Medium range order and optical properties of As2S3 glass

Low frequency Raman scattering and optical absorption edge were measured for As₂S₃ glasses quenched at temperature in the supercooling region of the glasses. It was found that both the Raman spectrum and the optical absorption edge shift to the lower energy side with the rise of the quenching temperature. The effects were interpreted in terms of the order of the arrangements of the layer-like clusters, which become more random as the quenching temperature goes higher.     

Carbohydrate-appended curdlans as a new family of glycoclusters with binding properties both for a polynucleotide and lectins

Beta-1,3-glucans having carbohydrate-appendages (alpha-D-mannoside, N-acetyl-beta-D-glucosaminide and beta-lactoside) at the C6-position of every repeating unit can be readily prepared from curdlan (a linear beta-1,3-glucan) through regioselective bromination/azidation to afford 6-azido-6-deoxycurdlan followed by chemo-selective Cu(i)-catalyzed [3 + 2]-cycloaddition with various carbohydrate modules having a terminal alkyne. The resultant carbohydrate-appended curdlans can interact with polycytosine to form stable macromolecular complexes consistent with two polysaccharide strands and one polycytosine strand. Furthermore, these macromolecular complexes show strong and specific affinity toward carbohydrate-binding proteins (lectins). Therefore, one can utilize these carbohydrate-appended curdlans as a new family of glycoclusters.     

Hydrogen generation from weak acids: electrochemical and computational studies of a diiron hydrogenase mimic

Extended investigation of electrocatalytic generation of dihydrogen using [(mu-1,2-benzenedithiolato)][Fe(CO)3]2 has revealed that weak acids, such as acetic acid, can be used. The catalytic reduction producing dihydrogen occurs at approximately -2 V for several carboxylic acids and phenols resulting in overpotentials of only -0.44 to -0.71 V depending on the weak acid used. This unusual catalytic reduction occurs at a potential at which the starting material, in the absence of a proton source, does not show a reduction peak. The mechanism for this process and structures for the intermediates have been discerned by electrochemical and computational analysis. These studies reveal that the catalyst is the monoanion of the starting material and an ECEC mechanism occurs.     

Relocation of active acetylcholinesterase to liposome-gel conjugate

Relocation of a glycosylphosphatidylinositol (GPI)-anchored protein acetylcholinesterase (AChE) in its enzymatically active form from proteovesicles containing human erythrocyte ghost membrane proteins onto a liposome-gel conjugate was examined. Liposomes of 1,2-dimyristoylphosphatidylcholine (DMPC) were immobilized on Sephacryl S-1000 gel that was chemically modified to bear hydrophobic octyl moieties. Upon coincubation of the liposome-gel conjugate with freely suspended proteovesicles prepared from erythrocyte ghosts, 50% of the AChE left the proteovesicles and immobilized onto the liposome-gel conjugate in 18 h. When the proteovesicles were immobilized and interacted with freely suspended plain liposomes, approximately 2% of the AChE appeared in the liposome fraction. The relocation of AChE apparently possesses strong preference for the liposome-gel conjugate, suggesting that the hydrophobic moieties on the gel could assist the relocation.     

Single Nucleotide Polymorphism Typing with a Surface Plasmon Resonance-Based Sensor Using Hybridization Enhancement Blockers

We constructed a simple method for discrimination of single nucleotide polymorphism (SNP) with a surface plasmon resonance (SPR)-based sensor by determining the binding volume (BV) between a target SNP allele and a probe complementary to the target. In the method, a novel additive termed “blocker,” which is a short single-stranded DNA complementary to the target, was used. The blocker enhanced the BV of the target only to the full-match probe 10-fold or more, so the SNP alleles could be discriminated readily. The effect of the blocker concentration was also examined. The BV to only a full-match probe increased with increasing the blocker concentration and reached a plateau at the concentration of 300–500 nM. To assess the effectiveness of this method, the SNP associated with progressive rod-cone degeneration in dog was determined. The results of genotyping with the method were in good agreement with those obtained by direct sequencing.     

