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The spin Hall effect of a Dirac Hamiltonian system is studied using semiclassical analyses and the Kubo formula. In this system, the spin Hall conductivity is dependent on the definition of spin current. All components of the spin Hall conductivity vanish when spin current is defined as the flow of spin angular momentum. In contrast, the off-diagonal components of the spin Hall conductivity are non-zero and scale with the carrier velocity (and the effective $g$-factor) when spin current consists of the flow of spin magnetic moment. We derive analytical formula of the conductivity, carrier mobility and the spin Hall conductivity to compare with experiments. In experiments, we use Bi as a model system that can be characterized by the Dirac Hamiltonian. Te and Sn are doped into Bi to vary the electron and hole concentration, respectively. We find the spin Hall conductivity ($\sigma_\mathrm{SH}$) takes a maximum near the Dirac point and decreases with increasing carrier density ($n$). The sign of $\sigma_\mathrm{SH}$ is the same regardless of the majority carrier type. The spin Hall mobility, proportional to $\sigma_\mathrm{SH}/n$, increases with increasing carrier mobility with a scaling coefficient of $\sim$1.4. These features can be accounted for quantitatively using the derived analytical formula. The results demonstrate that the giant spin magnetic moment, with an effective $g$-factor that approaches 100, is responsible for the spin Hall effect in Bi.

We study the Seebeck effect in the three-dimensional Dirac electron system based on the linear response theory with Luttinger's gravitational potential. The Seebeck coefficient $S$ is defined by $S = L_{12} / L_{11} T$, where $T$ is the temperature, and $L_{11}$ and $L_{12}$ are the longitudinal response coefficients of the charge current to the electric field and to the temperature gradient, respectively; $L_{11}$ is the electric conductivity and $L_{12}$ is the thermo-electric conductivity. We consider randomly-distributed impurity potentials as the source of the momentum relaxation of electrons and microscopically calculate the relaxation rate and the vertex corrections of $L_{11}$ and $L_{12}$ due to the impurities. It is confirmed that $L_{11}$ and $L_{12}$ are related through Mott's formula in low temperatures when the chemical potential lies above the gap ($|\mu| > \Delta$), irrespective of the linear dispersion of the Dirac electrons and unconventional energy dependence of the lifetime of electrons. On the other hand, when the chemical potential lies in the band gap ($|\mu| < \Delta$), Seebeck coefficient behaves just as in conventional semiconductors: Its dependences on the chemical potential $\mu$ and the temperature $T$ are partially captured by $S \propto (\Delta - \mu) / \kB T$ for $\mu > 0$. The Seebeck coefficient takes the relatively large value $|S| \simeq 1.7 \,\mathrm{m V/K}$ at $T \simeq 8.7\,\mathrm{K}$ for $\Delta = 15 \,\mathrm{m eV}$ by assuming doped bismuth., Comment: 11 pages, 5 figures

Spin currents proportional to the first- and second-order of the electric field are calculated in a specific tight-binding model with time-reversal symmetry. Specifically, a tight-binding model with time-reversal symmetry is constructed with chiral hopping and spin-orbit coupling. The spin conductivity of the model is calculated using the Boltzmann equation. As a result, it is clarified that the first-order spin current of the electric field vanishes, while the second-order spin current can be finite. Furthermore, the spin current changes its sign by reversing the chirality of the model. The present results reveal the existence of spin currents in systems with time-reversal symmetry depending on the chirality of the system. They may provide useful information for understanding the chirality-dependent spin polarization phenomena in systems with time-reversal symmetry.

Green materials for electron spin manipulation are essential for common spintronic applications. Recent studies have documented the efficient generation of spin torque using spin-orbit interactions (SOIs); however, SOI use relies on the employment of rare metals such as platinum. Here, we demonstrate that a nanometre-thick gradient from silicon to aluminium, which consists of readily available elements from earth resources, can produce a spin torque over three times as large as that of platinum, despite the weak SOI of these compositions. The spin-torque efficiency can be improved by decreasing the thickness of the gradient, while a sharp interface was not found to increase the spin torque. Moreover, the electric conductivity of the gradient material can be up to twice as large as that of platinum, which provides a way to reduce Joule heating losses and signal delays in spintronic device circuits. Our findings represent a pathway for sustainable spin manipulation.

