Neutron electric dipole moment measurement with a buffer gas comagnetometer

A neutron EDM measurement with a comagnetometer is discussed. For magnetometry, polarized xenon atoms are injected into a cylindrical cell where a cylindrically symmetric magnetic field and an electric field are applied for the EDM measurement. The geometric phase effect (GPE), which originates from particle motion in a magnetic field gradient, is analyzed in terms of the Dyson series. The motion of the xenon atom is largely suppressed because of a small mean free path. The field gradient is controlled by means of NMR measurements, where the false effect of Earth?s rotation is removed. As a result, the GPE is reduced below 10⁻²⁸e cm${10}^{-28}e\text{cm}$.     

Spallation ultracold neutron source of superfluid helium below 1 K

For the production of high-density ultracold neutrons (UCNs), we placed 0.8 K superfluid helium in a cold neutron moderator. We resolved previous heat-load problems in the spallation neutron source that were particularly serious below 1 K. With a proton-beam power of 400 MeV×1 μA, a UCN production rate of 4 UCN cm(-3) s(-1) at the maximum UCN energy of E(c)=210 neV and a storage lifetime of 81 s were obtained. A cryogenic test showed that the production rate can be increased by a factor of 10 with the same storage lifetime by increasing the proton-beam power as well as (3)He pumping speed.     

Naphthalene and Anthracene Complexes Sandwiched by Two {(Cp*)FeI} Fragments: Strong Electronic Coupling between the FeI Centers

The reactions of the half‐sandwich iron(II) complex [FeCl(Cp*)(tmeda)] ( 1 ; Cp*=η⁵‐C₅Me₅, TMEDA=N,N,N′,N′‐tetramethylethylenediamine) with potassium naphthalenide or potassium anthracenide gave the diamagnetic complexes [(Cp*)Fe(μ‐polyarene)Fe(Cp*)] (polyarene=naphthalene ( 2 ), anthracene ( 3a )), which have two {(Cp*)Fe} units bound to opposite faces of the polyarene. One of two {(Cp*)Fe} units in 3a is located over the central ring of anthracene while the other is positioned over an outer ring. The {(Cp*)Fe} unit bound to the central ring of 3a migrates to the outer ring upon heating in the solid state to give the isomer 3b . The electrochemical potential separations between successive one‐electron redox events for complexes 2 and 3b are large. The mixed valence complexes [ [2]+ ]⁺ and [ [3b]+ ]⁺ were synthesized by chemical oxidation. The mixed‐valence complex [ [3b]+ ]⁺ is charge delocalized on the Mössbauer timescale at 78 K, and its absorption spectrum shows an intervalence charge‐transfer band. Complex [ [2]+ ]⁺ exhibits two absorption bands in the near‐IR region and a slightly broadened doublet in the Mössbauer spectrum. DFT calculations were carried out to examine the electronic structures of these dinuclear iron(I) complexes to elucidate the factors responsible for their diamagnetism and to determine the degree of charge delocalization in the mixed‐valence complexes.     

Spectral compact difference hybrid computation of passive scalar in isotropic turbulence

An accurate and efficient hybrid numerical method is developed for direct numerical simulation of passive scalar in homogeneous turbulence for the Schmidt number 1 and 50. The hybrid method uses the standard Fourier spectral method for the incompressible Navier–Stokes equation and the combined compact difference scheme for the passive scalar transport equation. Accuracy of the method is carefully examined by comparing with the full spectral method regarding the spectra, probability density function, field structure of the passive scalar, and is found to be very satisfactory. The computational time for the hybrid method is decreased by 26% for the Schmidt number 1 when compared to the full spectral method, and by 77% for the Schmidt number 50 when the number of grid points for the velocity field is reduced under the scale separation.     

CXCR4 Stimulates Macropinocytosis: Implications for Cellular Uptake of Arginine-Rich Cell-Penetrating Peptides and HIV

1. Download : Download high-res image (261KB)
2. Download : Download full-size image

Highlights? CXCR4 was identified as a receptor to stimulate cellular uptake of R12 peptide ? Interaction with R12 stimulates internalization of CXCR4 via macropinocytosis ? SDF-1α and HIV-1 gp120 protein also induce macropinocytosis ? Macropinocytic uptake of HIV-1 diminished the infection of host cells     

Measurements of analyzing powers Ay, Axx, Ayy and Axz in dp elastic scattering at Ed = 56 MeV

The differential cross section and all components of the analyzing powers A_y, A_xx, A_yy and A_xz have been measured in dp elastic scattering at 56 MeV. This is the first measurement of A_xz in the cyclotron energy region. A_xz has been measured with the beam polarized in the horizontal plane using the polarization tagging method. Faddeev calculations have been performed for four cases of the NN interaction. The Coulomb correction gave smaller effects at the present energy than at lower energies. Three of them reproduce the experimental data well. The agreement between the calculations and data for A_xz was better than that reported at lower energy. The deuteron asymptotic D- to S-state ratio has been obtained and is consistent within the limits of uncertainty with previously obtained values.     

Photoaffinity labeling of the electroplax sodium channel with a photoreactive mu-conotoxin carrying a radioactive and chromogenic diazirine.

Photoreactive derivatives of mu-conotoxin GIIIA carrying a radioactive and chromogenic diazirine have been prepared as a photoaffinity labeling reagent for muscle-type sodium channels. When the reagent was photolyzed in the presence of the eel sodium channel, radioactivity was specifically incorporated into the channel protein.     

One-step synthesis of biotinyl photoprobes from unprotected carbohydrates

A simple and versatile approach for the preparation of carbohydrate photoprobes has been developed. By a single-step reaction at 37 degrees C, a biotinylated carbene-generating unit was introduced to the reducing end of unprotected carbohydrates. Micromole quantities of N-acetyllactosamine, Lewis X trisaccharide, and sialyl Lewis X tetrasaccharide were easily converted to their biotinylated photoreactive analogues, which enabled the nonradioisotopic chemiluminescent detection of the photolabeled products. Thus, a sequence of lectin photoaffinity labeling, from the probe synthesis to the detection of labeled protein, was readily accomplished within one week. Our strategy may be applicable to any aldehyde-bearing ligand.     

聚乙烯醇中的紫外偏振线性聚炔分子

本文通过研究共轭线性碳链分子，聚炔H(C≡C)_nH (n=5∽7)的电子吸收带，设计了适用于UV的光偏振膜. 激光烧蚀的聚炔分子被分散在聚乙烯醇膜中. 结构各向异性的性质使得多炔分子的UV吸收跃迁偶极子与分子轴平行，并且吸收仅发生在沿着分子轴具有电子矢量幅度的电磁波上. 多炔分子在固体聚乙烯醇膜中作为特定波长入射光的偏振分量之一的选择性吸收剂. 使用可旋转的偏振UV光研究包含聚炔分子的拉伸聚乙烯醇膜的吸收强度的角度依赖性，并根据线性二向色性理论中有序参数进行分析.