Clinical evaluation of immunoglobulin-E radioimmunoassay kit

An IgE RIA kit (Sandwich method; Dainabott), is used to obtain the following results. (1) Standard curve: Since the range of reproduction rate show 3.16-7.07% (C.V.), the curve become steep. (2) Incubations under controlled situation: Both of the incubations are controlled at 15-30 degrees C for 2 h. (3) Reproducibility test: Coefficients of variation (C.V.) of intra-assay and inter-assay variation are 2.32-3.94% and 2.92-3.92% respectively. (4) Recovery test: A result of the recovery test range between 100.1-101.7%. (5) Dilution test: Multiple dilution effects are observed. (6) Average counts of the serum IgE for the controlled and diseased groups: The average counts of the serum IgE for the controlled group, atopic diseased group, allergic rhinitis group and allergic bronchial asthma are 144.9 +/- 183.2 IU/ml, 1,099.0 +/- 2,782.4 IU/ml, 1,150.9 +/- 2,063.3 IU/ml and 600.7 +/- 686.4 IU/ml respectively. The value of the diseased groups have tendency to show higher averages than the controlled group. Since the controlled and diseased groups show wide distributions of the serum IgE level, there is no significant difference of two variations. However the diseased groups have tendency to show higher ratio of the serum IgE level in blood than the controlled groups. These basic researches are quite meaningful, because they are able to apply for a supplemental diagnosis of the atopic and parasitic disease.     

Exact diagonalization studies on two-band minimal model for iron-based superconductors

In order to explore a superconducting mechanism on iron-based superconductors, we numerically study a two-band minimal model considering two degenerate d_xz and d_yz orbitals on Fe atom. We perform exact diagonalization on a two-band and two-leg square ladder totally composed of 10 lattice sites, which is computationally equivalent to 4-leg 20-sites square-Hubbard-ladder. Consequently, we find that a robust pairing occurs in a wide parameter range when the intra-orbital repulsive interaction becomes smaller than the inter-orbital one. Moreover, the obtained binding energy can grow into much larger value than that obtained in the single band Hubbard model depending on the parameter range.     

In-Line Reactions and Ionizations of Vaporized Diphenylchloroarsine and Diphenylcyanoarsine in Atmospheric Pressure Chemical Ionization Mass Spectrometry

We propose detecting a fragment ion (Ph₂As⁺) using counter-flow introduction atmospheric pressure chemical ionization ion trap mass spectrometry for sensitive air monitoring of chemical warfare vomiting agents diphenylchloroarsine (DA) and diphenylcyanoarsine (DC). The liquid sample containing of DA, DC, and bis(diphenylarsine)oxide (BDPAO) was heated in a dry air line, and the generated vapor was mixed into the humidified air flowing through the sampling line of a mass spectrometer. Humidity effect on the air monitoring was investigated by varying the humidity of the analyzed air sample. Evidence of the in-line conversion of DA and DC to diphenylarsine hydroxide (DPAH) and then BDPAO was obtained by comparing the chronograms of various ions from the beginning of heating. Multiple-stage mass spectrometry revealed that the protonated molecule (MH⁺) of DA, DC, DPAH, and BDPAO could produce Ph₂As⁺ through their in-source fragmentation. Among the signals of the ions that were investigated, the Ph₂As⁺ signal was the most intense and increased to reach a plateau with the increased air humidity, whereas the MH⁺ signal of DA decreased. It was suggested that DA and DC were converted in-line into BDPAO, which was a major source of Ph₂As⁺.

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Photo‐Induced Anomalous Deformation of Poly(N‐Isopropylacrylamide) Gel Hybridized with an Inorganic Nanosheet Liquid Crystal Aligned by Electric Field

Poly‐(N‐isopropylacrylamide) (PNIPA) hydrogel films doped with uniaxially aligned liquid crystalline (LC) nanosheets adsorbed with a dye are synthesized and its anomalous photothermal deformation is demonstrated. The alignment of the nanosheet LC at the cm‐scale is easily achieved by the application of an in‐plane or out‐of‐plane AC electric field during photo‐polymerization. A photoresponsive pattern is printable onto the gel with μm‐scale resolution by adsorption of the dye through a pattern‐holed silicone rubber. When the gel is irradiated with light, only the colored part is photothermally deformed. Interestingly, the photo‐irradiated gel shows temporal expansion along one direction followed by anisotropic shrinkage, which is an anomalous behavior for a conventional PNIPA gel.