Showing papers by "Tokyo University of Science published in 2006"

Final report of the E821 muon anomalous magnetic moment measurement at BNL

Abstract: We present the final report from a series of precision measurements of the muon anomalous magnetic moment, a(mu)=(g-2)/2. The details of the experimental method, apparatus, data taking, and analysis are summarized. Data obtained at Brookhaven National Laboratory, using nearly equal samples of positive and negative muons, were used to deduce a(mu)(Expt)=11659208.0(5.4)(3.3)x10(-10), where the statistical and systematic uncertainties are given, respectively. The combined uncertainty of 0.54 ppm represents a 14-fold improvement compared to previous measurements at CERN. The standard model value for a(mu) includes contributions from virtual QED, weak, and hadronic processes. While the QED processes account for most of the anomaly, the largest theoretical uncertainty, approximate to 0.55 ppm, is associated with first-order hadronic vacuum polarization. Present standard model evaluations, based on e(+)e(-) hadronic cross sections, lie 2.2-2.7 standard deviations below the experimental result.

Measurement of neutrino oscillation by the K2K experiment

Abstract: We present measurements of {nu}{sub {mu}} disappearance in K2K, the KEK to Kamioka long-baseline neutrino oscillation experiment. One-hundred and twelve beam-originated neutrino events are observed in the fiducial volume of Super-Kamiokande with an expectation of 158.1{sub -8.6}{sup +9.2} events without oscillation. A distortion of the energy spectrum is also seen in 58 single-ring muonlike events with reconstructed energies. The probability that the observations are explained by the expectation for no neutrino oscillation is 0.0015% (4.3{sigma}). In a two-flavor oscillation scenario, the allowed {delta}m{sup 2} region at sin{sup 2}2{theta}=1 is between 1.9 and 3.5x10{sup -3} eV{sup 2} at the 90% C.L. with a best-fit value of 2.8x10{sup -3} eV{sup 2}.

Single-walled carbon nanotube growth from highly activated metal nanoparticles.

Abstract: We demonstrate that any metal, even gold, silver, and copper, can act as a catalyst for SWCNT synthesis in chemical vapor deposition (CVD). Metal nanoparticles 3 nm or less in diameter, introduced into CVD ambience immediately after heat treatment at 800-950 degrees C in air, produce SWCNTs. The activation method is effective for copper and various noble metals as well as for iron-family elements. This implies that any metal particle may produce SWCNTs when its size becomes 1-3 nm. In other words, carbon atoms can form SWCNTs in a self-assembling fashion on nanoparticles without the specific functions of iron-family elements.

Electrical Properties and Depolarization Temperature of (Bi1/2Na1/2)TiO3–(Bi1/2K1/2)TiO3 Lead-free Piezoelectric Ceramics

Abstract: The piezoelectric properties of a solid solution of the binary system, x(Bi1/2Na1/2)TiO3–(1-x)(Bi1/2K1/2)TiO3 [BNKT100x; x=0.50–0.98] were investigated, focusing on depolarization temperature, Td. Fine piezoelectric properties in lead-free piezoelectric ceramics were obtained near the morphotropic phase boundary (MPB) composition between the rhombohedral and tetragonal structures, and the highest electromechanical coupling factor, k33, and piezoelectric constant, d33, were 0.56 for BNKT84 and 157 pC/N for BNKT80, respectively. However, the Td of BNKT80 was low (174 °C). The Td of the MPB composition was low, and the Td near the MPB composition was sharply decreased. It is thought that BNKT70 is a candidate composition for lead-free actuator applications owing to its relatively large piezoelectric constant, d33 (126 pC/N), dynamic d33 (214 pm/V), and high depolarization temperature, Td (206 °C). In this study, we determined depolarization temperature, Td, from the temperature dependence of dielectric and piezoelectric properties.

Nonequilibrium Green's function approach to phonon transport in defective carbon nanotubes.

