Complete field-induced spectral response of the spin-1/2 triangular-lattice antiferromagnet CsYbSe2

Fifty years after Anderson's resonating valence-bond proposal, the spin-1/2 triangular-lattice Heisenberg antiferromagnet (TLHAF) remains the ultimate platform to explore highly entangled quantum spin states in proximity to magnetic order. Yb-based delafossites are ideal candidate TLHAF materials, which allow experimental access to the full range of applied in-plane magnetic fields. We perform a systematic neutron scattering study of CsYbSe2, first proving the Heisenberg character of the interactions and quantifying the second-neighbor coupling. We then measure the complex evolution of the excitation spectrum, finding extensive continuum features near the 120°-ordered state, throughout the 1/3-magnetization plateau and beyond this up to saturation. We perform cylinder matrix-product-state (MPS) calculations to obtain an unbiased numerical benchmark for the TLHAF and spectacular agreement with the experimental spectra. The measured and calculated longitudinal spectral functions reflect the role of multi-magnon bound and scattering states. These results provide valuable insight into unconventional field-induced spin excitations in frustrated quantum materials.

Quantum device designing (QDD) for future semiconductor engineering

In semiconductor device history, a trend is observed where narrowing and increasing the number of material layers improve device functionality, with diodes, transistors, thyristors, and superlattices following this trend. While superlattices promise unique functionality, they are not widely adopted due to a technology barrier, requiring advanced fabrication, such as molecular beam epitaxy and lattice-matched materials. Here, a method to design quantum devices using amorphous materials and physical vapor deposition is presented. It is shown that the multiplication gain M depends on the number of layers of the superlattice, N, as M = kN, with k as a factor indicating the efficiency of multiplication. This M is, however, a trade-off with transit time, which also depends on N. To demonstrate, photodetector devices are fabricated on Si, with the superlattice of Se and As₂Se₃, and characterized using current-voltage (I-V) and current-time (I-T) measurements. For superlattices with the total layer thicknesses of 200 nm and 2 μm, the results show that k_200nm = 0.916 and k_2μm = 0.384, respectively. The results confirm that the multiplication factor is related to the number of superlattice layers, showing the effectiveness of the design approach.

Inhibitory effect of aqueous extract of Cuminum cyminum L. seed on degranulation of RBL-2H3 cells and passive cutaneous anaphylaxis reaction in mice

Cuminum cyminum L. (cumin) seed is used as a spice in various countries. Although several functions of the components in cumin seed have been reported, the anti-allergic effect of the water-soluble component in cumin seed has not been reported yet. In this study, we focused on the suppressive effect of cumin seed aqueous extract on degranulation in order to reveal the anti-allergic effect of cumin. Cumin seed aqueous extract significantly suppressed the antigen-induced degranulation of rat basophilic leukemia cell line RBL-2H3 cells in a dose-dependent manner without cytotoxicity. The extract also inhibited the elevation of the intracellular calcium ion concentration induced by antigen. Immunoblot analysis revealed that the extract suppresses phosphorylation of phosphatidylinositol 3-kinase, Bruton's tyrosine kinase, phospholipase C-γ1/2, and Akt in the signaling pathways activated by antigen induction via FcεRI. Furthermore, the extract suppressed microtubule formation induced by antigen. In addition, oral administration of cumin seed aqueous extract significantly suppressed the passive cutaneous anaphylaxis reaction in BALB/c mice. Our findings suggest that cumin seed contains water-soluble components with the anti-allergic effect. Therefore, cumin seed has potential as anti-allergic functional food.

