Application of thiophilic chromatography to deplete serum immunoglobulins in sample preparation for bidimensional electrophoresis

Serum is a typical sample for non-invasive studies in clinical research. Its proteome characterization is challenging, since requires extensive protein depletion. Methods used nowadays for removal of high-abundance proteins are expensive or show quite often a low loading capacity, which has strong repercussions on the number of samples and replicates per analysis.In order to deplete immunoglobulins (Igs) and albumin (HSA) from 1 mL serum samples, we have developed a protocol based on a combination of thiophilic chromatography, not previously used in clinical proteomics, and a HSA-specific resin. Ig/HSA-depleted samples, immunoglobulinome and albuminone were analyzed by 2-DE. Thiophilic chromatography, coupled with HSA-depletion, allows a good 2-DE resolution as well as the visualization of new spots. Moreover, it yields enough protein to evaluate technical variability and facilitate subsequent protein identification. To validate the protocol, we carried out a preliminary comparative study between triplicate Igs/HSA-depleted serum samples from healthy control individuals and recently diagnosed/untreated rheumatoid arthritis (RA) patients. RA patients showed several acute phase proteins, as well as additional serum proteins, differentially and significantly regulated.Therefore, thiophilic chromatography can be used as an efficient and economical method in 2-DE to deplete immunoglobulins from large human serum samples before a more extensive fractioning.     

Structural elucidation of new ferulic acid-containing phenolic dimers and trimers isolated from maize bran

Four new phenolic dimers and trimers that contain ferulic acid moieties were isolated from the alkaline hydrolyzate of insoluble maize bran fiber and their structures were established by 1D/2D NMR and mass spectrometry. The biological role of one dimer remains unclear whereas the dimeric vanillin-ferulic acid-cross-product probably represents an oxidative degradation product from the corresponding diferulate. Both ferulic acid dehydrotrimers are able to cross-link polysaccharide chains. However, the 5-5/8-O-4(H₂O)-triferulic acid may be a cross-link in its identified structure whereas we assume that the identified 8-O-4/8-5(non-cyclic)-triferulic acid arose from a natural 8-O-4/8-5(cyclic)-triferulate analog during the saponification process.     

Synthesis of spherical nanoparticles of Cu2L2O5 (L=Ho, Er) from W/O microemulsions

Nanoparticles of Cu₂L₂O₅ (L=Ho, Er) (15–25 nm in size) were synthesised by the intermediate use of W/O microemulsions. In this process the aqueous cores of water/cetyltrimethylammonium bromide/n-octane/1-butanol microemulsions were used as microreactors for the precipitation of Cu₂Ho₂(CO₃)₄(OH)₂ (25–30 nm) and Cu₂Er₂(CO₃)₄(OH)₂ (10–40 nm) as precursors. These mixed salts were separated and further decomposed to the corresponding mixed oxides at 900°C for 16 h. All solids were characterised by scanning and transmission electron microscopy, IR, XRPD, ICP-OES, TGA, XPS measurements and elemental analyses.     

The use of chiral interaction reagents in the separation of D(−)-and L(+)-ascorbic acid by ion interaction reversed-phase HPLC

Summary An HPLC reversed-phase ion interaction reagent method is presented, which makes use of chiral compounds as the interaction reagents. By employing the optical isomeric forms of malic, tartaric and mandelic acids as the interaction reagents, a good separation of D(−) and L(+) ascorbic acid has been achieved. The method has also been applied to the identification of vitamin C in some medical formulations. The separation of te enantiomeric forms of DL malic acid has been attempted and a shor discussion is presented about the elution sequence in chromatographic separation of D- and L-enantiomers.     

An effective method for fast determination of artemisinin in Artemisia annua L. by high performance liquid chromatography with evaporative light scattering detection

Artemisinin isolated from the aerial parts of Artemisia annua L., is a promising and potent antimalarial drug, which meets the dual challenge posed by drug-resistant parasites and rapid progression of malarial illness. The aim of the current study was to develop a reliable and fast analytical procedure for the determination of artemisinin in A. annua using high performance liquid chromatography (HPLC) with evaporative light scattering detection (ELSD) in couple with microwave-assisted extraction (MAE) as an efficient sample preparation technique. The HPLC conditions were Agilent C18 column using water:acetonitrile (40:60 v/v) mixture as mobile phase at a flow rate of 1 mL min⁻¹. ELSD conditions were optimized at nebulizer-gas flow rate of 2.0 L min⁻¹ and drift tube temperature of 70 °C under the impactor off-mode, and the gain was set at 2. Afterwards, method validation system for HPLC-ELSD analysis was developed. Calibration range was 0.2-1.0 mg mL⁻¹ and correlation coefficient r was above 0.9990. Precision experiments showed relative standard deviation (R.S.D.) of retention time was less than 0.5% and R.S.D. of peak area was less than 1.30%. Inter-day and intra-day variabilities showed that R.S.D. was ranged from 1.01% to 4.66%. Limit of detection was less than 40 μg mL⁻¹ and limit of quantification was less than 100 μg mL⁻¹. Accuracy validation showed that average recovery was between 98.23% and 104.97%. The developed analytical procedure was successfully applied to determine the contents of artemisinin in the different parts of A. annua plants.     

L（1, 2）-edge-labelings for lattices

For a graph G and two positive integers j and k, an m-L(j, k)-edge-labeling of G is an assignment on the edges to the set {0, 1, 2,..., m}, such that adjacent edges which receive labels differ at least by j, and edges which are distance two apart receive labels differ at least by kThe λ j,k-number of G is the minimum m such that an m-L(j, k)-edge-labeling is admitted by GIn this article, the L(1, 2)-edge-labeling for the hexagonal lattice, the square lattice and the triangular lattice are studied, and the bounds for λ j,k-numbers of these graphs are obtained.     

Nonlinear Wave Equations in Infinite Waveguides

Abstract

We present sharp decay rates as time tends to infinity for solutions to linear Kleinc-Gordon and wave equations in domains with infinite boundaries like infinite waveguides, as well as the global well-posedness and the asymptotics for small data for the solutions to the associated nonlinear initial-boundary value problems.