Das Auflösungsvermögen des Szintiscanners “Szintitest” bei der Nierenszintigraphie

Der vom VEB Vakutronik WIB Dresden hergestellete Szintiscanner “Szintitites” wird auf seine Einsatzmöglichlichkeit für die Nierenszintigraphic geprüft. Dazu werden Szintigramme von Modellen aufgenommen, die in ihren Impulsdichten in der Gröβenordnung liegen, wie sie nach Applikation von 300 500µCi¹³¹ J-Hippuran über den Nieren und dem anderen Gewebe der Patienten gefunden werden. Zum Einsatz kommt dabei der Konuskollimator mit einer Apertur von 12 mm. Die besser auflösenden 9- und 19- Kanal-Kollimatoren scheiden für die Nierenszintigraphie mit dem “Szintitest” aus, da ihre Effektivität zu gering ist. Die Einflüsse der Abtastgeschwindigkeit, einer bestimmten Untergrundzählrate und eines variablen Abstandes zwischen Scanner und Objekt werden untersucht. Dabei zeigt sich, daβ ein Körperoberfläche, nicht erreicht werden kann. Das Auflösungsvermögen als 2 cm auch im günstigsten Fall von etwa 8 cm Abstand von der Nierenoberfläche, d. h. 2 4 cm von der Köperoberfläche, nicht werden kann. Das Auflösungsvermögen verschlechtert sich dagegen noch je nach Abstand und Untergrun von 2 auf 3 cm.     

E. I. Mass Spectrometry of 2,3-Tetralene-Oxygen Compounds

The ¹H-NMR spectra of meso-cis- and racemic-transtetralenediols-2,3 are in agreement with the differences in the structures of the isomeric cis- and trans-diols.¹     

Dielectric and structural relaxation phenomena in Na0.5Bi0.5TiO3 single crystal

Abstract

Dielectric permittivity studies of Na_0.5Bi_0.5TiO₃ single crystals in a broad range of frequency up to 10 MHz and temperature 300—823 K are reported. In this temperature range dielectric dispersion below 1 MHz has been found. The obtained data were fitted to the Cole-Cole relation. The mean relaxation time τ is strongly temperature dependent (0.04 ? 2.6 × 10^?5 s). A remarkable hysteresis effect in the values of τ on cooling and heating took place. The Δε(T) dependence (the maximal value of Δε ～ 400) is similar to the global ε′(T) response at low frequency. An isothermal structural transformation in Na_0.5Bi_0.5TiO₃ was observed by X-ray measurements. The order of the time in which the transformation takes place (～300 minutes) corresponds to the time in which the strongest time evolution of electric permittivity and time changes of dielectric dispersion were detected.     

Analysis of poly-β-hydroxybutyrate in environmental samples by GC-MS/MS

Application of gas chromatography-mass spectrometry (GC-MS) can significantly improve trace analyses of compounds in complex matrices from natural environments compared to gas chromatography only. A GC-MS/MS technique for determination of poly-β-hydroxybutyrate (PHB), a bacterial storage compound, has been developed and used for analysis of two soils stored for up to 319 d, fresh samples of sewage sludge, as well as a pure culture of Bacillus megaterium. Specific derivatization ¶of β-hydroxybutyrate (3-OH C_4?:?0) PHB monomer units by N-tert-butyl-dimethylsilyl-N-methyltrifluoracetamide (MTBSTFA) improved chromatographic and mass spectrometric properties of the analyte. The diagnostic fragmentation scheme of the derivates tert-butyldimethylsilyl ester and ether of β-hydroxybutyric acid (MTBSTFA-HB) essential for the PHB identification was shown. The ion trap MS was used, therefore the scan gave the best sensitivity and with MS/MS the noise decreased, so the S/N was better and also with second fragmentation the amount of ions increased compared to SIM. The detection limit for MTBSTFA-HB by GC-MS/MS was about 10^–13 g μL^–1 of injected volume, while by GC (FID) and GC-MS (scan) it was around 10^–10 g μL^–1 of injected volume. Sensitivity of GC-MS/MS measurements of PHB in arable soil and activated sludge samples was down to 10 pg of PHB g^–1 dry matter. Comparison of MTBSTFA-HB detection in natural soil sample by GC (FID), GC-MS (scan) and by GC-MS/MS demonstrated potentials and limitations of the individual measurement techniques.     

Azinyl sulfides. L.

The title compound, C₁₉H₁₃N₃S, is folded, with the central ring in a boat conformation. The folding angle between the two quinoline rings is 150.2 (1)°. The 14‐methyl substituent is in a quasi‐axial orientation with respect to the thia­zine ring. The S?N—C_methyl angle is 120.1 (1)°.     

