Theranostic Agent Combining Fullerene Nanocrystals and Gold Nanoparticles for Photoacoustic Imaging and Photothermal Therapy

Developing photoactivatable theranostic platforms with integrated functionalities of biocompatibility, targeting, imaging contrast, and therapy is a promising approach for cancer diagnosis and therapy. Here, we report a theranostic agent based on a hybrid nanoparticle comprising fullerene nanocrystals and gold nanoparticles (FGNPs) for photoacoustic imaging and photothermal therapy. Compared to gold nanoparticles and fullerene crystals, FGNPs exhibited stronger photoacoustic signals and photothermal heating characteristics by irradiating light with an optimal wavelength. Our studies demonstrated that FGNPs could kill cancer cells due to their photothermal heating characteristics in vitro. Moreover, FGNPs that are accumulated in tumor tissue via the enhanced permeation and retention effect can visualize tumor tissue due to their photoacoustic signal in tumor xenograft model mice. The theranostic agent with FGNPs shows promise for cancer therapy.     

Microstructure and Thermoelectric Properties of Dense YB<Subscript>22</Subscript>C<Subscript>2</Subscript>N Samples Fabricated Through Spark Plasma Sintering

Dense samples of the higher boride YB₂₂C₂N have been fabricated through the spark plasma sintering (SPS) method with different sintering aids. YB₂₂C₂N is a representative of a series of newly discovered rare-earth borocarbonitrides, which may be the long-awaited n-type counterpart of boron carbide, “B₄C.” The effect of Si, SiC, Al, and TiC additions on the sintering process of YB₂₂C₂N has been studied. The best sintered bodies with densities higher than 90% of theoretical density were obtained by means of SPS at 1700°C. We show that the additive choice and pressure have an effect on grain size and density. An investigation of the effect of atmosphere on the sintering behavior has also been carried out. It was found that sinterability is enhanced under nitrogen atmosphere. Thermoelectric properties of the materials sintered with additives have been evaluated, and we discuss their dependences on the fabrication process route.     

Processing and photocatalytic properties of Cu-grafted TiO2 powder from acid treated BaTiO3

The respective influences of calcination, drying methods, and washing conditions on the morphologies, surface properties, and photocatalytic activities of TiO₂ powders prepared from acid treatments of BaTiO₃ were investigated. Rutile powder was obtained using the treatment under strong acid conditions. It possesses a bundle-like shape and comprises rutile nanorods. After calcination, characteristic voids were observed in the particles. Anatase powder was obtained by adjusting pH values of a BaTiO₃ suspension to 2.5-3. Drying at 110 °C engendered the formation of spheroidal anatase, although freeze-dried anatase particles assembled into a flake-like shape. The freeze-dried samples show lower crystallinity. With grafting Cu ions, rutile exhibited better photocatalytic performance for the decomposition of gaseous 2-propanol (IPA) under visible light, although it did not work effectively for anatase.     

Rheological studies of nickel oxide and quartz/hematite mixture systems

This study aimed to investigate the rheology of two-mineral mixture systems as a function of pH and solid concentration. Single minerals (nickel oxide, quartz and hematite) and two-mineral systems (nickel oxide–quartz and nickel oxide–hematite) were studied. Rheology tests were conducted to investigate the effect of pH and solid concentration on shear yield stress of suspensions while zeta potential measurements of suspensions were used to explain the rheology results. Rheology results indicated that single mineral experiments showed that 5 and 10 vol.% of quartz and hematite had no shear yield stress whereas the one of nickel oxide was positive value. Shear yield stress of nickel oxide–quartz mixture and nickel oxide–hematite mixtures increased as increasing pH and solid concentration, and the value was higher than the one obtained with only nickel oxide. These results obtained with two-mineral mixture systems were explained by electrokinetic properties of the minerals, i.e. zeta potential of the minerals.     

A perturbation method for guiding center orbit following calculations in the presence of Coulomb collisions

An orbit following guiding center Monte Carlo calculation is presented which employs a general flux coordinate system in an axisymmetric plasma equilibrium. The calculation incorporates collision effects. Furthermore, a perturbation expansion is applied for the guiding center calculations in the presence of a frictional source.     