Fe-oxide concretions formed by interacting carbonate and acidic waters on Earth and Mars

Spherical Fe-oxide concretions on Earth, especially in Utah, USA, have been investigated as an analog of hematite spherules found in Meridiani Planum on Mars to support interpretations of water-rock interactions in early Mars. Although several formation mechanisms have been proposed for the Fe-oxide concretions on Earth, it is still unclear whether these mechanisms are viable because a precise formation process and precursor of the concretions are missing. This paper presents evidence that Fe-oxide concretions in Utah and newly found Fe-oxide concretions in Mongolia had spherical calcite concretions as precursors. Different formation stages of calcite and Fe-oxide concretions observed, both in Utah and Mongolia, indicate that calcite concretions initially formed within eolian sandstone strata and were dissolved by infiltrating Fe-rich acidic waters to form spherical FeO(OH) crusts due to pH buffering. The similarity between these Fe-oxide concretions on Earth and the hematite spherule occurrences in Meridiani Planum, combined with evidence of acid sulfate water influences on Mars, suggest that the hematite spherules also formed from dissolution of preexisting carbonate spherules possibly formed under a dense carbon dioxide early martian atmosphere.

Breakdown of Magnetic Order in the Pressurized Kitaev Iridate β-Li_{2}IrO_{3}

Temperature-pressure phase diagram of the Kitaev hyperhoneycomb iridate β-Li_{2}IrO_{3} is explored using magnetization, thermal expansion, magnetostriction, and muon spin rotation measurements, as well as single-crystal x-ray diffraction under pressure and ab initio calculations. The Néel temperature of β-Li_{2}IrO_{3} increases with the slope of 0.9  K/GPa upon initial compression, but the reduction in the polarization field H_{c} reflects a growing instability of the incommensurate order. At 1.4 GPa, the ordered state breaks down upon a first-order transition, giving way to a new ground state marked by the coexistence of dynamically correlated and frozen spins. This partial freezing in the absence of any conspicuous structural defects may indicate the classical nature of the resulting pressure-induced spin liquid, an observation paralleled to the increase in the nearest-neighbor off-diagonal exchange Γ under pressure.

Immunostimulatory effect of aqueous extract of Coriandrum sativum L. seed on macrophages

BACKGROUND

Coriandrum sativum L. seed is generally used as a spice and crude drug. Although many functions of the various components in C. sativum L. seed have been reported, the immunostimulatory effect of water-soluble components in C. sativum L. seed has not been studied. In the present study, we focused on the immunostimulatory effect of C. sativum L. seed aqueous extract (CAE) on macrophages as a novel health function of C. sativum L. seed components.

RESULTS

CAE significantly enhanced the production of tumor necrosis factor (TNF)-α and interleukin (IL)-6 in both RAW264.7 cells and peritoneal macrophages by enhancing the expression levels of these cytokine genes. CAE also stimulated nitric oxide (NO) production and the phagocytosis activity in RAW264.7 cells. We suggest that the activity of CAE is a result of the upregulation of mitogen-activated protein kinase and nuclear factor-κB cascades via TLR4. In addition, IL-6 production by peritoneal macrophages collected from CAE-administered mice was significantly enhanced, suggesting that CAE could stimulate macrophage activity in vivo.

CONCLUSION

The findings of the present study suggest that CAE contains a novel water-soluble component with an immunostimulatory effect on macrophages. CAE would contribute to activating host defense against pathogens by stimulating the innate immunity. © 2017 Society of Chemical Industry.

Identification of an argpyrimidine-modified protein in human red blood cells from schizophrenic patients: A possible biomarker for diseases involving carbonyl stress

Argpyrimidine (ARP) is an advanced glycation end product thought to be generated from a reaction between methylglyoxal and arginine residues in proteins. In this study, we observed marked accumulation of an approximately 56 kD protein, reactive to anti-ARP antibodies, in the red blood cells (RBCs) of some patients with refractory schizophrenia. This ARP-modified protein was purified from the blood of schizophrenic patients and identified as selenium binding protein 1 (SBP1) by LC-MS/MS. This is the first report of ARP-modified proteins accumulating in RBCs of patients with diseases involving carbonyl stress. We also observed high accumulation of ARP-modified SBP1 in the RBCs of patients with chronic kidney disease. Therefore, this modified protein may be a novel marker of carbonyl stress.