Abstract: We have developed a new theoretical formalism for phonon transport in nanostructures using the nonequilibrium phonon Green's function technique and have applied it to thermal conduction in defective carbon nanotubes. The universal quantization of low-temperature thermal conductance in carbon nanotubes can be observed even in the presence of local structural defects such as vacancies and Stone-Wales defects, since the long wavelength acoustic phonons are not scattered by local defects. At room temperature, however, thermal conductance is critically affected by defect scattering since incident phonons are scattered by localized phonons around the defects. We find a remarkable change from quantum to classical features for the thermal transport through defective carbon nanotubes with increasing temperature.

Photocatalytic Hydrogen Evolution on ZnS−CuInS2−AgInS2 Solid Solution Photocatalysts with Wide Visible Light Absorption Bands

Abstract: Pt-loaded ZnS−CuInS2−AgInS2 solid solutions showed photocatalytic activities for H2 evolution from aqueous solutions containing SO32- and S2- as sacrificial reagents under visible light irradiation (λ ≥ 420 nm). The crystal structures of the solid solutions were either zinc blende or wurtzite, depending on the composition. The diffuse reflectance and photoluminescence spectra of the solid solutions were shifted monotonically to longer wavelengths as the ratio of MInS2 (M = Cu and Ag) to ZnS increased, indicating that the energy band structure of the sold solution was controllable by the change in the composition. The ZnS−CuInS2−AgInS2 solid solutions exhibited absorption bands that were longer in wavelength than those for the ZnS−CuInS2 and ZnS−AgInS2 solid solutions, which is probably due to interactions between the Cu 3d and Ag 4d orbitals. The photocatalytic activity for H2 evolution was much improved by low-temperature synthesis (773−873 K) and the loading of Ru cocatalysts. The Ru-loaded Cu0.25Ag0.25...

The Rc and Rd genes are involved in proanthocyanidin synthesis in rice pericarp.

Abstract: Different colors, such as purple, brown, red and white, occur in the pericarp of rice. Here, two genes affecting proanthocyanidin synthesis in red- and brown-colored rice were elucidated. Genetic segregation analysis suggested that the Rd and A loci are identical, and both encode dihydroflavonol-4-reductase (DFR). The introduction of the DFR gene into an Rcrd mutant resulted in red-colored rice, which was brown in the original mutant, demonstrating that the Rd locus encodes the DFR protein. Accumulation of proanthocyanidins was observed in the transformants by the introduction of the Rd gene into the rice Rcrd line. Protein blot analysis showed that the DFR gene was translated in seeds with alternative translation initiation. A search for the Rc gene, which encodes a transacting regulatory factor, was conducted using available DNA markers and the Rice Genome Automated Annotation System program. Three candidate genes were identified and cloned from a rice RcRd line and subsequently introduced into a rice rcrd line. Brown-colored seeds were obtained from transgenic plants by the introduction of a gene containing the basic helix-loop-helix (bHLH) motif, demonstrating that the Rc gene encodes a bHLH protein. Comparison of the Rc locus among rice accessions showed that a 14-bp deletion occurred only in the rc locus.

Combined proline-surfactant organocatalyst for the highly diastereo- and enantioselective aqueous direct cross-aldol reaction of aldehydes.

Abstract: in water even in the presence of a surfactant. [5] There have been no successful asymmetric aldol reactions performed using organocatalysts in water in the absence of an organic cosolvent or other additives. Recently, we reported that a siloxyproline effectively catalyzes the highly diastereo- and enantioselective aldol reaction of ketones and aldehydes in the presence of water. [6] Barbas and co-workers reported the asymmetric aldol reaction of ketones and aldehydes in water catalyzed by a combination of a diamine and an acid. [7] Herein, we describe how combined proline–surfactant organocatalysis promotes the asymmetric direct aldol reaction of two different aldehydes in the presence of water and no other additives, with high diastereo- and enantioselectivity. The original version of this reaction reported by MacMillan and Northup was carried out in a polar organic solvent under proline catalysis, with introduction of the aldehyde donor by syringe pump. [8] The reaction of o-chlorobenzaldehyde and propanal (5 equiv) was selected as a model and performed in the presence of 18 equivalents of water and several putative organocatalysts (10 mol %, 24 h; see Scheme 1). The aldols were isolated after reduction to the corresponding diols

