80 research outputs found
Vector-like pairs and Brill–Noether theory
No full textAbstractHow likely is it that there are particles in a vector-like pair of representations in low-energy spectrum, when neither symmetry nor anomaly consideration motivates their presence? We address this question in the context of supersymmetric and geometric phase compactification of F-theory and Heterotic dual. Quantisation of the number of generations (or net chiralities in more general term) is also discussed along the way. Self-dual nature of the fourth cohomology of Calabi–Yau fourfolds is essential for the latter issue, while we employ Brill–Noether theory to set upper bounds on the number ℓ of vector-like pairs of chiral multiplets in the SU(5)GUT (5+5¯) representations. For typical topological choices of geometry for F-theory compactification for SU(5) unification, the range of 0≤ℓ≲4 for perturbative unification is not in immediate conflict with what is already understood about F-theory compactification at this moment
Lipopolysaccharide Induces Expression of Genes Encoding Pro-Inflammatory Cytokines and the Elastin-Degrading Enzyme, Cathepsin S, in Human Cervical Smooth-Muscle Cells
No full textMultiwalled carbon nanotube coating on titanium
No full textCarbon nanotubes (CNTs) have excellent chemical durability, mechanical strength, and electrical properties. Therefore, there is interest in CNTs for not only electrical and mechanical applications, but also biological and medical applications. We coated titanium, a common material for dental implants, with multiwalled carbon nanotubes (MWCNTs). First, titanium was aminated and covered with collagen. Then, the carboxylated MWCNTs were coated onto the collagen attached to the titanium plate. The collagen-coated titanium plate had a homogeneous MWCNT coating, which showed strong attachment to the titanium surface as a thin layer. The surface roughness was significantly increased with the MWCNT coating. MC3T3-E1 cells were cultured on the MWCNT-coated Ti plate, and showed good cell proliferation and strong cell adhesion. Therefore, the MWCNT coating for titanium could be useful for improvement of cell adhesion on titanium implants
Development of a multiwalled carbon nanotube coated collagen dish
No full textCarbon nanotubes (CNTs) are one of the most interesting nanomaterials because of their excellent characteristics. In this study, a transparent CNTs coating for cell culture dishes was developed and its properties for cell culture were estimated. Carboxylated multiwalled carbon nanotubes (MWCNTs) were dispersed in aqueous sodium cholate solution and applied on a collagen type I-coated cell culture dish (cover glass). The dish surface was homogeneously covered by MWCNTs without aggregation. The MWCNT-coated dish was slightly gray and had good transparency, so conventional optical microscopic observation of the cells on the MWCNT-coated dish was possible. Rat osteoblast-like cells cultured on the MWCNT-coated dish showed slightly lower viability and proliferation compared to the collagen-coated dish. The cell adhesion on the MWCNT-coated dish was much higher than that on the collagen-coated dish. Therefore, MWCNT-coating for dishes will be a useful new material for cell culture
Capture of bacteria by flexible carbon nanotubes
No full textCapture 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
Rapid analysis of metallic dental restorations using X-ray scanning analytical microscopy
No full textObjectives: 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
Rotational Slip Flow in Coaxial Cylinders by the Finite-Difference Lattice Boltzmann Methods
No full textAbstractRecent studies on applications of the lattice Boltzmann method (LBM) and the finite-difference lattice Boltzmann method (FDLBM) to velocity slip simulations are mostly on one-dimensional (1D) problems such as a shear flow between parallel plates. Applications to a 2D problem may raise new issues. The author performed numerical simulations of rotational slip flow in coaxial cylinders as an example of 2D problem. Two types of 2D models were used. The first were multi-speed FDLBM models proposed by the author. The second was a standard LBM, the D2Q9 model. The simulations were performed applying a finite difference scheme to both the models. The study had two objectives. The first was to investigate the accuracies of LBM and FDLBM on applications to rotational slip flow. The second was to obtain an experience on application of the cylindrical coordinate system. The FDLBM model with 8 directions and the D2Q9 model showed an anisotropic flow pattern when the relaxation time constant or the Knudsen number was large. The FDLBM model with 24 directions showed accurate results even at large Knudsen numbers.</jats:p
福島第一原発事故,2017年,福島市渡利・小倉寺の里山の汚染の実態
No full text2018-03-31In May of 2017, the author investigated the air radiation dose (1m above the ground) at the village forest in Watari and Oguraji areas. The range of the radiation dose was 0.15~1.77 μSv/h and its average was 0.56 μSv/h. In August of 2017, the author investigated the air radiation dose (1m above the ground) at the village forest in Watari area. The range of the radiation dose was 0.09~1.16 μSv/h and its average was 0.35 μSv/h. Decontamination work of this area started in 2012 and has been ended at the beginning of the investigation. However, the radiation dose rate in this area after the decontamination was still higher than the target value of 0.23 μSv/h tentatively proposed by Ministry of the Environment.2017年5月に福島市の渡利・小倉寺の里山において空間放射線率（高さ1m）を調査した．測定点は1039地点，空間放射線量率（地上1m）は0.15～1.77μSv/h，平均は0.56μSv/hであった．また，2017年8月，福島市渡利の弁天山においても同様の調査をした．測定点は830点，空間線量率(地上1m)は0.09～1.16μSv/h，平均は0.35μSv/hであった．公的な除染作業は，本調査時には終了している．しかし，空間放射線量率（地上1m）は除染の目標値0.23μSv/h以下には達していない．また，除染物を詰めた袋の放置，除染土の廃棄も見られた．departmental bulletin pape
Rapid and non-destructive analysis of metallic dental restorations using X-ray fluorescence spectra and light-element sampling tools
No full text1. Introduction: Recently, allergic diseases caused by dental metals have been increasing. Therefore, rapid and accurate analytical methods for the metal restorations in the oral cavities of patients are required. The purpose of this study was to develop a non-destructive extraction method for dental alloys, along with a subsequent, rapid and accurate elemental analysis. 2. Materials and Methods: Samples were obtained by polishing the surfaces of metal restorations using a dental rotating tool with disposable buffs and polishing pastes. As materials for the analysis, three dental alloys were used. To compare the sampling and analysis efficiencies, two buffs and seven pastes were used. After polishing the surface of a metal restoration, the buff was analyzed using X-ray scanning analytical microscopy (XSAM). 3. Results: The efficiency of the analysis was judged based on the sampling rate achieved and the absence of disturbing elements in the background in fluorescence X-ray spectra. The best results were obtained for the combination of TexMet as a buff with diamond as a paste. This combination produced a good collection efficiency and a plain background in the fluorescence X-ray spectra, resulting in a high precision of the analysis
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