The anomalous behaviour of Gd atoms (Fe1−xMnx)2 compounds

The educed Gd atoms in the X-structure (Th₆Mn₂₃-type) of Gd(Fe_1−xMn_x)₂ were magnetically investigated by comparing with Gd₆(Fe_1−yMn_y)₂₃ whose structure is Th₆Mn₂₃-type. The magnetic properties of Gd(Fe_1−xMn_x)₂ (0.4≤x≤0.7) were observed to be quite similar to those of Gd₆(Fe_1−yMn_y)₂₃ (0.4≤y≤0.7).     

Characterization of certified reference material for quantification of polychlorinated biphenyls and organochlorine pesticides in fish

Fish certified reference material (CRM), NMIJ CRM 7404-a, for the analysis of polychlorinated biphenyls (PCBs) and organochlorine pesticides (OCPs) was developed by the National Metrology Institute of Japan, part of the National Institute of Advanced Industrial Science and Technology. Fish samples (Japanese seabass) used for the preparation of the CRM were collected from Tokyo Bay, and the edible part was freeze-dried, pulverized, sieved, homogenized, and sterilized by γ-irradiation. This sample is in the form of a powder comprising approximately 10 g stored in a brown glass bottle. The certification was carried out using multiple analytical methods such as pressurized liquid extraction, Soxhlet extraction, saponification, and homogenization to ensure the reliability of analytical results; the certified values of target PCBs (PCB 28, PCB 70, PCB 105, PCB 153, and PCB 170) and OCPs (trans-nonachlor, dieldrin, p,p′-DDE, p,p′-DDT, and p,p′-DDD) were 1.05–14.0 μg kg⁻¹ and 1.57–18.0 μg kg⁻¹ for PCBs and OCPs, respectively. This is the first fish powder CRM in which PCBs and OCPs were determined by isotope dilution mass spectrometry.     

Freeze-thawing single human embryonic stem cells induce e-cadherin and actin filament network disruption via g13 signaling

Poor adhesion of single human embryonic stem (hES) cells after freeze-thawing causes death. To investigate mechanisms responsible for this, Rho-dependent protein kinase (ROCK) inhibitor Y-27632-treated and untreated single hES cells were analyzed for E-cadherin and F-actin distribution by immunostaining and phalloidin staining respectively and for G13 signaling pathway components by DNA microarray and quantitative polymerase chain reaction (PCR). Y-27632-treated cells clustered rapidly and maintained E-cadherin and F-actin distribution without losing Oct-3/4. Immediately after thawing, E-cadherin in untreated hES cells dotted along the membrane and then displayed eccentric cytoplasmic localization. Bleb formation and early Oct-3/4 loss occurred after F-actin network condensation in the cytoplasm. Microarray analyses and quantitative PCR indicated upregulation of two actin reorganization-associated components of the G13 signaling pathway, Arhgdib and Cdc42, in untreated cells. Considering these findings and that cell death was partly interrupted by Y-27632, E-cadherin and actin cytoskeleton network disruption through the G13 signaling pathway may cause hES cell death after freeze-thawing.     

Laser-induced fluorescence and infrared spectroscopic studies on the specific solvation of tris(1-(2-thienyl)-4,4,4-trifluoro-1,3-butanedionato)europium(III) in an ionic liquid

The extraction constant and the two-phase stability constant (K_D,Mβ₃) of tris(2-thenoyltrifluoroacetonato)europium(III) between 1-butyl-3-methylimidazolium bis(trifluoromethanesulfonyl)imide ([C₄mim][Tf₂N]) as an ionic liquid and an aqueous phase were determined by considering the extraction equilibria including anionic tetrakis(2-thenoyltrifluoroacetonato)europate(III). Specific solute-solvent interactions between the neutral Eu(III) chelate and [C₄mim][Tf₂N] molecules were revealed from the relationships between the distribution constant of the enol form of 2-thenoyltrifluoroacetone (Htta) as a proton chelate and the distribution constant (K_D,M) of the neutral Eu(III) chelate because the [C₄mim][Tf₂N] system gave the high K_D,Mβ₃ value compared with those in conventional molecular solvents such as benzene and 1,2-dichloroethane. The coordination environment of Eu³⁺ in the neutral Eu(III) chelate in [C₄mim][Tf₂N] was investigated by time-resolved laser-induced fluorescence spectroscopy and infrared absorption spectroscopy. Both methods consistently indicated that not only the Eu(III) chelate extracted but also Eu(tta)₃(H₂O)₃ synthesized as a solid crystal were almost completely dehydrated in [C₄mim][Tf₂N] saturated with water. Consequently, the higher K_D,M or extractability of the neutral Eu(III) chelate in the [C₄mim][Tf₂N] system can be ascribed to the dehydration of the Eu(III) chelate, which is caused by the specific solvation with [C₄mim][Tf₂N] molecules.     

