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Densities of solutions of the chiral (in the racemic form) trans -dimethyldiethylglycoluril (1,4-diethyl-3,6-dimethyltetrahydroimidazo[4,5- d ]imidazole-2,5(1 H ,3 H )-dione), being a promising tranquilizer Albicar, in ordinary (H 2 O) and heavy (D 2 O) water were measured using the Anton Paar DMA 5000 M high-precision vibrating tube densimeter. All experiments were performed within the temperature range between 278.15 K and 318.15 K (with a step of 10 K) at the pressure to be ca . 99.6 kPa. The solution aquamolality was ranged from ca . 0.02 to ca . 0.2 mol (55.51 mol of solvent) −1 for each of H/D isotopically distinguishable systems compared. The standard (partial at infinite dilution) molar volumes as well as expansibilities of the solute were derived from the solution density data. The behavior of solvent isotope effects (IEs) on the considered quantities were described taking account of structure- and interaction-related features of H 2 O and D 2 O media. It was confirmed that the Albicar hydration is enhanced overall in the D 2 O medium. The volumetric characteristics for the heterocyclic solute being studied were discussed in comparison with those for Mebicar (1,3,4,6-tetramethyl-derivative) and Bicaret (1,3,4,6-tetraethyl-derivative), using the previous our results. [ABSTRACT FROM AUTHOR]

We compare frameworks of nonstationary nonperiodic wavelets and periodic wavelets. We construct one system from another using periodization. There are infinitely many nonstationary systems corresponding to the same periodic wavelet. Under mild conditions on periodic scaling functions, among these nonstationary wavelet systems, we find a system such that its time-frequency localization is adjusted with an angular-frequency localization of an initial periodic wavelet system. Namely, we get the following equality lim j → ∞ ⁡ U C B ( ψ j P ) = lim j → ∞ ⁡ U C H ( ψ j N ) , where U C B and U C H are the Breitenberger and the Heisenberg uncertainty constants, ψ j P ∈ L 2 ( T ) and ψ j N ∈ L 2 ( R ) are periodic and nonstationary wavelet functions respectively. [ABSTRACT FROM AUTHOR]

An inequality refining the lower bound for a periodic (Breitenberger) uncertainty constant is proved for a wide class of functions. A connection of uncertainty constants for periodic and non-periodic functions is extended to this class. A particular minimization problem for a non-periodic (Heisenberg) uncertainty constant is studied. [ABSTRACT FROM AUTHOR]

[Display omitted] • Standard molar volumes of teotropine (tetramethylenediethylenetetramine – TMDETA) in water were determined densimetrically. • Density measurements were performed at temperatures from 278.15 K to 318.15 K (with a step of 10 K) at ambient pressure. • Like the related aminal solute urotropine (hexamethylenetetramine – HMTA), TMDETA has a structure-making effect in water. • Structure packing of the hydration complex formed becomes denser and thermally more stable when going from HMTA to TMDETA. • Structure-forming effect (due to hydrophobic effects and H-bonding) is greater in aqueous TMDETA as a bulkier aminal solute. The densities of aqueous solutions of tetramethylenediethylenetetramine (the teotropine pharmaceutical) with the solute molality from (0.01 to 0.12) mol·(kg water)−1 were measured at T = (278.15, 288.15, 298.15, 308.15, and 318.15) K and p = 0.1 MPa. The uncertainty in density measured using the Anton Paar DMA 5000 M densimeter (equipped with an oscillating U-tube) was estimated to be 0.03 kg m−3 or lower. The standard (apparent at infinite dilution) molar volumes and expansibilities of teotropine were computed. Based on the analysis of contributions to the standard molar volume in terms of the Scaled Particle Theory was confirmed that a bulkier molecule of teotropine interacts with water stronger than it does a molecule of urotropine or hexamethylenetetramine – the related aminal (cage-like) compound. [ABSTRACT FROM AUTHOR]

Densities of aqueous solutions of achiral 1,3-dimethylglycoluril (1,3-DMGU) and 1,3-diethylglycoluril (1,3-DEGU) were measured using a hermetically sealed vibrating-tube densimeter, with an uncertainty of 1 · 10 −5 g · cm −3 , at T = (278.15, 288.15, 298.15, 308.15, and 318.15) K and p = (99.6 ± 0.8) kPa. The solute molality was ranged from (0.06 to 0.39) and from (0.01 to 0.07) mol · kg −1 for the aqueous 1,3-DMGU and 1,3-DEGU, respectively. The standard (at infinite dilution) molar volumes and isobaric expansibilities for the 1,3-dialkyl- N -substituted glycolurils compared in water were calculated and discussed in comparison with the previously derived molar enthalpies and heat capacities of their dissolution (hydration). The temperature-dependent behavior of packing-related hydration effects was described taking into account the structural features of a solute molecule. [ABSTRACT FROM AUTHOR]

