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We demonstrate electrical tunnel spin injection from a ferromagnet to graphene through a high-quality Al2O3 grown by atomic layer deposition (ALD). The graphene surface is functionalized with a self-assembled monolayer of 3,4,9,10-perylene tetracarboxylic acid (PTCA) to promote adhesion and growth of Al2O3 with a smooth surface. Using this composite tunnel barrier of ALD-Al2O3 and PTCA, a spin injection signal of 30 ohm has been observed from non-local magnetoresistance measurements at 45 K, revealing potentially high performance of ALD-Al2O3/PTCA tunnel barrier for spin injection into graphene., Comment: 14 pages, 3 figures, accepted to Journal of Magnetism and Magnetic Materials

A chemoselective synthesis of poly(o-hydroxy-amide) as a polybenzoxazolc precursor has been developed. The polycondensation was carried out by addition of isophthaloyl dichloride to a solution of 3,3'-dihydroxybenzidine and lithium chloride in N-methylpyrrolidinone and gave the selective N-acylated polymer, poly(o-hydroxy-amide) with an inherent viscosity of 0.7 dL g -1 . The structure of the polymer was characterized by IR, 1 H, and 1 3 C NMR spectroscopies. The model reaction was studied in detail to demonstrate the feasibility of the chemoselective polyamidation using benzoyl chloride and o-aminophenol.

The ordered (-aacdbbdc-) polymer was prepared by the direct polycondensation of a pair of symmetric monomers (XabX), 4,4′-(oxydi-p-phenylene)dibutanoic acid (XaaX) and 2-methoxyisophthalic acid (XbbX), with a nonsymmetric monomer (YcdY), 4-aminobenzhydrazide, using the condensing agent diphenyl (2,3-dihydro-2-thioxo-3-benzoxazolyl)phosphonate (1). The polymerization was carried out by a one-pot procedure, that is, mixing the dicarboxylic acids, condensing agent 1 and triethylamine in NMP for 2 h at room temperature, followed by the addition of 4-aminobenzhydrazide. This polymerization proceeded smoothly, yielding the ordered polymer with an inherent viscosity of 0.34 dL g−1. The microstructure of the ordered polymer was confirmed by comparing the authentic ordered polymer in their 13C-NMR spectrum. © 1998 John Wiley & Sons, Inc. J. Polym. Sci. A Polym. Chem. 36: 2309–2314, 1998

We report magnetotransport measurements in ballistic graphene/hexagonal boron nitride mesoscopic wires where the charge carrier mean free path is comparable to wire width $W$. Magnetoresistance curves show characteristic peak structures where the peak field scales with the ratio of cyclotron radius $R_\textrm{c}$ and wire width $W$ as $W/R_\textrm{c} = 0.9 \pm 0.1$, due to diffusive boundary scattering. The obtained proportionality constant between $R_\textrm{c}$ and $W$ differs from that of a classical semiconductor 2D electron system where $W/R_\textrm{c} = 0.55$., Comment: 14 pages, 4 figures

To obtain basic data on the route of Giardia infection as zoonosis, we examined feces from 80 dogs and 16 cats for Giardia cysts and evaluated the detection rates. In addition, familial infection was studied in 3 family members of the patient with giardiasis. Giardia cysts were detected in 10 of the 80 dogs (12.5%) but none of the cats. Of the 10 dogs from which Giardia cysts were isolated, 6 had been maintained by the breeders. Tow other dogs were for examination in the research institutions. None of the family members of the patient with giardiasis had this infection. Since the detection rates of Giardia cysts in the dogs and cats were low, the possibility that human infection is acquired from dogs or cats seemed to be low. However, some of patients with giardiasis we encountered had never been abroad. This fact together with the presence of Giardia cysts in the dogs despite the low detection rates suggest that attention should be paid to the possible association between human giardiasis and pets since the number of people keeping pets is increasing.

We report on the fabrication and characterization of high quality graphene p–n–p junctions encapsulated by hexagonal boron nitride. By tuning the back gate and top gate bias voltages, a graphene p–n–p junction with tunable polarity and doping levels was realized. The p–n–p junction displayed distinct resistance oscillations, which was attributed to the Fabry–Perot interference of charge carriers in the p–n–p cavity. When a small magnetic field was applied, the oscillation phase was shifted by π, indicating the observation of Klein tunneling of charge carriers in the p–n–p junctions. The observation of Fabry–Perot interference and Klein tunneling with a macroscopic cavity length of L c = 500 nm demonstrates the markedly high quality of our graphene p–n–p junction.

The serological survey, analyzing sera which were obtained from Lyme disease suspected subjects was performed using immunoperoxidase (IP) test between July, 1987 and February, 1989. Fifteen seropositive subjects to Borrelia burgdorferi have been found in this survey, and these cases were considered to be true Lyme disease or highly suspected for this illness. Most of these seropositive cases geographically occurred in northern part of Japan, and both sexes and all age subjects were affected. In clinical manifestations, 5 cases developed a typical skin lesion of erythema chronicum migrans (ECM) followed by tick-bite. Neurologic manifestations were found in 6 cases, including one patient who also had ECM after a known tick bite. Of these neurologic manifestations, 4 cases had lymphocytic meningitis, 3 unilateral or bilateral facial palsy, and one encephalomyelitis. When 8 of these 15 sera were analyzed for antibodies to Lyme disease with ELISA, a poor agreement of serodiagnosis between IP test and ELISA has been found in the course of this study.