The Dzyaloshinskii-Moriya interaction, i.e., antisymmetric exchange interaction, combined with a Zeeman magnetic field gives rise to various magnetic states such as chiral, helical, and skyrmionic states. This interaction conventionally originates from spin-orbit coupling and thus needs somewhat heavy elements. In contrast, we here show a Dzyaloshinskii-Moriya interaction which is driven by electric current vorticity. We also find that the vorticity acts on localized spins as a Zeeman field, which may explain a recent experiment on current-driven magnetic skyrmion creation and annihilation without an external magnetic field in a device with a notch structure in FeGe. theory explains the control of skyrmion creation and annihilation by current direction and opens different possibilities for studies of magnetic textures by using structural settings.

Stool consistency is evaluated mainly in reference to indirect indicators such as water content or the appearance of stool forms using Bristol Stool Form Scale (BSFS). Methods of measurement are limited. We thus aimed to develop a simple protocol for direct measurement of stool consistency using the TA.XTExpress Texture Analyser (Stable Micro Systems Ltd.). We developed a protocol which enables mechanical quantification of the gram-force against a cylindrical probe (ø 6 mm) pushed into the stool surface at 2.0 mm/s to 5 mm depth. The consistency of 252 stools collected from 40 healthy Belgians was evaluated by the direct method and by the indirect indicators (water content and BSFS) for comparison. The log-transformed stool consistency values measured by the texture analyzer had a negative linear correlation with the stool water contents (rrm = − 0.781) with homoscedastic variance, suggesting the appropriateness of the new protocol. They showed a similar correlation with the BSFS, but with a large variance in the consistency values of normal stool forms. This correlation was much smaller for BSFS scored by subjects (rrm = − 0.587) than by experts (rrm = − 0.789), collectively indicating BSFS as a rough indicator of stool consistency susceptible to subjective bias despite its effectiveness in clinical use. The optimized direct method using the texture analyzer enables the accurate quantification of stool consistency, which facilitates understanding of the intestinal environment and function and thus may enhance the value of the stool as a predictor of human health.

Employing unbiased large-scale time-dependent density-matrix renormalization-group simulations, we demonstrate the generation of a charge-current vortex via spin injection in the Rashba system. The spin current is polarized perpendicular to the system plane and injected from an attached antiferromagnetic spin chain. We discuss the conversion between spin and orbital angular momentum in the current vortex that occurs because of the conservation of the total angular momentum and the spin-orbit interaction. This is in contrast to the spin Hall effect, in which the angular-momentum conservation is violated. Finally, we predict the electromagnetic field that accompanies the vortex with regard to possible future experiments., 12 pages, 11 figures

We study valley-dependent spin transport theoretically in monolayer transition-metal dichalcogenides in which a variety of spin and valley physics are expected because of spin-valley coupling. The results show that the spins are valley-selectively excited with appropriate carrier doping and valley polarized spin current (VPSC) is generated. The VPSC leads to the spin-current Hall effect, transverse spin accumulation originating from the Berry curvature in momentum space. The results indicate that spin excitations with spin-valley coupling lead to both valley and spin transport, which is promising for future low-consumption nanodevice applications., 6 pages, 5 figures

We theoretically propose a mechanism of thermoelectric power generation via transverse thermo-spin conversions. We consider a material with strong spin–orbit coupling (the target material) and apply a temperature gradient to the target material, where the temperature gradient induces a transverse spin current. By attaching ferromagnets to the target material, we show the conversion of the nonequilibrium spin accumulation induced by the spin current into the electric voltage based on an extension of the Valet–Fert theory used in the giant magnetoresistive effect. A series circuit application is also discussed.

