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Budesonide and flunisolide anhydrate were crystallized using the solution enhanced dispersion by supercritical fluids (SEDS) technique. The aim was to investigate the possibility of preparing different pure polymorphs.0.25% w/v solutions of each drug were prepared from acetone and methanol. Operating conditions were 40-80 degrees C and 80-200 bars. The flow rate of drug solution was 0.3 mL/min and that of CO2 was 9-25 mL/min. Sample characterizations included differential scanning calorimetry, X-ray powder diffraction, variable temperature X-ray diffraction, scanning electron microscopy, and solubility studies.The particle morphology of budesonide was dependent on the nature of the solvent. SEDS processing of flunisolide with acetone at 100 bars resulted in the formation of polymorphic mixtures at 80 degrees C and a new polymorph III at 60 C and 40 degrees C. With methanol at 100 bars another new polymorph IV was formed with different particle morphology at 80 degrees C and a polymorphic mixture at 60 degrees C.Using the SEDS, microparticles of crystalline budesonide were prepared and new polymorphs of flunisolide were produced. Particle characteristics were controlled by the temperature, pressure and relative flow rates of drug solution and CO2.

The magnetic properties of TlCo2Se2 have been investigated by means of first principles calculations. The magnetism of this compound is dominated by the contribution from the Co atoms, which form l ...

Structural and magnetic properties of single-crystal TlCo 2−x Cu x Se 2 , 0⩽x⩽1 , have been investigated by means of X-ray diffraction experiments and magnetisation measurements. TlCo2Se2 and TlCu2Se2 are isostructural, belonging to the ThCr2Si2 structure type, i.e. tetragonal sheet structures. From diffraction data on the solid solutions, we note superstructure formation at large Cu concentrations. The overall ordering at low temperature is antiferromagnetic, and the Neel temperatures scale linearly with x, falling drastically from 82 K (x=0) to 11 K (x=1). From fits to the Curie–Weiss law, the effective magnetic moments μeff and the asymptotic Curie temperatures θp were obtained. θp is positive, showing that the interactions within the sheets are of a ferromagnetic character.

In the Li-Cu-O system two new ternary phases have been found, tentatively described by the stoichiometries LiCu3O3 and LiCu2O2, and both containing Cu(I) and Cu(II). They exhibit p-type "hopping" conduction owing to localized charge carriers. Their powder patterns are successfully indexed on high-symmetry cells where the dimensions depend on a slightly variable stoichiometry. LiCu3O3 is tetragonal with a = 2.815 (.square root 2) angstrom and c = 8.88 angstrom. LiCu2O2 is orthorhombic with a = 5.72 angstrom, b = 2.86 angstrom and c = 12.4 angstrom.Li3Cu2O4, containing Cu(II) and Cu(III), is indexed on a C-centred monoclinic cell: a = 9.958 angstrom, b = 2.777, c = 7.281 angstrom and beta = 118.77-degrees.The solubility of lithium in CuO is maximally Li0.06Cu0.94O for supersaturation at 1100 K. The equilibrium solubility limit is about Li0.02Cu0.98O, for which the solid solution is still semiconducting. The temperature dependence of the magnetic susceptibility is similar to that of pure CuO but T(N) is considerably lower.

The structure of TlCu6S4 has been determined from single-crystal X-ray diffraction data, confirming (RF = 0.061, RwF = 0.059) a previous structure hypothesis that the compound is the third member of a structure series TlCu2nSn+1. The compound is tetragonal (space group I4/mmm, no. 139; Z = 2) with the cell parameters a = 3.9465 A , c = 24.230 A for nearly stoichiometric material. The investigated crystal was copper deficient, corresponding to the formula TlCu5.5S4 and to the cell parameters a = 3.9357 A , c = 24.183 A . Like the previous members of the series, this compound has metallic conduction owing to a high concentration of valence band holes. All the members of the series are layer structures with tetragonal symmetry, derived from anti-fluorite-type Cu2S with thallium layers interfoiling slabs with copper in tetrahedral voids of the sulphur lattice.

Utsumi et al., J. Solid State Chem. 107, 507, 1993, claim that LiCuO2 transforms from an orthorhombic modification to a monoclinic one by applying pressure. This interpretation is disputed on the basis of evidence from X-ray and neutron diffraction refinements which show that LiCuO2 is already monoclinic (NaCuO2 structure type) at ambient pressure.

