Inner-shell ionizations and satellites studied by the open-shell reference symmetry-adapted cluster/symmetry-adapted cluster configuration-interaction method

Open-shell reference version of the symmetry-adapted cluster (SAC) and SAC-configuration-interaction (CI) methods, termed open-shell reference (OR)-SAC and OR-SAC-CI methods, are developed and applied to inner-shell ionizations of CH4, NH3, H2O, and HF. The inner-shell ionization potentials and spectra calculated by the OR-SAC and OR-SAC-CI methods are in excellent agreement with the experimental data. Including both of the electron correlation and orbital relaxation is important for quantitative agreements. Timing comparisons with the SAC-CI general-R calculations that give similar high accuracies show an efficiency of the present OR-SAC and OR-SAC-CI methods.     

Fluorescence imaging of potassium ions in living cells using a fluorescent probe based on a thrombin binding aptamer-peptide conjugate

When a biotinylated FRET probe based on a peptide-thrombin binding aptamer conjugate was introduced together with streptavidin and biotinylated nuclear export signal peptide into HeLa cells, the resulting ternary complex enabled visualization of K(+) concentration changes in the cell.     

Multiple-output logic element based on an optical interference system

A multiple-output logic element using an optical interference system is proposed. The system acts as a logic gate array operating in parallel at certain positions divided over one period of the output fringe. A photoinduced refractive-index change material is incorporated in the system to perform the optical transformation of optical inputs into the phase change of a readout beam. It is shown that the logic gates obtained can be controlled arbitrarily in number and sorts by adjusting either the shift or the division of the output fringe. As an example, logic gates of AND, OR, NAND, NOR are implemented in parallel in the preliminary experiments.     

Biomimetic reactions of some macrocyclic diterpenes

Some macrocyclic diterpenes derived from euphohelioscopin A and euphornin have been stereoselectively converted into the jatropholane- and daphnane-type compounds and the known tricyclic compound which has been treated with phCOCl - pyridine to afford euphohelionone, the new type of diterpene isolated from euphorbia helioscopia L.     

A Method of Orthogonal Oligosaccharide Synthesis Leading to a Combinatorial Library Based on Stationary Solid‐Phase Reaction

A new, efficient synthesis of oligosaccharides, which involves solid‐phase reactions without mixing in combination with an orthogonal‐glycosylation strategy, is described. Despite a great deal of biological interest, the combinatorial chemistry of oligosaccharides is an extremely difficult subject. The problems include 1) lengthy synthetic protocols required for the synthesis and 2) the variety of glycosylation conditions necessary for individual reactions. These issues were addressed and solved by using the orthogonal‐coupling protocol and the application of a temperature gradient to provide appropriate conditions for individual reactions. Furthermore, we succeeded in carrying out solid‐phase reactions with neither mechanical mixing nor flow. In this report, the synthesis of a series of trisaccharides, namely, α/β‐L ‐Fuc‐(1→6)‐α/β‐D ‐Gal‐(1→2/3/4/6)‐α/β‐D ‐Glc‐octyl, is reported to demonstrate the eligibility of the synthetic method in combinatorial chemistry.     

Generation of an abasic site in an oligonucleotide by using acid-labile 1-deaza-2'-deoxyguanosine and its application to postsynthetic modification

We developed a new convenient method for generation of an abasic site at the 3'-terminus of an oligonucleotide. This method uses a 1-deaza-2'-deoxyguanosine residue, which easily undergoes depurination under acidic conditions. The abasic site of the oligonucleotide can be further modified with external functional groups. We report herein the chemical stability of 1-deaza-2'-deoxyguanosine in the oligodeoxynucleotide and the application to the postsynthetic modification of an oligonucleotide by utilizing the chemical property of 1-deaza-2'-deoxyguanosine. [Structure: see text]     

Cascade ultrafiltering of 210Pb and 210Po in freshwater using a tangential flow filtering system</p> </p>

Summary A rapid method was developed using ultrafilters with a tangential flow filtering system for molecular size separation of naturally occurring ²¹⁰Pb and ²¹⁰Po in a freshwater sample. Generally, ultrafiltering of a large volume water sample for measuring the nuclides was too time consuming and not practical. The tangential flow filtering system made the filtering time short enough to adapt for in-situ ultrafiltering the large volume sample. In this method, a 20 liter water sample was at first passed through the 0.45mm pore size membrane filter immediately after sample collection to obtain suspended particle matter [>0.45mm particulate fraction (PRT)]. Two ultrafilters (Millipore Pellicon 2^ò) were used sequentially. The nuclides in the filtrate were separated into three fractions: high molecular mass (100 kDa-0.45mm; HMM), low molecular mass (10 k-100 kDa; LMM) and ionic (<10 kDa; INC) fractions. It took 80 minutes to process the sample after collection. The cut-off molecular size of each ultrafilter was confirmed by size exclusion chromatographs (SEC) of the LMN and the HMM fractions. Adsorption of the nuclides and organic compounds in the sample onto the ultrafilters was negligibly small. Good reproducibility of the nuclide concentrations in each fraction was confirmed by repeated experiments. The method was successfully applied to obtaine the molecular size distributions of ²¹⁰Pb and ²¹⁰Po in an oligotrophic lake, Lake Towada located in the northern area of Japan.</p> </p>     

On‐target separation of analyte with 3‐aminoquinoline/α‐cyano‐4‐hydroxycinnamic acid liquid matrix for matrix‐assisted laser desorption/ionization mass spectrometry

3‐Aminoquinoline/α‐cyano‐4‐hydroxycinnamic acid (3AQ/CHCA) is a liquid matrix (LM), which was reported by Kumar et al. in 1996 for matrix‐assisted laser desorption/ionization (MALDI) mass spectrometry. It is a viscous liquid and has some advantages of durability of ion generation by a self‐healing surface and quantitative performance. In this study, we found a novel aspect of 3AQ/CHCA as a MALDI matrix, which converges hydrophilic material into the center of the droplet of analyte‐3AQ/CHCA mixture on a MALDI sample target well during the process of evaporation of water derived from analyte solvent. This feature made it possible to separate not only the buffer components, but also the peptides and oligosaccharides from one another within 3AQ/CHCA. The MALDI imaging analyses of the analyte‐3AQ/CHCA droplet indicated that the oligosaccharides and the peptides were distributed in the center and in the whole area around the center of 3AQ/CHCA, respectively. This 'on‐target separation' effect was also applicable to glycoprotein digests such as ribonuclease B. These features of 3AQ/CHCA liquid matrix eliminate the requirement for pretreatment, and reduce sample handling losses thus resulting in the improvement of throughput and sensitivity. Copyright © 2012 John Wiley & Sons, Ltd.     

Stereospecific synthesis of dinucleoside monophosphate aryl esters by using new condensing reagents

Abstract

New condensing reagents, arenesulfonyl 5-(pyridin-2-yl)tetrazoles have been synthesized and used for stereospecific synthesis of dinucleoside monophosphate aryl esters.