Experimental observation of light-induced solitary waves of analyte bands in capillary electrophoresis.

The phenomenon of electrophoresis in free solution has been studied theoretically down to the molecular level for decades. In addition, intermolecular photo-induced proton transfer reactions, which occur in a wide class of molecules (phenols and aminoarenes) as well as proteins (green fluorescent protein), were also studied extensively. However, the study of the effect of light-induced electrophoretic mobility changes of the analytes in electrophoresis was begun only recently. In the present work, capillary zone electrophoresis was chosen as the environment to measure the magnitude of these electrophoretic mobility shifts induced by light. Background electrolytes (running electrolytes) with high refractive indices were developed, allowing the capillary to work like an optical fiber. The experimental conditions for obtaining stable coupling and guided laser light along the liquid core are discussed. Experimental evidence of band compression is observed, leading to a solitary wave behavior of the analyte band (2-naphthol). These solitary waves result from competition between thermal diffusion (dispersion mechanism) and a nonlinear (band compression) effect due to the combined electrophoresis phenomenon and absorption of guided light by the molecules of the band (which are subjected to a "reversible intermolecular proton transfer reaction" as one of their decay routes). The possibilities of applying this effect to different methods and techniques are also discussed.     

N-isobutyloxycarbonylation for improved detection of 3'-hydroxystanozolol and its 17-epimer in doping control

An improved screening method was developed for 3'-hydroxystanozolol and its 17-epimer in human urine involving gas chromatography-mass spectrometry (GC-MS) with N-isobutyloxycarbonyl (isoBOC) and O-trimethylsilyl (TMS) derivatization. A procedure was reported previously for the pentane extraction of many steroids from urine in doping control, but it was not suitable for the detection of stanozolol metabolites. Compared with the n-pentane extraction method, which gave a poor recovery (< 10%), isoBOC extraction resulted in a good recovery (> 80%). The sensitivity and specificity of mixed N-isoBOC-O-TMS derivatization were adequate for the detection of 3'-hydroxystanozolol and its 17-epimer when 3 ml of urine was used with spiking at a level of 2 ng ml-1. When applied to a stanozolol-positive urine sample, the proposed method allowed rapid and sensitive screening for the detection of 3'-hydroxystanozolol and its 17-epimer.     

Titanium alkoxide complexes: condensed phase and gas phase comparisons

The complex [Ti(2,4-dimethyl-2,4-pentanediolate)2]2 (1) has been synthesized from [Ti(OiPr)4] by transesterification with a stoichiometric amount of 2,4-dimethyl-2,4-pentanediol. We have characterized complex 1 in the solid state by single-crystal X-ray diffraction and in the gas phase by desorption chemical ionization mass spectrometry (DCI-MS). The structural and mass spectrometric data show complex 1 to be stable as a dimer in both the solid and gas phases. The retention of dimeric nuclearity in the gas phase sets complex 1 apart from other simple titanium alkoxide complexes [Ti(OiPr)4] and [Ti(OMe)4]4 that give rise to respective families of molecular ions in the DCI-MS experiment. The highest mass molecular ions for Ti alkoxide complexes in the gas phase may reveal the highest nuclearity that these complexes achieve in condensed phases. According to this interpretation the complex [Ti(OiPr)4] is principally dimeric in the gas phase and probably also in the pure liquid phase and should be represented by the formula [Ti(OiPr)4]2.     

Characterizing dominates on a family of triangular norms

Dominates is a relation which can be defined on any collection of operations which (1) are defined on the same partially ordered set and (2) have the same identity. In this paper the family considered is a family {T _p } _p=?∞ ^∞ of triangular norms given, for any real numberp ≠ 0, by $$T_p (a,b) = \left[ {Max(a^p + b^p - 1,0} \right]^{{1 \mathord{\left/ {\vphantom {1 p}} \right. \kern-\nulldelimiterspace} p}} $$ and, forp=?∞, 0 or ∞, by taking appropriate limits of those already defined. We sayT _q dominatesT _p provided $$T_q (T_p (a,b),T_p (c,d)) \geqq T_p (T_q (a,c),T_q (b,d))$$ for alla,b,c,d in [0, 1]. The main result of this paper is that dominates is transitive on this family, in fact,T _q dominatesT _p if and only ifq ≦p.     

Use of low energy photon spectroscopy in activation analysis of noble metals with high-energy bremsstrahlung

Noble metals have been analyzed in high purity copper and a platinum ore to be certified as reference materials. Analyses were performed by photon activation analyses using both conventional gamma and low energy photon spectroscopy. Our values agree very well with those of other laboratories using various analysis methods. Low energy photon spectroscopy is more advantageous than gamma spectroscopy from various points of view.     

The electronic spectrum of the triethylamine-perfluoro-tert-butanol complex

The far-ultraviolet absorption spectrum of the triethylamine-perfluoro-tert-butanol complex has been measured in the gas phase. The photoelectron band of lowest energy has also been determined. It is about 13000 cm^?1 higher than for free triethylamine. Up to at least 60000 cm^?1, the UV spectrum is readily interpreted as a triethylamine spectrum shifted to higher frequencies by about 13000 cm^?1. The bands of lowest frequency are the 3s and 3p Rydberg bands which follow the ionization potential. Up to 60000 cm^?1, no charge transfer type band has been found.     

Synthesis of some 3-Methyl-11H-indolo[3,2-c] [1,8]naphthyridines. A New heterocyclic ring system

Some derivatives of 11H-indolo[3,2-c] [1,8]naphthyridine, a new heterocyclic system, have been prepared using the Fischer indole synthesis on the appropriately phenylhydrazones. The preparation of some substituted 5,6-dihydro-11H-indolo[3,2-c][1,8]naphthyridines is also described.     

The chemical ionization mass spectra of 2-tert-butyl-substituted 1,3-cycloalkanediol diacetates and dimethyl ethers

The chemical ionization (CI) mass spectra of the 2-tert-butyl-substituted 1,3-cyclopentane- and 1,3-cyclohexanediol diacetates and dimethyl ethers have been determined using isobutane and methane as reagent gases. From the differences in the spectra of these compounds, it clearly follows that steric and conformational effects are expresssed in the CI mass spectra. The relative impact of these effects, however, is strongly dependent on diol derivatization and 2-alkyl substitution.     

ENHANCED SUSCEPTIBILITY TO HPD-SENSITIZED PHOTOTOXICITY AND CORRELATED RESISTANCE TO TRYPSIN DETACHMENT IN SV-40 TRANSFORMED IMR-90 CELLS

Abstract— The response of a normal human cell strain, IMR-90 and a line derived from it by SV40 transformation were compared after treatment in vitro with hematoporphyrin derivative (HPD) and red light. Transformed cells were inactivated at a significantly higher rate than normal cells when assayed by clonogenic survival. Co-treatment with HPD and light also induces cellular resistance to enzymatic cleavage by trypsin; transformed cells exhibit a greater resistance than the normal cells to detachment from the growing surface. These data indicate that transformed cells may possess intrinsic characteristics that render them more sensitive than normal cells to HPD-induced phototoxicity and that the plasma membrane may be the site of differential toxicity.