Finding of <Emphasis Type="Italic">L</Emphasis><Subscript>2,3</Subscript> lines of the 148.16-keV γ transition in the <Superscript>161</Superscript>Ho nucleus

The preliminary experimental data on the spectrum of internal-conversion electrons of the erbium fraction in the range of electron energies near ～140 keV are reported. A photographic plate with a spectrogram of erbium fraction, exposed on the spectrometer of the Laboratory of Nuclear Problems (Joint Institute for Nuclear Research), was then measured on the PAVIKOM-1 microscopic complex (Lebedev Physical Institute). Due to the large number of spectral lines in this region, it was previously impossible to determine the intensities of the L ₂ and L ₃ lines of internal-conversion electrons for the 148.16-keV transition in the ¹⁶¹Ho nucleus. The use of the PAVIKOM-1 microscopic complex with a resolution of 0.01% made it possible to identify these lines and determine their intensities.     

Neuropeptide delivery to the brain: a von Willebrand factor signal peptide to direct neuropeptide secretion

Background  

Multiple neuropeptides, sometimes with opposing functions, can be produced from one precursor gene. To study the roles of the different neuropeptides encoded by one large precursor we developed a method to overexpress minigenes and establish local secretion.     

Analysis of Light Scattering Data on the Calcium Ion Sensitivity of Caseinate Solution Thermodynamics: Relationship to Emulsion Flocculation

We describe the quantitative interrelation between the thermodynamic parameters of caseinate submicelles in the presence of calcium ions (0-14 mM) in aqueous medium and the capacity of the protein to induce depletion flocculation in oil-in-water emulsions at pH 7.0 and ionic strength 0.05 mol dm(-3). Measurements have been made by static and dynamic multiangle laser light scattering of the weight-average molecular weight, the radius of gyration, the hydrodynamic radius, and the second virial coefficient of caseinate submicelles in aqueous solution. Successive thermodynamic approximations with and without consideration of correlations between caseinate submicelles have been used to calculate the osmotic pressure in caseinate aqueous solutions and the free energy of the depletion interaction between droplets in oil-in-water emulsions stabilized by caseinate. Numerical results from both thermodynamic approximations are in reasonably good agreement with experiment, predicting a pronounced decrease in the strength of the depletion attraction at concentrations of Ca(2+) in the range 4-8 mM (with a minimum value at 8 mM). This correlates well with the great enhancement of stability of these emulsions with respect to flocculation in comparison with systems having no added ionic calcium and emulsions with lower (2 mM) or higher (10 mM) Ca(2+) contents. Nevertheless, the allowance for interactive correlations between caseinate submicelles seems to lead to a better prediction of emulsion flocculation on a qualitative level over the whole range of Ca(2+) concentrations studied (2-14 mM). The calculated pronounced decrease in depletion interaction strength is attributable to marked changes in weight-average molecular weight and mean size of aggregates, and to more positive values of the second virial coefficient of caseinate submicelles with increasing Ca(2+) content. Finally, we discuss the part played by the electrical charge on the protein in determining the overall strength of the flocculation-inducing attractive interactions between droplets. Copyright 2001 Academic Press.     

Heterocyclization reactions using malononitrile dimer (2-aminopropene-1,1,3-tricarbonitrile)

Chemistry of Heterocyclic Compounds - In this work, we provide the first generalized and critical analysis of data on the chemistry of malononitrile dimer (2-aminopropene-1,1,3-tricarbonitrile)...     

Methods and instruments of high-resolution transient THz spectroscopy for diagnostics of socially important diseases

The results of spectroscopy of exhaled breath using specially developed THz spectrometers for noninvasive medical diagnostics of diabetes, pre-cancer states, and oncological diseases of the gastrointestinal tract organs, as well as for monitoring the efficiency of radiotherapy from the dynamics of nitrogen oxide content, are presented. The fine structure of DNA spectrum in the range of 300 to 375 GHz is investigated using a high-precision spectrometer composed of a frequency synthesizer (based on a backward-wave oscillator) and a high-Q cavity.     

Numerical Solution of a Surface Hypersingular Integral Equation by Piecewise Linear Approximation and Collocation Methods

Computational Mathematics and Mathematical Physics - A linear hypersingular integral equation is considered on a surface (closed or nonclosed with a boundary). This equation arises when the Neumann...     

Sigmatropic [1,3]-boron shift (permanent allylic rearrangement) in 3-allyl-3-borabicyclo[3.3.1]nonanes

2D ¹H-¹H EXSY NMR spectroscopy show that the free energy of activation ΔG ^≠ in six 3-allyl-3-borabicyclo[3.3.1]nonane derivatives is significantly higher (72–86 kJ mol^?1) than that in typical allylboranes (48–66 kJ mol^?1). For the first member of the series, viz., 3-allyl-3-borabicyclo[3.3.1]nonane, the activation parameters of the permanent allylic rearrangement were also determined (ΔH ^≠ = 82.7±3.4 kJ mol^?1, ΔS ^≠ = ?11.8±10.3 J mol^?1 K^?1, E _A = 85.5±3.4 kJ mol^?1, lnA = 29.2±1.2).     

Canonical conformal variables based method for stability of Stokes waves

We study the stability of Stokes waves in an ideal fluid of infinite depth. The perturbations that are either coperiodic with a Stokes wave (superharmonics) or integer multiples of its period (subharmonics) are considered. The eigenvalue problem is formulated using the conformal canonical Hamiltonian variables and admits numerical solution in a matrix-free manner. We find that the operator matrix of the eigenvalue problem can be factored into a product of two operators: a self-adjoint operator and an operator inverted analytically. Moreover, the self-adjoint operator matrix is efficiently inverted by a Krylov-space-based method and enjoys spectral accuracy. Application of the operator matrix associated with the eigenvalue problem requires only $O(N\log N)$ flops, where N is the number of Fourier modes needed to resolve a Stokes wave. Additionally, due to the matrix-free approach, $O(N^2)$ storage for the matrix of coefficients is no longer required. The new method is based on the shift-invert technique, and its application is illustrated in the classic examples of the Benjamin–Feir and the superharmonic instabilities. Simulations confirm numerical results of preceding works and recent theoretical work for the Benjamin–Feir instability (for small amplitude waves), and new results for large amplitude waves are shown.     

Phosphorylated imidazo[1,2-a]pyridines

The reaction of phosphorus(III) halides with imidazo[1,2-a]pyridines in the presence of bases leads to the formation of 3-phosphorylated imidazo[1,2-a]pyridines. The reaction proceeds in high yield and requires no catalysts. In the compounds obtained, in contrast to phosphorylated indolizines, the phosphorus–heterocycle bond is stable and not cleaved by dry hydrogen chloride, alcohols, or water. Imidazo[1,2-a]pyridines with the phosphinic and phosphinous groups can be alkylated both at the phosphorus and at the nitrogen atom of the heterocycle, the alkylation direction being dependent on the strength of the alkylation reagent used. © 1995 John Wiley & Sons, Inc.