NMR in the itinerant metamagnet Sr3Ru2O7

We have investigated the spin dynamics using 17O-NMR in the bilayered perovskite Sr3Ru2O7, which sits close to a metamagnetic quantum critical point. The nuclear spin-lattice relaxation rate divided by temperature 1/T1T is enhanced on approaching the metamagnetic critical field of approximately 7.9 T, and at the critical field 1/T1T continues to increase and does not show Fermi-liquid behavior down to 0.3 K. The temperature dependence of T1T in this region suggests the critical temperature Theta to be approximately 0 K, which is strong evidence that the spin dynamics possesses a quantum critical character. Comparison between uniform susceptibility and 1/T1T reveals that antiferromagnetic fluctuations instead of two-dimensional ferromagnetic fluctuations dominate the spin fluctuation spectrum at the critical field, which is unexpected for itinerant metamagnetism.

The role of eosinophils in Angiostrongylus cantonensis infection

Angiostrongylus cantonensis is the causative agent of human eosinophilic meningoencephalitis in the Pacific Islands and Southeast Asia. Prominent eosinophilia in the cerebrospinal fluid (CSF) of the patients has been used as one of the diagnostic criteria for the disease but the role(s) of the CSF eosinophils has remained to be elucidated. In this article, Kentaro Yoshimura, Hiroko Sugaya and Kazuto Ishido discuss the involvement of CSF eosinophils in the killing of intracranial worms and the damage of the central nervous system of the hosts, and consider why eosinophils in A. cantonensis infection play a more important role in nonpermissive hosts (including humans) than in the permissive rat host.

Effect of prestrain on martensitic transformation in a Ti46.4Ni47.6Nb6.0 superelastic alloy and its application to medical stents

The effect of applied strain on martensitic transformation in a superelastic Ti(46.4)Ni(47.6)Nb(6.0) alloy at room temperature was investigated by tensile tests, differential scanning calorimetry measurements, and X-ray diffraction. Reverse transformation starting (A(s)) and finishing (A(f)) temperatures increased with the application of tensile-strain over 13%, the undeformed specimen showing A(s) = -29.2 degrees C and A(f) = 17.9 degrees C, while the 13% predeformed alloy exhibited A(s) = 37.1 degrees C and A(f) = 40.2 degrees C. Furthermore, the values of the A(s) and A(f) for the predeformed alloy almost recovered to those of the undeformed alloy when heated to about 42 degrees C and then showed superelasticity again at room temperature. This characteristic is significant for application in sensors, actuators, and medical devices. Especially, medical stents with such qualities show promise as a new class of self-expandable stents with both excellent mountability and deliverability.

[Kinking of skeletonized internal thoracic artery graft]

A 66-year-old woman underwent coronary artery bypass grafting (CABG). Postoperative angiography on postoperative day (POD) 11 revealed that right internal thoracic artery (RITA) anastomosed to left anterior descending artery (LAD) had a kinking. The angiography performed 30 months after operation revealed no specific changes in the kinking of RITA and in the left ventricular function. Another case was a 74-year-old man with chronic renal failure under hemodialysis. He underwent CABG with left internal thoracic artery (LITA) to LAD. Post-operatively he had chest pain during hemodialysis. On POD 10, angiography revealed that LITA had a kinking with moderate stenosis and normal left ventricular function. The angiography performed 10 months after operation revealed no specific changes in the kinking of LITA. However, left ventriculography revealed akinesis in the antero-apical region. It suggested that the viability was lost due to the graft kinking of LITA and steal phenomenon on hemodialysis.

