Identification of oligosaccharides from histopathological sections by MALDI imaging mass spectrometry

Direct tissue analysis using matrix-assisted laser desorption/ionization (MALDI) mass spectrometry (MS) provides the means for in situ molecular analysis of a wide variety of biomolecules. This technology—known as imaging mass spectrometry (IMS)—allows the measurement of biomolecules in their native biological environments without the need for target-specific reagents such as antibodies. In this study, we applied the IMS technique to formalin-fixed paraffin-embedded samples to identify a substance(s) responsible for the intestinal obstruction caused by an unidentified foreign body. In advance of IMS analysis, some pretreatments were applied. After the deparaffinization of sections, samples were subjected to enzyme digestion. The sections co-crystallized with matrix were desorbed and ionized by a laser pulse with scanning. A combination of α-amylase digestion and the 2,5-dihydroxybenzoic acid matrix gave the best mass spectrum. With the IMS Convolution software which we developed, we could automatically extract meaningful signals from the IMS datasets. The representative peak values were m/z 1,013, 1,175, 1,337, 1,499, 1,661, 1,823, and 1,985. Thus, it was revealed that the material was polymer with a 162-Da unit size, calculated from the even intervals. In comparison with the mass spectra of the histopathological specimen and authentic materials, the main component coincided with amylopectin rather than amylose. Tandem MS analysis proved that the main components were oligosaccharides. Finally, we confirmed the identification of amylopectin by staining with periodic acid-Schiff and iodine. These results for the first time show the advantages of MALDI-IMS in combination with enzyme digestion for the direct analysis of oligosaccharides as a major component of histopathological samples.     

Subject Index to Volume 33

This paper reports the investigation of microdroplet sample preparation for phosphate, strontium and rubidium using X-ray fluorescence. Sample filter papers were prepared by drying under several different conditions and the front and the back sides of the filter papers were measured using X-ray fluorescence (XRF), scanning electron microscopy (SEM), X-ray diffraction (XRD), and electron-probe microanalysis (EPMA).

It was reported by Murata and Murokado that the elemental distribution difference between the front and the back sides after drying the filter paper led to erratic data.¹ It has been found that the intensity difference between the front and the back sides was due to the condensation of the material of interest on the surface of the filter papers and the amount of the condensed material on the filter paper was related to the temperature at which the filter paper was dried.

Optimum temperature at which a filter paper is dried and an appropriate internal standard are essential to reproducible measurements.     

Reductive carboxylation of alkyl halides with CO2 by use of photoinduced SmI2/Sm reduction system

Upon visible-light irradiation, reductive carboxylation of alkyl halides takes place by using a SmI₂/Sm mixed system under atmospheric CO₂ to afford the corresponding carboxylic acids in good to excellent yields.     

Characterization of NIES CRM No. 23 Tea Leaves II for the determination of multielements

A candidate environmental certified reference material (CRM) for the determination of multielements in tea leaves and materials of similar matrix, NIES CRM No. 23 Tea Leaves II, has been developed and characterized by the National Institute for Environmental Studies (NIES), Japan. The origin of the material was tea leaves, which were ground, sieved through a 106-μm mesh, homogenized, and then subdivided into amber glass bottles. The results of homogeneity and stability tests indicated that the material was sufficiently homogeneous and stable for use as a reference material. The property values of the material were statistically determined based on chemical analyses by a network of laboratories using a wide range of methods. Sixteen laboratories participated in the characterization, and nine certified values and five reference values were obtained. These property values of the candidate CRM, which are expressed as mass fractions, were close to the median and/or mean values of the mass fractions of elements in various tea products. The candidate CRM is appropriate for use in analytical quality control and in the evaluation of methods used in the analysis of tea and materials of similar matrix.     

Hydrodynamic limit for the Ginzburg–Landau ∇ϕ interface model with non-convex potential

The hydrodynamic limit of the Ginzburg–Landau $??$ interface model was derived in Funaki and Spohn (1997) and Nishikawa (2003) for strictly convex potentials. This paper deals with non-convex potentials under suitable assumptions on the free energy and identification of the extremal Gibbs measures which have been recently established at sufficiently high temperature in Cotar and Deuschel (2012). Because of the non-convexity, many difficulties arise, especially, on the identification of equilibrium states. We show the equivalence between the stationarity and the Gibbs property under quite general settings, and we complete the identification of equilibrium states. We also establish some uniform estimates for variances of extremal Gibbs measures.     