The interaction between spin and nanomechanical degrees of freedom attracts interest from the viewpoint of basic science and device applications. We study the magnon current induced by the torsional oscillation of ferromagnetic nanomechanical cantilever. We find that a finite Dzyaloshinskii-Moriya (DM) interaction emerges by the torsional oscillation, which is described by the spin gauge field, and the DM interaction leads to the detectably-large magnon current with frequency same as that of the torsional oscillation. Our theory paves the way for studying torsional spin-nanomechanical phenomena by using the spin gauge field., Comment: 5 pages, 4 figures

Electron transport in magnetic orders and the magnetic order dynamics have a mutual dependence, which provides the key mechanisms in spin-dependent phenomena. Recently, antiferromagnetic orders have been focused on as the magnetic order, where current-induced spin-transfer torques, a typical effect of electron transport on the magnetic order, have been debatable, mainly because of the lack of an analytic derivation based on quantum field theory. Here, we construct the microscopic theory of spin-transfer torques on the slowly varying staggered magnetization in antiferromagnets with weak canting. In our theory, the electron is captured by bonding/antibonding states, each of which is the eigenstate of the system, is doubly degenerate, and spatially spreads to sublattices because of electron hopping. The spin of the eigenstates depends on the momentum in general, and a nontrivial spin-momentum locking arises for the case with no site inversion symmetry, without considering any spin-orbit couplings. The spin current of the eigenstates includes an anomalous component proportional to a kind of gauge field defined by derivatives in momentum space and induces the adiabatic spin-transfer torques on the magnetization. Unexpectedly, we find that one of the nonadiabatic torques has the same form as the adiabatic spin-transfer torque, while the obtained forms for the adiabatic and nonadiabatic spin-transfer torques agree with the phenomenological derivation based on the symmetry consideration. This finding suggests that the conventional explanation for the spin-transfer torques in antiferromagnets should be changed. Our microscopic theory provides a fundamental understanding of spin-related physics in antiferromagnets.

We investigate an interfacial spin-transfer torque and $\beta$-term torque with alternating current (AC) parallel to a magnetic interface. We find that both torques are resonantly enhanced as the AC frequency approaches to the exchange splitting energy. We show that this resonance allows us to estimate directly the interfacial exchange interaction strength from the domain wall motion. We also find that the $\beta$-term includes an unconventional contribution which is proportional to the time derivative of the current and exists even in absence of any spin relaxation processes., Comment: 5 pages, 2 figures

Using response theory, we calculate the charge-current vortex generated by spin pumping at a point-like contact in a system with Rashba spin-orbit coupling. We discuss the spatial profile of the current density for finite temperature and for the zero-temperature limit. The main observation is that the Rashba spin precession leads to a charge current that oscillates as a function of the distance from the spin-pumping source, which is confirmed by numerical simulations. In our calculations, we consider a Rashba model on a square lattice, for which we first review the basic properties related to charge and spin transport. In particular, we define the charge- and spin-current operators for the tight-binding Hamiltonian as the currents coupled linearly with the U(1) and SU(2) gauge potentials, respectively. By analogy to the continuum model, the spin-orbit-coupling Hamiltonian on the lattice is then introduced as the generator of the spin current., 10 pages, 6 figures

We show theoretically that conversion between spin and charge by spin-orbit interaction in metals occurs even in a non-local setup where magnetization and spin-orbit interaction are spatially separated if electron diffusion is taken into account. Calculation is carried out for the Rashba spin-orbit interaction treating the coupling with a ferromagnet perturbatively. The results indicate the validity of the concept of effective spin gauge field (spin motive force) in the non-local configuration. The inverse Rashba-Edelstein effect observed for a trilayer of a ferromagnet, a normal metal and a heavy metal can be explained in terms of the non-local effective spin gauge field.

