Enhanced Infrared Intensity of Benzene-Iodine Complex

It is shown that an enhancement of infrared absorption bands observed in the molecular complex is due to change in vertical ionization energy of electron donor in the course of molecular vibrations. An enhanced infrared absorption intensity of 992 cm^ of benzene in benzene-iodine complex is calculated by a semi-empirical molecular orbital theory and the charge transfer theory of Mulliken, and also using the dipole moment value of benzene-iodine complex measured by Fairbrother. The calculated intensity value agrees well with the experimental value by Ferguson and Matsen

Infrared Absorption Spectra of Molecular Complexes of Pyridine. Part III : Molecular Complexes with Iodine and Iodine Halides

When iodine or iodine halides were dissolved in pyridine, new bands were observed at 624-627, 1012-1007, 1213, 1246, and 1454 cm^, which were assigned as the shifted bands of ν_, ν_1, ν_3, 2ν_ andν_ respectively of pyridine. The rest of the absorption bands of pyridine solutions was found as the same band location and intensity as those of the pure pyridine spectrum. Solid spectra of the complexes were assigned by an analogy with the solution spectra. The extent of shifts of 624-627 cm^ and 1007-1012 cm^ bands were correlated to electronegativities of interhalogen compounds, that is, iodine chloride made a band shift markedly from the pure pyridine spectrum

Infrared Absorption Spectra of Molecular Complexes of Pyridine. Part V : Molecular Complexes with Cu-, Co-, Ni- and Mn-Dihalides

The infrared spectra in the rock salt region of CuCl_2, CuBr_2, CoCl_2, CoBr_2, NiCl_2, NiBr_2 and MnCl_2 complexes of pyridine have been observed by the KBr pressed disc method. The infrared absorption bands corresponding to the C-H stretching vibrations diminished in intensity and the diminution has been discussed qualitatively. A tentative assignment of absorptions is presented. The spectra are insensitive to a spatial structure of the complex

The Use of Nanoscaled Fibers or Tubes to Improve Biocompatibility and Bioactivity of Biomedical Materials

Nanofibers and nanotubes have recently gained substantial interest for potential applications in tissue engineering due to their large ratio of surface area to volume and unique microstructure. It has been well proved that the mechanical property of matrix could be largely enhanced by the addition of nanoscaled fibers or tubes. At present, more and more researches have shown that the biocompatibility and bioactivity of biomedical materials could be improved by the addition of nanofibers or nanotubes. In this review, the efforts using nanofibers and nanotubes to improve biocompatibility and bioactivity of biomedical materials, including polymeric nanofibers/nanotubes, metallic nanofibers/nanotubes, and inorganic nanofibers/nanotubes, as well as their researches related, are demonstrated in sequence. Furthermore, the possible mechanism of improving biocompatibility and bioactivity of biomedical materials by nanofibers or nanotubes has been speculated to be that the specific protein absorption on the nanoscaled fibers or tubes plays important roles

Rapid analysis of metallic dental restorations using X-ray scanning analytical microscopy

Objectives: X-ray scanning analytical microscopy (XSAM) makes it possible to analyze small specimens in air without pretreatment. The purpose of this study was to utilize XSAM for the rapid analysis of metallic dental restorations by microsampling. Methods: Six different dental alloys were scratched with brand-new silicone points to obtain metal on the silicone point for compositional analysis. The fluorescent spectra of XSAM were measured to determine the metal attached to the specimen. Results: The major components of the six dental metals, except for palladium, were clearly detected. The identification of palladium was difficult since the fluorescent X-ray of palladium is quite close to that of rhodium, which is the source metal of the incident X-rays. However, with a slight modification of XSAM, palladium was also identified. The total time required for sampling and analysis with XSAM was less than 10 min. The amount of the attached metal was estimated to be less than 30 μg. This amount of sampling does not damage metal restorations. Significance: XSAM analysis using the microsampling technique is useful for the rapid analysis of metallic restorations

Capture of bacteria by flexible carbon nanotubes

Capture of bacteria with flexible carbon nanotubes (CNTs) was done in vitro. Bundles of single-walled carbon nanotubes (SWCNTs) or multi-walled carbon nanotubes (MWCNTs) was mixed with Streptococcus mutans. Precipitation assays and colony-forming unit formation assays showed free S. mutans in the solution was significantly decreased by the addition of the CNTs. Observation of the precipitate by scanning electron microscopy showed bacterial adhesion to CNTs. It has been shown that CNTs of different diameters have significantly different effects on the precipitation efficiency, and the manners in which they capture the cells are different. We found that MWCNTs (diameter of approximately 30 nm) had the highest precipitation efficiency, which was attributable to both their adequate dispersibility and aggregation activity. From observations by scanning electron microscopy, bundles of SWCNTs and thin MWCNTs (diameter of approximately 30 nm), which were moderately flexible, were easily wound around the curved surface of S. mutans. Bare CNTs having high adhesive ability could be useful as biomaterials, e.g., as tools for the elimination of oral pathogens at the nano-level

Quantitative analysis of biologic specimens by X-ray scanning analytic microscopy

X-ray scanning analytic microscopy (XSAM) can be used to visualize the elemental distribution in biologic specimens. In this article, the authors prepared standard specimens for XSAM and performed quantitative analysis of various elements dissolved in soft tissues. Two different types of standard specimens were prepared. Methylmethacrylate (MMA) resin-based standard specimens were prepared with organic compounds of elements for low-concentration standards and lithium borate glass-based standard specimens were prepared with oxides of elements for higher concentration standards. Using these standard specimens, the P and Ca concentrations in normal rat tissue and dissolved Ni, Fe, and Ni concentrations around metal-implanted tissues were quantitatively analyzed. The estimated concentrations of dissolved Fe, Cu, and Ni from the implants were 1000, 40, and 20 mM, respectively. From the concentration levels causing inflammation around these implants, the high toxicity for soft tissue of Ni and Cu at low concentrations, for example, 10 mM, was confirmed. The toxicity of Cu was estimated as next to that of Ni. In contrast, Fe had low toxicity despite high concentrations of dissolved Fe of as much as 1000 mM. In this article, it was possible to estimate the nonmetallic elements and low-concentration metallic elements dispersed in soft tissue by XSAM