Signatures of a magnetic field-induced unconventional nematic liquid in the frustrated and anisotropic spin-chain cuprate LiCuSbO4

Modern theories of quantum magnetism predict exotic multipolar states in weakly interacting strongly frustrated spin-1/2 Heisenberg chains with ferromagnetic nearest neighbor (NN) inchain exchange in high magnetic fields. Experimentally these states remained elusive so far. Here we report strong indications of a magnetic field-induced nematic liquid arising above a field of ~13 T in the edge-sharing chain cuprate LiSbCuO₄ ≡ LiCuSbO₄. This interpretation is based on the observation of a field induced spin-gap in the measurements of the ⁷Li NMR spin relaxation rate T ₁^-1 as well as a contrasting field-dependent power-law behavior of T ₁^-1 vs. T and is further supported by static magnetization and ESR data. An underlying theoretical microscopic approach favoring a nematic scenario is based essentially on the NN XYZ exchange anisotropy within a model for frustrated spin-1/2 chains and is investigated by the DMRG technique. The employed exchange parameters are justified qualitatively by electronic structure calculations for LiCuSbO₄.

Evidence for a Field-Induced Quantum Spin Liquid in α-RuCl_{3}

We report a ^{35}Cl nuclear magnetic resonance study in the honeycomb lattice α-RuCl_{3}, a material that has been suggested to potentially realize a Kitaev quantum spin liquid (QSL) ground state. Our results provide direct evidence that α-RuCl_{3} exhibits a magnetic-field-induced QSL. For fields larger than ∼10  T, a spin gap opens up while resonance lines remain sharp, evidencing that spins are quantum disordered and locally fluctuating. The spin gap increases linearly with an increasing magnetic field, reaching ∼50  K at 15 T, and is nearly isotropic with respect to the field direction. The unusual rapid increase of the spin gap with increasing field and its isotropic nature are incompatible with conventional magnetic ordering and, in particular, exclude that the ground state is a fully polarized ferromagnet. The presence of such a field-induced gapped QSL phase has indeed been predicted in the Kitaev model.

Complex Field-Induced States in Linarite PbCuSO4(OH)2 with a Variety of High-Order Exotic Spin-Density Wave States

Low-temperature neutron diffraction and NMR studies of field-induced phases in linarite are presented for magnetic fields H∥b axis. A two-step spin-flop transition is observed, as well as a transition transforming a helical magnetic ground state into an unusual magnetic phase with sine-wave-modulated moments ∥H. An effective J[over ˜]_{1}-J[over ˜]_{2} single-chain model with a magnetization-dependent frustration ratio α_{eff}=-J[over ˜]_{2}/J[over ˜]_{1} is proposed. The latter is governed by skew interchain couplings and shifted to the vicinity of the ferromagnetic critical point. It explains qualitatively the observation of a rich variety of exotic longitudinal collinear spin-density wave, SDW_{p}, states (9≥p≥2).

Methoxychlor enhances degranulation of murine mast cells by regulating FcεRI-mediated signal transduction

Methoxychlor, an organochlorine insecticide developed to replace DDT (dichlorodiphenyltrichloroethane), has been reported to induce mast cell degranulation and to enhance IgE-mediated allergic responses. However, the mechanisms underlying these effects are not clear. To clarify potential mechanisms, the effects of methoxychlor on degranulation of mast cells were examined. Degranulation responses were evaluated using RBL-2H3 cells and mouse bone marrow-derived mast cells with either the antigen-induced or calcium ionophore-induced stimulation. Phosphorylation of enzymes related to signaling events associated with mast cell degranulation was analyzed by immunoblotting. Effects on vascular permeability in the passive cutaneous anaphylaxis reaction were evaluated following oral administration of methoxychlor to BALB/c mice. The results indicated that methoxychlor caused increased mast cell degranulation in the presence of antigen, whereas it had no effect on calcium ionophore-induced degranulation of RBL-2H3 cells. Immunoblot analyses demonstrated that the phosphorylation level of phosphoinositide 3-kinase (which plays a central role in mast cell signaling) was increased by methoxychlor during antigen-induced degranulation. In addition, methoxychlor activated the signaling pathway via the high-affinity IgE receptor by inducing phosphorylation of Syk and PLCγ1/2, which transfer the signal for degranulation downstream. Lastly, oral administration of methoxychlor exhibited a tendency to promote vascular permeability in passive cutaneous anaphylaxis model mice. Taken together, the results here suggested that methoxychlor enhanced degranulation through FcεRI-mediated signaling and promoted allergenic symptoms involved in mast cell degranulation.

