Nickel(II) complexes of 3-acetyl-4,5-dihydro-1,2,4-triazole hydrazones

3-Acetyl-1,2,4-triazole hydrazones (3b,c) and methylhydrazone (4d) were prepared by reacting triazoles (1b–d) with an excess of hydrazines at room temperature. Square planar nickel(II) complexes (8b,c) of (3b,c) were obtained from their reaction with Ni(OAc)₂ in a 2:1 mol ratio in EtOH at room temperature. The spectral data suggest structures (8b,c) for the obtained complexes, which result from ring opening of the triazole ring followed by recyclization to give the 5-arylhydrazono-2,3-dihydro-4H-1,2,4-triazine ligand (7b,c). The reaction of triazole methylhydrazone (4d) with Ni(OAc)₂ in EtOH resulted, however, in the formation of the starting triazole (1d). All new compounds were characterized by elemental analysis, i.r., ¹H-n.m.r. ¹³C-n.m.r. and hrms.     

Biodistribution of the bone imaging agents99mTc-DHPE and99mTc-MDP in rats

The self life of the freeze-dried formulation kits utilized for the preparation of the new bone imaging radiopharmaceutical^99mTc-1,2-dihydroxy-1,2-bis/dihydroxyphosphinyl/ethane /^99mTc-DHPE/ has been investigated as well as the toxicity of the DHPE. In a biodistribution investigation of^99mTc-DHPE in rats, in comparison to^99mTc-methylenediphosphanate /^99mTc-MDP/,^99mTc-DHPE exhibited a certain extent higher skeleton uptake, a higher blood clearance rate, a very low concentration in other organs, a satisfactory biological stability and excretion primarily through the kidneys. These properties demonstrate that^99mTc-DHPE is a new promising skeleton imaging radio-pharmaceutical.     

Super spline spaces of smoothnessr and degreed≥3r+2

The problem of computing the dimension of spaces of splines whose elements are piecewise polynomials of degreed withr continuous derivatives globally has attracted a great deal of attention recently. We contribute to this theory by obtaining dimension formulae for certain spaces of super splines, including the case where varying amounts of additional smoothness is enforced at each vertex. We also explicitly construct minimally supported bases for the spaces. The main tool is the Bernstein-Bézier method.Communicated by Klaus Höllig.     

Mercury Speciation in Fish by High-Performance Liquid Chromatography (HPLC) and Post-Column Ultraviolet (UV)-Photochemical Vapor Generation (PVG): Comparison of Conventional Line-Source and High-Resolution Continuum Source (HR-CS) Atomic Absorption Spectrometry (AAS)

An ultraviolet-photochemical generator (UV-PVG) capable of post-column on-line transformation of both organic and inorganic mercury species to cold vapor (Hg⁰) with subsequent detection by quartz tube-atomic absorption spectrometry (QT-AAS) was developed. Mercury(II), methylmercury(I), ethylmercury(I), and phenylmercury(I) were successfully detected after separation by reversed-phase high-performance liquid chromatography (RP-HPLC). Two types of AAS detectors were compared. The first was a commonly used line-source instrument while the second was a high-resolution continuum source (HR-CS) AAS. The latter provided better limits of detection: 0.47?µg?L^?1 for Hg(II), 0.84?µg?L^?1 for methylmercury(I), 0.80?µg?L^?1 for ethylmercury(I), and 2.0?µg?L^?1 for phenylmercury(I). The repeatability at 30?μg?L^?1 was 3.6%, 4.1%, 6.2%, and 4.5% for these species (n?=?10). These figures of merit were comparable with those reported for more sensitive atomic fluorescence spectrometry. Nine sample extraction procedures were investigated. Extraction by tetramethylammonium hydroxide and HCl at 75?°C was selected as the only method compatible with the proposed separation and detection steps providing high extraction efficiency and no changes in mercury speciation. The applicability of the proposed high-performance liquid chromatography–ultraviolet-photochemical vapor generation–quartz tube-atomic absorption spectrometry method was demonstrated using fish samples and certified reference materials (CRM) DOLT-4 (dogfish liver) and ERM-CE464 (tuna fish). The results were comparable to those obtained by a reference method based on L-cysteine extraction and high-performance liquid chromatography–inductively coupled plasma-mass spectrometry (HPLC–ICP-MS) determination.     

Influence of substitutions on asymmetric dihydroxychlorins with regard to intracellular uptake, subcellular localization and photosensitization of Jurkat cells

The search for new efficient sensitizers for photodynamic therapy (PDT) points to improve photophysical properties like absorption in the red region and singlet oxygen quantum yield as well as to control the localization of the sensitizer within the tumour cell. Depending on their physicochemical properties and their uptake mechanism, sensitizers can reach different intracellular concentrations and localize in different subcellular compartments. Moreover, the preferential localization of a sensitizer in target organelles, like mitochondria or lysosomes, could determine the cell death mechanism after PDT. This study aimed to investigate the influence of substitutions on dihydroxychlorins with regard to intracellular uptake, subcellular localization and cell death pathway. Moreover, the effect of a liposome-based delivery system was tested. The intracellular uptake was found to be strictly dependent on the sensitizer molecular structure and the means of its delivery. The most polar sensitizer in this study (compound 3) had, depending on incubation time, an intracellular concentration 2-8 times higher than the unsubstituted chlorin 1. All investigated photosensitizers localize predominantly in lysosomes but after longer incubation times weak fluorescence intensity was also detected in mitochondria and Golgi apparatus. The cell death pathway was found to be influenced by the sensitizer intracellular concentration and the applied light doses. In general, the increasing amphiphilicity of the sensitizer molecules is correlated with an increased sensitizer uptake and an increased rate of necrotic cells after irradiation.     

