Control of self-aggregation of fullerenes by connection with calix[4]arene: solvent- and guest-effects to particle size

A new molecular design of fullerene derivatives exhibiting trigger-responsive self-aggregation in organic solvents has been established. Calix[4]arene was covalently connected with fullerene in order to apply host-guest interaction to the aggregation control. The self-assembly behaviour was studied in organic solvents by UV-vis absorption spectroscopy, dynamic light scattering and transmission electron microscopy. Results show that the bisfullerene formed self-aggregations with a low polydispersity index due to the fullerenes' tendency to aggregate in polar organic solvents. Furthermore, the aggregate sizes can be changed readily by solvent composition and the addition of guest cations. Especially, disaggregation of the bisfullerene was induced by addition of LiClO4 or NaClO4.     

A novel enhancement assay for immunochromatographic test strips using gold nanoparticles

The immunochromatographic assay is a well-known and convenient diagnostic system. In this report, the development of a novel enhancement assay for the test strips is described. Additionally, this highly sensitive immunochromatographic assay was applied to detect human chorionic gonadotropin hormone (HCG) as the model case. The primary antibody-conjugated gold nanoparticles were used as the enhancer of the standard method. The primary antibodies were immobilized within a defined detection zone (test line) on the diagnostic nitrocellulose membrane. The secondary antibodies were conjugated with colloidal gold nanoparticles. In combination with an effective sample pretreatment, the gold-conjugated antibodies and the primary antibodies formed a sandwich complex with the target protein. Within the test line, the sandwich complex was immobilized, and furthermore, concentrated by the enhancer resulting in a localized surface plasmon resonance (LSPR) phenomenon and a distinct red color on the test line. The intensity of color of the red test line (signal intensity), which correlated directly with the concentration of the target protein in the standard or spiked samples, was assessed visually and by computer image analysis using a three-determination analysis. Under optimum conditions, the limit of detection (LOD) for HCG assay was 1 pg/mL. When using human serum, 10 pg/mL of HCG could be detected. We have also spiked total prostate-specific antigen (TPSA) in female serum. The LOD for TPSA was determined as 0.2 ng/mL. With this method, the quantitative determination of the target protein could be completed in less than 15 min. Our novel immunochromatographic strips using the enhancing method based on LSPR of gold nanoparticles are useful as a rapid and simple screening method for the detection of important analytes for medical applications, environmental monitoring, food control, and biosecurity.      

Oxidative dehydrogenation of ethane over Cr/ZSM-5 catalysts using CO2 as an oxidant

Highly active catalysts for oxidative dehydrogenation of ethane with CO2 were characterized by temperature-programmed reduction (TPR), temperature-programmed oxidation (TPO), Fourier transform infrared (FTIR) spectroscopy, and X-ray absorption fine-structure (XAFS) analysis. In the active catalysts, Cr/H-ZSM-5 (SiO2/Al2O3 > 190), Cr6+ = O, or possibly Cr5+ = O was the catalytic species on the zeolite support. In contrast, little Cr6+ (or Cr5+) was detected in the less-active catalysts. The Cr6+ (or Cr5+) species was reduced to an octahedral Cr3+ species by treatment with ethane at 773 K, and the reduced Cr species was reoxidized to the Cr6+ (or Cr5+) species by treatment with CO2 at 673-773 K. The Cr redox cycle played an important role in the catalyst's high activity.     

Intravenous administration of mesenchymal stem cells exerts therapeutic effects on parkinsonian model of rats: Focusing on neuroprotective effects of stromal cell-derived factor-1α

Background

Junctional adhesion molecule-A (JAM-A) is an adhesive protein expressed in various cell types. JAM-A localizes to the tight junctions between contacting endothelial and epithelial cells, where it contributes to cell-cell adhesion and to the control of paracellular permeability.

Results

So far, the expression pattern of JAM-A has not been described in detail for the different cell types of the adult brain. Here we show that a subset of proliferating cells in the adult mouse brain express JAM-A. We further clarify that these cells belong to the lineage of NG2-glia cells. Although these mitotic NG2-glia cells express JAM-A, the protein never shows a polarized subcellular distribution. Also non-mitotic NG2-glia cells express JAM-A in a non-polarized pattern on their surface.

Conclusions

Our data show that JAM-A is a novel surface marker for NG2-glia cells of the adult brain.     

CO2 motion in carbon dioxide deuterohydrate determined by applying maximum entropy method to neutron powder diffraction data

Crystal structures of carbon dioxide deuterohydrate were studied by neutron powder diffraction at temperatures from 10 to 200 K. Maps of scattering length density distribution were obtained using a maximum entropy method (MEM), which clarified the motion of CO₂ molecules in the hydrate. In small cages, the carbon atom of the CO₂ molecule is at the center of the cage, and the oxygen atoms of CO₂ revolve freely around the carbon atom. In large cages, the carbon atom also is at the center of the cage, but the oxygen atoms tend to revolve around the carbon atom along the plane parallel to the hexagonal facets of the cage.     

Cross-sectional characterization of cupric oxide nanowires grown by thermal oxidation of copper foils

CuO nanowires have been synthesized by heating a Cu foil in an ambient condition. The diameters of nanowires can be controlled by changing the annealing temperature. The morphology, composition, and structure were analyzed by using X-ray diffraction (XRD) and scanning electron microscope (SEM). To investigate the detailed layering structure of the substrates after oxidation, the cross-sectional analysis was also performed by using field emission-SEM and energy dispersive X-ray spectroscopy (EDX). The EDX measurements indicated that the CuO nanowires were grown on the CuO/Cu₂O layer, which was formed on the surface of Cu foil.     

Nondestructive analysis of silver in gold foil using synchrotron radiation X-ray fluorescence spectrometry.

Small particles of gold foil detached from an indoor decoration might be important evidence to associate a suspect with a crime scene. We have investigated the application of elemental analysis using synchrotron radiation X-ray fluorescence spectrometry to discriminate small particles of gold foil. Eight kinds of gold foil samples collected in Japan were used in the experiments. As a result of synchrotron radiation X-ray fluorescence spectrometry, only two elements, gold and silver, were detected from all gold foil samples. The intensity ratios of AgKalpha/AuLalpha showed good correlation with the content ratios of Ag/Au. The variation of intensity ratio within a same sample was sufficiently small compared with those of different samples. Therefore the comparison of this intensity ratio can be an effective method to discriminate small particles originating from different types of gold foil.