Electrophoresis of Diffuse Soft Particles

Abstract: A theory is presented for the electrophoresis of diffuse soft particles in a steady dc electric field. The particles investigated consist of an uncharged impenetrable core and a charged diffuse polyelectrolytic shell, which is to some extent permeable to ions and solvent molecules. The diffuse character of the shell is defined by a gradual distribution of the density of polymer segments in the interspatial region separating the core from the bulk electrolyte solution. The hydrodynamic impact of the polymer chains on the electrophoretic motion of the particle is accounted for by a distribution of Stokes resistance centers. The numerical treatment of the electrostatics includes the possibility of partial dissociation of the hydrodynamically immobile ionogenic groups distributed throughout the shell as well as specific interaction between those sites with ions from the background electrolyte other than charge-determining ions. Electrophoretic mobilities are computed on the basis of an original numerical scheme allowing rigorous evaluation of the governing transport and electrostatic equations derived following the strategy reported by Ohshima, albeit within the restricted context of a discontinuous chain distribution. Attention is particularly paid to the influence of the type of distribution adopted on the electrophoretic mobility of the particle as a function of its size, charge, degree of permeability, and solution composition. The results are systematically compared with those obtained with a discontinuous representation of the interface. The theory constitutes a basis for interpreting electrophoretic mobilities of heterogeneous systems such as environmental or biological colloids or swollen/deswollen microgel particles.

Large-Scale Fabrication of Ordered Nanoporous Alumina Films with Arbitrary Pore Intervals by Critical-Potential Anodization

Abstract: Various ordered nanoporous alumina films with arbitrary pore intervals from 130 to 980 nm were fabricated on aluminum by a critical-potential anodization approach with sulfuric, phosphoric, oxalic, glycolic, tartaric, malic, and citric acid electrolytes under 70-450 V. The pore intervals of the porous alumina films were linearly proportional to applied potentials, with corresponding dominated territories to the electrolytes. In addition to pore interval, the self-ordering extent of pore arrangement was also improved with increasing anodizing potentials, leading to highly ordered porous alumina films at critical-high potentials. A cell separation phenomenon occurred for the films formed in sulfuric and glycolic acid solutions at the critical potentials, thus leading to the formation of highly ordered alumina nanotubule arrays. The critical-potential anodization in the other electrolytes produced self-organized porous alumina films with two-layered pore walls and pore bases. The basic principle for achieving porous alumina films with desired pore intervals is controlling the balance of the growth of barrier layer and the pore generation by adjusting the acidity, the concentration, and temperature of electrolytes. The porous alumina films formed in various electrolytes were transparent, and the transmittances of the films were inversely proportional to the applied potentials or the pore intervals.

Preparation of highly dispersed core/shell-type titania nanocapsules containing a single Ag nanoparticle.

Abstract: Core/shell-type titania nanocapsules containing a single Ag nanoparticle were prepared. Ag nanoparticles were prepared using the reduction of silver nitrate with hydrazine in the presence of cetyltrimethylammonium bromide (CTAB) as protective agent. The sol-gel reaction of titanium tetraisopropoxide (TTIP) was used to prepare core/shell-type titania nanocapsules with CTAB-coated Ag nanoparticles as the core. TEM observations revealed that the size of the core (Ag particle) and the thickness of the shell (titania) of the core/shell particles obtained are about 10 nm and 5-10 nm, respectively. In addition, the nanocapsules were found to be dispersed in the medium as individual particles without aggregation. Moreover, titania coating caused the surface plasmon absorption of Ag nanoparticles to shift toward the longer wavelength side.