Indirect atomic absorption and atomic emission spectrometric determination of antazoline,hydralazine and amiloride hydrochlorides and quinine sulphate

Ion-association complexes of antazoline HCl [I], hydralazine HCl [II], amiloride HCl [III] and quinine sulphate [IV] with [Co(SCN)₄]^2– and [Co(NO₂)₆]^3– were precipitated and the excess unreacted cobalt complex was determined. A new method using atomic emission and atomic absorption spectrometry for the determination of the above drugs in pure solutions and pharmaceutical preparations is given. The drugs can be determined in the ranges 0.3–3.0, 0.19–1.96, 0.3–3.0, and 0.78–7.82 mg/25 ml solutions of I, II, III, and IV, respectively, with mean relative standard deviations of 0.65–2.03 % and recovery values of 95.76–101.2% indicating high precision and accuracy.     

Analysis of Mepivacaine in Human Serum by Gas Chromatography After Solid-Phase Extraction

A method using solid-phase extraction (SPE) has been developed for analysis of mepivacaine in human serum. A procedure for isolation of mepivacaine and lidocaine (internal standard) from human serum by use of Chromosorb 104 (acrylonitrile–divinylbenzene polymer) as extraction adsorbent is described in detail. Analysis was performed by gas chromatography on an HP-INNOWax (cross-linked PEG) capillary column, with flame ionization detection, after splitless injection. Relative standard deviations ranged between 3.6 and 4.4 for a serum mepivacaine concentration of 0.5 g mL^–1 and between 4.7 and 5.9 for a concentration of 1 g mL^–1. Recoveries were approximately 95%. The method was applied in a stomatological clinic to healthy volunteers to whom anesthesia with mepivacaine was administered.     

Molten sodium nitrite—potassium nitrite eutectic: the reaction of some compounds of molybdenum

Molybdenum(VI) oxide, ammonium molybdate and molybdic acid reacted in molten sodium nitrite—potassium nitrite eutectic to form orthomolybdate, nitrogen dioxide and nitric oxide (with nitrate as a secondary product), a more polymerised polymolybdate being formed as an intermediate product. Tungsten(VI) oxide reacted similarly but less rapidly. Molybdenum and tungsten metals reacted to form the orthoxyanion and nitrogen, the latter metal reacting considerably faster and forming smaller amounts of nitric oxide and nitrous oxide. Reaction temperatures and stoichiometries are given and reaction pathways suggested.     

Synergistic effects of ion-pairing in the enantiomeric separation of basic compounds with cyclodextrin derivatives in nonaqueous capillary electrophoresis

The enantiomeric separation of various kinds of basic pharmaceuticals has been investigated in nonaqueous capillary electrophoresis (NACE) systems using an ion-pairing reagent in combination with cyclodextrins (CDs). The simultaneous addition to the methanolic background electrolyte (BGE) of (+)-S-camphorsulfonate or alkanesulfonates and an anionic beta-cyclodextrin derivative, heptakis(2,3-dimethyl-6-sulfato)-beta-cyclodextrin (HDMS-beta-CD), led to partial or complete enantioresolution in most cases. In the absence of ion-pairing reagent, the enantiomeric resolution obtained with this CD derivative was most often completely lost or strongly reduced, indicating the important role of ion-pairing in the chiral recognition mechanism in these NACE systems. The influence of the nature and concentration of the counterion and the anionic CD derivative on the enantioseparation of basic compounds was studied. Synergistic effects between these two kinds of charged additives were clearly observed.     

Efficient approaches toward the solid-phase synthesis of new heterocyclic azoniaspiro ring systems: synthesis of tri- and tetrasubstituted 10-oxo- 3,9-diaza-6-azoniaspiro[5.5]undecanes

[Reaction: see text]. An efficient approach for the parallel solid-phase synthesis of novel heterocyclic azoniaspiro ring systems is described. The target compounds, the 1,8,9-trisubstituted 10-oxo-3,9-diaza-6-azoniaspiro[5.5]undecanes, were obtained starting from resin-bound reduced dipeptides. The azoniaspiro cation was formed by intramolecular attack of a tertiary nitrogen on pendent alpha-bromocarbonyl. N-3 acylated and N-3 alkylamino carbonyl derivatives of the 1,8,9-trisubstituted 10-oxo-3,9-diaza-6-azoniaspiro[5.5]undecanes were obtained following in solution treatment of the N-3 azoniaspiro derivatives with different carboxylic acids and isocyanates.