One-dimensional (1D) nanostructured and nanocomposited LiFePO4: its perspective advantages for cathode materials of lithium ion batteries

Nanostructured materials have attracted recent research interest as battery materials due to their expected enhancement of properties. The characteristic nanoscale dimension and its structuring guarantees improved charge and mass transfer during charge/discharge processes. Among the potential cathode materials investigated as a substitute to LiCoO(2), one of the most promising materials is LiFePO(4) with olivine structure (LFP). In this perspective article, the current research and development in the synthesis and electrochemical studies of nanostructured LFP are reviewed with a special emphasis on one-dimensional (1D) nanostructures and nanocompositing with 1D conductive materials. In addition to various examples of 1D LFP with detailed synthetic methods, why 1D nanostructures could be meaningful is discussed in terms of a geometric point of view and the anisotropic lithiation/de-lithiation mechanism of LFP.     

Flat lightlike hypersurfaces in Lorentz–Minkowski 4-space

The lightlike hypersurfaces in Lorentz–Minkowski space are of special interest in Relativity Theory. In particular, the singularities of these hypersurfaces provide good models for the study of different horizon types. We introduce the notion of flatness for these hypersurfaces and study their singularities. The classification result asserts that a generic classification of flat lightlike hypersurfaces is quite different from that of generic lightlike hypersurfaces.     

Experimental evidence of energy-controlled switching in amorphous semiconductors

The switching delay time and transition time, and threshold voltage for the onset of switching in the amorphous semiconductor Si₁₂Ge₁₀As₃₀Te₄₈ have been measured under various conditions using rectangular voltage pulses. The results show that both the threshold voltage and the delay time decrease, but the transition time increases with increasing temperature; and that these switching properties are strongly dependent on the width and the repetition rate of applied pulses. It is proposed that the delay time is associated with the time required for the formation of a filament to cause switching, and that the transition time is associated with the transit time of a carrier across the switching filament. All the experimental phenomena indicate clearly that the switching process is energy-controlled.     

Binding of 2-amino-4-chloro-m-benzenedisulfonamide as a metabolite of hydrochlorothiazide to erythrocytes

2-Amino-4-chloro-m-benzenedisulfonamide (ACBS) is a metabolite of hydrochlorothiazide. We reported that the ACBS concentration in erythrocytes was higher than in plasma in a patient. Therefore the binding of ACBS to rabbit erythrocyte was studied. The Scatchard plot showed the nonlinear plot and the horizontal asymptote. Curvature in this plot indicated the existence of 2 classes of binding. One class was at a specific site, probably at carbonic anhydrase. Chromatographic data seemed to support the possibility.     

A synthetic method suitable for the rapid preparation of 13N-labeled dermorphin analogue, H-Tyr-D-Met(O)-Phe-Gly-NH2 (SD-62).

A synthetic method suitable for the preparation of 13N-labeled dermorphin analogue, H-Tyr-D-Met(O)-Phe-Gly-NH2 (SD-62), was established; i.e., SD-62 was synthesized by a 5 min treatment of the active ester precursor with ammonia. When the 13N-labeled SD-62, prepared by this method with [13N]ammonia, was administered into mice, the time profile of the radioactivity accumulation in the brain paralleled well that of the analgesic activity.     

Nineteen-membered pentaazamacrocyclic complexes bearing tetraamide groups

A new series of CoII, NiII, CuII and ZnII complexes incorporating pentaazamacrocyclic ligands has been prepared via the template condensation of o-aminobenzoic acid with succinic or phthalic acids in the presence of diethylenetriamine. The overall geometry and mode of bonding have been deduced on the basis of elemental analyses, i.r., 1H-n.m.r., e.p.r. and u.v.-vis. spectral studies, and conductivity and magnetic susceptibility measurements. An octahedral geometry is proposed for all the complexes, where five coordination sites are occupied by the macrocyclic nitrogens and the sixth by an anion.     

Polymerization of β-carbomethoxypropionaldehyde

High molecular weight crystalline poly(carbomethoxyethyl)oxymethylene was prepared from β-carbomethoxypropionaldehyde with the use of organometallic compounds. The characterization, fractionation, x-ray analysis, and viscosity measurement were carried out. Degradation by hydrochloric acid gave a highly crystalline but soluble polymer of a lower molecular weight. It was interesting to note the high solubility character of the polymer in organic solvents in contrast to the poor solubility of the isomeric poly(acetoxyethyl)oxymethylene. From the relationship among the intrinsic viscosity, Huggins' constant, and the solubility parameter of solvent, the solubility parameter of the polymer was determined to be 9.3 (cal/ml)^1/2.     

In vivo imaging of brain dopaminergic neurotransmission system in small animals with high-resolution single photon emission computed tomography.

High-resolution single photon emission computed tomography (SPECT) provides a unique capability to image the biodistribution of radiolabeled molecules in small laboratory animals. Thus, we applied the high-resolution SPECT to in vivo imaging of the brain dopaminergic neurotransmission system in common marmosets using two radiolabeled ligands, [123I]2beta-carbomethoxy-3beta-(4-iodophenyl)tropane (beta-CIT) as a dopamine transporter (DAT) ligand and [123I]iodobenzamide (IBZM) as a dopamine D2 receptor (D2R) ligand. Specific images of the striatum, a region with a high density of dopaminergic synapses, were obtained at 240 min and 60 min after injection of [123I]beta-CIT and [123I]IBZM, respectively. Furthermore, a significantly low accumulation of [123I]beta-CIT in the striatum was observed in MPTP-treated animals compared with results for a control group, and a similar accumulation in the control group was observed with the pretreatment of deprenyl in the MPTP-treated animals. However, the striatal accumulation of [123I]IBZM showed no changes among the control, MPTP-treated, and deprenyl-MPTP-treated groups. These SPECT imaging results agreed well with those of DA concentration and motor behavior. Since MPTP destroys nigrostriatal dopamine nerves and produces irreversible neurodegeneration associated with Parkinsonian syndrome, SPECT imaging data in this study demonstrated that deprenyl shows its neuroprotective effect on Parkinsonism by protecting against the destruction of presynaptic dopamine neurons.