Phase Transition Temperatures and Piezoelectric Properties of (Bi1/2Na1/2)TiO3–(Bi1/2K1/2)TiO3–BaTiO3 Lead-Free Piezoelectric Ceramics

Abstract: The phase transition temperatures of x(Bi1/2Na1/2)TiO3–y(Bi1/2K1/2)TiO3–zBaTiO3) [x+y+z=1, y:z=2:1] [abbreviate to BNBK2:1(x)] ceramics were investigated using electrical measurements. We discussed the determination of the depolarization temperature, Td, and defined the Td for (Bi1/2Na1/2)TiO3 (BNT)-based solid solutions. We also determined the rhombohedral–tetragonal phase transition temperatures, TR–T, for BNBK2:1(x), and verified them using dielectric and piezoelectric measurements. It was demonstrated that TR–T corresponded with Td at x=0.94. The existence of an intermediate phase with ferroelectric and antiferroelectric properties at temperatures higher than the Td around the morphotropic phase boundary (MPB) was also revealed.

An unconventional myosin in Drosophila reverses the default handedness in visceral organs

Abstract: The internal organs of animals often have left-right asymmetry. Although the formation of the anterior-posterior and dorsal-ventral axes in Drosophila is well understood, left-right asymmetry has not been extensively studied. Here we find that the handedness of the embryonic gut and the adult gut and testes is reversed (not randomized) in viable and fertile homozygous Myo31DF mutants. Myo31DF encodes an unconventional myosin, Drosophila MyoIA (also referred to as MyoID in mammals; refs 3, 4), and is the first actin-based motor protein to be implicated in left-right patterning. We find that Myo31DF is required in the hindgut epithelium for normal embryonic handedness. Disruption of actin filaments in the hindgut epithelium randomizes the handedness of the embryonic gut, suggesting that Myo31DF function requires the actin cytoskeleton. Consistent with this, we find that Myo31DF colocalizes with the cytoskeleton. Overexpression of Myo61F, another myosin I (ref. 4), reverses the handedness of the embryonic gut, and its knockdown also causes a left-right patterning defect. These two unconventional myosin I proteins may have antagonistic functions in left-right patterning. We suggest that the actin cytoskeleton and myosin I proteins may be crucial for generating left-right asymmetry in invertebrates.

Antiangiogenic and Antitumor Activities of IL-27

Abstract: IL-27 is a novel IL-6/IL-12 family cytokine playing an important role in the early regulation of Th1 responses. We have recently demonstrated that IL-27 has potent antitumor activity, which is mainly mediated through CD8 + T cells, against highly immunogenic murine colon carcinoma. In this study, we further evaluated the antitumor and antiangiogenic activities of IL-27, using poorly immunogenic murine melanoma B16F10 tumors, which were engineered to overexpress single-chain IL-27 (B16F10 + IL-27). B16F10 + IL-27 cells exerted antitumor activity against not only s.c. tumor but also experimental pulmonary metastasis. Similar antitumor and antimetastatic activities of IL-27 were also observed in IFN-γ knockout mice. In NOD-SCID mice, these activities were decreased, but were still fairly well-retained, suggesting that different mechanisms other than the immune response are also involved in the exertion of these activities. Immunohistochemical analyses with Abs against vascular endothelial growth factor and CD31 revealed that B16F10 + IL-27 cells markedly suppressed tumor-induced neovascularization in lung metastases. Moreover, B16F10 + IL-27 cells clearly inhibited angiogenesis by dorsal air sac method, and IL-27 exhibited dose-dependent inhibition of angiogenesis on chick embryo chorioallantoic membrane. IL-27 was revealed to directly act on HUVECs and induce production of the antiangiogenic chemokines, IFN-γ-inducible protein (IP-10) and monokine induced by IFN-γ. Finally, augmented mRNA expression of IP-10 and monokine induced by IFN-γ was detected at the s.c. B16F10 + IL-27 tumor site, and antitumor activity of IL-27 was partially inhibited by the administration of anti-IP-10. These results suggest that IL-27 possesses potent antiangiogenic activity, which plays an important role in its antitumor and antimetastatic activities.