In the p-type metal TlCu2Se2, monovalent copper may be substituted by various metals with higher valence. The physical properties of the system TlCu2−xFexSe2 have been studied as a function of the composition in some detail, with emphasis on the range 0

Previous claims of a compound TlCu9S5 are rejected. The true composition is TlCu7S4, the compound being isostructural with NH4Cu7S4 and TlCu7Se4 (crookesite). The body-centred tetragonal cell (a=10.1797 A andc=3.8585 A) contains two formula units.

The ternary compound TlCu 2 Se 2 , which has a ThCr 2 Si 2 -type structure, was characterized by means of miscellaneous physical measurements. It is a p-type metal with a Fermi energy of 1.3 eV. There is one hole (effective mass, 1.3 m 0 ) per formula unit in the valence band. In addition to metallic conduction the delocalized holes give rise to Pauli paramagnetism. There was no conclusive evidence for a phase transition in the temperature range 25–600 K.

High-temperature silica-tube syntheses and room-temperature copper extraction experiments of the single phases found with the former technique have established five new ternary phases in the Tl Cu Se system. The compositions were determined by microprobe analysis. The new phases have been crystallographically characterized by means of single-crystal and powder diffraction: TlCu 3 Se 2 (CsAg 3 S 2 type), a = 15.2128(7)A, b = 4.0115(2)A, c = 8.3944(4)A, β = 111.700°(4); Tl 5 Cu 14 Se 10 (new type), C2/m ?) a = 18.097(2)A, b = 3.9582(2)A, c = 18.118(2)A, β = 116.089°(7); TlCu 5 Se 3 (new type, P 4¯n2?), a = 12.9023(2)A, c = 3.9905(1)A; TlCu 5− x Se 3 (new type, Pnn 2?), a = 12.43(1)A, b = 12.80(1)A, c = 3.93(1)A; TlCu 7 Se 4 (NH 4 Cu 7 S 4 type), a = 10.4524(2)A, c = 3.9736(1)A. The latter phase may be considered as stoichiometric crookesite.

The compound TlCu2S2 was synthesized at room temperature by chemical treatment of TlCu3S2 made at 670 K. It is tetragonal with cell parameters a = 3.7771(1) A and c = 13.3791(9) A ; it is metastable and decomposes on heating at 390(5) K into a three-phase mixture of TlCuS, TlCuS2 and TlCu4S3. According to electrical transport measurements (resistivity, Seebeck and Hall effects) it is metallic owing to the presence of one valence-band hole per formula unit. The Fermi energy of 2.1(1) × 10−19 J and the hole effective mass of 1.3m0 are similar to the data previously obtained for isostructural TlCu2Se2.

Mossbauer studies on a mosaic of single crystals of the layered compound TlFe 2− x Se 2 have been carried out at various temperatures between 100 and 460 K. A magnetic transition occurs at ∼450 K. The magnetic ordering within the FeSe layers is antiferromagnetic with the spins oriented along the tetragonal axis. X-Ray diffraction data indicated ordering of the iron vacancies at the chosen composition ( x ∼ 0.3) yielding a supercell with a volume five times that of the ThCr 2 Si 2 type subcell, the cell parameters being a = 8.6909(5) A and c = 14.005(1) A.

The nature of the defect structure of crystals of V 4 As 3 has been studied by electron diffraction and electron microscopy methods. Lattice images reveal that planar defects of the chemical twinning type are common in the orthorhombic α-V 4 As 3 crystals. Thermal decomposition, yielding negative crystals, was also studied.

Beim Versuch, einen fur die Rontgen-Strukturverfeinerung geeigneten TaNiP-Kristall auszulesen, wird die neue Phosphidphase (I) mit tetragonaler Symmetrie entdeckt.

The compound TlCu2S2 was synthesized at room temperature by chemical treatment of TlCu3S2 made at 670 K. It is tetragonal with cell parameters a = 3.7771(1) A and c = 13.3791(9) A ; it is metastable and decomposes on heating at 390(5) K into a three-phase mixture of TlCuS, TlCuS2 and TlCu4S3. According to electrical transport measurements (resistivity, Seebeck and Hall effects) it is metallic owing to the presence of one valence-band hole per formula unit. The Fermi energy of 2.1(1) × 10−19 J and the hole effective mass of 1.3m0 are similar to the data previously obtained for isostructural TlCu2Se2.

