Two-dimensional polyacrylamide gel electrophoresis, with immobilized pH gradients in the first dimension, of barley seed proteins: discrimination of cultivars with different malting grades.

The suitability of high-resolution two-dimensional gel electrophoresis for barley cultivar discrimination and for classification with respect to their malting properties was studied. Seed proteins of 14 barley cultivars with different malting qualities were extracted with urea/dithiothreitol/Nonidet P-40 buffer and subjected to two-dimensional gel electrophoresis with immobilized pH gradients in the first dimension (IPG-DALT). The results of IPG-DALT were compared to the protein patterns obtained by a standard technique, sodium dodecyl sulfate polyacrylamide gel electrophoresis of hordeins. Sodium dodecyl sulfate-gel electrophoresis yielded seven different "B" and four different "C" hordein patterns; "A" and "D" hordein patterns were uniform in all cultivars tested. Four cultivars could be distinguished unequivocally, the others were classified into three groups containing between two and five cultivars. In contrast to these findings. IPG-DALT yielded three different "A", eight different "B", four different "C" and two different "D" hordein patterns. When the "A", "B", "C" and "D" hordein patterns were combined, ten cultivars exhibited unique hordein patterns whereas the remaining ones were classified into two groups containing two cultivars each. Moreover, when albumin and globulin proteins were used for evaluation in addition to the hordeins, all cultivars could be discriminated by IPG-DALT. IPG-DALT, performed on small-scale and/or ready-made gels, proved to be an ideal complementary system to one-dimensional electrophoretic methods for routine seed testing purposes because of its speed, reliability, and simplicity. IPG-DALT was also applied to study the relationship between the different polypeptide patterns and the malting quality. Although cultivars with identical one-dimensional protein patterns but different malting quality could be successfully differentiated by IPG-DALT, a direct correlation between specific protein spots or protein patterns to the malting quality was not found within the cultivars tested.     

Interaction in the molten system Rb2O‐P2O5‐TiO2‐NiO. Crystal structure of the langbeinite‐related Rb2Ni0.5Ti1.5(PO4)3

The interaction in the molten system Rb₂O‐P₂O₅‐TiO₂‐NiO was investigated at different molar ratios Rb/P = 0.5‐1.3, fixed Ti/P = 0.15, Ti/Ni = 1.0 at temperature range 1073–953 K. The conditions of formation of complex phosphates RbTi₂(PO₄)₃, Rb₂Ni_0.5Ti_1.5(PO₄)₃ and RbNiPO₄ have been determined. The new phosphate Rb₂Ni_0.5Ti_1.5(PO₄)₃ (space group P2₁3, a = 9.9386(2) Å) has been obtained and investigated by the single crystal X‐ray diffraction and FTIR‐spectroscopy. It has langbeinite‐like structure, that is built up from mixed (Ni/Ti)O₆‐octahedra and РО₄‐tetrahedra. Rubidium atoms are located in closed cavities of 3D‐framework.     

Nd3+:Y3Al5O12 laser ceramics: Influence of the size of yttrium oxide particles on sintering

The influence of the size of Y₂O₃ powder particles on the structure formation and densification of Nd³⁺:Y₃Al₅O₁₂ laser ceramics has been studied. It is shown that the use of 50- and 100-nm yttrium oxide particles makes it possible to synthesize single-phase yttrium aluminum garnet at temperatures of 1200 and 1500°C, respectively, whereas in the case of 5000-nm yttrium oxide particles 2-h exposure at a temperature of 1500°C yields only 80 wt % of the Nd³⁺:Y₃Al₅O₁₂ phase. Bulk swelling of pressed samples during sintering of 2.94Y₂O₃-0.06Nd₂O₃-5Al₂O₃ powders with the size ratio of the initial particles R(Al₂O₃/Y₂O₃) ～ 5 is observed. The application of different-sized powders (R ～ 2.5) provides quantitative ratios between phases in the 3Y₂O₃-5Al₂O₃ system at which shrinkage in a temperature range of 20–1500°C is dominant. Laser ceramics 0–2 at % Nd³⁺:Y₃Al₅O₁₂ have been obtained by the solid-phase sintering of oxide powders (R ～ 2.5). The slope efficiency for 1 at % Nd³⁺:Y₃Al₅O₁₂ laser ceramics is found to be 33%.

     

The triple pyrophosphate Cs3CaFe(P2O7)2

The complex phosphate tricaesium calcium iron bis(diphosphate), Cs₃CaFe(P₂O₇)₂, has been prepared by the flux method. Isolated [FeO₅] and [CaO₆] polyhedra are linked by two types of P₂O₇ groups into a three‐dimensional framework. The latter is penetrated by hexagonal channels along the a axis where three Cs atoms are located. Calculations of caesium Voronoi–Dirichlet polyhedra give coordination schemes for the three Cs atoms as [8 + 3], [9 + 1] and [9 + 4]. The structure includes features of both two‐ and three‐dimensional frameworks of caesium double pyrophosphates.     