Highly efficient dye-sensitized solar cells composed of mesoporous titanium dioxide

Abstract: In this study, mesoporous TiO2 using the template method with a short-range ordered-framework structure was successfully used as an electrode material in dye-sensitized solar cells. The best efficiency, 10.0%, was achieved under illumination by simulated AM 1.5 solar light (100 mW cm−2). This high light-to-electricity energy conversion efficiency is attributed to the novel physicochemical properties of mesoporous TiO2, which include high surface area, uniform nanochannels, and a homogeneous nanocrystalline structure. The high surface area adsorbs large quantities of the sensitized dye, resulting in the generation of a higher photocurrent density. A significant influence of the mesopore structure on photovoltaic performance was also observed based on these novel properties.

Factors governing ferroelectric switching characteristics of thin VDF/TrFE copolymer films

Abstract: A series of ferroelectric switching measurements are performed on the 75/25mol% vinylidene fluoride/trifluoroethylene copolymer thin films with various structures to elucidate the factors governing the switching characteristics of such films. It is shown that the spin-coated and well-annealed samples exhibit a remanent polarization Pr of 85 mC/m2. Unlike that in previous reports, the switching time taus of these samples is independent of thickness down to 50 nm if Au electrodes are used instead of Al electrodes. Thin films with different metal electrodes exhibit anisotropic taus due to a potential difference between metal electrodes produced by their work function difference. A train of unipolar short on-off electric field pulses induce a slow but full polarization reversal whose time evolution supports the nucleation and growth mechanism. Continuous switching under bipolar on-off electric field pulses reveals an accelerated polarization reversal with decreasing pulse width. This means that taus is a function of not only applied electric field but also the preceding poling conditions. Fatigue is significantly improved using Au electrodes instead of Al electrodes. The results are discussed in relation to the microscopic features of the VDF/TrFE copolymer and the underlying nucleation-growth mechanism

Experimental signature of medium modifications for rho and omega mesons in the 12 GeV p+A reactions.

Abstract: The invariant mass spectra of e{sup +}e{sup -} pairs produced in 12 GeV proton-induced nuclear reactions are measured at the KEK Proton Synchrotron. On the low-mass side of the {omega} meson peak, a significant enhancement over the known hadronic sources has been observed. The mass spectra, including the excess, are well reproduced by a model that takes into account the density dependence of the vector meson mass modification, as theoretically predicted.

Development of the Face Robot SAYA for Rich Facial Expressions

Abstract: The purpose of this study is to develop an interactive communication system that communicates with human beings emotionally. Since the face and its expressions are the most important role for natural communication, we have been developing a face robot that can express facial expressions similar to human beings. In this study, we show a new type face robot SAYA. All McKibben pneumatic actuators are distributed to the surface of the face like a human muscle in order to improve the structure of the face robot and facial muscle movement (Action unit) for natural facial expressions. Since the bending manner of coil spring might be similar to human cervical vertebra, we developed the new head motion mechanism by using coil spring for realizing human like head motion. In this paper, we describe the structure of face robot SAYA and the way of constructing new neck mechanism. We have confirmed that SAYA has ability to express fine facial expressions.

Electrochemical and In Situ XAFS-XRD Investigation of Nb2O5 for Rechargeable Lithium Batteries

Abstract: Nb 2 O 5 exhibits various crystal systems, such as orthorhombic (o), tetragonal (t), and monoclinic (m), among which Nb 2 O 5 synthesized at 900-1000°C is commercially used as a cathode material of the 2-V lithium ion battery. The battery performances depended on the structure of Nb 2 O 5 , and the t-Nb 2 O 5 synthesized at 1000°C exhibited an excellent cycling performance with a large discharge capacity of 190 mAh (g oxide) -1 . The structural variations of Nb 2 O 5 during electrochemical reaction were examined. The in situ synchrotron radiation-X-ray diffraction (XRD) measurement indicated that o- and t-Nb 2 O 5 maintain their original crystal lattices, accompanying a small change in the cell volume even after the Li intercalation. The in situ X-ray absorption fine structure (XAFS) analysis of o- and t-Nb 2 O 5 revealed that the continuous variation from Nb 5+ to Nb 4+ took place during the intercalation process. A significant rearrangement of the Nb-O octahedra accompanied by the change of Nb-O and Nb-Nb interactions occurred in both structures with Li intercalation. XRD and XAFS data suggests that the two-dimensional layer structure of t-Nb 2 O 5 seems to be more flexible regarding the Li intercalation compared with the three-dimensional structure of o-Nb 2 O 5 . This may account for the better cyclic performance of the former material as the electrode material.

