Evaluation of parameters critical to observing proteins inside living Escherichia coli by in-cell NMR spectroscopy

Our recently developed in-cell NMR procedure now enables one to observe protein conformations inside living cells. Optimization of the technique demonstrates that distinguishing the signals produced by a single protein species depends critically on protein overexpression levels and the correlation time in the cytoplasm. Less relevant is the selective incorporation of (15)N. Poorly expressed proteins, insoluble proteins, and proteins that cannot tumble freely due to associations within the cell cannot yet be observed. We show in-cell NMR spectra of bacterial NmerA and human calmodulin and discuss limitations of the technique as well as prospects for future applications.     

Pulsed photothermal phase-shift spectroscopy for weak absorption measurement

A novel photothermal phase-shift spectroscopy configuration based on the retro-reflected beam interference has been developed and its operational principle is described. The weak absorption measurement ability of this technique is experimentally proven with a water/ethanol solution of standard Pyronine G dye and the limit of detection is found to be 1.8 x 10(-6) absorbance. Potential applications of the technique are discussed.     

Alpha-induced reactions on natural erbium

Stacks of natural erbium were bombared with -particles with energie of 85 MeV. Cumulative cross sections for the productions of different nuclei were measured using -ray spectroscopy. The data are compared with the theoretical predictions provided by the equilibrium and preequilibrium reaction model.     

Resolution of a paradox in the electrophoresis of DNA in agarose gels

A paradox was observed in a previous study of the electrophoresis of linear DNA fragments in agarose gels (D. L. Holmes and N. C. Stellwagen, Electrophoresis 1990, 11, 5-15). The pore size of the agarose matrix was more accurately determined if the root-mean-square radius of gyration was used to measure DNA macromolecular size. However, the Ogston equations were obeyed and other gel parameters such as the apparent fiber radius and fiber volume appeared to be better described if the geometric mean radius was used to measure DNA size. This paradox can be resolved if relative mobilities (with respect to the smallest DNA molecule in the data set) are used to construct the Ferguson plots, instead of absolute mobilities. Using relative mobilities and the root-mean-square radius of gyration, the Ogston equations are obeyed and the pore size of the matrix is consistent with values determined by other methods.     

Dehydrogenation of propane on aluminoplatinum catalysts modified with Re,Zr, Sc,and Sn

The effect of addition of Re, Zr, Sc, and Sn on an aluminoplatinum catalyst in the reaction of dehydrogenation of propane was investigated. It was shown that addition of 0.2–0.5% Zr, Sc, or Re virtually does not alter the catalytic properties of the aluminoplatinum catalyst (APC); addition of 0.2% Sn increases the activity, selectivity, and stability of Pt/Al₂O₃. The amount of coke deposited on the APC after the first 5 min of work decreases by three times in the presence of Sn. The coke is more enriched with hydrogen than the other systems formed on the surface of Pt-Sn/Al₂O₃.Deceased.Translated from Izvestiya Akademii Nauk SSSR, Seriya Khimicheskaya, No. 4, pp. 765–771, April, 1991.     

Beryllium diffusion across GaAs/(Al,Ga)As heterojunctions and GaAs/AlAs superlattices during MBE growth

Beryllium diffusion during MBE growth of (Al, Ga)As layers, (Al, Ga)As/GaAs heterojunctions and GaAs/AlAs superlattices has been studied by electrochemical C-V and secondary ion mass spectrometry (SIMS) concentration profiling, in conjunction with transmission electron microscopy. Diffusion times were comparatively short since they were limited to part of the growth sequence, so non-equilibrium effects had a significant influence. The results are consistent with an interstitial-substitutional mechanism in which lattice site incorporation becomes more difficult with increasing band gap enthalpy. Incorporation involves a kick-out reaction which leads to the observed disordering of the superlattices.     

Rotation of the universe

We study the problem of a possible rotation of the observable Universe (Metagalaxy) from the point of view of the general-relativistic theory of gravitation. We employ the concept of a hierarchical structure of reality, based on the existence of Eddington-Dirac large numbers. From the Einstein equations in their Landau-Raichaudhuri form we derive expressions for the angular momentum and angular velocity of the rotation of the Metagalaxy. These expressions give an coinciding in order of magnitude with the observed one. Using the formulas obtained, and using the hierarchy relation (large number relation), we obtain the Stanyukovich formula S N^3/2 which relates the number of nucleons in the Metagalaxy N and its angular momentum S. We show that the angular velocity may decrease in inverse proportionality to the scale factor, which may explain its small value at this time. We show that the source of rotation in cosmology can be space-time torsion, induced by the spin of fermionic matter.Translated from Izvestiya Vysshikh Uchebnykh Zavedenii, Fizika, No. 3, pp. 12–16, March, 1987.The authors are grateful to V. F. Panov for the discussion of this paper and valuable comments.