High performance liquid chromatographic analysis of six conjugated and unconjugated estrogens in serum.

Six estrogens-estrone, equilin, estradiol, sodium estrone sulphate, sodium equilin sulphate and sodium 17-alpha-dihydroequilin sulphate in dog serum were successfully separated and quantified by a high performance liquid chromatographic method developed in our laboratories. The mobile phase was optimized by studying the effects of an organic modifier (acetonitrile) and an ion pairing reagent (tetrabutylammonium hydroxide). The serum sample work-up procedure was designed to recover both conjugated and unconjugated estrogens. The optimum method involved acetonitrile to precipitate serum proteins/peptides and extract estrogens. Residues were reconstituted in 50% acetonitrile in water for injection. The detection limits for these six estrogens via UV detection ranged from 0.5 to 5 ng on-column with a signal-to-noise ratio (S/N) of 10 for a 20 microL injection and via fluorescence 0.1 ng on-column for 17-beta-estradiol. Validation data are included for all six estrogens.     

The 2880-Å emission spectrum of I2: Ion-pair states near 47 000 cm−1

An emission system of I₂ in Ar in the region 2830–2890 Å is examined under high resolution and found to display fine violet-degraded band structure. This system is interpreted as a charge-transfer transition originating from an ion-pair state near 47 000 cm^?1 and terminating on a weakly bound state which dissociates to two ground-state atoms. This interpretation is supported by spectral simulations employing a bound-free model. The transition is tentatively assigned as $\text{0}{}_{\mathrm{<mtext>g</mtext>}}{}^{\mathrm{?}}\text{→ 2431 0}{}_{\mathrm{<mtext>u</mtext>}}{}^{\mathrm{?}}\text{(}{}^3\text{Π}\text{)}$, according to which the excited state becomes the fourth ion-pair state near 47 000 cm^?1 to be experimentally characterized, and the lower state is the last component of the lowest ³Π state to be identified. The vibrational assignments include about 45 bands in ¹²⁷I₂ and ¹²⁹I₂, spanning v′ = 0–4 and v″ = 6–19, but with the numbering of the lower state remaining uncertain by several units. The main spectroscopic constants for the excited state are T_e = 47 070 cm^?1, ?_e = 105.7 cm^?1, ?_ex_e = 0.49 cm^?1. The spectral simulations place the lower state's potential curve 34 650 cm^?1 below the upper state at R = R′_e, with slope ?850 cm^?1/Å. For our “best” numbering of the lower state, ?_e = 20.5 cm^?1, ?_ex_e = 0.29 cm^?1, T_e = 12 190 cm^?1, and D_e = 360 cm^?1.     

Magnetic monopoles in SU(3) and SU(2) gauge theories without Higgs' scalars

We show that certain known singular solutions for pure SU(3) Yang-Mills theory carry magnetic charges with respect to both U(1) subgroups of SU(3). A topological characterisation in terms of monopoles is given to the SU(2) singular solutions of Wu and Yang.     

On the matched-asymptotic solution of elastodynamic problems: Loading over a semi-infinite rectangular boundary

The paper discusses the solution to an elastodynamic problem of an infinite medium excited by loads acting over a semi-infinite rectangular boundary whose height 2a is assumed small compared to the wavelengths of interest. The solution is developed using the method of matched-asymptotics in conjunction with an application of the Wiener-Hopf technique for the outer problems and the Muskhelishvili-Kolosov complex functions for the inner problems. The solutions are matched mutually and the resulting stress behaviour, as far as it is described by the inner limit to the outer solution, is also derived.     

Low temperature heat capacity of LaRu2 by a.c. technique

The low temperature heat capacity data of a small bulk sample of LaRu₂ show that the structural transformation occurring at T_m ～ 29.5K is rather spread out. The electronic heat capacity coefficient, γ, and Debye temperature, θ_D, are found to be respectively $\text{8.5}\text{mJ}\text{g}$. atom K² and 164 K. The multiple anomalies below T_m and T_c (4.45 K) are discussed.     

Pressure effects on the semiconductor-semimetal transition in Ti2O3

Hydrostatic pressure has negligible effect on the resistivity anomaly and thec _H /a _H ratio of Ti₂O₃. The results are consistent with the band-crossing mechanism wherein the a ^T and e ^T bands cross as thec _H /a _H ratio increases.     

Low temperature heat-capacity measurements of V3Ga and Nb3Al

By low temperature heat capacity measurements using the a.c. technique, we show indirectly that martensitic transformations do occur in V₃Ga and Nb₃Al.