Fundamental studies on thyroid stimulating hormone immunoradiometric assay kit (TSH RIABEAD II)

We have reported fundamental studies on the TSH immunoradiometric assay, using TSH RIABEAD II kit (Dainabot). The sensitivity of the assay was 0.03 mu IU/ml and its C.V. was 27.2%. Intra- and inter-assay C.V. were less than 5%. Dilution test and recovery test were good. Serum TSH level was 0.3-4.0 mu IU/ml in normal subjects, less than 0.03 mu IU/ml in untreated Graves' disease and subacute thyroiditis. Therefore, it was found that the clear difference exist in serum TSH levels between normal subjects and patients with untreated Graves' disease. There was a well correlation on the serum TSH levels between this method and TSH radioimmunoassay kit (Amerlex TSH, r = 0.983). Especially, the measurement of serum TSH levels, using immunoradiometric assay kit, was useful for the diagnosis of patients with Graves' disease.     

Low-temperature specific heat of Er2Ba4Cu7O15-δ

The magnetic ordering of Er ions in Er₂Ba₄Cu₇O_15-δ (δ = 0:7 and δ = 0:08) has been studied by low temperature heat capacity measurements. The Néel temperature T _N of Er₂Ba₄Cu₇O_15-δ is almost independent of the oxygen concentration (TN = 0:54K for δ = 0:08 and T _N = 0:50K for δ = 0:7). While an anisotropic two-dimensional (2D) Ising model describes the experimental data very well for Er₂Ba₄Cu₇O_14:92, this model cannot be applied to the oxygen reduced sample Er₂Ba₄Cu₇O_14:3. By using a model consisting of 1D-Ising chains and of 2D-Ising clusters of Er³⁺ ions we could fit the specific heat data of Er₂Ba₄Cu₇O_14:3 accurately. Our measurements show clearly that with the reduction of the oxygen content the in-plane anisotropy of the magnetic exchange coupling increases.     

Synthesis of a bicyclic dipeptide with the shape of β-turn central part

A bicyclic dipeptide derivative with fixed conformation simulating that of the two central amino acid residues in type II′ β-turn has been synthesized starting from L-glutamic acid and L-cysteine in short steps.     

Inversion of the Abel Integral Equation by Use of Simple Interpolation Formulas

The Abel integral equation in plasma spectroscopy is numerically solved by applying the Bessel four-point interpolation formula of degree two. The method is mathematically tractable, simplifying the Bockasten method. Tests through numerical simulations show that the method is as accurate as more elaborate methods, such as Bockasten, Minerbo-Levy, Piessens, etc.     

Studies on extraction of copper(II) with 1-phenyl-3-methyl-4-acyl-5-pyrazolone

The extraction of Cu(II) with 1-phenyl-3-methyl-4-acyl-5-pyrazolone (HA), in different organic solvents has been studied. The extraction mechanism of Cu(II) and the composition of the extracted species has been determined. Cu(II) was extracted as CuA₂, or in the presence of TOPO, as CuA₂TOPO. The extraction constants do not change regularly with increasing the length of acyl chain in the 1-phenyl-3-methyl-4-acyl-5-pyrazolone derivatives. The effect of the temperature on the extraction of Cu(II) has also been investigated.     

Cleavage of vinyl carbon-silicon bond with tetrabutylammonium fluoride

Dimethylphenylsilyl group is removed from a vinyl carbon with tetrabutylammonium fluoride. The presence of phenyl group on silicon atom plays a critical role. The cleavage of allyldimethylsilyl- and alkoxydimethylsilyl groups also proceeds very easily.     

A note on stochastic phase lockings in a relaxation oscillator forced by a sine input with additive noise

Summary Noise effects on phase lockings in a system consisting of a piecewise-linear van der Pol relaxation oscillator driven by a periodic input are studied. The problem of finding the period of the oscillator is reduced to the first-passage-time problem of the Ornstein-Uhlenbeck process with time-varying boundary. Using the probability density functions of the first-passage time, the operator which governs a transition of an input phase density after one cycle of the oscillator is defined. Phase lockings in a stochastic sense are investigated on the basis of the density evolution by the operator. Paper presented at the International Workshop ?Fluctuations in Physics and Biology: Stochastic Resonance, Signal Processing and Related Phenomena?, Elba, 5–10 June 1994.     

Ultraviolet photoemission spectroscopy of (TaSe4)2I

The vacuum ultraviolet photoemission spectra of quasi-one-dimensional charge density wave ( CDW ) system, (TaSe₄)₂I, were measured for photon energies between 32 and 100 eV at room temperature ( in the normal phase ) and at about 100 K ( in the CDW phase ). The spectrum of Ta 4f core-levels has shown no additional splitting due to the two different Ta sites. The spectra of the valence and conduction bands have revealed the resonant enhancement for the excitation of the Ta 5p core states, which demonstrates the remarkable hybridization of Ta 5d orbitals with Se 4p orbitals with binding energies smaller than 4 eV. In the CDW phase, the partial cross section decreases for both Ta 5d bands and Se 4p bands with Ta 5d components.     

Statistical mechanics of thermal diffusion

Expressions of the flows of atoms A and B of a binary system in a crystal are derived as the response to the imposed gradients of temperature and chemical potentials. The formulation is done using the pair approximation of the Path Probability Method of irreversible statistical mechanics and atomic migration is assumed to be via the vacancy mechanism. The energy carried by photons (and electrons) under the temperature gradient is assumed to be independent of the atomic flux. For the case near equilibrium, linear relations are derived among the atomic fluxes, the energy flux (associated with atomic flux) and the gradients. The Onsager reciprocal relations are proved to hold among the coefficients, including those related to energy flows. The heat of transport (energy carried by a diffusing atom) and the heat conduction due to atomic flux are thus unambigously derived.