Deposition from the vapour phase during induction plasma treatment of alumina powders

A study was carried out of the induction plasma melting of alumina powders (particle mean diameter, ¯d _p=24.5 m), (Ar/H₂ or Ar/N₂ plasma, plate power, 40 kW) under reduced pressure conditions (400 torr). The results reveal that in the process, partial vaporization of the alumina powders takes place in the hot region of the discharge. As the molten particles cool down and solidify, the deposits from the vapour phase was formed with the spheroidized particles. In all treatments with the Ar/H₂ and Ar/N₂ plasmas, a condensate of ultrafine alumina fume (d _p<200 nm) was obtained. The fine particles consisted essentially of metastable -, - and -phases. Needle-like crystals(0.1–0.3 m diameter, by 5–15 m long) were observed when operating with an Ar/N₂ plasma at powder feed rates exceeding 10 g min^–1. Electron diffraction analysis revealed that the needles were whiskers, whose structure was very similar to - or -aluminas with an hexagonal close-packed oxygen lattice. The change of morphology is related to the degree of supersaturation in the vapour phase.     

Numerical analysis of a reactive extrusion process. Part I: Kinetics study on grafting of vinylsilane to polyethylene

For controlling a reactive extrusion process in the subsequent study. the model equations of reaction kinetics and shear viscosity were studied. We focused on a free radical reaction between the molten polyethylene and vinylsilane. The kinetics model was expressed as a reaction rate equation with an apparent rate constant. The shear dependent of reacted polyethylene was formulated by employing the modified Cross model proposed in our early study. In addition, the average molecular weight was considered to correlate the shear viscosity with the reaction kinetics, leading to a series of rheo‐kinetics formulas. The experiments were carried out in a specific batch mixer suitably designed for sampling in arbitrary periods. Their reaction conversions, molecular weight distributions, and shear viscosity were measured, respectively, with an induced coupled plasma (ICP) emission spectrochemical analyzer, a high temperature gel permeation chromatography (GPC), and a capillary rheometer. Determining the parameters in each model, a simulator is set to investigate an engineering extrusion process.     

Modulation of visual attention assessed using the Stroop task during the menstrual cycle: Comparison between the menstrual and ovulation phases

Women might have changes in perception and cognition of colours according to hormonal changes during the menstrual cycle. Colours are often associated with specific emotional facial expressions, but how these two factors interact with each other and differ according to the cycle has remained unclear. We investigated attentional interference between colours and emotional facial expressions for women in the menstrual compared to the ovulation phases by colour judgment based on the Stroop tasks. Participants identified the colours (either red, yellow, or blue) of three types of face stimuli (happy, neutral, or sad) and corresponding scrambled face stimuli by pressing buttons, and we recorded participants' reaction times. The results showed better performance in the menstrual phase than in the ovulation phase. An interference effect was not observed. However, in the scrambled face stimuli task, only the reaction time for happy scrambled face shape and red did not differ between the phases. Thus, participants might pay stronger attention to faces with colours in the menstrual phase than in the ovulation phase but weaker attention to scrambled face shapes in the menstrual phase.     

Synthesis of chloromethylstyrene‐tetraethyleneglycol dimethacrylate copolymer beads having various phenolic derivatives immobilized via amide bond and their antioxidation activity

Resins having phenolic derivatives were prepared by treating a resin (RAS‐4G), having benzylamino groups, with benzoic acids containing phenolic hydroxyl groups. The RAS‐4G was prepared by treating macroreticular chloromethylstyrene‐tetraethyleneglycol dimethacrylate (4G) copolymer beads with potassium phthalimide in N,N‐dimethylformamide, followed by reflux in an ethanol/hydrazine monohydrate mixture. 4‐Hydroxy benzoic acid, (2,4‐, 3,4‐, and 3,5‐)dihydroxy benzoic acids, 3,4,5‐trihydroxy benzoic acid, etc., were used as benzoic acids with phenolic hydroxyl groups. The antioxidation ability of the resins having phenolic derivatives was investigated against the generation of 1,4‐dioxane hydroperoxide. The resins showed high inhibition ability against the generation of hydroperoxide. In particular, the resin (RAS‐4G‐3,4‐DHBA) having two phenolic hydroxyl groups had the highest inhibition ability. The resins were found to act as radical scavengers during the generation of 1,4‐dioxane hydroperoxide by UV irradiation in the presence of oxygen. © 2005 Wiley Periodicals, Inc. J Appl Polym Sci 97: 2097–2104, 2005     

Birefringent imaging spectrometer

A Fourier-transform imaging spectrometer, believed to be novel, based on the Savart polariscope is presented. There is no slit in this instrument, which means that it has a high throughput. The principle and the system configuration are described. Several preliminary experimental results are shown.     