Tributyltin induces cell cycle arrest at G1 phase in the yeast Saccharomyces cerevisiae

Tributyltin (TBT) has long been recognized as a major environmental pollutant that can cause significant damage to the cellular functions as well as disruption of endocrine homeostasis. TBT induces apoptosis accompanied by production of reactive oxygen species (ROS) in mammalian and yeast cells. We observed that the budding yeast cells exposed to this compound at low concentrations exhibited cell growth arrest, but not cell death. Flow cytometric analysis of yeast cells without synchronization and morphological assessment of cells synchronized at M phase by nocodazole treatment indicated that TBT-exposed Saccharomyces cerevisiae cells were arrested at G1 phase of the cell cycle. This arrest was recovered by the addition of N-acetylcysteine, suggesting the involvement of ROS production by TBT. This is the first study to evaluate the action of TBT on cell cycle events.

Phenylhydroquinone induces loss of thymocytes through cell cycle arrest and apoptosis elevation in p53-dependent pathway

ortho-Phenylphenol has been employed in post-harvest treatment of citrus fruits. Although o-phenylphenol has been reported to cause carcinomas in the urinary tract in rats, toxicity to the immune organs is still unknown. Herein, we report that administration of o-phenylphenol induces thymic atrophy and loss of thymocytes in female BALB/c mice. The influence seems to result from inhibition of the thymocyte development, because increased and decreased populations of the CD4⁻ CD8⁻ double-negative and CD4⁺ CD8⁺ double-positive thymocytes were observed in the o-phenylphenol-administered mice, respectively. ortho-Phenylphenol is metabolized to phenylhydroquinone by cytochrome P450 monooxygenases. Phenylhydroquinone made cell cycle of thymocytes to be arrested through reduced expression of the genes associated with G₂/M phase and through phosphorylation of p53 at Ser15. Phosphorylation of p53 at Ser15 was upregulated by activation of not only ATR but also Erk1/2 and p38, leading to increase of apoptosis. Gene expression of cytochrome P450 1A1 (CYP1A1) was promoted in thymocytes from the o-phenylphenol-administered mice. Overall, our results suggest that o-phenylphenol induces CYP1A1 expression and is metabolized into phenylhydroquinone by the expressed CYP1A1 in thymocytes. The produced phenylhydroquinone in turn induces inhibition of thymocyte development through cell cycle arrest and apoptosis in the p53-dependent pathway.

Spermine enhances IgM productivity of human-human hybridoma HB4C5 cells and human peripheral blood lymphocytes

The polyamine spermine was assessed for enhancement of IgM production by human-human hybridoma, HB4C5 cells, under serum-free conditions. IgM production of HB4C5 cells was stimulated approximately 6-fold by the addition of 7.3 mM of spermine. The facilitating effect was observed soon after inoculation. In spite of suppression of cell growth, the IgM production rate was accelerated for at least 5 days without medium change. Moreover, laser confocal microscopic analysis revealed that the IgM content inside HB4C5 cells was increased by spermine treatment. These findings suggest that spermine enhances specific IgM productivity of the hybridoma line. Spermine also facilitated IgM production by human peripheral blood lymphocytes under serum-free conditions. This result implies that spermine enhances immunoglobulin production of not only specific hybridoma lines, but also non-specific immunoglobulin producers. Immunoglobulin production stimulating activity of spermine was accelerated 2-fold by the addition of DNA whith a chain length of about 400-7000 base pairs (bp). However, degraded short-chain DNA fragments (less than 200 bp) did not facilitate the immunoglobulin production stimulating activity of spermine.

