Screening analysis of RoHS directive hazardous substances (phthalate esters and bromodiphenyl ethers) by novel mass spectrometry using soft ionization.

In 2013, the European Union expanded the list of hazardous substances contained in the RoHS Directive. In addition, certain phthalate esters, such as dibutyl phthalate (DBP), butyl benzyl phthalate (BBP), di-2-ethylhexyl phthalate (DEHP) and diisobutyl phthalate (DIBP), will be categorized as RoHS-prohibited substances starting from July 2019. Although pyrolysis-gas chromatography-mass spectrometry (Py-GC-MS) is a promising analytical method for the screening of phthalate esters, we have developed a novel soft-ionization MS method that is quantitative as well as faster and more convenient for this purpose. The sample was measured three times, after providing the calibration curve using a powdery standard material of SPEX. The data collection time is 5 min, and continuous measurements are completed within 8 min per sample. The mass spectrum was corrected by dividing the intensity by the sample weight. For the coefficient of variation, DBP was 2.9%, BBP was 3.4%, DEHP was 3.6%, and good reproducibility was observed. Precise analyses of phthalate esters using traditional methods can require solvent extraction times of up to 24 h as well as special techniques. Therefore, a screening method that can be easily carried out by anyone within ten minutes is very attractive.

Effects of Microstructure on Electrode Properties of Nanosheet-Derived Hx(Ni1/3Co1/3Mn1/3)O2 for Electrochemical Capacitors.

Nanosheet-derived Hx(Ni1/3Co1/3Mn1/3)O2 was prepared by restacking (Ni1/3Co1/3Mn1/3)O2 nanosheets with large or small lateral sizes and their electrochemical properties in a 1 M KOH aqueous solution; microstructural factors were compared with those of bulk Hx(Ni1/3Co1/3Mn1/3)O2 (HNCM). The electrodes composed of small nanosheets exhibited very large capacitances of 1241 F·g-1 (395 mAh·g-1) at a current density of 50 mA·g-1, and 430 F·g-1 (100 mAh·g-1) at a large current density of 1000 mA·g-1. These large capacitances resulted from a heterogeneous layer structure with a large surface area and pore volume. The electrodes of large nanosheets, with a strongly interconnected microstructure and a surface area slightly larger than that of HNCM, exhibited good cycle stability and capacitances larger than that of HNCM. Microstructural control through the restacking of (Ni1/3Co1/3Mn1/3)O2 nanosheets improved the electrochemical properties of Hx(Ni, Co, Mn)O2.

Specific response of osteoblast-like cells on hydroxyapatite layer containing serum protein.

Accelerations of bone-like apatite deposition and cell growth on an electrically polarized ceramic hydroxyapatite have been reported. A relationship between these phenomena was investigated in a previous report, and then it was suggested that osteoblast-like cell's (MC3T3-E1) growth had relevance to the mineral growth. The effect of the formed apatite layer especially appeared to be on the cell adhesion. The acceleration of cell proliferation on the polarized HAp has been shown using fibroblastic cell (L929) and nerve cell (SK-N-SH) lines, therefore the effect of the layer on L929 and SK-N-SH was investigated to support the mechanism of acceleration of cell proliferation by polarization of HAp. In this study, the effect of the bone-like apatite layer was not confirmed on L929 cell's growth. On the other hand, the acceleration of nerve cell's proliferation was confirmed on the formed apatite layer. However, the remarkable improvement of the cell adhesion of SK-N-SH was not confirmed on the apatite layer. Consequently, it was considered that the bone-like apatite containing serum protein obtained by the coprecipitation of bone-like apatite and serum protein has a pronounced role only in the activity of osteoblast-like cells.

Octacalcium phosphate-based cement as a pulp-capping agent in rats.

OBJECTIVE: The purpose of this study was to evaluate the pulpal response to an octacalcium phosphate (OCP)-based cement used as a pulp-capping material. STUDY DESIGN: The pulps of 60 maxillary first molars of male Sprague-Dawley rats were exposed and then capped directly by using either OCP-based cement or a calcium hydroxide slurry (control). Histologic examinations were performed at 1, 2, and 5 weeks after the surgical procedure, and the results were analyzed statistically by using the Mann-Whitney U test (P<.05). RESULTS: One week after pulp capping, the initial formation of reparative dentin in the exposed areas was more notable in the calcium hydroxide group than in the OCP-based cement group. At 2 weeks, reparative dentin covered by a layer of odontoblast-like cells was observed in both groups. However, at 5 weeks, reparative dentin consisting of regular dentinal tubules was observed more frequently in the OCP-based cement group. CONCLUSION: OCP-based cement allowed favorable healing processes to occur in the dental pulp.

Effect of bone-like layer growth from culture medium on adherence of osteoblast-like cells.

The electrical polarization of ceramic HAp had an effect on the acceleration of bone restoration. Cell behavior in the bone-like growth layer was investigated. The deposits on the ceramic HAp was grown and formed layers by soaking in alpha-minimum essential medium supplemented with 10% fetal bovine serum (alpha-MEM supplemented with 10% FBS). The shapes of the adhering cells on the grown layer gradually changed from spindle to flat with growth of the layer. On the totally grown layer that was grown on the ceramic HAp by soaking in alpha-MEM supplemented with 10% FBS for 7 days, all the adhering cells were flat and the surface was filled with the grown cells. From these results, it was revealed that the grown layer on the ceramic HAp is one of the activation factors of cell growth. Consequently, cell growth was reinforced by acceleration of the layer growth on the negatively charged surface of the polarized ceramic HAp.