Size distribution and genetic structure in relation to clonal growth within a population of Magnolia tomentosa Thunb. (Magnoliaceae)

To establish a baseline for conservation of a threatened clonal tree, Magnolia tomentosa, we investigated size distribution and genetic structure within a population, using six microsatellite markers. Within the study site, 1044 living ramets (stems) were distinguished into 175 genets (individuals). The mean number of ramets per genet was 5.97, and 76% of all genets had multiple ramets. Genets, which apparently produced new ramets through sprouting and layering, were generally composed of several large ramets and many small ramets. Spatial autocorrelation analysis of microsatellite alleles revealed positive autocorrelation over short distances for both ramets and genets. The Moran's I-value of ramets in the shortest distance class was 3.8 times larger than that of genets, reflecting the effect of clonal growth. To analyse the size-class differences in genetic structure, the 175 genets were separated into two size classes, small and large. The correlogram for the small genets exhibited positive spatial autocorrelation in the shortest distance class, but this was not the case for the correlogram for the large genets, indicating that genetic structure is weakened or lost through self-thinning as the genets grow. The FIS value over all loci for the small genets was positive and deviated significantly from zero, while the corresponding value for the large genets was close to zero. The excess homozygotes in the small genets may be the result of genetic substructuring and/or inbreeding, and the reduction in homozygote frequency from the small to large genets may be because of loss of genetic structure and/or inbreeding depression.

Measurement of the 101Ru-Knight shift of superconducting Sr2RuO4 in a parallel magnetic field

101Ru-Knight shift (101K) in the spin-triplet superconductor Sr2RuO4 was measured under magnetic fields parallel to the c axis (perpendicular to the RuO2 plane), which is the promising superconducting (SC) d-vector direction in a zero field. We succeeded in measuring K(c) in the field range from 200 to 1200 Oe and at temperatures down to 80 mK, using nuclear-quadrupole-resonance spectra. We found that (101)K(c) is invariant with respect to the field and temperature on passing through H(c2) and T(c) above 200 Oe. This indicates that the spin susceptibility along the c axis does not change in the SC state, at least, in the field greater than 200 Oe. The results imply that the SC d vector is in the RuO2 plane when the magnetic field is applied to the c axis.

Lactobacillus reuteri in bovine milk fermented decreases the oral carriage of mutans streptococci

The effect of Lactobacillus reuteri against one of the major cariogenic organism, Streptococcus mutans, was studied. Yogurt products containing L.reuteri showed a significant growth inhibitory effect against S. mutans, whilst yoghurts with lactobaccilli other than L. reuteri did not show such inhibition. Further, double-blind, placebo-controlled trial demonstrated that consuming yogurt with L. reuteri significantly reduced the oral carriage of mutans streptococci, compared with the placebo yogurt.

Novel phase separation and spin dynamics of lightly doped La2-xSr2CuO4 probed by La-nuclear quadrupole resonance

We report novel magnetic properties in the slightly hole-doped Mott-insulator La(2-x)SrxCuO4 via the La-nuclear quadrupole resonance (NQR) measurements. At x=0.018, the antiferromagnetic (AFM) La-NQR spectrum affected by internal fields comes out as the temperature decreases below T(N) approximately 150 K, whereas the nonmagnetic one persists to be observed down to a temperature T(f) approximately 20 K at which the nuclear-relaxation rate has a pronounced peak. This demonstrates that the phase separation of nonmagnetic and AFM phases occurs between T(f) and T(N). The novel phase separation is suggested as due to the partial destruction of the AFM phase caused by mobile holes via the formation of an extended spin-singlet state between Cu-derived spins and hole spins.

Post-challenge hyperglycaemia is an independent risk factor for arterial stiffness in Japanese men

AIMS

Arterial stiffness is an independent predictor of cardiovascular disease, but the impact of post-challenge hyperglycaemia on arterial stiffness is unknown. To investigate the association between arterial stiffness and post-challenge hyperglycaemia, we measured the second derivative of photoplethysmogram as an indicator of arterial stiffness.

METHODS

This study was done in 159 asymptomatic Japanese men aged 50.7 +/- 13.0 years. All subjects underwent a 75-g oral glucose tolerance test and measurement of the second derivative of photoplethysmogram.