DNS of turbulent Couette flow with emphasis on the large-scale structure in the core region

Abstract: A series of direct numerical simulation (DNSs) of the turbulent plane Couette flow were performed with various box lengths, L x = 24h, 32h, 45h and 64h, where h is the channel height. The Reynolds numbers Re w (= U w h/ν) of 3000 and 8600 were chosen, where U w is the relative wall speed between top and bottom walls and ν is the kinematic viscosity. In the core region, the meandering of the large-scale structure (LSS) has been captured with a long box size (L x ≥ 32h). Correspondingly, the streamwise two-point correlation decreases and becomes negative at half the box length. The effect of the computational box size on the statistics, e.g. turbulence intensities, is also examined. Significant Reynolds-number dependence is observed in the streamwise LSS. For the higher Reynolds number, both the visualized instantaneous flow field and the pre-multiplied energy spectra show that the LSS can be present, with a finite wavelength of 21–32h in the streamwise direction and a spanwise spacing of 2.1–2.5h. The stru...

The novel β-secretase inhibitor KMI-429 reduces amyloid β peptide production in amyloid precursor protein transgenic and wild-type mice

Abstract: Alzheimer's disease (AD) is a neurodegenerative disorder characterized by the accumulation of amyloid plaques and neurofibrillary tangles in the brain. The major component of the plaques, amyloid beta peptide (Abeta), is generated from amyloid precursor protein (APP) by beta- and gamma-secretase-mediated cleavage. Because beta-secretase/beta-site APP cleaving enzyme 1 (BACE1) knockout mice produce much less Abeta and grow normally, a beta-secretase inhibitor is thought to be one of the most attractive targets for the development of therapeutic interventions for AD without apparent side-effects. Here, we report the in vivo inhibitory effects of a novel beta-secretase inhibitor, KMI-429, a transition-state mimic, which effectively inhibits beta-secretase activity in cultured cells in a dose-dependent manner. We injected KMI-429 into the hippocampus of APP transgenic mice. KMI-429 significantly reduced Abeta production in vivo in the soluble fraction compared with vehicle, but the level of Abeta in the insoluble fraction was unaffected. In contrast, an intrahippocampal injection of KMI-429 in wild-type mice remarkably reduced Abeta production in both the soluble and insoluble fractions. Our results indicate that the beta-secretase inhibitor KMI-429 is a promising candidate for the treatment of AD.

Sfrp1 and Sfrp2 regulate anteroposterior axis elongation and somite segmentation during mouse embryogenesis.

Abstract: Regulation of Wnt signaling is essential for embryonic patterning Sfrps are secreted Wnt antagonists that directly interact with the Wnt ligand to inhibit signaling Here, we show that Sfrp1 and Sfrp2 are required for anteroposterior (AP) axis elongation and somitogenesis in the thoracic region during mouse embryogenesis Double homozygous mutations in Sfrp1 and Sfrp2 lead to severe shortening of the thoracic region By contrast, a homozygous mutation in one or the other exerts no effect on embryogenesis, indicating that Sfrp1 and Sfrp2 are functionally redundant The defect of a shortened thoracic region appears to be the consequence of AP axis reduction and incomplete somite segmentation The reduction in the AP axis is partially due to abnormalities in cell migration of pre-somitic mesoderm from the end of gastrulation Aberrant somite segmentation is associated with altered oscillations of Notch signaling, as evidenced by abnormal Lfng and Hes7 expression during somitogenesis in the thoracic region This study suggests that Wnt regulation by Sfrp1 and Sfrp2 is required for embryonic patterning