As a strongly spin-orbit coupled metallic model with ferromagnetism, we have considered an extended Stoner model to the relativistic regime, named Dirac ferromagnet in three dimensions. In the previous paper~[Phys. Rev. B 90, 214418 (2014)], we studied the transport properties giving rise to the anisotropic magnetoresistance~(AMR) and the anomalous Hall effect~(AHE) with the impurity potential being taken into account only as the self-energy. The effects of the vertex corrections~(VCs) to AMR and AHE are reported in this paper. AMR is found not to change quantitatively when the VCs is considered, although the transport lifetime is different from the one-electron lifetime and the charge current includes additional contributions from the correlation with spin currents. The side-jump and the skew-scattering contributions to AHE are also calculated. The skew-scattering contribution is dominant in the clean case as can be seen in the spin Hall effect in the non-magnetic Dirac electron system., Comment: 21 pages, 7 figures

Torque can be provided to magnetization in nanomagnets directly by electric current and/or voltage. This technique enables electric current (voltage)-to-spin conversion without electromagnetic induction, and has been intensively studied for memory device applications. Among the various kinds of torque, torque induced by spin-orbit splitting has recently been found. However, quantitative understanding of bulk-related torque and interface-related torque is still lacking because of their identical symmetry for current-in-plane devices. In this paper, we propose that a pure interface-related torque can be characterized by spin-torque ferromagnetic resonance with a current-perpendicular-to-plane tunnel junction. Epitaxial Fe-MgO-V tunnel junctions are prepared to characterize the interface-related torque at Fe-MgO. We find that the current-driven torque is negligible, and a significant enhancement of the voltage-driven torque is observed when the MgO barrier thickness decreases. The maximum torque obtained is as large as 2.8×10^{−5} J/(Vm^{2}), which is comparable to the voltage-controlled magnetic anisotropy of 180 fJ/Vm. The voltage-driven torque shows strong dc-bias-voltage dependence that cannot be explained by conventional voltage-controlled magnetic anisotropy. Tunnel anisotropic magnetoresistance spectroscopy suggests that the torque is correlated to an interface state at the Fe-MgO. This surface-state-sensitive electric modulation of magnetic properties provides new insight into the field of interface magnetism.

Three Gram-positive-staining strains isolated from fermented stinky tofu brine were rod-shaped, non-motile, asporogenous, facultatively anaerobic, heterofermentative and did not exhibit catalase activity. Comparative analyses of 16S rRNA, rpoA and pheS gene sequences demonstrated that the novel strains were members of the genus Lactobacillus. On the basis of 16S rRNA gene sequence similarity, the type strains of Lactobacillus collinoides (98.6 %), Lactobacillus paracollinoides (98.6 %) and Lactobacillus similis (99.6 %) were the closest neighbours. However, DNA–DNA reassociation values with these strains were less than 10 %. The phenotypic and genotypic features demonstrated that these isolates represent a novel species of the genus Lactobacillus, for which the name Lactobacillus odoratitofui sp. nov. is proposed. The type strain is YIT 11304T (=JCM 15043T =BCRC 17810T =DSM 19909T).

Yeast contamination is a problem in the food industry as a cause of spoilage. Moreover, various species of yeasts are known to be capable of causing opportunistic infections in humans. We have developed a real-time quantitative PCR (qPCR) assay to directly detect and quantify nine emerging opportunistic yeast species (Candida albicans, Candida glabrata, Candida parapsilosis, Candida tropicalis, Clavispora lusitaniae, Filobasidiella neoformans, Issatchenkia orientalis, Trichosporon asahii, and Trichosporon jirovecii) in dairy product samples. We designed six primer pairs, conserved sequences of the variable D1/D2 domains of the 26S rRNA gene, to detect the yeasts and demonstrated their specificity. The qPCR assay could accurately quantify emerging opportunistic yeasts in an artificially contaminated dairy product. qPCR with the primer pairs we designed, was very sensitive and will allow producers to enumerate contaminating yeasts and identify whether they are opportunistic pathogens, in only 4 to 5h. This assay can easily be extended to other food items and to a variety of food-monitoring initiatives.

