Capillary high-performance liquid chromatography-electrospray ionization mass spectrometry using monolithic columns and carbon fiber electrospray ionization emitters

Monolithic columns having long hydrocarbon chains were prepared by in-situ polymerization in capillary fused silica tubing. The capillary columns were coupled with a newly developed carbon fiber electrospray ionization (ESI) emitter for proteomic analysis using sheathless capillary HPLC-ESI mass spectrometry (MS). The sample loading capacity and chromatographic performance of the styrene-based monolithic column, which was prepared by photo-polymerization of octylstyrene (OS) and divinylbenzene (DVB) were compared with that of the methacrylate-based monolithic column composed of lauryl methacrylate (LMA) and ethylene dimethacrylate (EDMA). The sample loading ability of tryptic digested protein in poly-OS (POS)-DVB column was higher than that of poly-LMA (PLMA)-EDMA column, possibly due to the irregular and rugluous surface offering a greater surface area of POS-DVB stationary phase. The POS-DVB column also provided better separation efficiency in the separation of high concentration (10 microg) of tryptic digested albumin bovine serum (BSA). Due to the successful interface of a highly efficient monolithic column and a stable, durable carbon fiber emitter, low femtomole levels of peptides were successfully separated and identified in the presence of large amounts of tryptic digested protein.     

Extraction chromatographic separation of iron from complex liquid samples and the determination of <Superscript>55</Superscript>Fe

Summary Iron separation is described from liquid samples with a high concentration of ions that enables simple determination of ⁵⁵Fe. One of the described methods consists of iron precipitation from a large volume seawater by sodium hydroxide and/or ammonium carbonate and separation from other elements (Ca, Sr, Cu, Mg, etc.) on a TRU column with 4M HCl or 8M HNO₃. In the other procedure iron is separated directly from a mixture of seawater samples and HCl on a TRU column. In both methods, the iron recovery is almost 100%. After separation, ⁵⁵Fe is determined by counting with a liquid scintillation counter. The binding of Fe and Zn on TEVA, U/TEVA and TRU resins from seawater solutions of HCl and HNO₃depends on the type of the resin, concentration of acid and other ions. Iron and zinc can be separated from seawater on a U/TEVA column with 2M HCl.     

Identification of a new naphthalene and its derivatives from the bulb of eleutherine americana with inhibitory activity on lipopolysaccharide-induced nitric oxide production

A new naphthoquinone, (-)-3-[2-(acetyloxy)propyl]-2-hydroxy-8-methoxy-1,4-naphthoquinone (1) was isolated from the bulb of Eleutherine americana MERR. et HEYNE (Iridaceae) together with two known compounds, eleutherinol (6) and 1,5-dihydroxy-3-methylanthraquinone (7) which were found in this species for the first time. The other known compounds, (-)-isoeleutherin (2), (+)-eleutherin (3), (-)-hongconin (4), and (+)-dihydroeleutherinol (5) which were reported previously from this species, were also isolated in the present study. Compounds 2-6 exhibited potent inhibitory activity on nitric oxide production in RAW 264.7 lipopolysaccharide-activated mouse macrophage cells with IC(50) values of 7.7, 11.4, 19.8, 21.7, and 34.4 microM, respectively, whereas the other two compounds, 1 and 7, were inactive. The structure of compound 1 was elucidated by spectroscopic data analysis including 1D and 2D NMR experiments.     

μSR study of internal magnetic fields in superconducting La1.9Sr0.1CuO4 in the mK region

Muon-spin-rotation (μSR) experiments were performed on superconducting La_1.90Sr_0.10CuO₄ in zero external field. Below 2 K, a fast depolarization of the muon signal is observed, indicating that internal magnetic fields are present at the muon site. The average magnitude of the magnetic field in La_1.90Sr_0.10CuO₄ is in the order of 3 mT and thus approximately 14 times smaller than the corresponding field in antiferromagnetic La₂CuO₄. The present data support theoretical models of superconductivity in which magnetic correlations are responsible for pairing.     

Study on the electrodeposition of organic and inorganic thermoelectric materials for composite preparation

We report on the cathodic synthesis of bismuth telluride. X-ray diffraction results proved successful preparation, while elementary analysis indicated a tellurium rich compound. Cyclic voltammetric measurements outlined the kinetic pattern. The organic thermoelectric materials (thiophene-type conducting polymers) were characterized by in situ spectral and conductance techniques.     

Ergodic theorem for infinite iterated function systems

1IntroductionandProblem IteratedFunctionSystems(IFS)theorycanbesaidtobethecontinuationanddevelopment ofdynamicalsystemtheory.DynamicalsystemstheorydealswithiterationofonemapbutIFS theorydealswithiterationofmanymaps. IFStheory’srootwasveryearlybutthebeginningofactivedevelopmentwasHutchinson’s paper(1981).Heresearchedselfsimilarityoffractalsetsusingsystemoffinitenumberofsimilar contractionmapsofRn.Barnsleycalledafinitesetofcontractionmappsasaniteratedfunction systemsandsystemizedIFStheo…     

Spin transition in heptanuclear star-shaped iron(III)–antimony(V) NCS- and CN-bridged compounds

The precursor [Fe^III(L)Cl] (LH₂ = N,N′-bis(2′-hydroxy-benzyliden)-1,6-diamino-3-azahexane) has been prepared and Mössbauer spectroscopy assigned a high-spin (S = 5/2) state at room temperature. The precursor is combined with the bridging units [Sb^V(X)₆]^? (X = CN^?, NCS^?) to yield star-shaped heptanuclear clusters [(LFe^III–X)₆Sb^V]Cl₅. The star-shaped compounds are in general high-spin systems at room temperature. On cooling to 20 K some of the iron(III) centers switch to the low-spin state as indicated by Mössbauer spectroscopy, i.e. multiple electronic transitions. While the cyano-bridged complex performs a multiple spin transition the thiocyanate-compound shows no significant population at both temperatures.