Ca(2)Y(2)Cu(5)O(10): the first frustrated quasi-1D ferromagnet close to criticality

Ca(2)Y(2)Cu(5)O(10) is built up from edge-shared CuO(4) plaquettes forming spin chains. From inelastic neutron scattering data we extract an in-chain nearest-neighbor exchange J(1)≈-170  K and the frustrating next-neighbor J(2)≈32  K interactions, both significantly larger than previous estimates. The ratio α=|J(2)/J(1)|=0.19±0.01 places the system close to the critical point α(c)=0.25 of the J(1)-J(2) chain but in the 1D ferromagnetic regime. We establish that the vicinity to criticality only marginally affects the dispersion and coherence of the spin-wave-like magnetic excitations but instead results in a dramatic T dependence of high-energy Zhang-Rice singlet excitation intensities.

Double exchange ferromagnetism in the Peierls insulator state

We study the effects of opening the band gap on the double exchange ferromagnetism. Applying the density-matrix renormalization group method and an analytical expansion from the dimer limit to the one-dimensional double exchange model, we demonstrate for a relevant region of the exchange coupling that, in the weak dimerization regime, the Peierls gap opens in the fully spin-polarized conduction band without affecting its ferromagnetism, whereas in the strong dimerization regime, the ferromagnetism is destroyed, and the Mott gap opens instead, leading the system to the antiferromagnetic quasi-long-range order. An insulator version of double exchange ferromagnetism is thus established.

Suppressive effects of the leaf of Terminalia catappa L. on osteoclast differentiation in vitro and bone weight loss in vivo

Oral administration of Terminalia catappa extract (TCE; 1,000 mg/kg) for 5 wk suppressed bone weight loss and trabecular bone loss in ovariectomized mice. An in vitro experiment showed that TCE (1.3-20 µg/mL) did not increase alkaline phosphatase activity, which would indicate osteoclast formation, in osteoblast-like 3T3-L1 cells. On the other hand, TCE (12.5 µg/mL) markedly decreased the number of tartrate resistant acid phosphatase (TRAP)-positive multinucleated cells, which would indicate osteoclast formation, in a co-culture system (bone marrow cells/osteoblastic UAMS-32 cells). A detailed analysis of the stages of osteoclast differentiation revealed that TCE mainly suppressed the differentiation of bone marrow mononuclear cells into osteoclast progenitor cells in the presence of M-CSF and TGF-β. An additional experiment using fractionated TCE revealed that the water-soluble fraction suppressed the bone weight loss in OVX-mice and osteoclast differentiation in vitro. Therefore, the suppressive effects of TCE on bone weight loss in mice might be due to the suppressive effects of highly polar components on the early stage of osteoclast differentiation.

Nobiletin suppresses adipocyte differentiation of 3T3-L1 cells by an insulin and IBMX mixture induction

BACKGROUND

Nobiletin is a citrus flavonoid which possesses the flavone structure with six methoxy groups. Although nobiletin has been reported to display anti-inflammatory, anti-tumor, and anti-diabetes activities, its effect on adipocyte differentiation remained unclear. In the present study, we investigated the effect of nobiletin on the differentiation of 3T3-L1 preadipocytes into adipocytes.

METHODS

3T3-L1 preadipocytes were treated with nobiletin under various differentiation conditions. The effect of nobiletin on adipocyte differentiation was evaluated by oil red O staining, real-time RT-PCR, and Western blotting.

RESULTS

Nobiletin significantly suppressed the differentiation of 3T3-L1 preadipocytes into adipocytes, upon induction with insulin together with a cAMP elevator such as 3-isobutyl-1-methylxanthine (IBMX), by downregulating the expression of the gene encoding peroxisome proliferator-activated receptor (PPAR) γ2. In addition, nobiletin decreased the phosphorylation of cAMP-response element-binding protein (CREB) and strongly enhanced the phophorylation of signal transducer and activator of transcription (STAT) 5.

GENERAL SIGNIFICANCE

Nobiletin has a suppressive effect on the differentiation of preadipocytes into adipocytes when cells were induced with a general differentiation cocktail such as insulin, IBMX, and dexamethasone.