Abstract: A family of Parseval periodic wavelet frames is constructed. The family has optimal time–frequency localization (in the sense of the Breitenberger uncertainty constant) with respect to a family parameter and it has the best currently known localization with respect to a multiresolution analysis parameter. [Copyright &y& Elsevier]

Abstract: Densities of dilute solutions of 1,3-dimethyl-2-imiazolidinone in H2O and D2O, with the solute mole-fractions ranging up to 0.01, have been measured with an error of 1.5·10−5 g·cm−3 at (278.15, 288.15, 298.15, 308.15, 313.15, and 318.15)K and atmospheric pressure using a vibrating-tube densimeter. The partial molar volumes of the dissolved DMI (down to the infinite dilution) and solvent (H2O or D2O) as well as the excess molar volumes of the isotopically distinguishable solutions have been calculated. The effects of the solvent isotope substitution, solute concentration and temperature on the volume changes caused by DMI hydration have been considered. The obvious relationship between the D2O–H2O solvent isotope effects on the partial molar volume and enthalpy of solution of DMI has been discovered. [Copyright &y& Elsevier]

• Densities of urea and tetramethylurea solutions in ethylene glycol were measured at (288.15–328.15) K and p = 99.6 kPa. • Standard partial molar volumes and isobaric expansibilities and pair interaction coefficients for solutes were computed. • A structure packing of solvation complex becomes denser on going from TMU to U and, in a less degree, from EG to water. • Coefficients of solute – solute interactions are positive for U and negative for TMU in EG, decreasing with temperature. • Temperature has differentiating effect on trends of changing standard partial expansibility of U and TMU as solutes in EG. The densities of urea (U) and tetramethylurea (TMU) solutions in ethylene glycol (EG) at the solute molality range up to 1.5 mol·kg−1 were measured with the uncertainty of 0.03 kg·m−3 at T = (288.15, 298.15, 308.15, 318.15 and 328.15) K and p = 99.6 kPa using a vibrating-tube densimeter. The standard partial molar volumes and isobaric expansibilities as well as parameters of the solvent-induced solute–solute pair interactions for both ureas were calculated. The results were discussed in terms of hydrophilic and hydrophobic nature of U and TMU, respectively, and also on the background of the suggestion that EG, like liquid water, forms the hydrogen bond spatial network. [ABSTRACT FROM AUTHOR]

Densities of highly dilute solutions of protiated and deuterated water in N,N-dimethylformamide and N,N-dimethylacetamide, with the solute mole fractions ranging up to 0.012, were measured with an error of 1.0 · 10−5 · cm3 · mol−1 at T = (278.15, 288.15, 298.15, 308.15 and 318.15) K and atmospheric pressure using a precise sealed vibrating-tube densimeter. Apparent molar volumes and apparent molar isobaric expansibilities (down to the infinite dilution) of water isotopologues were calculated. The temperature-dependent behavior of D2O–H2O solute isotope effects on the apparent molar quantities under study were described taking into account the structural features of the amide-solvating media compared. [Copyright &y& Elsevier]

Rare earth tantalates La0.075Ta2O5.113, Eu0.089Ta2O5.134 and Yb0.051Ta2O5.077 have been prepared by solid state reaction at P=7.0GPa and T=1050–1100°C and studied by X-ray diffraction, thermal analysis and electron microscopy. Low hydrated amorphous tantalum, lanthanum, europium and ytterbium hydroxides were used as starting materials. Aqueous as well as anhydrous compounds were obtained. Title tantalates are crystallized in the structure type of F–Ta2O5 [Zibrov et al. Russ. J. Inorg. Chem. 48 (2003) 464–471] [5]. The structure was refined by the Rietveld method from X-ray powder diffractometer data: La0.075Ta2O5.113, a=10.5099(2), b=7.2679(1), c=6.9765(1)Å, V=532.90(1)Å3, Z=6, space group Ibam; Eu0.089Ta2O5.134, a=10.4182(3), b=7.2685(1), c=6.9832(1)Å, V=528.80(2)Å3, Z=6, space group Ibam; Yb0.051Ta2O5.077, a=10.4557(2), b=7.3853(1), c=6.8923(1)Å, V=532.21(1)Å3, Z=6, space group Ibam. RE atoms do not replace the tantalum in its positions but the only water in the channels of the structure. Highly charged cations RE+3 compress the unit cell so that its volume becomes less than that of F–Ta2O5. Significant decrease of the unit cell volume after water removal from the structure is possible due to the puckering of pentagonal bipyramid layers and change of the corrugation angle in the layer. [ABSTRACT FROM AUTHOR]