ESR spectrometer with a loop-gap resonator for cw and time resolved studies in a superconducting magnet

The design and performance of an electron spin resonance spectrometer operating at 3 and 9 GHz microwave frequencies combined with a 9-T superconducting magnet are described. The probehead contains a compact two-loop, one gap resonator, and is inside the variable temperature insert of the magnet enabling measurements in the 0-9T magnetic field and 1.5-400 K temperature range. The spectrometer allows studies on systems where resonance occurs at fields far above the g approximately 2 paramagnetic condition such as in antiferromagnets. The low quality factor of the resonator allows time resolved experiments such as, e.g., longitudinally detected ESR. We demonstrate the performance of the spectrometer on the NaNiO2 antiferromagnet, the MgB2 superconductor, and the RbC60 conducting alkaline fulleride polymer.     

Nica’s <Emphasis Type="Italic">q</Emphasis>-Convolution is Not Positivity Preserving

It is shown that the q-convolution of Nica is not positivity preserving unless q=0 or q=1, i.e. the q-convolution of two probability measures with finite moments of all orders is not necessarily a probability measure.Supported by Grant-in-Aid for JSPS Fellows     

Intranasal irradiation with the xenon chloride ultraviolet B laser improves allergic rhinitis

We earlier reported that the 308 nm xenon chloride (XeCl) ultraviolet B (UVB) laser is highly effective for the treatment of inflammatory skin diseases. Since UVB irradiation has been shown to exert both local and systemic immunosuppression, we investigated the clinical efficacy of UVB irradiation in allergic rhinitis. In an open study, groups of patients with severe allergic rhinitis received intranasal irradiation with a 308 nm XeCl UVB excimer laser for two weeks. In the low-dose group (n=10), treatment was given twice weekly, starting with 0.25x the individual minimal erythema dose (MED), whereas patients in the medium-dose group (n=8) were treated four times weekly, starting with 0.4x MED. In each group, the dosage was gradually increased. Evaluation was based on the symptom scores. The effect of the XeCl laser on the skin prick test reaction was also studied. In the low-dose group, seven patients completed the study, and there was no improvement in the nasal symptoms. In the medium-dose group, the XeCl UVB irradiation significantly inhibited the rhinorrhoea, the sneezing, the nasal obstruction and the total nasal score (p<0.05). The XeCl UVB excimer laser also inhibited the allergen-induced skin prick test in a dose-dependent manner. These results suggest that the XeCl UVB excimer laser might serve as a new therapeutic tool in the treatment of allergic rhinitis.     

Unwinding of DNA polymerases by the antitumor drug,cis-diamminedichloroplatinum(II)

The helix-turn-helix motifs of the DNA binding domains of human polymerase-alpha and polymerase-kappa are dramatically perturbed upon binding to cisplatin with concomitant release of zinc.     

Maskierung mit Kaliumjodid bei direkten Titrationen von Kupfer(II) mit Äthylendiamintetraessigsäure

Zusammenfassung Die Jodidoxydation durch Cu(II) wird in Anwesenheit von Ammoniak, Natriumtartrat, citrat oder -oxalat infolge Komplexbildung verhindert. Daher kann man z. B. Quecksüber(II) in Anwesenheit der genannten Komplexbildner mit Kaliumjodid maskieren und Kupfer(II) durch direkte Titration mit ÄDTA gegen Murexid, Brenzcatechinviolett, Chromazurol S, PAN oder PAR als Indikator bestimmen.

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Masking with potassium iodide in direct titrations of copper(II) with ethylenediamine tetraacetic acid

Summary The formation of a complex prevents the iodide oxidation by Cu(II) in the presence of ammonia, sodium tartrate, citrate, or oxalate. Hence mercury(II) for instance, can be masked against potassium iodide in the presence of these complex formers, and Cu(II) can be determined by direct titration with EDTA in the presence of murexide, pyrocatechol violet, chromazurol, PAN or PAR as indicator.

     

Solution-phase parallel synthesis of a pyridinium pyrazol-3-olate inner salt library using a three-component reaction

We present here the discovery of a novel, versatile, multicomponent reaction leading to various 4-[4-(pyridinium-1-yl)-2,5-dioxo-2,5-dihydro-1H-pyrrol-3-yl]-2H-pyrazol-3-olate inner salts. The structure of the unusual zwitterionic inner salts was elucidated, and the scope of the novel reaction was investigated. After rapid optimization, the reaction was adapted to parallel synthesis, and an 800-membered compound library was produced.     

