Fluorimetric determination of the levels of urinary neopterin and serum thiobarbituric acid reactive substances in the nonagenarians

Twelve self-sustaining nonagenarians, 10 women and two men, aged 94+/-3 years, and eight institutionalised nonagenarians, eight women, aged 91+/-1 year as well as 11 control subjects, seven women and four men, aged 84+/-5 years entered the study. Urinary neopterin, an indicator of systemic immune activation, and serum thiobarbituric acid reactive substances (TBARS), a marker of lipoperoxidation, were determined initially, and collection of the blood and urine samples was repeated at 3-month interval. Neopterin was measured in the urine specimens by reversed-phase high performance liquid chromatography. A C(18) reversed-phase column 3.3x150 mm, 5 mum-diameter packing Separon SGX was used. Potassium phosphate buffer (15 mmol l(-1), pH 6.4) at flow rate of 0.8 ml min(-1) was used as mobile phase. After centrifugation (5 min, 1300xg) and diluting 100 mul of urine specimens with 1.0 ml of mobile phase containing 2 g of disodium-EDTA per litre, a 20 mul sample was injected on a column. Neopterin was identified by its native fluorescence (353 nm excitation, 438 nm emission). Creatinine was determined by Jaffé kinetic reaction after dilution of sample 1:50 (v/v). The concentration of neopterin in urine was expressed as neopterin/creatinine ratio (mumol mol(-1) creatinine). TBARS were determined spectrofluorometrically using LS-5 spectrofluorimeter (excitation wavelength 528 nm, emission wavelength 558 nm) after extraction with n-butanol treatment with thiobarbituric acid. The significance of differences between nonagenarians and control group was examined by ANOVA-Kruskal-Wallis tests, using statistical software NCSS 6.0.21 (Kaysville, UT, 1996). The decision on significance was based on P=0.05. Urinary neopterin was significantly higher in institutionalised compared to self-sustaining subjects and controls (625+/-565 vs. 203+/-63 mumol mol(-1) creatinine, and 198+/-128 mumol mol(-1) creatinine, respectively, P=0.006). The serum TBARS were higher in both groups of nonagenarians (3.23+/-1.16 mumol l(-1) and 2.69+/-0.39 vs. 2.12+/-0.83 mumol l(-1) for the self-sustaining, institutionalised and controls, respectively, P=0.023). We conclude that the fluorimetric determinations of urinary neopterin and serum TBARS can be useful for the monitoring health status in the elderly patients.     

Wind tunnel simulation of air pollution dispersion in a street canyon

Physical simulation was used to study pollution dispersion in a street canyon. The street canyon model was designed to study the effect of measuring flow and concentration fields. A method of C02-laser photoacoustic spectrometry was applied for detection of trace concentration of gas pollution. The advantage of this method is its high sensitivity and broad dynamic range, permitting monitoring of concentrations from trace to saturation values. Application of this method enabled us to propose a simple model based on line permeation pollutant source, developed on the principle of concentration standards, to ensure high precision and homogeneity of the concentration flow. Spatial measurement of the concentration distribution inside the street canyon was performed on the model with reference velocity of 1.5 m/s.     

Racemization barriers of 1,1'-binaphthyl and 1,1'-binaphthalene-2,2'-diol: a DFT study

Density functional theory has been applied to the study of various pathways and transition states for the configurational inversion of 1,1'-binaphthyl (1) and 1,1'-binaphthalene-2,2'-diol (2). The preferred pathway is found to be anti with centrosymmetric transition state. Whereas the reaction path of 1 goes downhill from transition to ground state, in the case of 2 it contains one unexpected local minimum. Very satisfactory agreement with available experimental values of activation Gibbs energies is achieved.     

Ca at C82 isomers: computed temperature dependency of relative concentrations

Relative concentrations of nine isomers of Ca at C82 derived from the C82 isolated-pentagon-rule satisfying cages are computed in a wide temperature interval. The computations are based on the Gibbs energy constructed from partition functions supplied with molecular parameters from density functional theory calculations. Five structures show significant populations at higher temperatures: C2v > Cs > C2 > C3v > Cs. The computed relative stabilities agree well with available observations.     

The Chemistry of Dichloromethylenammonium Salts (“Phosgenimonium Salts”)

Dichloromethylenammonium salts, particularly dichloromethylenedimethylammonium chloride, occupy a unique place as stable but reactive building blocks for synthesis. They contain three mobile chlorine atoms activated by an amino group on the same carbon atom. These salts can be regarded as chlorinated Vilsmeier or Mannich reagents and are thus at a higher oxidation level. As in the Mannich or Vilsmeier reaction, the carbon condenses here as an electrophile with formation of C? C or C? hetero atom bonds in a variety that is still far from being exhausted.     

Complexes of iron(III) salen and saloph Schiff bases with bridging dicarboxylic and tricarboxylic acids

Six new dinuclear or trinuclear FeIII complexes involving tetradentate Schiff bases N,N′-bis(salicylidene)ethylenediamine (salenH2) or bis(salicylidene)-o-phenylenediamine (salophH2) with 2,5-pyridinedicarboxylic acid, acetylenedicarboxylic acid or 1,3,5-benzenetricarboxylic acid have been synthesized and characterized by means of elemental analysis, i.r. spectroscopy, thermal analyses, conductivity measurements and variable-temperature magnetochemical measurements to the temperature of liquid nitrogen. The complexes can be characterized as high-spin distorted octahedral FeIII bridged by carboxylic acids. The dicarboxylic or tricarboxylic acids play a role as bridges for weak antiferromagnetic intramolecular exchange. The antiferromagnetic coupling parameters J vary in the -1.99 to -5.47cm-1 range for the dimers, whilst the values are -2.35 and -1.42cm-1 for the salen and saloph trimers, respectively. One complex, namely [{Fe(saloph)}2(2,5-dicarpy)]middot H2O, obeys the Curie-Weiss law. This revised version was published online in June 2006 with corrections to the Cover Date.     

Wechselwirkungen in Kristallen. 106. Mitteilung. Die Klaviatur der Na⊕-Koordinationszahlen in ihren Carbazolanion-Salzen

Interaction in Crystals: The Keyboard of Na⊕ Coordination Numbers in Its Carbazole Anion Salts Some local minima in the shallow potential of the system carbazole anion, sodium cation, and the ethers tetrahydrofuran, 1,2-dimethoxyethane, diglyme, triglyme, tetraglyme, 15-crown-5 as well as 2.2.1-cryptand are explored experimentally and by quantum-chemical calculations. Three prototype contact-ion multiples of Na⊕-solvated carbazole anion M? salts have been crystallized and structurally characterized: polyether-solvated monomers [M?Na⊕_solv]₁, solvent-shared dimers [M?Na⊕_solv]₂, and solvent-separated polyions [(M?)nNa?_solv](^n?1)? [Na⊕_solv](n_?1). The Na⊕ coordination numbers stretch from 3 to 7 as illustrated by the compounds [(M?)₃Na+]??[Na+(2.2.1-crytand)]₂ for 3 and 7, [(M?)₂Na+(THF)₂]? [Na⊕(2.2.1-cryptand)] for 4 and 7, [M? Na+(diglyme)]₂ for 5, or [M? Na+(l 5-crown-5)] for 6. Structural comparison is based on literature analogies as well as on results of MNDO calculations concerning charge distribution and enthalpies of formation. Taken together, the results demonstrate the delicate energy balance, by which cation solvation can influence the formation of organic salts.