Crystal structure of nickel paratungstate B Ni<Subscript>5</Subscript>[W<Subscript>12</Subscript>O<Subscript>40</Subscript>(OH)<Subscript>2</Subscript>]·37H<Subscript>2</Subscript>O

From the solution of the system Na₂WO₄-HNO₃-Ni(NO₃)₂-H₂O acidified to Z = ν(H⁺)/ν(WO ₄ ^2? ) = 1.29, the green crystals of nickel paratungstate B Ni₅[W₁₂O₄₀(OH)₂]·37H₂O are isolated. By FTIR spectroscopy the isopoly anion is shown to belong to the structural type of paratungstate B. Using single crystal X-ray analysis, the structure of Ni₅[W₁₂O₄₀(OH)₂]·37H₂O is solved (M _r = 3840.36, monoclinic, P2₁/c space group, a = 21.9061(6) Å, b = 14.9297(4) Å, c = 22.1391(6) Å, β = 107.609(3)°, V = 6901.4(3)ų at T = 293 K, Z = 4, d_x = 3.696 g/cm³, F ₀₀₀ = 6944, μ = 21.368 mm^?1, ?33 ≤ h ≤ 33, ?22 ≤ k ≤ 22, ?33 ≤ l ≤33; the final uncertainty values for the observed reflections are R _F = 0.0532, wR ² = 0.0831 (R _F = 0.1088, wR ² = 0.0894 over all independent reflections), S = 0.978; CSD-421468).     

Modification of the Pictet–Spengler reaction in the synthesis of fused 2,3-benzodiazocines

A new strategy for the synthesis of the eight-membered heterocyclic skeleton of tetrahydro-quinazolino[3,2-c][2,3]benzodiazocin-15-ones, based on the Pictet–Spengler reaction of 3-amino-2-[2-(3,4-dimethoxyphenyl)ethyl]quinazolin-4(3H)-one with carbonyl compounds in acidic media, is proposed.     

Synthesis of 2-amino-4,5,7-triarylimidazo[1,5-b]pyridazines

The reaction of 4-aryl-1,2-diaminoimidazoles with 1-aryl-2,3-dibromo-3-(4-nitrophenyl)propanones, 2-bromo-1-phenyl-3-(4-chlorophenyl)propenone, and 1,3-diarylpropynones yields 2-amino-4,5,7-triarylimidazo[1,5-b]pyridazines. The structure of one of these products was determined by x-ray diffraction analysis. Kharkov State University, 310077 Kharkov, Ukraine. Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 10, pp. 1397–1403, October, 1998.     

Molecular structural features of unsymmetrical ortho analogs of POPOP

The electronic spectra and structures of sterically hindered molecules of unsymmetrical ortho-analogs of POPOP containing electron donor subsitituents in the oxadiazole part of the molecule have been studied (1-(5′-phenyloxazol-2-yl)-2-(5-phenyl-1,3,4-oxadiazol-2-yl)benzene derivatives (I)). X-Ray structural analysis was carried out on the dimethylamino derivative of I. It was found that the conformation of the molecules of the investigated compounds is determined by the conformation of the starting 2-(5-phenyloxazol-2-yl)benzoic acid and its acid chloride used in the synthesis of the ortho POPOP analogs. In the series of unsymmetrical ortho POPOP analogs there arises a unique possibility for changes in the structure of the oxadiazole part of the molecule to affect the position of the spectral emission almost without affecting the long wavelength absorption band in the process. There were thus prepared efficient organic luminophores having an anomalously large Stokes fluorescence shift. Kharkov State University, Kharkov 310077. Institutefor Monocrystals. National Academy of Sciences of Ukraine, Kharkov 310001. Translated from Khimiya Geterotsiklicheskikh Soedinenii. No. 11, pp. 1549–1558, November, 1997.     

Production of Y3Al5O12 and Y2O3 nanopowders for optical ceramics

The physical and technical conditions for reproducible production of nanodispersed yttrium aluminum garnet (Y₃Al₅O₁₂, YAG) and yttrium oxide (Y₂O₃) powders by chemical coprecipitation have been investigated. It is established that the obtained YAG nanopowders have enhanced reactivity, which significantly decreases the temperature range of interaction in the Y₂O₃-Al₂O₃ system in comparison with ceramic synthesis. It is shown that vacuum heat treatment may lead to reversible transformation of the YAG crystal structure from cubic to tetragonal.