RESULTS

According to the World Health Organization criteria (1998), 110 subjects had normal glucose tolerance, 10 had impaired fasting glucose, 30 had impaired glucose tolerance, and nine had diabetes. The b/a ratio (an index of arterial stiffness) showed a significant relationship with age (r = 0.58, P < 0.0001), height (r = -0.33, P < 0.0001), 2-h post-challenge glucose (r = 0.32, P < 0.0001), systolic blood pressure (r = 0.22, P = 0.006), and diastolic blood pressure (r = 0.21, P = 0.009). After adjustment for age and height, there were significant correlations between the b/a ratio and diastolic blood pressure (r = 0.18, P = 0.02), fasting glucose (r = 0.16, P = 0.049), and 2-h post-challenge glucose (r = 0.21, P = 0.009). Stepwise multiple regression analysis showed that only age (beta= 0.006, SE = 0.0007, P < 0.001) and 2-h post-challenge glucose (beta = 0.0005, SE = 0.0002, P < 0.05) contributed significantly to the b/a ratio (adjusted R(2) = 0.38).

CONCLUSIONS

These results indicate that post-challenge hyperglycaemia is an independent risk factor for arterial stiffness.

Multiple first-order metamagnetic transitions and quantum oscillations in ultrapure Sr3Ru2O7

We present measurements on ultraclean single crystals of the bilayered ruthenate metal Sr3Ru2O7, which has a magnetic-field-tuned quantum critical point. Quantum oscillations of differing frequencies can be seen in the resistivity both below and above its metamagnetic transition. This frequency shift corresponds to a small change in the Fermi surface volume that is qualitatively consistent with the small moment change in the magnetization across the metamagnetic transition. Very near the metamagnetic field, unusual behavior is seen. There is a strong enhancement of the resistivity in a narrow field window, with a minimum in the resistivity as a function of temperature below 1 K that becomes more pronounced as the disorder level decreases. The region of anomalous behavior is bounded at low temperatures by two first-order phase transitions. The implications of the results are discussed.

A novel technique to evaluate the adhesion of Candida species to gingival epithelial cells

We developed an in vitro ATP assay technique to extract cellular and fungal ATP separately, which allowed to evaluate quantitatively the adhesion of the yeasts to monolayers of human gingival epithelial cells. Thirteen isolates of Candida spp. representing three species (i.e. Candida albicans, C. tropicalis and C. glabrata) were used in the present study. When the adherent capacity of the Candida species was compared, C. albicans exhibited highest capacity of adherence to gingival epithelial cells, followed by C. tropicalis, and C. glabrata was the lowest [analysis of variance (ANOVA), P < 0.01]. The germ tubes of C. albicans exhibited significantly higher adherence capacity than their blastoconidia cells (ANOVA, P < 0.01), which was not observed with a C. albicans isolate, defect of germ tube formation. Our results suggested that the adherence of C. albicans is promoted by germ tube formation and may play an important role in the pathogenesis of the fungus.

Argyrophilic dark neurons represent various states of neuronal damage in brain insults: some come to die and others survive

Argyrophilic dark neurons (DNs) reflect the early histopathological state of neurons following various brain insults. We examined the fate of DNs, about to either die or recover, following two types (heavy and light damage) of brain insult. Wistar rats were injected ibotenic acid unilaterally into the hippocampal CA1 region (ibotenic acid [IA] injection) or were forced to swim (SWIM). Argyrophil III (DNs)-, activated caspase-3 immuno-, TUNEL- and hematoxylin-eosin (H-E)-staining and ultrastructural examinations were then performed. One to three hours after IA injection, typical DNs (argyrophilic both in somata and dendrites) with corkscrew-like dendrites were densely packed in the pyramidal cell layer of hippocampal CA1 around the injection site. After 12-24 h, DNs were argyrophilic only in the somata and proximal dendrites but absent in distal dendrites in the CA1 region. However, at this time typical DNs were found in remote areas. At 3 h, caspase-3 activation was detected at the injection site, which increased to a peak level after 12 h. Three to 7 days after injection, TUNEL positive cells were detected in the CA1 pyramidal cell layer. Immediately following SWIM, "brown" rather than "dark" neurons were detected in the various areas and most frequently in the CA1 pyramidal cell layer. No typical DNs were detected over the first 3 days. Some activation of caspase-3 was detected in a few CA3 pyramidal cells but no TUNEL-positive cells were detected. Ultrastructural examination revealed a diffuse distribution of aggregated silver particles in the dendrites and cytoplasm of pyramidal cells at the sites of IA injection. After SWIM, silver particles were detected mainly on mitochondria of affected cells. These data suggest that DNs provide a measure of neuronal damage: typically dark neurons with broad damage to the cytoskeleton of dendrites would die, while non-typical brown neurons, that may have a disturbance in mitochondria, predominantly survive.