Previous claims of a compound TlCu9S5 are rejected. The true composition is TlCu7S4, the compound being isostructural with NH4Cu7S4 and TlCu7Se4 (crookesite). The body-centred tetragonal cell (a=10.1797 A andc=3.8585 A) contains two formula units.

Es entspricht einem weitverbreiteten rationalistischen Glaubenssatz der Verwaltung anzunehmen, das ihre Aufgabenerfullung im Allgemeininteresse erfolge, objektiven Sachzwangcharakter besitze und die Struktur sich — was immer man darunter versteht — nach den Erfordernissen der Aufgabenbewaltigung bestimme. Diesem Glaubenssatz folgt auch, zahlreichen offiziellen politischen Dokumenten zufolge, die Forschungspolitik des Bundes, wenn man die Bundesforschungsberichte1 zugrunde legt oder die zahlreichen Veroffentlichungen des derzeit amtierenden Bundesministers fur Forschung und Technologie2 liest. Diese Forschungspolitik ist jedoch gepragt durch drei zumindest teilweise widerspruchliche Grundaussagen: 1. Forschungspolitik ist aktive und antizipative Strukturpolitik, d.h. es wird ein politischer Steuerungsanspruch geltend! gemacht3. 2. Forschungslenkung und Wirtschaftslenkung werden unter Betonung der Autonomie der Forschung und Freiheit der Marktwirtschaft abgelehnt4, d.h. der politische Steuerungsanspruch wird systemimmanent als Akzeptanz von Anreizen definiert. 3. Bei den Anreizen stehen Finanzsubventionen im Vordergrund, ohne das bislang in den zahlreichen offiziellen Verlautbarungen5 versucht worden ware, aus der Akzeptanz der finanziellen Subventionen die politische Zielakzeptanz zu begrunden.

The structure of NH4Cu7−xS4 has been investigated using X-ray single crystal diffraction at varying temperatures. The room temperature structure is best described as a tetragonal crystalline framework with channels incorporating some of the copper atoms in a disordered, almost amorphous, manner. The crystallographic description based primarily on the framework renders the space group I4/m and a unit cell with a=10.2695(5) A and c=3.8094(3) A. Upon cooling below 270 K, the copper atoms in the channels start to order. To begin with, the compound adopts the CsAg7S4 structure type with the unit-cell parameters a=10.289(1) A and c=7.704(1) A. Upon further cooling, incommensurate orderings occur, in accordance with the fact that a copper deficient sample was used in the investigation (x≈0.16).

Progressive pulmonary arterial hypertension (PAH) is a rare condition with high morbidity and mortality. Paediatric PAH distinguishes itself from PAH in adults, but is still poorly characterized. Paediatric PAH presents itself with non-specific symptoms which often results in later diagnosis. Determination of the correct underlying diagnosis in paediatric PAH is complex, and must therefore take place at specialized centres. Paediatric progressive PAH is usually either idiopathic or associated with congenital heart disease. Pediatric PAH frequently co-occurs with dysmorphic abnormalities, which may point towards aetiological mechanisms. Recent reports suggest an improved survival and exercise tolerance due to treatment with new second-generation drugs for paediatric PAH. In the Netherlands, the care for children with PAH is centralised to guarantee the optimization of diagnosis and treatment in accordance with the most recent scientific insights.

The structure of LiCu2O2 was solved using two sets of X-ray diffraction twin-crystal data. Extended twinning creates virtual tetragonal symmetry. The compound crystallizes in Pnma (62) with unit-cell parameters a = 5.72 angstrom, b = 2.86 angstrom and c = 12.4 angstrom with a certain homogeneity range. The structure consists of LiCu(II)O2 layers interleaved by layers of Cu(I) connected to oxygen in an almost linear coordination. Lithium and copper(II) have five oxygen neighbours in pyramidal arrangements that run as parallel bands through edge connections. Electron diffraction was used for characterizing the twinning.