Two novel micro-organisms, designated strains YIT 10443(T) and YIT 10738, were isolated from airag, a traditional fermented mare's milk from Mongolia. The two strains were Gram-positive-staining, non-motile, asporogenous, catalase-negative, facultatively anaerobic rods of various shapes. Comparative analyses of 16S rRNA and ClpC ATPase (clpC) gene sequences and the presence of fructose-6-phosphate phosphoketolase (F6PPK) demonstrated that the novel strains were members of the genus Bifidobacterium. On the basis of 16S rRNA gene sequence similarity, the type strains of Bifidobacterium minimum (96.6 %) and Bifidobacterium psychraerophilum (95.7 %) were the closest neighbours of the novel strains, and DNA-DNA reassociation values with these strains were found to be lower than 15 %. The phenotypic and genotypic features demonstrated that the two strains represent a single, novel Bifidobacterium species, for which the name Bifidobacterium mongoliense sp. nov. is proposed. The type strain is YIT 10443(T) (=JCM 15461(T) =DSM 21395(T)).

Thirty six Gram-positive, rod-shaped, non-spore-forming, non-motile bacterial strains were isolated from the non-salted pickle solution used in producing sunki products, a traditional Japanese pickle. The novel strains were discriminated and separated into four groups by amplified fragment length polymorphism profiling, and by analysis based on recA gene sequences. The strains were classified into four species groups belonging to the Lactobacillus buchneri species group, which consists of L. buchneri, Lactobacillus diolivorans, Lactobacillus hilgardii, Lactobacillus kefiri, Lactobacillus parabuchneri and Lactobacillus parakefiri. The phenotypic and genotypic features of the four groups demonstrated that they represented four novel species, for which the names Lactobacillus kisonensis sp. nov. (type strain YIT 11168(T)=NRIC 0741(T)=JCM 15041(T)=DSM 19906(T)), Lactobacillus otakiensis sp. nov. (type strain YIT 11163(T)=NRIC 0742(T)=JCM 15040(T)=DSM 19908(T)), Lactobacillus rapi sp. nov. (type strain YIT 11204(T)=NRIC 0743(T)=JCM 15042(T)=DSM 19907(T)) and Lactobacillus sunkii sp. nov. (type strain YIT 11161(T)=NRIC 0744(T)=JCM 15039(T)=DSM 19904(T)) are proposed.

Three Gram-positive, catalase-negative, motile, rod-shaped bacteria were isolated from fermented stinky tofu brine. These strains, designated YIT 11306(T), YIT 11317 and YIT 11318, were discriminated from five isolates on the basis of randomly amplified polymorphic DNA profiles. They produced l-lactic acid as the main end product from glucose without gas formation, synthesized dextran from sucrose and hydrolysed aesculin. Ammonia was not produced from arginine. Comparative 16S rRNA gene sequence analysis demonstrated that the novel isolates were members of the genus Lactobacillus. Based on levels of 16S rRNA gene sequence similarity, the three novel strains were related most closely to the type strains of Lactobacillus mali (97.2 %) and Lactobacillus satsumensis (96.8 %). However, levels of DNA-DNA relatedness between the novel isolates and the type strains of L. mali and L. satsumensis were less than 10 %. The phenotypic and genotypic data demonstrate that the three strains represent a single novel species of the genus Lactobacillus, for which the name Lactobacillus capillatus sp. nov. is proposed. The type strain is YIT 11306(T) (=JCM 15044(T)=BCRC 17811(T)=DSM 19910(T)).

Lactobacillus casei strain Shirota (LcS) has been used in the production of fermented milk products for many years and is one of the most intensively studied probiotics. To evaluate the ability of LcS to proliferate in human intestines after it has been ingested, we developed a PCR-based method to identify and quantify LcS using an LcS-specific primer set (pLcS) derived from a randomly amplified polymorphic DNA (RAPD) analysis. We confirmed the high specificity of the pLcS primer set in 167 bacterial strains (57 strains of L. casei and 110 other strains of bacteria commonly isolated from human feces). The method's ability to identify LcS matched that of an ELISA using a monoclonal antibody and a RAPD analysis in a representative sample of colonies cultured from human feces. The detection limit of quantitative PCR (qPCR) using pLcS was 10(4.6) per gram of feces. The number of LcS in feces detected with qPCR was highly and significantly correlated with the number of LcS added to fecal samples within the range of 10(4.6) to 10(9.6) per gram feces (r(2)=0.999, P

