Effects of functional groups in glow discharge polymerization

Summary Glow discharge polymerizations of allyltrimethylsilane (ATMS) and trimethylvinyloxysilane (TMVOS) were investigated by elemental analysis and infrared spectroscopy. The formed polymers were far different in elemental composition from the starting materials, and possessed high carbon and hydrogen contents. There was less difference in an infrared-spectral sense between the two polymers from ATMS and TMVOS. A polymer-forming process in a discharge state is discussed.     

Formation and Crystallization of Yttrium Aluminosilicate Glasses Containing Calcium Oxide

Formation of yttrium aluminosilicate glasses containing calcium oxide from batches melted at 1550°C was investigated. Densities and thermal expansion coeflcients were measured for some glasses. In a specific compositional region, crystals with a needlelike habit were observed in the glass matrix. A crystal in the form of a tubular hexagonal prism was identified as Ca₄Y₆0(Si0₄)₆.     

Formation of Aluminosilicate Glasses Containing Rare-Earth Oxides

Formation of aluminosilicate glasses containing oxides of rare-earth elements, e.g. Sc, Ce, Pr, Nd, Eu, Gd, Tb, Dy, Ho, Er, and Yb, was studied by melting at 1550°C and air quenching. The upper limit of the amount of rare-earth oxide which can be incorporated into the aluminosilicate glasses decreases according to the lanthanide contraction.     

Application of Ligature-Induced Periodontitis in Mice to Explore the Molecular Mechanism of Periodontal Disease

Periodontitis is an inflammatory disease characterized by the destruction of the periodontium. In the last decade, a new murine model of periodontitis has been widely used to simulate alveolar bone resorption and periodontal soft tissue destruction by ligation. Typically, 3-0 to 9-0 silks are selected for ligation around the molars in mice, and significant bone loss and inflammatory infiltration are observed within a week. The ligature-maintained period can vary according to specific aims. We reviewed the findings on the interaction of systemic diseases with periodontitis, periodontal tissue destruction, the immunological and bacteriological responses, and new treatments. In these studies, the activation of osteoclasts, upregulation of pro-inflammatory factors, and excessive immune response have been considered as major factors in periodontal disruption. Multiple genes identified in periodontal tissues partly reflect the complexity of the pathogenesis of periodontitis. The effects of novel treatment methods on periodontitis have also been evaluated in a ligature-induced periodontitis model in mice. This model cannot completely represent all aspects of periodontitis in humans but is considered an effective method for the exploration of its mechanisms. Through this review, we aimed to provide evidence and enlightenment for future studies planning to use this model.     

Characterization of Insoluble Layers Formed by NaOH Attack on the Surface of a ZrO2-Containing Silicate Glass

The durability of an alkali-resistant glass containing ZrO₂ in NaOH solution was studied by scanning electron microscopy. Insoluble Zrrich reaction-product layers ∼1 to 3 μm thick were observed on the surface of glass which had been soaked for 25 d in 2N NaOH at 95°C. In some cases the layer seems to be an adherent film, but in others it adheres loosely to the glass surface and does not seem to effectively block alkali attack .     

In Vitro Cytological Responses against Laser Photobiomodulation for Periodontal Regeneration

Periodontal disease is a chronic inflammatory disease caused by periodontal bacteria. Recently, periodontal phototherapy, treatment using various types of lasers, has attracted attention. Photobiomodulation, the biological effect of low-power laser irradiation, has been widely studied. Although many types of lasers are applied in periodontal phototherapy, molecular biological effects of laser irradiation on cells in periodontal tissues are unclear. Here, we have summarized the molecular biological effects of diode, Nd:YAG, Er:YAG, Er,Cr:YSGG, and CO₂ lasers irradiation on cells in periodontal tissues. Photobiomodulation by laser irradiation enhanced cell proliferation and calcification in osteoblasts with altering gene expression. Positive effects were observed in fibroblasts on the proliferation, migration, and secretion of chemokines/cytokines. Laser irradiation suppressed gene expression related to inflammation in osteoblasts, fibroblasts, human periodontal ligament cells (hPDLCs), and endothelial cells. Furthermore, recent studies have revealed that laser irradiation affects cell differentiation in hPDLCs and stem cells. Additionally, some studies have also investigated the effects of laser irradiation on endothelial cells, cementoblasts, epithelial cells, osteoclasts, and osteocytes. The appropriate irradiation power was different for each laser apparatus and targeted cells. Thus, through this review, we tried to shed light on basic research that would ultimately lead to clinical application of periodontal phototherapy in the future.     

Parallel stimulations of in vitro and in situ [35S]GTPgammaS binding by endomorphin 1 and DAMGO in mouse brains

Metabotropic activities of endomorphin 1, a candidate for endogenous mu-opioid receptor ligands, were examined in comparison with the actions of [D-Ala2, N-Me-Phe4, Gly5ol]-enkephalin/DAMGO, a well-known synthetic mu-opioid agonist. Endomorphin 1 stimulated [35S]GTPgammaS binding to synaptic membranes from the mouse amygdala in a naloxone-reversible manner. DAMGO had the same effect in such preparations. In in situ [35S]GTP-gammaS binding experiments using brain sections, both endomorphin 1 and DAMGO similarly stimulated this binding in specific cellular locations throughout the brain regions. These findings strongly support the view that endomorphin 1 selectively acts on a mu-opioid receptor.     

Microstructure of porous anodic oxide films on aluminium

Microstructure of porous anodized films of aluminium prepared in sulphuric acid solution are different from those prepared in an oxalic or phosphoric acid solution. Transmission electron microscopy reveals a multilayer or higher order structure in the former films. Infrared spectra and specific surface area were also studied for these films and new functional properties of the films suitable for new materials were found. In contrast to the fibrous colloidal structure in the cells and barrier layer in the conventional films anodized in a sulphuric acid solution at d.c. 15 V, a network structure is formed in the cells and barrier layer in the hard films prepared at higher voltage of d.c. 25 V. The microstructure changes according to the anodizing conditions. A new model for these sulphuric acid films is presented, i.e. the cell walls are constructed from five layers and the fracture of the films occurs at the centre of the cell walls. Centre barrier layer (4 to 6 nm in thickness) composed of aluminium oxide of high crystallinity was found in a barrier layer at the bottom of the pore, and the thickness is independent on the applied voltage of the anodizing. Increase in thickness of the barrier layer due to applied voltage is governed by that of the outer barrier layer.     

Yellow Coatings Produced on Glasses and Aluminum by the Sol-Gel Process

The preparation of CeO₂-TiO₂ coatings by the sol-gel dip-coating process, with curing at 500°C, was studied. The films were brilliant yellow and adherent to soda-lime glass, a PbO-containing glass, and aluminum foil. The transmittance, chromaticity, thickness, phase content, and surface microstructure of the films were determined.