Toward the racemic total synthesis of hederacines A and B: construction of an advanced tricyclic intermediate

Progress toward the total synthesis of hederacines A and B is described. Our approach involves an allylic cyanate-to-isocyanate rearrangement, eneyne ring-closing metathesis, and a transannular reaction between the C-5 amino group and the C-12 position of the perhydroazuleno[5,6-b]furanone intermediate.     

Fibrin glue increases the cell survival and the transduced gene product secretion of the ceiling culture-derived adipocytes transplanted in mice

The development of clinically applicable scaffolds is important for the application of cell transplantation in various human diseases. The aims of this study are to evaluate fibrin glue in a novel protein replacement therapy using proliferative adipocytes and to develop a mouse model system to monitor the delivery of the transgene product into the blood and the fate of the transduced cells after transplantation. Proliferative adipocytes from mouse adipose tissue were transduced by a retroviral vector harboring the human lecithin-cholesterol acyltransferase (lcat) gene, and were subcutaneously transplanted into mice combined with fibrin glue. The lcat gene transduction efficiency and the subsequent secretion of the product in mouse adipocytes were enhanced using a protamine concentration of 500 μg/ml. Adipogenesis induction did not significantly affect the lcat gene-transduced cell survival after transplantation. Immunohistochemistry showed the ectopic enzyme production to persist for 28 days in the subcutaneously transplanted gene- transduced adipocytes. The increased viability of transplanted cells with fibrin glue was accompanied with the decrease in apoptotic cell death. The immunodetectable serum LCAT levels in mice implanted with the fibrin glue were comparable with those observed in mice implanted with Matrigel, indicating that the transplanted lcat gene-transduced adipocytes survived and functioned in the transplanted spaces with fibrin glue as well as with Matrigel for 28 days. Thus, this in vivo system using fibrin is expected to serve as a good model to further improve the transplanted cell/scaffold conditions for the stable and durable cell-based replacement of defective proteins in patients with LCAT deficiency.     

Pushing exercise program to correct glottal incompetence

A voice therapy program using pushing exercises to correct glottal incompetence is described. The program utilizes various types of instrumentation to determine whether or not a given patient is likely to benefit from the treatment. The program also provides feedback of target voices. Three cases with incomplete glottal closure and subsequent vocal dysphonia characterized by an asthenic breathy quality are used to illustrate the program. Details of the program, termination criteria, and problems and precautions learned from treating 29 patients over a 3-year period are presented.     

Core-level photoemission of the Si(1 1 1)– -Ag surface using synchrotron radiation

The evolution of Si 2p core-level photoemission during a structural conversion from the Si (1 1 1)– -Ag to the Si(1 1 1)– -Ag superstructures induced by Ag adatoms adsorption at 140 K was studied using synchrotron radiation. The component from the top-layer Si-trimer atoms on the former surface was found to split into two components in the latter surface. The result is discussed in terms of a relaxation in some of the Si trimers induced by Ag adatoms sitting on the nearby Ag triangles of the -Ag substrate. The intensity ratio between the split components is a key to exclude some structure models proposed so far for the phases.     

Differences in the yields of polycyclic aromatic hydrocarbons by pressurized liquid extraction and the Japanese official method

To improve the extraction of polycyclic aromatic hydrocarbons (PAHs) from sediment samples, we optimized the conditions of pressurized liquid extraction (PLE). The yields increased as the extraction temperature increased from 100 to 190 degrees C, but the effect of increasing pressure (from 15 to 20 MPa) was small. Parameters of 190 degrees C and 20 MPa, near the maximum of the equipment, gave the highest yield. Under these conditions, the yields of 17 PAHs were 1.5 - 34 times those obtained by the Japanese official method (shaking and ultrasonic extraction with acetone at room temperature).     

Accurate Quantification of Polycyclic Aromatic Hydrocarbons in Environmental Samples Using Deuterium-labeled Compounds as Internal Standards

For the accurate quantification of polycyclic aromatic hydrocarbons (PAHs) in environmental samples by isotope-dilution mass spectrometry (IDMS) and gas chromatography-mass spectrometry (GC-MS), we used deuterium-labeled PAHs (D-PAHs) as internal standards for microg g(-1)-level certified reference materials and corresponding calibration solutions. Although pressurized liquid extraction (PLE) causes significant biases in the analytical results for ng g(-1)-level samples (2.4 - 15%), biases in the analytical results by PLE (190 degrees C, 20 MPa, 2 cycles) were small (<2.3%) and negligible for microg g(-1)-level samples when expanded uncertainty (coverage factor k = 2) was considered.