Photoluminescence properties of multilayer oxide films intercalated with rare earth ions by the layer-by-layer technique

Multilayer oxide films consisting of a TiO-Eu3+-TiO-Tb3+-NbO-Tb3+-NbO-Eu3+ unit which was prepared by the layer-by-layer technique, showed photoluminescence with a high intensity containing both red and green lights.     

Preferential destruction of metallic single-walled carbon nanotubes by laser irradiation

Upon laser irradiation in air, metallic single-walled carbon nanotubes (SWNTs) in carbon nanotube thin film can be destroyed in preference to their semiconducting counterparts when the wavelength and power intensity of the irradiation are appropriate and the carbon nanotubes are not heavily bundled. Our method takes advantage of these two species' different rates of photolysis-assisted oxidation, creating the possibility of defining the semiconducting portions of carbon nanotube (CNT) networks using optical lithography, particularly when constructing all-CNT FETs (without metal electrodes) in the future.     

Notable temperature effect on the stereoselectivity in the photochemical [2+2] cycloaddition reaction (Paternò-Büchi reaction) of 2,3-dihydrofuran-3-ol derivatives with benzophenone

A notable temperature effect (nonlinear Eyring plot) on stereoselectivity, trans-configured oxetane 2 versus cis-configured oxetane 2, is reported in the photochemical [2+2] cycloaddition reaction (Paternò-Büchi reaction) of 2,3-dihydrofuran-3-ol derivatives 1 with benzophenone.     

Molecular recognition of mono- and disaccharides through interaction with p-iodophenylboronic acid in capillary electrophoresis with a chemiluminescence detection system

Molecular recognition of mono- and disaccharides was performed making use of the interaction between their diol groups and p-iodophenylboronic acid in capillary electrophoresis (CE) with a chemiluminescence (CL) detection system. p-Iodophenylboronic acid acted as an enhancer for luminol-horseradish peroxidase-hydrogen peroxide CL reaction. p-Iodophenylboronic acid was injected as a sample into the present system to give a CL peak on the electropherogram. The CL intensities were examined using running buffers including mono- and disaccharides. The CL intensities with 1-methyl-D-glucoside, D-saccharose, D-maltose, D-glucose, and D-fructose decreased in this order. The decrease in CL intensity was based on the formation by p-iodophenylboronic acid of cyclic esters with mono- and disaccharides, particularly with those including cis-diol groups. That is, the decrease in CL intensity affected the specific complexation between p-iodophenylboronic acids and saccharides, leading to the molecular recognition of saccharides. We also report separation of a mixture of p-iodophenol and p-iodophenylboronic acid as well as estimation of the apparent binding constant between p-iodophenylboronic acid and saccharides taking advantage of their molecular recognition behavior.     

Total synthesis and structural revision of hericerin

The total synthesis of hericerin, a pollen growth inhibitor from Hericium erinaceum, was achieved. We found that the reported structure of hericerin should be revised to be the carbonyl regioisomer.     

Establishment of a microplate-formatted cell-based immunoassay for rapid analysis of nucleotide excision repair ability in human primary cells

DNA photolesions induced by UV, cyclobutane pyrimidine dimer (CPD) and (6-4) photoproduct (6-4PP), are repaired by nucleotide excision repair (NER) in human cells. Various immunoassays using monoclonal antibodies specific for the photolesions have been developed and widely used for the analysis of cellular NER activity. In this study, we have newly developed a microplate-formatted cell-based immunoassay, based on indirect immunofluorescence staining with lesion-specific antibodies combined with an infrared imaging system. Using this assay, we show the repair kinetics of CPD and 6-4PP in various fibroblasts from newborn and adult donors with no age-related difference. Furthermore, epidermal keratinocytes and melanocytes exhibit comparable NER activity, and calcium ion-induced differentiation of keratinocytes has no significant impacts on their NER activity. We also evaluated the effects of a proteasome inhibitor, MG132, and a histone deacetylase inhibitor, sodium butyrate, on NER efficiency using this assay. All these results suggest that the new assay is highly useful for the rapid and quantitative analysis of NER activity in various primary cells with limited growth activity and is applicable to a screening system for drugs affecting NER efficiency.     

Ultrasound therapy modulates osteocalcin expression during bone repair in rats

The aim of this study was to measure the temporal pattern of the protein expression of RUNX2, RANKL, OPG, and osteocalcin after ultrasound therapy during the process of bone healing by immunohistochemistry. The animals were randomly distributed into two groups: control or ultrasound-treated group. A non-critical size bone defects were surgically created at the upper third of the tibia. The treatments started 24 h post-surgery, and they are performed for 3, 6, and 12 sessions, with an interval of 48 h. A low-intensity pulsed ultrasound (1.5 MHz, 1:4 duty cycle, intensity SATA 30 mW/cm², 20 min/session, stationary mode application) was used. On days 7, 13, and 25 post-injury, rats were killed individually by carbon dioxide asphyxia. The tibias were removed for analysis. The histopathological analysis pointed out no remarkable differences between groups for all periods evaluated. However, immunohistochemical data revealed that ultrasound therapy produced an up-regulation of osteocalcin at day 7th and 13th post-surgery. Taken together, our results indicate that ultrasound therapy modulates osteocalcin expression during bone repair in rats as depicted by differential immunopression at the initial and intermediate stages of recovery.     

Gas permeability of phosphatidylcholine impregnated in a porous cellulose nitrate membrane

Egg-yolk phosphatidylcholine (EPC) and dipalmitoyl phosphatidylcholine (DPPC) were impregnated in a porous cellulose nitrate membrane, and permeabilities of oxygen, nitrogen, and carbon dioxide through these composite-type membranes were measured. Gases are suggested to permeate across the membrane by an activated flow of the solution—diffusion type through the impregnated lipid matrix. The EPC-filled membrane shows higher permeability and smaller activation energy of permeation compared to the DPPCfilled membrane, which is ascribed to the higher mobility of fatty acid chains of EPC compared to those of DPPC.     

An intermittent frequency offset lock of a transverse Zeeman laser to an iodine stabilized He-Ne laser

A single-mode frequency stabilized laser with modulation-free and moderate power is desired as a light source for an ultra-high resolution interferometer system and/or a rapid laser calibration system. For this purpose, we developed a new stabilized laser system that utilizes intermittent control of a 2 mW transverse Zeeman stabilized He-Ne laser (Zeeman laser) with an iodine stabilized He-Ne laser (I2 stabilized laser). Because of the intermittent control, working time of the I2 stabilized laser is reduced. The Zeeman laser has two operational modes: independent and slave mode. In the independent mode, the Zeeman laser is stabilized through control of Zeeman beat frequency. Temperature dependent drift of the oscillation frequency during the independent mode is periodically corrected by the slave operation utilizing frequency offset locking to the I2 stabilized laser. Frequency instability of the Zeeman laser in independent and slave modes is 7.7X10-11 and 2.0X10-11, respectively, at the sampling time of 100 s.