Reaction of 3,5-diamino-4-nitropyrazole with electrophilic reagents

The interaction of 3,5-diamino-4-nitropyrazole with such electrophilic reagents as acetic anhydride, dimethylformamide acetal, orthoformic ester, and ketones has been studied. Derivatives of pyrazolol[1,5-a]pyrimidines were formed on reaction with 1,3-diketones and some of their properties have been studied.Center for Drug Chemistry, All-Russian Chemical and Pharmaceutical Research Institute (VNIKhFI), Moscow 119815. Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 3, pp. 329–335, March, 1997.     

Quadratic Functionals with General Boundary Conditions

The purpose of this paper is to give the Reid ``Roundabout Theorem' for quadratic functionals with general boundary conditions. In particular, we describe the so-called coupled point and regularity condition introduced in [16] in terms of Riccati equation solutions. Accepted 27 February 1996     

Superradiance of polaritons in finite one-dimensional crystals of increasing length: Passage from a dimer to an infinite crystal

Solutions of the dispersion equations for polariton states in finite one-dimensional crystals of arbitrary length are obtained. The appearance and evolution of the radiative and nonradiative polariton branches are traced as the length varies from two monomers to limiting values, above which the spectrum no longer undergoes significant changes. The dependences of the frequencies and radiative widths on the polariton wave vector are found for various orientations of the dipole moment of the quantum transition. The evolution of superradiance as the length of the crystal increases is traced. Some previously unknown significant features of the polariton spectrum are noted particularly the damping of the branch traditionally termed nonradiative as a consequence of emission from the end faces. Fiz. Tverd. Tela (St. Petersburg) 40, 2136–2140 (November 1998)     

Microencapsulation of DNA Within alginate microspheres and crosslinked chitosan membranes for in vivo application

Calf thymus DNA was microencapsulated within crosslinked chitosan membranes, or immobilized within chitosan-coated alginate microspheres. Microcapsules were prepared by interfacial polymerization of chitosan, and alginate microspheres formed by emulsification/ internal gelation. Diameters ranged from 20 to 500 Μm, depending on the formulation conditions. Encapsulated DNA was quantifiedin situ by direct spectrophotometry (260 nm) and ethidium bromide fluorimetry, and compared to DNA measurements on the fractions following disruption and dissolution of the microspheres. Approximately 84% of the DNA was released upon core dissolution and membrane disruption, with 12% membrane bound. The yield of encapsulation was 96%. Leakage of DNA from intact microspheres/capsules was not observed. DNA microcapsules and microspheres were recovered intact from rat feces following gavage and gastrointestinal transit. Higher recoveries (60%) and reduced shrinkage during transit were obtained with the alginate microspheres. DNA was recovered and purified from the microcapsules and microspheres by chromatography and differential precipitation with ethanol. This is the first report of microcapsules or microspheres containing biologically active material (DNA) being passed through the gastrointestinal tract, with the potential for substantial recovery.     

High Resolution Study of Deuterated Hydrogen Sulfide in the Region 2400-3000 cm

High resolution Fourier transform spectra of deuterated hydrogen sulfide have been recorded in the region 2400-3000 cm⁻¹. Rotational structures of the ν₁ + ν₂, ν₂ + ν₃ bands of D₂³²S, of the ν₃ and ν₁ + ν₂ bands of HD³²S, and of the ν₁ + ν₂ band of HD³⁴S were analyzed. Band centers and rotational, centrifugal distortion, and resonance parameters were obtained, which reproduce the initial values of the upper energy levels within a mean accuracy of 1.39 × 10⁻⁴ cm⁻¹ for the states (110) and (011) of D₂³²S, 1.61 × 10⁻⁴ cm⁻¹ and 1.82 × 10⁻⁴ cm⁻¹ for the states (001) and (110) of HD³²S, and 2.09 × 10⁻⁴ cm⁻¹ for the state (110) of HD³⁴S, respectively.     

Synthesis of ω-amino- and ω-carboxyalkylamides of N-acetylmuramoyl-L-alanyl-D-isoglutamine

The synthesis has been effected of derivatives of MDP having a spacer with an amino or carboxy group. The final stage of the synthesis was the condensation of Boc-L-Ala-D-iGln with 6-aminohexanol (followed by the two-stage replacement of the hydroxy by an azido group) or with benzyl 6-aminohexanoate.Simferopol' State University. Translated from Khimiya Prirodnykh Soedinenii, No. 1, pp. 122–125, January–February, 1993.     

Synthesis of furaxanenitrolic acids

Previously unreported furoxanenitrolic acids have been synthesized.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 8, pp. 1117–1119, August, 1993.     

Using dynamic data exchange to exchange information between Visual Basic and Matlab : Application to a diode array spectrophotometer

Photodiode array spectrometers are increasingly being coupled to flow analysis and separation techniques. Computer programs are needed to control the data acquisition from each photodiode and to handle the data. The Microsoft Visual Basic programming language is used along with a DLL library and dynamic data exchange (DDE) to allow communication with the MATLAB computational environment.     

线状锗等离子体X射线线谱的时间分辨测量

用自行研制的X射线条纹晶体谱仪首次测量了线状锗等离子体的X射线时间分辨谱。给出了类Ne-锗L线共振线的时间演化过程,并用类Ne-锗L线共振线与其双电子俘获伴线的相对强度比粗估了锗等离子体的电子温度及其随时间的变化,实验给出了X光激光增益区介质的电子温度为400～760eV,同时给出了电子温度保持相对恒定的时间不小于90ps(电子温度变化小于2％)。