Fourier Transform of Symmetric Gauss Measures on the Heisenberg Group

An explicit form is derived for the Fourier transform of symmetric Gauss measures on the Heisenberg group at the Schrödinger representation. Using this explicit formula, necessary and sufficient conditions are given for the convolution of two symmetric Gauss measures to be a symmetric Gauss measure and for commutability of two symmetric Gauss measures. Moreover, necessary and sufficient conditions are presented for the convolution of two symmetric Gauss convolution semigroups to be a convolution semigroup. May 8, 2001     

Well Ordering Groups with no Monotone Arithmetic Progressions

Károlyi–Kós and Ardal–Brown–Jungic proved that every vector space over \(\mathbb {Q}\) has an ordering with no monotone three term arithmetic progression (3-AP). We show that every solvable group has a well ordering with no monotone 6-AP, and each hypoabelian group has an ordering omitting monotone 5-APs. Finally, we prove that every group has a well ordering with no infinite monotone AP.     

Microanalytical method development for Fe, Cu and Zn determination in colorectal cancer cells

Microanalytical methods suitable for the determination of Fe, Cu in HT-29 (human colon adenocarcinoma) cells treated with different iron compounds (Fe(II) sulfate, Fe(III) chloride, Fe(III) citrate and Fe(III) transferrin) and cultured in medium supplemented or not with 10% (v/v) fetal calf serum (FCS) by total reflection X-ray fluorescence spectrometry (TXRF) and simultaneous graphite furnace atomic absorption spectrometry (GF-AAS) were developed. The developed TXRF method was also suitable for Zn determination in the samples. The main advantage of the proposed methods is the execution of all sample preparation steps following incubation and prior to the elemental analysis in the same Eppendorf tubes. Sample preparation was performed at microscale (115 μL sample volume) with 65% nitric acid and 30% hydrogen peroxide. According to scanning electron microscopic measurements, the organic matrix of the cell samples could be eliminated to the extent that accurate results were obtained for Cu and Fe by analyzing the same samples by TXRF and GF-AAS. Concerning the iron uptake, HT-29 cells incubated in FCS-free medium contained Fe in cca. 5-50 times higher amounts compared to cells cultured in FCS supplemented medium. Pronounced differences in the iron uptake compared to the iron supply (inorganic vs. organic chelated as well as iron(II) vs. iron(III)) were observed in the case of cell lines incubated in FCS-free medium.     

An integrated portable Raman sensor with nanofabricated gold bowtie array substrates for energetics detection

An integrated field-portable surface enhanced Raman scattering (SERS) sensing system has been developed and evaluated for quantitative analysis of energetics such as perchlorate (ClO(4)(-)) and trinitrotoluene (TNT) at environmentally relevant concentrations and conditions. The detection system consists of a portable Raman spectrometer equipped with an optical fiber probe that is coupled with novel elevated gold bowtie nanostructural arrays as a sensitive and reproducible SERS substrate. Using the standard addition technique, we show that ClO(4)(-) and TNT can be quantified at concentrations as low as 0.66 mg L(-1) (or ~6.6 μM) and 0.20 mg L(-1) (~0.9 μM), respectively, in groundwater samples collected from selected military sites. This research represents the first step toward the development of a field SERS sensor which may permit rapid, in situ screening and analysis for various applications including national security, chemical, biological and environmental detection.     

Synthesis and in vitro antiproliferative activity of novel androst-5-ene triazolyl and tetrazolyl derivatives

A straightforward and reliable method for the regioselective synthesis of steroidal 1,4-disubstituted triazoles and 1,5-disubstituted tetrazoles via copper(I)-catalyzed cycloadditions is reported. Heterocycle moieties were efficiently introduced onto the starting azide compound 3β-acetoxy-16β-azidomethylandrost-5-en-17β-ol through use of the "click" chemistry approach. The antiproliferative activities of the newly-synthesized triazoles were determined in vitro on three human gynecological cell lines (HeLa, MCF7 and A2780) using the microculture tetrazolium assay.     

Lanthanide dota-like complexes containing a picolinate pendant: structural entry for the design of Ln(III)-based luminescent probes

In this contribution we present two ligands based on a do3a platform containing a picolinate group attached to the fourth nitrogen atom of the cyclen unit, which are designed for stable lanthanide complexation in aqueous solutions. Potentiometric measurements reveal that the thermodynamic stability of the complexes is very high (log K = 21.2-23.5), being comparable to that of the dota analogues. Luminescence lifetime measurements performed on solutions of the Eu(III) and Tb(III) complexes indicate that the complexes are nine coordinate with no inner-sphere water molecules. A combination of density functional theory (DFT) calculations and NMR measurements shows that for the complexes of the heaviest lanthanides there is a major isomer in solution consisting of the enantiomeric pair Λ(δδδδ) and Δ(λλλλ), which provides square antiprismatic coordination (SAP) around the metal ion. Analysis of the Yb(III)-induced paramagnetic shifts unambiguously confirms that these complexes have SAP coordination in aqueous solution. For the light lanthanide ions however both the SAP and twisted-square antiprismatic (TSAP) isomers are present in solution. Inversion of the cyclen ring appears to be the rate-determining step for the Λ(δδδδ) ? Δ(λλλλ) enantiomerization process observed in the Lu(III) complexes. The energy barriers obtained from NMR measurements for this dynamic process are in excellent agreement with those predicted by DFT calculations. The energy barriers calculated for the arm-rotation process are considerably lower than those obtained for the ring-inversion path. Kinetic studies show that replacement of an acetate arm of dota by a picolinate pendant results in a 3-fold increase in the formation rate of the corresponding Eu(III) complexes and a significant increase of the rates of acid-catalyzed dissociation of the complexes. However, these rates are 1-2 orders of magnitude lower than those of do3a analogues, which shows that the complexes reported herein are remarkably inert with respect to metal ion dissociation.     

Halogen

Ohne Zusammenfassung     

Synthesis of Novel <Emphasis Type="Italic">D</Emphasis>-<Emphasis Type="Italic">Seco</Emphasis>-Pregnenes

Summary. A new synthetic route was developed for the preparation of trans-3-hydroxy-16,17-seco-pregna-5,17(20)-dien-16-al, using Grob fragmentation as the key step. This seco-steroid contains a formyl group and an unsaturated side-chain in a sterically favourable position, and is therefore a promising starting material for the synthesis of novel condensed steroid heterocycles.Received March 22, 2003; accepted April 22, 2003 Published online September 25, 2003     

Determination of Pt in urine of tram drivers by sector field inductively coupled plasma mass spectrometry

The Platinum Group Elements (PGEs) used in automotive catalytic converters are partly emitted into the air during use and can enter the human respiratory system. Due to the increasing use of automotive catalytic converters, the importance of this problem cannot be overlooked.The goal of this investigation was to determine the concentration of Pt in the urine of individuals occupationally exposed to urban air with heavy traffic. Sector field inductively coupled plasma mass spectrometry (SF–ICP–MS) was used for determination of Pt in the urine of tram drivers. 38 and 34 subjects were investigated in Vienna and Budapest, respectively. Samples were taken from the tram drivers both before and after the shift.The results for Pt were compared to those from a previous study performed by our team. The comparison showed that the concentration medians were 4 times higher than the previous ones. Moreover, the values in Budapest were about twice as high as those from Vienna. A partly significant change could be observed between the two sets of data: before, and after the shift.