Microstructure and analysis of oxide scales formed on Cr-Si-Ni compacts in air and H2O-containing atmosphere

The purpose of this study was to characterize the oxide scales formed on various Cr-Si-Ni compacts at 1273 K in air and H₂O-containing atmosphere by TEM. It was found that CrSi₂-(5-20)mass%Ni compacts form double layer scales, consisting of an outer Cr₂O₃ layer and an inner SiO₂ layer. The oxide scale changed from SiO₂- to Cr₂O₃-based scale with an increase in the Ni concentration. However, it was observed that the oxide scale formed in H₂O-containing atmospheres showed local SiO₂ growth into the substrate. This result suggests that the inward oxidant diffusion promotes the local growth of SiO₂ in the H₂O-containing atmospheres.     

Influence of swelling of noncrystalline regions in silk fibers on modification with methacrylamide

The degrees of swelling of noncrystalline regions of domestic and tussah silk fibers were investigated by measuring the small-angle X-ray scattering intensity of the fibers in wet conditions and analyzing the scattering intensity based on a two-phase model, i.e., crystalline regions and water-swollen noncrystalline regions. The influence of the degree of swelling of noncrystalline regions on the graft treatment of these fibers with methacrylamide was investigated. The changes in the structure caused by the graft treatment were also analyzed using the wide-angle X-ray diffraction measurements. As compared with the tussah silk fibers, the domestic silk fibers showed a larger degree of swelling of the noncrystalline regions, and gained a larger amount of resin by the graft treatment. The crystallites with smaller sizes in the tussah silk fibers were destroyed preferentially by the graft treatment. For the domestic silk fibers, the crystallites were destroyed more seriously and rather homogeneously independent of the crystallite sizes. © 1996 John Wiley & Sons, Inc.     

Preparation of poly(N-isopropylacrylamide)–SiO2 hybrid gels and their thermosensitive properties

The swelling and adsorption behavior of poly(N-isopropylacrylamide)–SiO₂ hybrid gels, derived from copolymerization of N-isopropylacrylamide and 3-methacryloxypropyltrimethoxysilane (MPTMOS) and following hydrolysis and condensation, were investigated. The hybrid gels exhibited temperature dependence of both the swelling ratio and adsorption of solutes, and their temperature dependence of both the swelling ratio and adsorption of solutes, and their temperature dependence was related to the MPTMOS content in the hybrid gels. In addition, the modification of thermosensitive properties of the hybrid gels could be achieved by treatment with other silane compounds. © 1996 John Wiley & Sons, Inc.     

Thermogravimetric behavior of perfluoropolyether

In this article, two kinds of perfluoropolyether (PFPE) with different terminal groups were investigated using thermogravimetric analysis (TGA), infrared (IR) spectroscopy, gel permeation chromatography (GPC), and gas chromatography/gas mass spectrum (GC/MS) analysis. PFPEs with a hydroxyl or carboxylic acid terminal group were more heat stable than was PFPE with carboxylic methyl ester. Perfluoropropylene oxide-type PFPE with a perfluoroethyl terminal group at one end tends to lose weight more rapidly than does copolymer-type PFPE with dihydroxyl or dicarboxyl methyl ester terminal groups at both ends. The residual weight fraction of PFPE with a perfluoroethyl terminal group was dependent on the average molecular weight. The number-average molecular weight of PFPE can be calculated from the peak intensity ratio between the polar group and C F stretching by measuring the IR spectrum of PFPE. The number-average molecular weight of PFPE increased because of the evaporation loss of its low molecular weight fraction and the crosslinking reaction of PFPE with increase in temperature. GC/MS analysis showed that the main product of the pyrolysis of PFPE was hexafluoropylene. We speculated on the PFPE degradation mechanism and the optimum PFPE chemical structure in terms of heat stability. © 1996 John Wiley & Sons, Inc.     

H∞ control and filtering with initial uncertainty for infinite dimensional systems

The H_∞-control problem with a non-zero initial condition for infinite dimensional systems is considered The initial conditions are assumed to be in some subspace. First the H_∞ problem with full information is considered and necessary and sufficient conditions for the norm of an input-output operator to be less than a given number are obtained, The characterization of all admissible controllers is also given. This result is then used to solve the general H^∞ control problem and the filtering problem with initial uncertainty. The filtering problem on finite horizon involves the estimate of the state at final time. The set of all suboptimal filters is given both on finite and infinite horizons.