Preparation of thermosensitive cellophane-graft-N-isopropylacrylamide copolymer membranes and permeation of solutes through the membranes

Thermosensitive membranes with high mechanical strength were prepared by heterogeneous graft copolymerization of N-isopropylacrylamide (NIPAAm) onto cellophane in a nitric acid solution using cerium ammonium nitrate as an initiator, and the permeation behavior of solutes such as lithium chloride and poly(ethylene glycol)s (PEGs) through the membranes at various temperatures was investigated. The degree of graft copolymerization of NIPAAm on cellophane depended on temperature, time, initiator concentration, and so on. The copolymer membranes having a high content of the NIPAAm moiety could be obtained at 25°C for 24 h. The permeation of Li⁺ through the membranes was affected by temperature, i.e., the permeation rate of Li⁺ increased with increasing temperature up to 32°C and then decreased rapidly above 35°C. The permeation rate of Li⁺ through the copolymer membranes at 40°C decreased considerably, but that at 20°C decreased slightly with an increasing amount of the NIPAAm moiety in the membranes. The permeation rate of PEGs with a molecular weight more than 1000 through the cellophane-g-NIPPAm copolymer membranes was considerably suppressed and only the permeation rate of PEG300 increased with increasing temperature up to 35°C and then decreased at 40°C. © 1997 John Wiley & Sons, Inc. J Appl Polym Sci 66: 209–216, 1997     

Combination of Near-Infrared Photoimmunotherapy Using Trastuzumab and Small Protein Mimetic for HER2-Positive Breast Cancer

Near-infrared photoimmunotherapy (NIR-PIT) is a promising cancer therapy based on a monoclonal antibody conjugated to a photosensitizer (IR700Dye) that is activated by near-infrared light irradiation. We previously reported on the use of NIR-PIT with a small protein mimetic, the Affibody molecule (6–7 kDa), instead of a monoclonal antibody. In this study, we investigated a combination of NIR-PIT for HER2-positive breast cancer cells (SK-BR3, MDA-MB361, and JIMT1) with HER2 Affibody-IR700Dye conjugate and trastuzumab-IR700Dye conjugate. HER2 Affibody and trastuzumab target different epitopes of the HER2 protein and do not compete. In vitro, the combination of NIR-PIT using both HER2 Affibody-IR700Dye conjugate and trastuzumab-IR700Dye conjugate induced necrotic cell death of HER2-positive breast cancer cells without damage to HER2-negative breast cancer cells (MCF7). It was more efficient than NIR-PIT using either the HER2 Affibody-IR700Dye conjugate alone or the trastuzumab-IR700Dye conjugate alone. Additionally, this combination of NIR-PIT was significantly effective against HER2 low-expressing cancer cells, trastuzumab-resistant cells (JIMT1), and brain metastatic cells of breast cancer (MDA-MB361). Furthermore, in vivo imaging exhibited the strong fluorescence intensity of both HER2 Affibody-IR700Dye conjugates and trastuzumab-Alexa488 conjugates in HER2-positive tumor, indicating that both HER2 Affibody and trastuzumab specifically bind to HER2-positive tumors without competing with each other. In conclusion, the combination of NIR-PIT using both HER2 Affibody and trastuzumab expands the targeting scope of NIR-PIT for HER2-positive breast cancer.     

Preparation of poly(vinyl alcohol)-graft-N-isopropylacrylamide copolymer membranes with triphenylmethane leucocyanide and permeation of solutes through the membranes

Thermo- and photosensitive hydrogel membranes were prepared by graft copolymerization of an N-isopropylacrylamide (NIPAAm) and triphenylmethane leucocyanide (LeCN) monomer onto poly(vinyl alcohol) (PVA). The yield of the graft copolymerization as well as the content of the poly(NIPAAm) segments grafted onto PVA was depressed by copolymerization of the LeCN monomer. The change in the permeation rate of poly(ethylene glycol)s through the hydrogel membranes was induced photochemically by dissociation of LeCN moieties in the membranes. © 1998 John Wiley & Sons, Inc. J Appl Polym Sci 67:1931–1937, 1998     

Formation of thermosensitive copolymer beads having phosphinic acid groups and adsorption ability for metal ions

Hydrophilic thermosensitive copolymer beads having phosphinic acid groups were prepared by suspension copolymerization of acryloyloxypropyl n‐octylphosphinic acid (APPO), N‐isopropyl acrylamide (NIPAAm), and tetraethyleneglycol dimethacrylate (4G). The thermosensitivity and the adsorption ability of the copolymer beads for metal ions beads were studied. The APPO‐NIPAAm‐4G copolymer beads were obtained in a good yield by suspension copolymerization of monomers (APPO, NIPAAm, and 4G) dissolved in chloroform, in a saturated Na₂SO₄ aqueous solution in the presence of surfactant and MgCO₃. The APPO‐NIPAAm‐4G copolymer beads had higher adsorption ability for lanthanide metal ions (Eu³⁺, Sm³⁺, Nd³⁺, or La³⁺) than for main transition metal ions (Cu²⁺, Ni²⁺, or Co²⁺). Furthermore, it was also found that the APPO‐NIPAAm‐4G copolymer beads had selective adsorption ability between lanthanide metal ions, and the order of adsorption ability for lanthanide metal ions was as follows: Eu³⁺ > Sm³⁺ > Nd³⁺ > La³⁺. The selective adsorption for these metal ions from their mixed solutions was performed by both a batch method and a column method. © 2005 Wiley Periodicals, Inc. J Appl Polym Sci 99: 449–460, 2006     

Synthesis of Anatase-Type TiO2 Nanocrystallites Via a Redox Route

Anatase nanocrystallites showing high surface area (∼62 m²/g) and good photocatalytic property have been obtained by pyrolyzing at 600°C for 4 h an ammonium titanyl double sulfate precursor (α-(NH₄)₂TiO(SO₄)₂) synthesized via a redox approach, that is, by oxidizing an aqueous solution of titanium trichloride (TiCl₃) with ammonium peroxodisulfate ((NH₄)₂S₂O₈), followed by reacting with ammonium sulfate ((NH₄)₂SO₄).