Determination of creatinine in human serum by short-end injection capillary zone electrophoresis

A new ultra-rapid free-solution capillary zone electrophoresis method to measure serum creatinine is presented. Procedural parameters such as injection mode, concentration and pH of phosphate running buffer and acidic deproteinization of serum samples were investigated. Short-end injection permits a decrease of the analysis time by injecting samples at the outlet end of a silica capillary closest to the detection window, so reducing the migration distance. Thus, when a capillary with an effective length of 10.2 cm and a 40 mmol/L sodium phosphate buffer pH 2.35 was used, the obtained migration time of the creatinine peak was the shortest never described before, about 1.1 min. These conditions give a good reproducibility of the migration times (coefficient of variation, CV% < 0.5) and the peak areas (CV% < 2.8). Intra- and interassay CV were 3.06 and 6.26%, respectively, and analytical recovery was 99.4%. We compared our proposed method to Jaffé colorimetric assay, by measuring serum creatinine in 128 normal subjects. The obtained data were analyzed by the Passing and Bablok regression and Bland-Altman test. Creatinine concentration in healthy subjects was also used to investigate on its relationships with plasma thiols levels.     

Volatile Constituents of Achillea ligustica All. by HS-SPME/GC/GC-MS. Comparison with Essential Oils Obtained by Hydrodistillation from Corsica and Sardinia

The volatile components extracted from the headspace (HS) of Achillea ligustica All. samples and their separated organs using solid phase microextraction (SPME) were investigated by gas chromatography and gas chromatography-mass spectrometry. Fiftyseven compounds were identified, the main components were camphor (14.2–29.8%), artemisia ketone (0.3–26.7%), santolina alcohol (0.5–9.4%), camphene (3.0–9.0%) and trans-sabinyl acetate (1.6–5.5%). Moreover, the chemical composition of Corsican and Sardinian A. ligustica oils obtained from flowers and leafy stems harvested in four regions of both islands, were investigated. Two collective oils of A. ligustica were also investigated, comparison between both oils as well as from data literature were reported. A comparison of hydrodistillation and HS-SPME extraction of volatile components in term of isolation time, plant-consuming and chemical composition was discussed. HS-SPME technique was clearly fast in contrast to hydrodistillation (90 min/300 min). HS extraction was performed with a much smaller amount of plant than hydrodistillation. Although the aromatic profiles of HS-fractions and oils showed several quantitative differences HS-SPME can be applied to routine control analysis of aromatic and medicinal plants.

     

J/psi production in Indium-Indium collisions at 158 GeV/nucleon

The NA60 experiment studies muon pair production at the CERN Super Proton Synchrotron. In this Letter we report on a precision measurement of J/psi in In-In collisions. We have studied the J/psi centrality distribution, and we have compared it with the one expected if absorption in cold nuclear matter were the only active suppression mechanism. For collisions involving more than approximately 80 participant nucleons, we find that an extra suppression is present. This result is in qualitative agreement with previous Pb-Pb measurements by the NA50 experiment, but no theoretical explanation is presently able to coherently describe both results.     

φ production in In–In collisions at 158 A GeV

The NA60 experiment has measured muon pair production in In–In collisions at 158 AGeV at the CERN SPS. This paper presents a high statistics measurement of φ→μ μ meson production. Differential spectra, yields, mass and width are measured as a function of centrality and compared to previous measurements in other colliding systems at the same energy. The width of the rapidity distribution is found to be constant as a function of centrality, compatible with previous results. The decay muon polar angle distribution is measured in several reference frames. No evidence of polarization is found as a function of transverse momentum and centrality. The analysis of the p _T spectra shows that the φ has a small radial flow, implying a weak coupling to the medium. The T _eff parameter measured in In–In collisions suggests that the high value observed in Pb–Pb in the kaon channel is difficult to reconcile with radial flow alone. The absolute yield is compared to results in Pb–Pb collisions: though significantly smaller than measured by NA50 in the muon channel, it is found to exceed the NA49 and CERES data in the kaon channel at any centrality. The mass and width are found to be compatible with the PDG values at any centrality and at any p _T : no evidence for in-medium modifications is observed.     

DFT and multinuclear magnetic resonance studies of diazenedicarboxylates and related compounds

A number of diazenedicarboxylates have been studied by multinuclear magnetic resonance ((17)O, (15)N, (13)C) and compared with analogous fumaric, maleic, and phthalic diesters; the investigation of selected compounds of these classes was complemented by density functional theory (DFT) calculations using a polarizable continuum model (PCM) for the solvent, employing the PBE0 functional together with the 6-311G(d,p) basis set for geometry optimization, and the 6-311 + G(2d,p) basis set for calculating the NMR shielding using the gauge-including atomic orbital (GIAO) method. This combined approach provided important information about the preferred conformations in chloroform and their influence on the NMR parameters.     

A new HPLC method for serum neopterin measurement and relationships with plasma thiols levels in healthy subjects

Neopterin, a pyrazinopyrimidine compound, serves as a marker of cellular immune system activation, and it can be used as a prognostic predictor for certain types of diseases. We propose a new simple HPLC method to measure serum neopterin with highly sensitive fluorimetric detection. After TCA serum protein precipitation, the supernatant was diluted five times, injected into a C18 reversed-phase column and eluted at a flow rate of 1.5 mL/min by an isocratic water-acetonitrile (99:1) mobile phase. The natural fluorescence of the molecule was detected at excitation wavelength 353 nm and emission 438 nm. In these conditions the neopterin retention time was about 4 min. Our proposed method was compared with a validated chromatographic separation, and the obtained data of the serum neopterin from 35 healthy volunteers were analysed by Passing-Bablok regression and Bland-Altman test. Neopterin measurement in healthy subjects was also employed to investigate on its potential relationships with plasma thiols levels.     

High yield synthesis of 4H‐1,4‐benzothiazine‐1,1‐dioxide derivatives

4H‐1,4‐Benzothiazine‐1,1‐dioxide derivatives were synthesized through a sequence of almost quantitative reactions. The commercial starting material 2‐(methylsulfanyl)aniline was Boc‐protected, N‐acylated and oxidized at the sulfur atom to obtain a sulfonyl derivative. An anionic transposition of the acyl group followed by asimultaneous deprotection‐cyclization gave the title products in excellent yields. All products and intermediates were fully characterized.