[Is the quality of off-pump coronary artery bypass grafting equivalent to that of conventional coronary artery bypass grafting]

We analyzed 44 patients undergoing coronary artery bypass grafting (CABG) from November 2001 to March 2003. Of 44 patients, 40 patients (29 men and 11 women; mean age 68.1 +/- 9.2 years) underwent off-pump CABG (OPCAB) [90.9%]. The mean number of bypass grafts was 2.53 +/- 0.78. In-hospital mortality was none and major complications except for one case of reexploration for bleeding were not seen. The early patency rate of over-all grafts was 94.6%. The quality of OPCAB was considered to be equivalent to conventional CABG.

Comonomer unit composition and thermal properties of poly(3-hydroxybutyrate-co-4-hydroxybutyrate)s biosynthesized by Ralstonia eutropha

A series of poly(3-hydroxybutyrate-co-4-hydroxybutyrate)s [P(3HB-co-4HB)s] with different 4HB content, biosynthesized by Ralstonia eutropha H16 with mixed carbon sources of 4-hydroxybutyric acid (4HBA) and butyric acid, were fractionated by solvent/nonsolvent fractionation into copolyester fractions with different 4HB content and narrower compositional distribution. The fractions obtained were classified into two groups, 3HB- and 4HB-rich P(3HB-co-4HB)s. The thermal properties were investigated for these fractionated copolyesters. With increasing 4HB content, the melting temperature at first decreased while 3HB content was rich, and then increased while 4HB content was rich. The glass transition temperature decreased linearly with increasing 4HB content. The 4HB-rich P(3HB-co-4HB) was found to be immiscible with the 3HB-rich P(3HB-co-4HB), as two glass transitions corresponding to those of respective P(3HB-co-4HB)s were observed by DSC. It was concluded that as-produced bacterial P(3HB-co-4HB) samples used in this study should be considered as immiscible polymer blends.

IGF-I gene transfer by electroporation promotes regeneration in a muscle injury model

The goal of this study was to determine whether insulin-like growth factor-I (IGF-I) gene delivery by electroporation promotes repair after muscle injury. An injury-repair model was created using mice in which a hamstring muscle was cut and sutured. A total of 50 microg of IGF-I DNA or green fluorescent protein (GFP) DNA (both in pCAGGS) was injected into the lesion and introduced into muscle cells by electrostimulation using an electric pulse generator. The number of regenerating muscle fibers in the IGF-I DNA group was significantly more than that in the GFP DNA group at 2 weeks after injection. The diameter of regenerating muscle fibers from the IGF-I DNA group was larger than that of the GFP DNA group at 4 weeks after injection. There was no significant difference in the serum IGF-I concentration between the IGF-I DNA group and the GFP DNA group at 1, 2, and 4 weeks after injection. However, muscle IGF-I concentration in the IGF-I DNA injection group was significantly greater than that in the GFP DNA injection group at 2 weeks after injection. These results demonstrated that the effects of enhanced IGF-I production were local and limited to the injected area. The ratio (injected/uninjected; intact) of the amplitude of compound muscle action potentials (CMAP) in the IGF-I DNA injection group was greater than that in the GFP DNA injection group at 4 weeks after injection and of the control group. In conclusion, IGF-I gene transfer by electroporation proved to be a simple, safe, inexpensive, and effective method to promote the regeneration of injured muscles in our injury model.

A human case of gnathostomiasis nipponica confirmed indirectly by finding infective larvae in leftover largemouth bass meat

A human case of creeping eruption due to Gnathostoma nipponicum was confirmed indirectly by finding infective advanced third-stage larvae in leftover largemouth bass meat. This is the first report indicating that the largemouth bass (Micropterus salmoides) serves as a source of G. nipponicum infection in humans.