16S rRNA gene-targeted group-specific primers were designed and validated for specific detection and quantification of the Clostridium leptum subgroup and the Atopobium cluster. To monitor the predominant bacteria in human feces by real-time PCR, we used these specific primers together with four sets of group-specific primers for the Clostridium coccoides group, the Bacteroides fragilis group, Bifidobacterium , and Prevotella developed in a previous study (T. Matsuki, K. Watanabe, J. Fujimoto, Y. Miyamoto, T. Takada, K. Matsumoto, H. Oyaizu, and R. Tanaka, Appl. Environ. Microbiol. 68: 5445-5451, 2002). Examination of DNA extracted from the feces of 46 healthy adults showed that the C. coccoides group was present in the greatest numbers (log 10 10.3 ± 0.3 cells per g [wet weight] [average ± standard deviation]), followed by the C. leptum subgroup (log 10 9.9 ± 0.7 cells per g [wet weight]), the B. fragilis group (log 10 9.9 ± 0.3 cells per g [wet weight]), Bifidobacterium (log 10 9.4 ± 0.7 cells per g [wet weight]), and the Atopobium cluster (log 10 9.3 ± 0.7 cells per g [wet weight]). These five bacterial groups were detected in all 46 volunteers. Prevotella was found in only 46% of the subjects at a level of log 10 9.7 ± 0.8 cells per g (wet weight). Examination of changes in the population and the composition of the intestinal flora for six healthy adults over an 8-month period revealed that the composition of the flora of each volunteer remained stable throughout the test period.

We have isolated four strains of Rhodococcus which specifically degrade estrogens by using enrichment culture of activated sludge from wastewater treatment plants. Strain Y 50158, identified as Rhodococcus zopfii , completely and rapidly degraded 100 mg of 17β-estradiol, estrone, estriol, and ethinyl estradiol/liter, as demonstrated by thin-layer chromatography and gas chromatography-mass spectrometry analyses. Strains Y 50155, Y 50156, and Y 50157, identified as Rhodococcus equi , showed degradation activities comparable with that of Y 50158. Using the random amplified polymorphism DNA fingerprinting test, these three strains were confirmed to have been derived from different sources. R. zopfii Y 50158, which showed the highest activity among these four strains, revealed that the strain selectively degraded 17β-estradiol during jar fermentation, even when glucose was used as a readily utilizable carbon source in the culture medium. Measurement of estrogenic activities with human breast cancer-derived MVLN cells showed that these four strains each degraded 100 mg of 17β-estradiol/liter to 1/100 of the specific activity level after 24 h. It is thus suggested that these strains degrade 17β-estradiol into substances without estrogenic activity.

A highly sensitive quantitative PCR detection method has been developed and applied to the distribution analysis of human intestinal bifidobacteria by combining real-time PCR with Bifidobacterium genus- and species-specific primers. Real-time PCR detection of serially diluted DNA extracted from cultured bifidobacteria was linear for cell counts ranging from 10 6 to 10 cells per PCR assay. It was also found that the method was applicable to the detection of Bifidobacterium in feces when it was present at concentrations of >10 6 cells per g of feces. Concerning the distribution of Bifidobacterium species in intestinal flora, the Bifidobacterium adolescentis group, the Bifidobacterium catenulatum group, and Bifidobacterium longum were found to be the three predominant species by examination of DNA extracted from the feces of 46 healthy adults. We also examined changes in the population and composition of Bifidobacterium species in human intestinal flora of six healthy adults over an 8-month period. The results showed that the composition of bifidobacterial flora was basically stable throughout the test period.

