Application of a New Microtensile Bond Strength Testing Technique for the Evaluation of Enamel Bonding.

OBJECTIVE: To evaluate adhesives' enamel bonding performance utilising the traditional microtensile bond strength test (µTBST) and a new double-sided microtensile bond strength test (DµTBST) to assess the suitability of the latter. METHODS: A 'tug-of-war' direct encounter design was employed to compare the enamel bond strengths of two universal adhesives and their different application modes simultaneously under the same tensile load applied to double-sided bonded specimens. Clearfil Universal Bond (CU; Kuraray, Kurashiki, Japan) and Scotchbond Universal Adhesive (SB; 3M ESPE, St Paul, MN, USA) were applied in self-etch (S) and etch-and-rinse (E) mode on 110 human molar samples to perform two experiments. Experiment 1 compared the enamel bond strengths of the combinations of adhesive application modes utilising µTBST. The data were analysed using a Welch analysis of variance (ANOVA), followed by a Games-Howell test. Experiment 2 employed DµTBST to determine the suitability of the new double-sided bonded assembly and ascertain which of the adhesive application mode combinations was superior. The data were analysed using a Kaplan-Meier survival analysis, followed by pairwise comparisons with a Mantel-Cox log-rank test. The level of significance was set at P ˂ 0.05. RESULTS: The µTBST results did not show significant differences for CUE vs CUS, SBE vs SBS, CUS vs SBS and CUS vs SBE (P ˃ 0.05); however, from DµTBST, the survival distributions for the interventions were statistically significantly different (χ2(3) = 145.130, P ˂ 0.0005), indicating the superiority of universal adhesive CU over SB and application mode E over S with certainty. CONCLUSION: DµTBST was able to add more discerning outcomes to the µTBST results, indicating that the new technique could become a valuable adjunct to the conventional method.

Risk assessment of fluoride and arsenic in groundwater and a scenario analysis for reducing exposure in Inner Mongolia.

In contrast to Mongolia, family-owned land in Inner Mongolia is separated by fences, preventing the free movement of nomads and leading people to rely heavily on the same source of groundwater for their domestic water needs. Therefore, it is important to clarify groundwater quality and understand the associated human health concerns. To evaluate the risks of drinking groundwater to human health in Inner Mongolia, we examined groundwater quality by field surveys, a human health risk analysis, and a scenario analysis. During the summer of 2015 in Inner Mongolia, we measured the concentrations of major ions, metals, metalloids, and rare earth metals in groundwater samples (n = 32) and river water samples (n = 10), for which there were no known anthropogenic contamination sources. In addition, as part of a scenario analysis, samples of tap water (n = 1), snowmelt (n = 1), and bottled water (n = 1) were also evaluated. We used our analytical results to calculate hazard quotient (HQ) ratios by means of a probabilistic risk assessment method. The results indicated that residents who drank groundwater every day might have risk concerns for F- (mean ± standard deviation, 2.51 ± 1.80 mg L-1; range, 0.07-7.70 mg L-1) and As (6.49 ± 9.64 µg L-1; 0.31-47.0 µg L-1). We observed no relationships between well depth or any geophysical variation and groundwater quality. On the basis of the scenario analysis results, we concluded that using snow as a source of drinking water in winter could reduce health risks associated with using groundwater for this population in Inner Mongolia.

Evaluation of QT interval using a linear model in individual cynomolgus monkeys.

INTRODUCTION: The cynomolgus monkey, one of a number of primate species phylogenetically close to humans, is commonly used in cardiovascular research, but a method for determination of the RR interval-corrected QT interval in this species needs greater consideration. The objectives of this study were to determine a method for evaluating QT interval in cynomolgus monkeys individually, disregarding RR interval change artifacts, and to investigate prerequisite information for this method. METHODS: The physiological QT-RR relationship for practical evaluation of QT interval was recorded and analyzed by 24-hour telemetric ECG monitoring. A linear model for log-transformed QT and RR intervals was used to correct the QT interval from RR interval change artifacts for each animal. Sample size was also estimated based on the simulation results. RESULTS: Histograms showed that both QT and RR intervals had a right-heavy tail distribution. QT interval corrected individually by the linear model formula showed smaller within-animal variability than QTb and QTf, which were corrected by Bazett's formula and Fridericia's formula. The simulation results showed that the individual correction factor, beta(i), could be reliably estimated when at least 24 pairs of QT-RR baseline data were available. DISCUSSION: As with humans, QT interval in cynomolgus monkeys varies widely between individuals. Therefore, a method for correcting QT interval individually should be considered, whenever extensive untreated data are available.

Individual reference intervals of hematological and serum biochemical parameters in cynomolgus monkeys.

Cynomolgus monkeys, one of a number of primates phylogenetically close to humans, are commonly used in animal studies. The purpose of this study was to assess biological variations in hematological and serum biochemical parameters in cynomolgus monkeys. Summary statistics and reference intervals were calculated using data from 95 male and 95 female Chinese-bred cynomolgus monkeys aged 3 to 7 years showing no abnormalities during the breeding period. Within- and between-animal variations were estimated using a random-effect analysis of variance (ANOVA), then, a simple method that applies prior information was proposed to estimate individual reference intervals. Parameters including MCV, MCH, PT, ALP, total cholesterol, and creatinine appeared to show a large between-animal variation; thus, it is considered that individual reference intervals for these parameters would be relatively small in comparison with overall reference intervals.