Local sensitivity to stimulus orientation and spatial frequency within the receptive fields of neurons in visual area 2 of macaque monkeys

We used dynamic dense noise stimuli and local spectral reverse correlation methods to reveal the local sensitivities of neurons in visual area 2 (V2) of macaque monkeys to orientation and spatial frequency within their receptive fields. This minimized the potentially confounding assumptions that are inherent in stimulus selections. The majority of neurons exhibited a relatively high degree of homogeneity for the preferred orientations and spatial frequencies in the spatial matrix of facilitatory subfields. However, about 20% of all neurons showed maximum orientation differences between neighboring subfields that were greater than 25 deg. The neurons preferring horizontal or vertical orientations showed less inhomogeneity in space than the neurons preferring oblique orientations. Over 50% of all units also exhibited suppressive profiles, and those were more heterogeneous than facilitatory profiles. The preferred orientation and spatial frequency of suppressive profiles differed substantially from those of facilitatory profiles, and the neurons with suppressive subfields had greater orientation selectivity than those without suppressive subfields. The peak suppression occurred with longer delays than the peak facilitation. These results suggest that the receptive field profiles of the majority of V2 neurons reflect the orderly convergence of V1 inputs over space, but that a subset of V2 neurons exhibit more complex response profiles having both suppressive and facilitatory subfields. These V2 neurons with heterogeneous subfield profiles could play an important role in the initial processing of complex stimulus features.

(-)-Secoisolariciresinol attenuates high-fat diet-induced obesity in C57BL/6 mice

Flaxseed lignan, secoisolariciresinol has been reported to possess health benefits. We previously synthesized each stereoisomer of secoisolariciresinol and found that (-)-secoisolariciresinol reduces lipid accumulation and induces adiponectin production in 3T3-L1 adipocytes. Here we show the effects of (-)-secoisolariciresinol on high-fat diet-induced obesity in C57BL/6 male mice. Oral administration of (-)-secoisolariciresinol for 28 consecutive days significantly suppressed the gain of body weight. Increased serum adiponectin level and decreased gene expression of fatty acid synthase and sterol regulatory element-binding protein-1c in liver, which are related to fatty acid synthesis, were observed in the mice orally administered with (-)-secoisolariciresinol. In addition, subcutaneous injection of (-)-secoisolariciresinol also significantly suppressed the gain of body weight. Serum leptin levels were significantly increased by treating with (-)-secoisolariciresinol or (-)-enterolactone. Subcutaneous injection of (-)-secoisolariciresinol, (-)-enterolactone, or (-)-enterodiol promoted gene expression of acyl-CoA oxidase, carnitine palmitoyl transferase-1, and peroxisome proliferator-activated receptor α, which are related to β-oxidation. Overall results suggest that (-)-secoisolariciresinol exerts a suppressive effect on the gain of body weight of mice fed a high-fat diet by inducing gene expression of adiponectin, resulting in the altered expression of various genes related to the synthesis and β-oxidation of fatty acids.

Saturation field of frustrated chain cuprates: broad regions of predominant interchain coupling

A thermodynamic method to extract the interchain coupling (IC) of spatially anisotropic 2D or 3D spin-1/2 systems from their empirical saturation field H(s) (T=0) is proposed. Using modern theoretical methods we study how H(s) is affected by an antiferromagnetic (AFM) IC between frustrated chains described in the J(1)-J(2)-spin model with ferromagnetic 1st and AFM 2nd neighbor in-chain exchange. A complex 3D-phase diagram has been found. For Li(2)CuO(2) and Ca(2)Y(2)Cu(5)O(10), we show that H(s) is solely determined by the IC and predict H(s)≈61 T for the latter. With H(s)≈55 T from magnetization data one reads out a weak IC for Li(2)CuO(2) close to that obtained from inelastic neutron scattering.

