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.     

Examples of Hermitian manifolds with pointwise constant anti-holomorphic sectional curvature

We construct non-compact examples of Hermitian manifolds with pointwise constant anti-holomorphic sectional curvature. Our examples are obtained by conformal change of the metric on an open set of the complex space form.     

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.     

Turbulent heat transfer in a flat plate boundary layer disturbed by a cylinder

Augmentation of heat transfer from a flat plate using a turbulence promoter has been studied. A circular cylinder 8 mm in diameter was placed in the turbulent boundary layer detached from the flat plate. It was located parallel to the plate and perpendicular to the flow direction. Clearance, c, between the cylinder and the flat plate was varied in nine steps: c=0, 1, 2, 3, 4, 6, 11, 20 and 29.5 mm. Measurements were made of the local heat transfer coefficients, mean velocity profiles, turbulence intensity profiles, static pressure and skin friction. Experimental results showed that the heat transfer deterioration which occurs just downstream of the cylinder at c=0 mm can be removed by displacing the cylinder a small distance from the wall. The improvement in heat transfer is mainly due to the unsteadiness of the recirculating flow on the plate and the effect of intense turbulence arriving at the near wall region from the lower shear layer of the cylinder wake. Heat transfer augmentation is most effective when c=4 mm and becomes less effective when c is increased more than 6 mm. The enhancement disappears far downstream from the cylinder.     

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.