Mouse lymphoma thymidine kinase gene mutation assay: Follow‐up meeting of the international workshop on Genotoxicity testing—Aberdeen, Scotland, 2003—Assay acceptance criteria, positive controls, and data evaluation

Abstract: The Mouse Lymphoma Assay (MLA) Workgroup of the International Workshop on Genotoxicity Testing (IWGT), comprised of experts from Japan, Europe, and the United States, met on August 29, 2003, in Aberdeen, Scotland, United Kingdom. This meeting of the MLA Workgroup was devoted to reaching a consensus on the appropriate approach to data evaluation and on acceptance criteria for both the positive and negative/vehicle controls. The Workgroup reached consensus on the acceptance criteria for both the agar and microwell versions of the MLA. Recommendations include acceptable ranges for mutant frequency, cloning efficiency, and suspension growth of the negative/vehicle controls and on criteria to define an acceptable positive control response. The recommendation for the determination of a positive/negative test chemical response includes both the requirement that the response exceeds a defined value [the global evaluation factor (GEF)] and that there also be a positive dose-response (evaluated by an appropriate statistical method).

Measurement of the quasielastic axial vector mass in neutrino interactions on oxygen

Abstract: The weak nucleon axial-vector form factor for quasielastic interactions is determined using neutrino interaction data from the K2K Scintillating Fiber detector in the neutrino beam at KEK. More than 12 000 events are analyzed, of which half are charged-current quasielastic interactions ${\ensuremath{ u}}_{\ensuremath{\mu}}n\ensuremath{\rightarrow}{\ensuremath{\mu}}^{\ensuremath{-}}p$ occurring primarily in oxygen nuclei. We use a relativistic Fermi gas model for oxygen and assume the form factor is approximately a dipole with one parameter, the axial-vector mass ${M}_{A}$, and fit to the shape of the distribution of the square of the momentum transfer from the nucleon to the nucleus. Our best fit result for ${M}_{A}=1.20\ifmmode\pm\else\textpm\fi{}0.12\text{ }\text{ }\mathrm{GeV}$. Furthermore, this analysis includes updated vector form factors from recent electron scattering experiments and a discussion of the effects of the nucleon momentum on the shape of the fitted distributions.

IL-27 Suppresses CD28-Medicated IL-2 Production through Suppressor of Cytokine Signaling 3

Abstract: IL-27 is a novel IL-6/IL-12 family cytokine that not only plays a role in the early regulation of Th1 differentiation, but also exerts an inhibitory effect on immune responses, including the suppression of proinflammatory cytokine production. However, the molecular mechanism by which IL-27 exerts the inhibitory effect remains unclear. In this study we demonstrate that IL-27 inhibits CD28-mediated IL-2 production and that suppressor of cytokine signaling 3 (SOCS3) plays a critical role in the inhibitory effect. Although IL-27 enhanced IFN-γ production from naive CD4+ T cells stimulated with plate-coated anti-CD3 and anti-CD28 in the presence of IL-12, IL-27 simultaneously inhibited CD28-mediated IL-2 production. Correlated with the inhibition, IL-27 was shown to augment SOCS3 expression. Analyses using various mice lacking a signaling molecule revealed that the inhibition of IL-2 production was dependent on STAT1, but not on STAT3, STAT4, and T-bet, and was highly correlated with the induction of SOCS3 expression. Similar inhibition of CD28-mediated IL-2 production and augmentation of SOCS3 expression by IL-27 were observed in a T cell hybridoma cell line, 2B4. Forced expression of antisense SOCS3 or dominant negative SOCS3 in the T cell line blocked the IL-27-inudced inhibition of CD28-mediated IL-2 production. Furthermore, pretreatment with IL-27 inhibited IL-2-mediated cell proliferation and STAT5 activation, although IL-27 hardly affected the induction level of CD25 expression. These results suggest that IL-27 inhibits CD28-mediated IL-2 production and also IL-2 responses, and that SOCS3, whose expression is induced by IL-27, plays a critical role in the inhibitory effect in a negative feedback mechanism.