Intrinsic Spin Decay Length in Antiferromagnetic Insulator

We report intrinsic spin decay length of an antiferromagnetic insulator. We found that at an antiferromagnetic/ferromagnetic interface, a spin current generated by spin pumping is strongly suppressed by two-magnon scattering. By eliminating the two-magnon contribution, we discovered that the characteristic length of spin decay in NiO changes by two-orders of magnitude through the paramagnetic to antiferromagnetic transition. The spin decay length in the antiferromagnetic state is longer than 100 nm, which is an order of magnitude longer than previously believed. These results provide a crucial piece of information for the fundamental understanding of the physics of spin transport

Voltammetric study of interaction of Co(phen)33+ with DNA at gold nanoparticle self-assembly electrode

ArticleElectrochimica Acta. 50(4): 1049-1055 (2004)journal articl

Voltammetry of immobilized cytochrome c on novel binary self-assembled monolayers of thioctic acid and thioctic amide modified gold electrodes

ArticleJOURNAL OF ELECTROANALYTICAL CHEMISTRY. 590(2): 173-180 (2006)journal articl

A sensor for superoxide in aqueous and organic/aqueous media based on immobilized cytochrome c on binary self-assembled monolayers

ArticleBiosensors and Bioelectronics. 23(2):241-247journal articl

Absolute calibration of GafChromic film for very high flux laser driven ion beams.

We report on the calibration of GafChromic HD-v2 radiochromic film in the extremely high dose regime up to 100 kGy together with very high dose rates up to 7 × 1011 Gy/s. The absolute calibration was done with nanosecond ion bunches at the Neutralized Drift Compression Experiment II particle accelerator at Lawrence Berkeley National Laboratory (LBNL) and covers a broad dose dynamic range over three orders of magnitude. We then applied the resulting calibration curve to calibrate a laser driven ion experiment performed on the BELLA petawatt laser facility at LBNL. Here, we reconstructed the spatial and energy resolved distributions of the laser-accelerated proton beams. The resulting proton distribution is in fair agreement with the spectrum that was measured with a Thomson spectrometer in combination with a microchannel plate detector

Electrochemical characterization of poly(acrylamide) membrane coated on a gold disk electrode in acetonitrile

ArticleJOURNAL OF ELECTROANALYTICAL CHEMISTRY. 579(1): 25-31 (2005)journal articl

Acid Responsive Hydrogen-Bonded Organic Frameworks

A porous hydrogen-bonded organic framework (HOF) responsive to acid was constructed from a hexaazatrinaphthylene derivative with carboxyphenyl groups (CPHATN). Precise structures of both 1,2,4-trichlorobenzene solvate [CPHATN-1(TCB)] and activated HOF with permanent porosity (CPHATN-1a) were successfully determined by single-crystalline X-ray diffraction analysis. Permanent porosity of CPHATN-1a was evaluated by gas sorption experiments at low temperature. CPHATN-1a also shows significant thermal stability up to 633 K. Its crystals exhibit a rich photochemistry thanks to intramolecular charge-transfer and interunit proton-transfer reactions. Femtosecond (fs) experiments on crystals demonstrate that these events occur in ≤200 fs and 1.2 ps, respectively. Moreover, single-crystal fluorescence microscopy reveals a shift of the emission spectra most probably as a result of defects and a high anisotropic behavior, reflecting an ordered crystalline structure with a preferential orientation of the molecular dipole moments. Remarkably, CPHATN-1a, as a result of the protonation of pyradyl nitrogen atoms embedded in its π-conjugated core, shows reversible vapor acid-induced color changes from yellow to reddish-brown, which can be also followed by an ON/OFF of its emission. To the best of our knowledge, this is the first HOF that exhibits acid-responsive color changes. The present work provides new findings for developing stimuli responsive HOFs.Hisaki I., Suzuki Y., Gomez E., et al. Acid Responsive Hydrogen-Bonded Organic Frameworks. Journal of the American Chemical Society. 141(5), 2111-2121, (2019), 6 February 2019; © 2019 American Chemical Society. https://doi.org/10.1021/jacs.8b12124

Genetic and environment effects on structural neuroimaging endophenotype for bipolar disorder: a novel molecular approach

We investigated gene–environment effects on structural brain endophenotype in bipolar disorder (BD) using a novel method of combining polygenic risk scores with epigenetic signatures since traditional methods of examining the family history and trauma effects have significant limitations. The study enrolled 119 subjects, including 55 BD spectrum (BDS) subjects diagnosed with BD or major depressive disorder (MDD) with subthreshold BD symptoms and 64 non-BDS subjects comprising 32 MDD subjects without BD symptoms and 32 healthy subjects. The blood samples underwent genome-wide genotyping and methylation quantification. We derived polygenic risk score (PRS) and methylation profile score (MPS) as weighted summations of risk single nucleotide polymorphisms and methylation probes, respectively, which were considered as molecular measures of genetic and environmental risks for BD. Linear regression was used to relate PRS, MPS, and their interaction to 44 brain structure measures quantified from magnetic resonance imaging (MRI) on 47 BDS subjects, and the results were compared with those based on family history and childhood trauma. After multiplicity corrections using false discovery rate (FDR), MPS was found to be negatively associated with the volume of the medial geniculate thalamus (FDR = 0.059, partial R2 = 0.208). Family history, trauma scale, and PRS were not associated with any brain measures. PRS and MPS show significant interactions on whole putamen (FDR = 0.09, partial R2 = 0.337). No significant gene–environment interactions were identified for the family history and trauma scale. PRS and MPS generally explained greater proportions of variances of the brain measures (range of partial R2 = [0.008, 0.337]) than the clinical risk factors (range = [0.004, 0.228])

Diamagnetic Suppression of Component Magnetic Reconnection at the Magnetopause

We present particle-in-cell simulations of collisionless magnetic reconnection in a system (like the magnetopause) with a large density asymmetry across the current layer. In the presence of an ambient component of the magnetic field perpendicular to the reconnection plane the gradient creates a diamagnetic drift that advects the X-line with the electron diamagnetic velocity. When the relative drift between the ions and electrons is of the order the Alfven speed the large scale outflows from the X-line necessary for fast reconnection cannot develop and the reconnection is suppressed. We discuss how these effects vary with both the plasma beta and the shear angle of the reconnecting field and discuss observational evidence for diamagnetic stabilization at the magnetopause.Comment: 10 pages, 10 figures; accepted by JGR; agu2001.cls and agu.bst include