Evaluation of radiation dose and image quality for dental cone-beam computed tomography in pediatric patients.

Children are sensitive to radiation; therefore, it is necessary to reduce radiation dose as much as possible in pediatric patients. In addition, it is crucial to investigate the optimal imaging conditions as they considerably affect the radiation dose. In this study, we investigated the effect of different imaging conditions on image quality and optimized the imaging conditions for dental cone-beam computed tomography (CBCT) examinations to diagnose ectopic eruptions and impacted teeth in children. To achieve our aims, we evaluated radiation doses and subjective and objective image quality. The CBCT scans were performed using 3D Accuitomo F17. All combinations of a tube voltage (90 kV), tube currents (1, 2, 3 mA), fields of view (FOVs) (4 × 4, 6 × 6 cm), and rotation angles (360°, 180°) were used. Dose-area product values were measured. SedentexCT IQ cylindrical phantom was used to physically evaluate the image quality. We used the modulation transfer function as an index of resolution, the noise power spectrum as an index of noise characteristics, and the system performance function as an overall evaluation index of the image. Five dentists visually evaluated the images from the head-neck phantom. The results showed that the image quality tended to worsen, and scores for visual evaluation decreased as tube currents, FOVs and rotation angles decreased. In particular, image noise negatively affected the delineation of the periodontal ligament space. The optimal imaging conditions were 90 kV, 2 mA, 4 × 4 cm FOV and 180° rotation. These results suggest that CBCT radiation doses can be significantly reduced by optimizing the imaging conditions.

Interface of Phospholipid Polymer Grafting Layers to Analyze Functions of Immobilized Oligopeptides Involved in Cell Adhesion.

The aim of this study was to design a material surface for use in the analysis of the behavior of biomolecules at the interface of direct cell contact. A superhydrophilic surface was prepared with poly(2-methacryloyloxyethyl phosphorylcholine) (PMPC), which was grafted onto a substrate with controlled polymer chain density. An arginine-glycine-aspartic acid (RGD) peptide was immobilized at the surface of the polymer graft surface (PMPC-RGD surface). Initial adhesion of the cells to this substrate was observed. The PMPC-RGD surface could enable cell adhesion only through RGD peptide-integrin interactions. The density and movability of the RGD peptide at the terminal of the graft PMPC chain and the orientation of the RGD peptide affected the density of adherent cells. Thus, the PMPC graft surface may be a good candidate for a new platform with the ability to immobilize biomolecules to a defined position and enable accurate analysis of their effects on cells.

The crystal structure of [Mg(dmso)6][BPh4]2 and the formation mechanism of the conformer on the basis of conformational analysis.

The crystal structure of a new magnesium(ii) complex, [Mg(dmso)6][BPh4]2 (1) (dmso: dimethylsulfoxide), was determined, and the reason for the observed structure was clarified by conformational analysis. For a dmso-ligand arm, three conformations, α, ß, and γ, are possible. The α-arm is the most energetically favourable and is suitable for reducing the steric repulsion between the arms; the ß-arm is less energetically favourable, but can be stabilized by interaction with surroundings (e.g. CHπ interaction); the γ-arm is not energetically favourable, but is effective in reducing the size of the complex cation. From the conformational analysis, the most stable conformer of the [Mg(dmso)6]2+ complex cation was found to be the α6 conformer, and the complex cation in dmso solution was predicted to exist as a mixture of α6, α5ß, and trans-α4ß2 species. On the contrary, in the crystal structure, the trans-ß2γ4 species, considered to be unstable, was observed. From the conformational analysis in the tetraphenylborate surroundings, the trans-ß2γ4 structure was found to become more stable, due to its small size suitable for crystal packing with bulky tetraphenylborate anions.

Removal mechanism of sulfamethazine and its intermediates from water by a rotating advanced oxidation contactor equipped with TiO2-high-silica zeolite composite sheets.