For the detection and identification of predominant bacteria in human feces, 16S rRNA-gene-targeted group-specific primers for the Bacteroides fragilis group , Bifidobacterium, the Clostridium coccoides group, and Prevotella were designed and evaluated. The specificity of these primers was confirmed by using DNA extracted from 90 species that are commonly found in the human intestinal microflora. The group-specific primers were then used for identification of 300 isolates from feces of six healthy volunteers. The isolates were clearly identified as 117 isolates of the B. fragilis group, 22 isolates of Bifidobacterium , 65 isolates of the C. coccoides group, and 17 isolates of Prevotella , indicating that 74% of the isolates were identified with the four pairs of primers. The remaining 79 isolates were identified by 16S ribosomal DNA sequence analysis and consisted of 40 isolates of Collinsella , 24 isolates of the Clostridium leptum subgroup, and 15 isolates of disparate clusters. In addition, qualitative detection of these bacterial groups was accomplished without cultivation by using DNA extracted from the fecal samples. The goal for this specific PCR technique is to develop a procedure for quantitative detection of these bacterial groups, and a real-time quantitative PCR for detection of Bifidobacterium is now being investigated (T. Requena, J. Burton, T. Matsuki, K. Munro, M. A. Simon, R. Tanaka, K. Watanabe, and G. W. Tannock, Appl. Environ. Microbiol. 68: 2420-2427, 2002). Therefore, the approaches used to detect and identify predominant bacteria with the group-specific primers described here should contribute to future studies of the composition and dynamics of the intestinal microflora.

We propose a model ferromagnet based on the Dirac Hamiltonian in three spatial dimensions, and study its transport properties which include anisotropic magnetoresistance (AMR) and anomalous Hall (AH) effect. This relativistic extension allows two kinds of ferromagnetic order parameters, denoted by $\bm{M}$ and $\bm{S}$, which are distinguished by the relative sign between the positive- and negative-energy states (at zero momentum) and become degenerate in the non-relativistic limit. Because of the relativistic coupling between the spin and the orbital motion, both $\bm{M}$ and $\bm{S}$ induce anisotropic deformations of the energy dispersion (and the Fermi surfaces) but in mutually opposite ways. The AMR is determined primarily by the anisotropy of the Fermi surface (group velocity), and secondarily by the anisotropy of the damping; the latter becomes important for ${\bm M}=\pm{\bm S}$, where the Fermi surfaces are isotropic. Even when the chemical potential lies in the gap, the AH conductivity is found to take a finite non-quantized value, $\sigma_{ij} = -(\alpha /3\pi^2 \hbar) \epsilon_{ijk} S_k $, where $\alpha$ is the (effective) fine structure constant. This offers an example of Hall insulator in three spatial dimensions., Comment: 17 pages, 6 figures

We developed a PCR-based method to detect and quantify viable Bifidobacterium bifidum BF-1 cells in human feces. This method (PMA-qPCR) uses propidium monoazide (PMA) to distinguish viable from dead cells and quantitative PCR using a BF-1-specific primer set designed from the results of randomly amplified polymorphic DNA analysis. During long-term culture (10 days), the number of viable BF-1 cells detected by counting the number of CFU on modified MRS agar, by measuring the ATP contents converted to CFU, and by using PMA-qPCR decreased from about 10 10 to 10 6 cells/ml; in contrast, the total number of (viable and dead) BF-1 cells detected by counting 4′,6-diamidino-2-phenylindolee (DAPI)-stained cells and by using qPCR without PMA and reverse transcription-qPCR remained constant. The number of viable BF-1 cells in fecal samples detected by using PMA-qPCR was highly and significantly correlated with the number of viable BF-1 cells added to the fecal samples, within the range of 10 5.3 to 10 10.3 cells/g feces (wet weight) ( r > 0.99, P < 0.001). After 12 healthy subjects ingested 10 10.3 to 10 11.0 CFU of BF-1 in a fermented milk product daily for 28 days, 10 4.5 � 1.5 (mean � standard deviation [SD]) BF-1 CFU/g was detected in fecal samples by using strain-specific selective agar; in contrast, 10 6.2 � 0.4 viable BF-1 cells/g were detected by using PMA-qPCR, and a total of 10 7.6 � 0.7 BF-1 cells/g were detected by using qPCR without PMA. Thus, the number of viable BF-1 cells detected by PMA-qPCR was about 50 times higher ( P < 0.01) than that detected by the culture-dependent method. We conclude that strain-specific PMA-qPCR can be used to quickly and accurately evaluate viable BF-1 in feces.

