A Generalized Sampling Theorem with the Inverse of an Arbitrary Square Summable Sequence as Sampling Points

In this article a generalized sampling theorem using an arbitrary sequence of sampling points is derived. The sampling theorem is a Kramer-type sampling theorem, but unlike Kramer's theorem the sampling points are not necessarily eigenvalues of some boundary value problems. The theorem is then used to characterize a class of entire functions that can be reconstructed from their sample values at the points t_n = an + b if n = 0, 1, 2, ... and t_n = an + c if n = 0, -1, -2, ..., where a, b, c are arbitrary constants. The reconstruction formula is derived explicitly in the form of a sampling series expansion. When a = 1, b = 0 = c, the famous Whittaker-Shannon-Kotel'nikov sampling theorem is obtained as a special case.     

Temperature dependence of the iron hyperfine field distribution in amorphous Fe-rich Fe-Zr alloys

The temperature dependence of the iron hyperfine field distribution is reported in melt-quenched amorphous Fe-Zr alloys. The most remarkable feature is the compositinal change in the shape of the average hyperfine field versus temperature curves. The unusual increase in the average hyperfine field below about 85 K is a characteristic feature of the RSG systems; however, no anomaly is observed in the width of the hyperfine field distribution as a function of temperature. The results cannot be properly explained in the framework of the existing spin glass models.     

Synthesis of dihalocarbene derivatives of estafiatin guaianolide

Adducts of dihalocarbenes generated from chloroform and bromoform were prepared by reaction with estafiatin guaianolide. Their structures were established by XSA. __________ Translated from Khimiya Prirodnykh Soedinenii, No. 5, pp. 453–455, September–October, 2007.     

Synthesis of 5‐Radioiodoarabinosyl Uridine Analog for Probing the HSV‐1 Thymidine Kinase Gene

Tumor cells transduced with herpes simplex virus thymidine kinase gene have been intensively applied to the field of positron emission tomography via imaging of its substrate. As a pilot synthesis approach, a facile preparation of 5‐[¹²⁵I] iodoarabinosyl uridine starting from commercially available uridine is reported herein.     

Applicability of the critical chromatography concept to proteomics problems: Dependence of retention time on the sequence of amino acids

A peptide separation model based on the technique of liquid chromatography of macromolecules at the critical condition was proposed. In terms of this model, the array of experimental data on the separation of peptides is considered. The main phenomenological parameters of the model—effective adsorption energies of amino acid residues—were determined, thus allowing the influence of character of their alternation in the chain on retention times to be predicted. The model is applicable to investigation into the feasibility of separation in different chromatographic modes of not only peptides with the same amino acid composition and different sequences of units in the chain but also peptides containing amino acid isomers and mirror sequences with different terminal groups.     

Synthesis and functional properties of thermosensitive polymer derivatives of proteins

N,N-Diethylacrylamide-N-acryloylphthalimide copolymers have been synthesized. The LCST of the synthesized copolymers decreases with increase in both the molecular mass of the copolymers and the content of more hydrophobic N-acryloylphthalimide units. Through the reaction of the copolymers with the proteinase enzyme inhibitor, ovomucoid, the polymer derivatives of protein have been prepared. It has been shown that the biological activity of ovomucoid and the LCST of polymer derivatives increase with the amount of the immobilized ovomucoid. The effect of biologically active media on the LCST values of polymer derivatives has been studied.