The removal of antibiotic sulfamethazine (SMT) and its intermediates from water was investigated using a rotating advanced oxidation contactor (RAOC) equipped with TiO2-high-silica zeolite composite sheets. SMT was readily removed from water through adsorption onto high-silica zeolite and photocatalytic decomposition by TiO2 inside the composite sheet. Some degradation intermediates were retained and photocatalytically decomposed inside the composite sheet. Relatively hydrophobic intermediates such as hydroxylated SMT were captured inside the sheets, whereas hydrophilic intermediates were distributed in water. This was attributed to the hydrophobic interactions in the adsorption mechanism of high-silica zeolite. The time courses of the NH4+, NO3-, and SO42- ion concentration during the RAOC treatment of SMT were evaluated. After treatment by RAOC for 24 h, approximately 94% of nitrogen derived from the amino and sulfanilamide groups and 39% of sulfur from the sulfanilamide group were mineralized, which indicated that the mineralization behavior of SMT treated by RAOC was different from that treated by TiO2 powder. These results strongly suggested that the dissociation of the amino group and cleavage of the sulfonamide group and subsequent dissociation of the amino group preferentially proceeded inside the composite sheets.

Adsorptive removal and photocatalytic decomposition of sulfamethazine in secondary effluent using TiO2-zeolite composites.

We investigated the adsorption and decomposition of sulfamethazine (SMT), which is used as a synthetic antibacterial agent and discharged into environmental water, using high-silica Y-type zeolite (HSZ-385), titanium dioxide (TiO2), and TiO2-zeolite composites. By using ultrapure water and secondary effluent as solvents, we prepared SMT solutions (10 µg/L and 10 mg/L) and used them for adsorption and photocatalytic decomposition experiments. When HSZ-385 was used as an adsorbent, rapid adsorption of SMT in the secondary effluent was confirmed, and the adsorption reached equilibrium within 10 min. The photocatalytic decomposition rate using TiO2 in the secondary effluent was lower than that in ultrapure water, and we clarified the inhibitory effect of ions and organic matter contained in the secondary effluent on the reaction. We synthesized TiO2-zeolite composites and applied them to the removal of SMT. During the treatment of 10 µg/L SMT in the secondary effluent using the composites, 76% and more than 99% of the SMT were decomposed within 2 and 4 h by photocatalysis. The SMT was selectively adsorbed onto high-silica Y-type zeolite in the composites. Resultantly, the inhibitory effect of the coexisting materials was reduced, and the composites could remove SMT more effectively compared with TiO2 alone in the secondary effluent.

[Suggestion to school pharmacists to utilize absolute humidity parameter for maintaining air-conditioning].

One of the major roles of a school pharmacist is to maintain adequate air conditioning in the school to prevent the spread of infectious diseases. Influenza, the most important infectious disease at school, can be a cause of temporary closure of classes. We ordinarily examine relative humidity (RH), a popular parameter in the pharmaceutical field. However, RH is the ratio of vapor pressure to saturation vapor pressure at the indicated temperature and does not indicate the actual amount of water in the atmosphere. RH is temperature-dependent and varies easily with temperature. The use of absolute humidity (AH) is not common among school pharmacists because calculating AH from the measured temperature is not straightforward. In addition, commercially available humidity meters are usually designed for RH. We surveyed the relationship between climate data and influenza epidemics in Kobe from 2007 to 2012. We found that AH is more closely correlated with the number of patients than RH and that there is an AH threshold at which an influenza outbreak can occur in Kobe: 10 g/m(3). The 2009 epidemic pattern, when influenza A (H1N1) virus spread throughout the country, was irregular and AH did not correlate with the number of patients. Because AH can be easily measured using a computer without the need of any additional instruments, we suggest that school pharmacists utilize AH in combination with temperature as a better parameter for predicting the onset of influenza epidemics. When AH in Kobe decreases to 10 g/m(3), schools should be immediately cautioned.