Determination of EDTA by catalytic amperometric and catalytic potentiometric titration at a small constant current

Summary Amperometric and potentiometric methods at a small constant current were developed to follow the course of catalytic titrations. In ammoniacal medium EDTA was determined by titration with 0.1 M copper(II) chloride in the presence of hydrogen peroxide as the indicator. Amounts of 42.26–126.87 mg of EDTA were determined with a maximal average deviation of 0.55 %. The results obtained are in good agreement with those of comparable methods.

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Bestimmung von ÄDTA mit Hilfe der katalytischen amperometrischen und der katalytischen potentiometrischen Titration bei kleinem konstantem Strom

Zusammenfassung Die amperometrische und die potentiometrische Methode bei kleinem konstantem Strom wurden für die Verfolgung katalytischer Titrationen ausgearbeitet. ÄDTA wurde in Ammoniakmedium mit 0,1 M Kupfer(II)-chlorid in Anwesenheit von Wasserstoffperoxid als Indicator titriert. Mengen von 42,26–126,87 mg ÄDTA wurden mit einer mittleren Abweichung von 0,55% bestimmt. Die Ergebnisse stimmen gut mit denen vergleichbarer Methoden überein.

The authors thank the SIZ for researchs of SAP Vojvodina for the partial financial support of the present work.     

Saturated heterocycles. Part 209. Synthesis of 1-cyclohexyl-substituted isoquinoline derivatives

In contrast with earlier literature data [7], both acrylic esters and acrylonitrile underwent Michael addition to l-methyl-3,4-dihydroisoquinolines 1-4 to yield the diesters 5-9 or the dinitrile 10 , respectively. Compounds 5-10 were converted by Claisen condensation to 1-[(3′-methoxycarbonyl- or 1-[(3′-ethoxycarbonyl-4′-oxo)-l'-cyclohexyl]-3,4-dihydroisoquinoline derivatives 11-16 . Several derivatives of 12 were prepared. The new compounds possess various pharmacological actions.     

On Raman optical activity sign-switching between the ground and excited states leading to an unusual resonance ROA induced chirality

Raman optical activity (ROA) spectra recorded for a chiral naphthalene diimide derivative (nBu-NDI–BINAM) dissolved in a series of solvents exhibit strong solute to solvent induced chirality with: (1) dominating bands of solvents, (2) nBu-NDI–BINAM resonance ROA (RROA) bands which are barely visible, (3) monosignate RROA Solvent spectra with an unexpected sign concordant with that of the ECD band of the resonant electronic state, (4) bisignate RROA bands for a few solvents, and (5) superposition of non-resonant and resonant ROA bands of the chiral solvents. The unusual ROA enhancement was explained in terms of resonance energy transfer with resonant Raman emission. The surprising RROA sign-switching was found to be due to specific conformational equilibria where one solute conformer dominates in the ground and the other in the first excited singlet state, and, the signs of the related ECD bands of these two conformers are opposite.

Unusual solute to solvent induced chirality in ROA comes from specific conformer equilibria in the ground and the excited states.     

Structural variability of endotoxins from R-type isogenic mutants of Shigella sonnei

The structural variations in the rough-type endotoxins [lipopolysaccharides (LPSs)] of Shigella sonnei mutant strains (S. sonnei phase II-4303, R41, 562H and 4350) were investigated by Matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF-MS) and tandem MS. A series of S. sonnei mutants had previously been the subject of analytical studies on the biosynthesis of heptose components in the core oligosaccharide region of LPSs. This study gives a complete overview on the structures of the full core and lipid A of S. sonnei mutant strains by MS. We found that the LPSs of the isogenic rough mutants were formed in a step-like manner containing 0:1:2:3 heptose in the deep core region of 4350, 562H, R41 and 4303, respectively, and the longest LPS from the mutant S. sonnei 4303 contained also five hexoses. The structural variations in the lipid A moiety and in the oligosaccharide part of the intact LPS were followed by MALDI-TOF-MS/MS. For the dissolution and the ionization of the samples, 2,5-dihydroxybenzoic acid in citric acid solution was applied as matrix. The detailed evaluation of the mass spectra indicates heterogeneity in the lipid part due to the differences in the phosphate and fatty acid composition.