The use of direct probe mass spectrometry for the differentiation of meat species

Two studies were performed in which samples of freeze-dried meat from different species were subjected to replicate analysis by direct probe mass spectromety (DPMS). In the first study samples were obtained from six different muscles from each of three animal species, cattle, chicken and rabbit. In the second study one sample was taken from each of four individual animals from each of six species, cattle, chicken, horse, pig, rabbit and sheep. The spectra were analysed by statistical procedures which determined the ions responsible for the greatest degree of discrimination and the intersample relationships were displayed either as a two-dimensional scatter diagram or non-linear map. The results showed that DPMS was able to differentiate the species of origin of these meats. The reliability of the analysis procedures was tested with further replicates, not included in the original data analysis, which were treated as unknowns and also by using other data analysis techniques which did not require prior knowledge of the groups involved. The test samples fitted extremely well into their respective groups and there was very good agreement between the results from the defined and non-defined data.     

Infrared-microwave two-photon spectroscopy with13C16O2 and12C18O2 lasers of the ν2-band of ammonia

A tunable microwave frequency was added to, or subtracted from fixed frequency¹³C¹⁶O₂ and¹²C¹⁸O₂ laser lines using the nonlinearity of molecular absorptions. In this way the frequency of 30 transitions of the ν₂-band of ammonia were measured with an accuracy of ±0.0005 cm⁻¹. A further four transitions were measured with an accuracy of ±0.0001 cm⁻¹ by saturating the two-photon transition and observing the Lamb dip. For laser lines up to 11 GHz off-resonant with in frared transitions Doppler-limited signals were observed with microwave power densities of only 10 mW/cm² using a wide-band intracavity cell.     

Splines under tension in integral transfer problems

Splines under tension are used to develop an interpolatory representation of integral radiation operators. A quantitative measure of the stability of this representation is derived and approximated in terms of local grid lengths and the tension parameter; for example, cubic splines (zero tension parameter) are shown to be approximately stable when the ratio of successive grid lengths is between (1+√3)^-1 and (1+√3). Scaling procedures for determining the tension constant from the structure of the grids and the characteristics of the problem at hand are discussed, and the utility of these procedures is illustrated by application to the formation of resonance lines in two-dimensional media with exponential height variation of opacity.     

Infrared spectra and rotational isomerism of ethyl fluoroformate and ethyl propiolate

The infrared absorption spectra of ethyl fluoroformate and ethyl propiolate have been examined in the vapour, solution and solid states. For both esters evidence is found of rotational isomerism arising from internal rotation about the O-C₂H₅ bond, in close agreement with previous work on other ethyl esters.     

The Ionization Energies of Di-n-Alkyl Diacetylenes

The He(Iα) photoelectron spectra and the ionization energies of symmetrically substituted di-n-alkyl-diacetylenes R-(C?C)₂-R (with R ? CH₃, C₂H₅, n-C₃H₇, n-C₄H₉) are presented. The effect of the alkyl substitutents is that the two acetylenic ionization energies, I_v,1 and I_v,2, shift by the same amount, i.e. their difference I_v,2 – I_v,1 remains constant (2.45 ± 0.05 eV). Between 12.5 eV and 17 eV the band system in the photoelectron spectrum of R-(C?C)₂-R is superimposable with that in the spectrum of the corresponding alkane, RH, with the exception of a uniformly small shift of all the bands to higher ionization energy.     

A measurement of the electromagnetic form factor of the eta meson and of the branching ratio for the eta Dalitz decay

In an optical spark chamber experiment we have obtained a sample of 80 eta Dalitz decays (η → e⁺e^?γ) and have measured the eta electromagnetic form factor to be F(X) = 1.0?(0.22 ±0.45)X, where X=M_ee²/M_η², and the branching ratio (η→e⁺e^?γ/(η→π⁺π^?π⁰)= (0.0082 ± 0.0020).     

Superconductivity in Pb-PbTe thin film structures

The critical temperatures of thin superconducting films of Pb in intimate contact with PbTe have been measured resistively. The films were formed by sequential deposition and by co-evaporation of Pb and PbTe. The results show a depression of the critical temperature.