A blue luminescent binuclear cadmium-orotate coordination polymer: synthesis,crystal structure,and thermogravimetric analysis

Assembly of orotic acid (H₃Or, 1,2,3,6-tetrahydro-2,6-dioxo-4-pyrimidinecarboxylic) and Cd(NO₃)·6H₂O yielded a coordination polymer, [(Cd(Hor)·2.5H₂O)₂]_n (1), which has been characterized by X-ray single-crystal diffraction, TGA, and ?uorescence spectra. Single-crystal X-ray structural analyses reveal that 1 is a hydrogen-bonded binuclear Cd-orotate coordination polymer in which both Cd²⁺ ions have different coordination environments with identical distorted octahedral geometry. Crystal data for 1: monoclinic, space group P2₁/n, a = 7.0209(10) Å, b = 13.974(2) Å, c = 17.541(3) Å, β = 98.842(2)°, V = 1700.5(4) Å, Z = 4, R1 = 0.0269, wR2 = 0.0612, θ_max = 25.960. The emission spectrum of the Cd-complex recorded with 265 nm excitation wavelength reveals the complex has strong blue luminescence with the peak maximum 420 nm (2.95 eV) as a result of the n–π* and π–π* transitions on the H₃Or ligand.     

Effect of Supersaturation and Temperature on the Growth Morphology of Ammonium Oxalate Monohydrate Crystals Obtained from Aqueous Solutions

The experimental results of a study of the effect of supersaturation and temperature on the growth morphology of ammonium oxalate monohydrate [(NH₄)₂C₂O₄H₂O; AO] single crystals obtained from aqueous solutions at 30 and 40 °C and supersaturation up to 9% are presented. The observations are analysed in terms of theoretical morphology, growth models and attachment energy for growth units in steps of growing faces.     

Synthesis and structure of 5,5′,6,6′,7,7′,8,8′-octahydro-1,1′-di(methylthio)-3,3′-biisoquinoline

Title compound, C₂₀H₂₄N₂S₂, crystallizes in the orthorhombic system, space group Pbca, with cell constants a = 5.1968(5) Å, b = 15.6692(11) Å, c = 22.3881(11) Å , Z = 4, T = 293 K, D_cal = 1.299 g cm^–3. The structure was solved by direct methods and refined to R value of 0.0465 for 1566 reflections. Two methylthio-octahydroisoquinoline parts of molecule are related by the center of symmetry and possess the trans conformation. This conformation is more energetically stable than cis but the molecule can rotate about the C(6)–C(6) central bond at room temperature (molecular mechanics calculations). There is a short intramolecular contact C(5)–H(51) N(1) in the molecule. The molecules in the crystal form molecular layers parallel to (001) crystallographic plane and the molecular packing is determined by the van der Waals forces only.     

Intra- versus intermolecular hydrogen bonds in salicylamide derivatives

The crystal structures, solid-state infrared patterns, and thermal properties of two polymorphs of 4-nitrosalicylanilide are presented. In both polymorphs, intramolecular hydrogen bonds are found between the phenol oxygen and the amide proton, and intermolecular hydrogen bonds are found between the amide carbonyl oxygen and the phenol proton. These hydrogen bond patterns are compared to those found in other known salicylamide derivatives and an analysis is given of the factors contributing to preferences for intra- or intermolecular hydrogen bonds in these structures. Crystal data: polymorph, orthorhombic,Pbca,a=11.003(4),b=27.959(7),c=7.622(5) Å,Z=4,V=2345(3) ų, andR=0.038 (1351 reflections); polymorph, monoclinic,P2₁/a,a=28.36(1),b=11.64(1),c=7.293(8) Å,=90.68(6)°,Z=8,V=2408 ų, andR=0.043 (2425 reflections).     

Crystal and molecular structure of 17-β-methyllupanine perchlorate

The formula of the title compound is C₁₆H₂₇ClN₂O₅,MW = 362.9 orthorhombic,P2₁2₁2₁,a = 8.403(1),b= 13.133(1),c= 15.972(2) Å,Z = 4,D _x = 1.37 g cm^–3, (CuK) = 2.2 mm^-1. The lupanine skeleton has atrans-trans configuration. The ringA has a half-chair conformation, theB andD rings adopt a chair form, and theC ring forms a boat. The lupanine cations are linked together by the intermolecular hydrogen bonds forming infinite chains alongb. The N(16) ... O(C2) distance is 2.763(7) Å.