Heavy oil fraction induces the dysplastic sperm in male mouse

Heavy oil is one of the most serious pollutants in marine ecosystem. The poisonous influences of the chemical substances contained in heavy oil on many kinds of marine organisms are widely studied. However, the influence of the chemical compounds in heavy oil on our health has not been cleared yet. In order to reveal the poisonous influences of these chemical compounds on mammalian reproductive system, water-soluble fraction (WSF) extracted from heavy oil was administrated to mice for 2 weeks. WSF-administrated mice were crossed with either WSF- or distilled water-administrated group for mating experiment. When WSF-administrated male mice were used as a father, it reduced not only mating ratio, but also neonatal male ratio. The numbers of sperms of WSF-administrated male mice were decreased. In addition, abnormality of sperms such as bent or twisted tail was increased approximately 6-fold by WSF intake. The level of testosterone in serum from WSF-administrated mice was lower than that from control mice. Testosterone is the most important for the spermatogenesis in vertebrate. It is supposed from these findings, the decrease in the number of sperms may relate with the reduction of sex hormone level in serum. It is suggested from these results that the chemical substances in WSF affected the sperm function in reproductive system of male mice.

Inhibition of myotube formation by paraquat in the myoblast cell line C2C12

Paraquat (PQ) is one of the most frequently used pesticides in worldwide. In most countries, PQ is used without restrictions. To investigate the effect of PQ on myogenesis, cultures of C2C12, a useful model to study differentiation of myoblasts into myotubes, were exposed to various concentrations of PQ. Myotube formation did not occur in the presence of 50 µM PQ. Although cell death was not observed at this concentration, growth inhibition was evident in the growth medium. Production of myosin heavy chain, a myogenesis marker protein, decreased dose dependently with the concentration of PQ, which was added to the C2C12 cell culture during differentiation. Inhibition of myogenesis by PQ was not reversed by the addition of ascorbic acid. These results show that PQ is a strong inhibitor of muscle differentiation in vitro.

Spin gap in the zigzag spin-1/2 chain cuprate Sr(0.9)Ca(0.1)CuO(2)

We report a comparative study of (63)Cu nuclear magnetic resonance spin lattice relaxation rates T(1)(-1) on undoped SrCuO(2) and Ca-doped Sr(0.9)Ca(0.1)CuO(2) spin chain compounds. A temperature independent T(1)(-1) is observed for SrCuO(2) as expected for an S=1/2 Heisenberg chain. Surprisingly, we observe an exponential decrease of T(1)(-1) for T<90 K in the Ca-doped sample evidencing the opening of a spin gap. The data analysis within the J(1)-J(2) Heisenberg model employing density-matrix renormalization group calculations suggests an impurity driven small alternation of the J(2)-exchange coupling as a possible cause of the spin gap.

Bfr1p is responsible for tributyltin resistance in Schizosaccharomyces pombe

ATP-binding cassette (ABC) transporter plays an important role for resistance against xenobiotics. There are eleven ABC transporter genes in the genome of fission yeast Schizosaccharomyces pombe. We examined the role of ABC transporter against the toxicity of tributyltin chloride (TBT), a widespread environmental pollutant, in cell growth. Among individual ABC transporter mutants, the growth of a mutant deficient in Bfr1p, a plasma membrane-embedded transporter, was extremely sensitive to TBT. The lethal TBT concentration inducing 50% of cell death (LC(50)) was 25 µM for the parent strain and 10.2 µM for the bfr1∆ mutant. Thus, Bfr1p was responsible for TBT resistance in S. pombe.

Low Temperature Fabrication of (Ba, Sr)TiO3 Thin Films by ECR Plasma CVD

Physical and electrical properties are investigated for (Ba, Sr)TiO3 (BST) films prepared by electron cyclotron resonance (ECR) plasma chemical vapor deposition (CVD) at relatively low temperatures, between 450 °C and 500 °C. The crystallinity of BST, estimated by X-ray diffraction and from the grain size, is greatly improved when the temperature is raised from 450 °C to 500 °C. Also better crystallinity is obtained for films grown at a deposition rate of 1.1 nn/min than at 2.7 nm/min. The mass transport rates of metal organic sources under our deposition conditions are estimated. The BST film composition is precisely controlled using the results of the investigation on mass transport. At near stoichiometric composition, i.e., (Ba+Sr)/Ti=0.97, and Ba/(Ba+Sr)=0.4, the films grown at 500 °C are found to have the largest dielectric constant, measured using flat capacitors with Pt bottom electrodes. A dielectric constant of 160 is obtained for 27 nm thick films grown at 500 °C and at 1.1 nm/min, without post-deposition annealing. These films exhibit the smallest SiO2 equivalent thickness of 0.65 nm and a leakage current density of 4.6x10−7 A/cm2 at plus IV.