Dirac electrons in two-dimensional continuum space subject to $\ensuremath{\delta}$-function impurities, which have inherent ultraviolet divergence, fail to be gauge-invariant if regularized by the standard momentum (Brillouin-zone) cutoff. A regularization scheme which respects gauge invariance is proposed here based on the cutoff in the impurity-potential range. The relation to a lattice model, which has no ultraviolet divergence, is also discussed.

The composition of the human gut microbiota is related to host health, and it is thought that dietary habits may play a role in shaping this composition. Here, we examined the population size and prevalence of six predominant bacterial genera and the species compositions of genus Bifidobacterium (g-Bifid) and Bacteroides fragilis group (g-Bfra) in 42 healthy Belgian adults by quantitative PCR (qPCR) over a period of one month. The population sizes and prevalence of these bacteria were basically stable throughout the study period. The predominant g-Bifid species were Bifidobacterium adolescentis and Bifidobacterium longum ss. longum, and the predominant g-Bfra species were Bacteroides vulgatus, Bacteroides uniformis, and Bacteroides ovatus. The Belgian gut microbiota data were then compared with gut microbiota data from 46 Japanese subjects collected according to the same protocol (Matsuki et al., Appl. Environ. Microbiol. 70, 167-173, 2004). The population size and prevalence of Bifidobacterium catenulatum group were significantly lower in the Belgian gut microbiota than in the Japanese gut microbiota (P 0.001); however, the population size and prevalence of g-Bifid did not differ. This species-level qPCR analysis will be helpful for investigating the diversity of gut microbiota among ethnic groups.

An optical inspection system for the inner wall of a pipe has been developed. This system uses the projection of a circular pattern formed by a conically reflecting mirror on the inner wall, and detection of circular images from the illuminated circumferential surface. Irregularities of the images due to corrosion or accumulation of deposits on the inner surface are inspected by this system. Inspection of the shape of the inner wall has been impossible by current methods. The experimental system reported in this paper has the following practical specifications: resolution of detection on ±0.1 mm, and inspection speed of 30 mm/s at an interval of 1 mm along the pipe. The system is now being used for practical inspection.

Natural products obtained from marine invertebrates such as sponges and tunicates are attractive sources of drugs. However, a critical obstacle in the development of these compounds is the problem of supply. In most cases, neither chemical synthesis nor mariculture of invertebrates is economically feasible. Due to structural similarities, many marine natural products are suspected to be produced by associated microorganisms. A favorable strategy for the production of such compounds is to use culturable microorganisms. Here we report that didemnin B, a tunicate-derived depsipeptide, has been isolated from a culturable bacterium, Tistrella mobilis YIT 12409.

The taxonomic status of the species Lactobacillus durianis and Lactobacillus vaccinostercus is briefly summarized and experimental evidence concerning their similarity is presented. Highly similar 16S rRNA gene sequences (99.8 % similarity over 1523 bp), partial recA gene sequences (99.5 % similarity over 600 bp) and partial hsp60 gene sequences (99.1 % similarity over 924 bp) suggest that the two species are closely related. Moreover, a high DNA–DNA binding level (87 %) and similar genomic DNA G+C contents (41–44 mol% for both species) as well as similar biochemical characteristics support the evidence that they constitute a single species. Consequently, according to Rules 38 and 42 of the Bacteriological Code, the name Lactobacillus vaccinostercus, the oldest legitimate name, must be maintained and the name Lactobacillus durianis should be considered a later heterotypic synonym.

Corrigendum Corrigendum to “Identification and quantification of Lactobacillus casei strain Shirota in human feces with strain-specific primers derived from randomly amplified polymorphic DNA” [Int. J. Food Microbiol. 126 (2008) 210–215] Junji Fujimoto⁎, Takahiro Matsuki, Masae Sasamoto, Yasuaki Tomii, Koichi Watanabe⁎ Yakult Central Institute for Microbiological Research, 1796 Yaho, Kunitachi, Tokyo 186-8650, Japan