Synthesis of hydrophobic phase-tagged prolyl peptides featuring rapid reaction/separation

Hydrophobically tagged prolyl peptides were synthesized using an electrochemically modified prolyl moiety. The hydrophobic tag served a useful handle for the repetitive reaction/separation steps during solution-phase peptide synthesis. Furthermore, the tag was also effective as an anchor on solid phases for the evaluation of activity of immobilized peptides.     

Improvement in reliability of probabilistic test of significant differences in GeneChip experiments.

A probabilistic test (FUMI theory) for GeneChip experiments has been proposed for selecting the genes which show significant differences in the gene expression levels between a single pair of treatment and control. This paper describes that the reliability of the judgment by the FUMI theory can be enhanced, when the selected genes are referred to biomolecular-functional networks of a commercial database. The genes judged as being differently expressed are grouped into a cluster in the biomolecular networks. It is also demonstrated that false positive genes have a trend in the networks to be isolated from each other, and also away from the clustered genes, since the false positive genes are randomly selected.     

Convergence of finite dimensional distributions of heat kernel measures on loop groups

In this paper we consider heat kernel measure on loop groups associated to the H^1/2-metric. Unlike H^s-case (s>1/2), there is a difficulty that H^1/2 is not contained in the space of continuous loops. So we take limits. There are two limiting methods. One is to use delta functions and to let s go down to 1/2. The other is to fix s at 1/2 and to approximate the delta functions. For the second approach, a generalization of heat kernel measures is needed. Then, the first approach can be obtained as a special case of the second one. The limit in the sense of finite dimensional distribution is the fictitious infinite dimensional Haar measure.     

Synthesis and Structures of Yb4Rh7Ge6 and Yb4Ir7Ge6

Larger single crystals of Yb₄Rh₇Ge₆ and Yb₄Ir₇Ge₆ were prepared from arc‐melted precursor alloys Rh₇Ge₆ and Ir₇Ge₆ and elemental ytterbium via the Bridgman method using tungsten crucibles. Yb₄Rh₇Ge₆ and Yb₄Ir₇Ge₆ were investigated by X‐ray diffraction on powders and single crystals. Both germanides crystallize with the cubic U₄Re₇Si₆ type structure, space group Im3m. Structure refinement from X‐ray single crystal diffractometer data yielded a = 825.3(1) pm, wR2 = 0.0292, 106 F² values, 10 variable parameters for Yb₄Rh₇Ge₆ and a = 826.6(2) pm, wR2 = 0.0486, 150 F² values, 10 variable parameters for Yb₄Ir₇Ge₆. The structures contain two crystallographically independent transition metal (T) atoms with octahedral (T1) and tetrahedral (T2) germanium coordination. The octahedra and tetrahedra are condensed via common corners and edges forming complex three‐dimensional [T₇Ge₆] networks in which the trivalent ytterbium atoms fill voids of coordination number 14.     

An electrochemical on-field sensor system for the detection of compost maturity

A maturity sensor system was developed, based on the combination of three electrically measured parameters, pH, NH₄⁺ concentration, and phosphatase activity in the water extracts of compost samples. One of these parameters, the apparent phosphatase activity in crude test solutions was determined using screen-printed carbon strips (SPCSs) coated with α-naphthyl phosphate (α-NP) in Nafion film. The phosphatase activity was monitored in connection with differential pulse voltammetry (DPV) with an aliquot (30 μL) of the test solution on SPCS. The phosphatase activity sensor was validated using alkaline phosphatase (ALP) in Tris-HCl buffer (pH 8.0) and acid phosphatase (ACP) in citric acid buffer (pH 5.0). The activity of the spiked enzymes in the water extract of the compost sample could be confirmed with the change of corresponding oxidation peak current signal of the product, α-naphthol. The water extracts of compost samples (n = 24) collected in various composting days were applied to our compost maturity sensor system, and the conventional germination tests. Using multiple regression analysis, the germination index (GI) was expressed by the multi-linear regression equation consisting of pH, NH₄⁺ concentration, and the phosphatase activity. The calculated GI from the regression equation had a good correlation with the measured GI of the corresponding composts (r = 0.873). As a result, we have determined an equation for the determination of the compost stability using our portable sensor system rapidly at the composting site.     

Simple enrichment of thiol‐containing biomolecules by using zinc(II)–cyclen‐functionalized magnetic beads

A simple and efficient method based on magnetic‐bead technology has been developed for the enrichment of thiol‐containing biomolecules, such as l ‐glutathione and cysteine‐containing peptides. The thiol‐binding site on the bead is a mononuclear complex of zinc(II) with 1,4,7,10‐tetraazacyclododecane (cyclen); this is linked to a hydrophilic cross‐linked agarose coating on a particle that has a magnetic core. All steps for the thiol‐affinity separation are conducted in aqueous buffers with 0.10 mL of the magnetic beads in a 1.5 mL microtube. The entire separation protocol for thiol‐containing compounds, from addition to elution, requires less than one hour per sample, provided the buffers and the zinc(II)–cyclen‐functionalized magnetic beads have been prepared in advance. The thiol‐affinity magnetic beads are reusable at least 15 times without a decrease in their thiol‐binding ability, and they are stable for six months at room temperature.     

Laser ablation of toluene liquid for surface micro-structuring of silica glass

Microstructures with well-defined micropatterns were fabricated on the surfaces of silica glass using a laser-induced backside wet etching (LIBWE) method by diode-pumped solid state (DPSS) UV laser at the repetition rate of 10 kHz. For a demonstration of flexible rapid prototyping as mask-less exposure system, the focused laser beam was directed to the sample by galvanometer-based point scanning system. Additionally, a diagnostics study of plume propagation in the ablated products of toluene solid film was carried out with an intensified CCD (ICCD) camera.     

Reinvestigation of microwave spectrum of dimethyl ether and rs structures of analogous molecules

Microwave spectra of dimethyl ether and its sixteen isotopic species have been measured. For species with singlet spectra, a least-squares analysis of observed transition frequencies gave rotational and five quartic centrifugal distortion constants. For species with multiplet spectra due to the methyl internal rotation, a least-squares analysis of observed multiplet frequencies gave not only unperturbed rotational and five quartic centrifugal distortion constants but also the quantities related to the methyl internal rotation. The r_s structures from (CH₃)₂O, CH₃OCD₃, and (CD₃)₂O species as the parent species, respectively, were compared with one another. The proposed r_s structure has been established from all the species measured and was compared with the r_s-like structure obtained by a diagnostic least-squares method and with the reported structure. The r_s structure of the present molecule was compared with the reported structures of dimethyl sulfide and dimethyl silane in relation to the tilt phenomenon. The r_s structure of dimethyl sulfide was revised based on the present comparison.