Oral administration of paraquat perturbs immunoglobulin productivity in mouse

Paraquat is one of the most widely used herbicides in the world and has been known to injure lungs, liver and skin in animals and human. Hence, it is important to understand the manner of paraquat in mammals. We studied the effect of paraquat on the immune function of mouse in vitro and in vivo. When splenocytes were cultured in vitro with various concentrations of paraquat, IgA productivity was not affected while IgG and IgM productivity decreased. On the other hand, Oral administration of paraquat for 1, 2 or 3 weeks increased IgA level but decreased IgM levels in serum of mice. Similarly IgA productivity increased while IgM productivity decreased. These results suggest that paraquat perturbs the lymphocytes immunoglobulin productivity in an immunoglobulin class-dependent manner.

Tributyltin induces Yca1p-dependent cell death of yeast Saccharomyces cerevisiae

Tributyltin chloride (TBT), an environmental pollutant, is toxic to a variety of eukaryotic and prokaryotic organisms. Although it has been reported that TBT induces apoptotic cell death in mammalian, the action of TBT on eukaryotic microorganisms has not yet been fully investigated. In this study we examined the mechanism involved in cell death caused by TBT exposure in Saccharomyces cerevisiae. The median lethal concentration of TBT was 10 microM for the parent strain BY4741 and 3 microM for the pdr5Delta mutant defective in a major multidrug transporter, respectively. Fluorescence microscopic observations revealed nuclear condensation and chromatin fragmentation in cells treated with TBT indicating that cells underwent an apoptosis-like cell dearth. TBT-induced cell death was suppressed by deletion of the yca1 gene encoding a homologue of the mammalian caspase. In parallel, reactive oxygen species (ROS) were produced by TBT. These results suggest that TBT induces apoptosis-like cell death in yeast via an Yca1p-dependent pathway possibly downstream of the ROS production. This is the first report on TBT-induced apoptotic cell death in yeast.

Pharmacokinetics of Fluorinated 2-nitroimidazole Hypoxic Cell Radiosensitizers in Murine Peripheral Nervous Tissue

We have previously reported that KU-2285, a 2-nitroimidazole with a fluorinated N1-substituent (-CH2-CF2CONH(CH2)nOH, n = 2), was a promising hypoxic cell radiosensitizer. In this study the pharmacokinetics of KU-2285 and its related compounds (n = 3 and n = 4) were compared with those of etanidazole (a 2-nitroimidazole with an N1-substituent of -CH2CONH(CH2)nOH, n = 2) and its related compounds (n = 3 and n = 4) to assess the effects of incorporation of a CF2 group. The lipophilicity of the fluorinated compounds was higher than that of etanidazole, as measured by the octanol/water partition coefficient. As the number of CH2 groups increased, the lipophilicity of the compounds in both the KU-2285 and etanidazole series increased. The brain tissue levels of the fluorinated compounds were as low as those of the etanidazole derivatives, while the biological half-lives of the fluorinated compounds in peripheral nervous tissues were shorter than those of related non-fluorinated compounds.

Congenital duplication of lower extremity--a case report and review of the literature

Congenital duplication of the lower extremity is quite rare. Only 26 cases have been reported so far. A female infant with incomplete duplication of lower limb and with hypothyroidism was reported. Her mother's pregnancy and delivery was uneventful. A tube-like skin tissue was found on the posterior aspect of the infant's left thigh. Her left foot presented equinovarus deformity. There were three extra toes on the plantar side of her foot. A band of skin with a thin horny layer, similar to the dorsal surface, could be seen on the sole. The skin tube on the thigh was simply resected. A neuro-vascular-islanded toe was made from the plantar toes and rotated to restore five toes on the foot. The transferred toe thrived in accordance with the surrounding toes. The patient could run without difficulty at the age of 3. Previous reports about this case are summarised and reviewed here.