Non-classical control of solid-state aggregation-induced enhanced circularly polarized luminescence in chiral perylene diimides

Organic fluorescent molecules are gaining importance because of their potential applications in many devices. Optically active N,N′-bis((1R)-1-naphthylethyl)perylene-3,4,9,10-tetracarboxylic diimide [(R,R)-1-BNP] and N,N′-bis((1R)-2-naphthylethyl)perylene-3,4,9,10-tetracarboxylic diimide [(R,R)-2-BNP] and their antipode, [(S,S)-1-BNP and (S,S)-2-BNP], emit aggregation-induced enhanced (AIEnh) circularly polarized luminescence (CPL) on both a solid organic polymer film (poly(methyl methacrylate)) and solid inorganic KBr pellet. An opposite chirality is essential for generating CPL of inverted sign. However, a pair of enantiomeric organic molecules may not always be easy to prepare. Interestingly, the chiral perylene fluorophores synthesized in this study can emit both positive and negative AIEnh-CPL in the solid state, depending on their position on the naphthylene groups. In addition, no CPL was observed in these compounds from their dilute solutions.     

Alternate field evaporation by changing laser pulsing and voltage pulsing dynamically for atom probe analysis

Time-of-flight mass analysis in atom-by-atom scale is performed in atom probe (AP) by pulsed field evaporation of sample material. The pulsed field evaporation is triggered by superposing voltage pulse or shooting laser pulse together with stationary voltage for evaporation field. Voltage pulse which has been used from the establishment of AP in the 1960s is going to be replaced by short pulsed laser with high repetition rate in the nanometer scale characterization of materials by 3-dimensional AP. The criterion for choosing appropriate trigger method is not clear because it is difficult to compare the result of 2 triggering method applied on the same sample in atomic scale. The precise comparison of 2 triggering method was enabled by applying voltage pulse and laser pulse alternately to the identical sample. The results of composition and spatial information reflected the mechanism of assisting field evaporation. But the evaporation order was almost random or disordered showing no correlation between 2 triggering method. To make clear the correlation between voltage pulsing and laser pulsing, the authors report their new system forcing alternate evaporation switching to the other trigger after the detection of ion in 1 trigger between voltage and laser.     

A Pyrene-Modified Serinol Nucleic Acid Nanostructure Converts the Chirality of Threoninol Nucleic Acids into Circularly Polarized Luminescence Signals

Herein is reported a circularly polarized luminescent (CPL) probe that can respond to the chirality of nucleic acids. An achiral nanostructure was prepared by the hybridization of symmetric serinol nucleic acid (SNA) containing pyrene-modified residues. When chiral oligomers that were complementary to the SNA were added, they induced helicity into the SNA nanowire. Efficient circular dichroism (CD) signal amplification was observed when pyrene was attached to uracil bases through a rigid alkynyl linker. Both CPL and CD signals were observed; they depended on the chirality of the added acyclic threoninol nucleic acid (aTNA) oligomer. This system can be used to convert the chirality of chiral biomolecules into chiroptical signals.     

Asymptotics toward the planar rarefaction wave for viscous conservation law in two space dimensions

This paper is concerned with the asymptotic behavior of the solution toward the planar rarefaction wave connecting and for the scalar viscous conservation law in two space dimensions. We assume that the initial data tends to constant states as , respectively. Then, the convergence rate to of the solution is investigated without the smallness conditions of and the initial disturbance. The proof is given by elementary -energy method.

     

New approach to axial coupling constants in the QCD sum rule

We derive new QCD sum rules for the axial coupling constants by considering the correlation functions of axial-vector currents in a one-nucleon state. The QCD sum rules tell us that the axial coupling constants are expressed by nucleon matrix elements of quark-gluon composite operators which are related to the sigma terms and the moments of parton distributions. The results for the isovector axial coupling constants and the eighth component of the SU(3)(f) octet are in good agreement with experiment.