Accuracy and dimensional reproducibility by model scanning, intraoral scanning, and CBCT imaging for digital implant dentistry.

BACKGROUND: Recently, it has become possible to analyze implant placement position using the digital matching data of optical impression data of the oral cavity or plaster models with cone beam computed tomography (CBCT) data, and create a highly accurate surgical guide. It has been reported that CBCT measurements were smaller than the actual values, termed shrinkage. Matching of digital data is reliable when the plaster model or intraoral impression values show shrinkage at the same rate as the CBCT data. However, if the shrinkage rate is significantly different, the obtained digital data become unreliable. To clarify digital matching reliability, we examined dimensional reproducibility and shrinkage in measurements obtained with a model scanner, intra-oral scanner (iOS), and CBCT. MATERIALS AND METHODS: Three implants that were arranged in a triangle were fixed in an acrylic plate. The distance between each implants were measured using model scanner, iOS, and CBCT. The actual size measured by electronic caliper was regarded as control. RESULTS: All values measured with CBCT were significantly smaller than that of model scanner, iOS, and control (p<0.001). The model scanner shrinkage was 0.37-0.39%, iOS shrinkage was 0.9-1.4%, and CBCT shrinkage was 1.8-6.9%. There were statistically significant differences among the shrinkage with iOS, CBCT, and model scanner (p<0.001). CONCLUSION: Our findings showed that all measurements obtained with those modalities showed shrinkage as compared to the actual values. In addition, CBCT shrinkage was largest among three different measuring methods. They indicated that data matching between CBCT and scanner measurements requires attention in regard to the reliability of values obtained with those devices.

Thermoelectric Properties of (Ba,K)Zn2As2 Crystallized in the ThCr2Si2-type Structure.

The compound Ba1-xKxZn2As2 has a low-temperature phase (α-phase) crystallized in the α-BaCu2S2-type structure and a high-temperature phase (ß-phase) crystallized in the ThCr2Si2-type structure. We successfully obtained the ß-phase at room temperature as a metastable state by quenching from above the structural phase transition. This allowed us to determine the thermoelectric properties of the ß-phase from room to high temperature in the range of 0.00 ≤ x ≤ 0.10. The lattice thermal conductivity is quite low, with a value less than 1 W/mK at 773 K, independent of x. The effective suppression may be due to lattice instability in the underdoped region and to randomness in the overdoped region. The maximum dimensionless figure-of-merit ZT was 0.30 at 773 K for x = 0.03 with the power factor of 0.61 mW/mK2, which is relatively high for a ThCr2Si2-type structure. The results demonstrate the effectiveness of quenching for obtaining a low lattice thermal conductivity, thus providing a new method for attaining high thermoelectric performance.

Substitutional and interstitial impurity p-type doping of thermoelectric Mg2Si: a theoretical study.

The narrow-gap magnesium silicide semiconductor Mg2Si is a promising mid-temperature (600-900 K) thermoelectric material. It intrinsically possesses n-type conductivity, and n-type dopants are generally used for improving its thermoelectric performance; however, the synthesis of p-type Mg2Si is relatively difficult. In this work, the hole doping of Mg2Si with various impurity atoms is investigated by performing first principles calculations. It is found that the Ag-doped systems exhibit comparable formation energies ΔE calculated for different impurity sites (Mg, Si, and interstitial 4b ones), which may explain the experimental instability of their p-type conductivity. A similar phenomenon is observed for the systems incorporating alkali metals (Li, Na, and K) since their ΔE values determined for Mg (p-type) and 4b (n-type) sites are very close. Among boron group elements (Ga and B), Ga is found to be favorable for hole doping because it exhibits relatively small ΔE values for Si (p-type) sites. Furthermore, the interstitial insertion of Cl and F atoms into the crystal lattice leads to hole doping because of their high electronegativity.

Binding of PICK1 PDZ domain with calcineurin B regulates osteoclast differentiation.

The calcineurin/nuclear factor of activated T cell (NFAT) signaling pathway plays a major role in osteoclast differentiation; however, the proteins that react with the calcineurin-NFAT complex in osteoclasts to regulate osteoclastogenesis remain unclear. Here, we present evidence that PICK1 also positively regulates calcineurin B in osteoclasts to activate NFAT to promote osteoclastogenesis. mRNA and protein expression of PICK1 in murine primary bone marrow macrophages (BMMs) was significantly increased during RANKL-induced osteoclast differentiation. The interaction of PICK1 with calcineurin B in BMMs was confirmed by co-immunoprecipitation. An inhibitor of the PICK1 PDZ domain significantly decreased osteoclastogenesis marker gene expression and the number of TRAP-positive multinucleated cells among RAW264.7 osteoclast progenitor cells. Overexpression of PICK1 in RAW264.7 cells significantly increased the number of TRAP-positive mature osteoclasts. Increased NFAT activation with transcriptional activation of PICK1 during RAW264.7 osteoclastogenesis was also confirmed in a tetracycline-controlled PICK1 expression system. These results suggest that the PDZ domain of PICK1 directly interacts with calcineurin B in osteoclast progenitor cells and promotes osteoclast differentiation through activation of calcineurin-NFAT signaling.

PICK1 binds to calcineurin B and modulates the NFAT activity in PC12 cells.

In the central nervous system, calcineurin has been implicated in a number of Ca2+-sensitive pathways, including the regulation of neurotransmitter release and modulation of synaptic plasticity. PDZ domain-containing proteins also play an important role in the targeting and clustering of synaptic proteins. Using a yeast two-hybrid screen, we herein identified the PDZ domain-containing protein PICK1 as a specific interactor of calcineurin B. The interaction of calcineurin B and PICK1 was confirmed by GST pull-down assay in HEK293 cells and immunoprecipitation using rat brain lysate. Calcineurin B contains the consensus C-terminal peptide sequence required for interacting with the PDZ domain. The deletion of this sequence was sufficient to abolish the interaction between calcineurin B and PICK1. In addition, the knockdown of PICK1 by RNA interference inhibited the calcineurin-dependent activation of NFAT in PC12 cells. These results suggest that PICK1 may be a positive regulator of calcineurin in the central nervous system.

Decreased levels of adiponectin in obese patients with gastroesophageal reflux evaluated by videoesophagography: possible relationship between gastroesophageal reflux and metabolic syndrome.

BACKGROUND: Body mass index (BMI) and obesity are reportedly associated with symptoms of gastroesophageal reflux disease (GERD). The present study was designed to investigate the effect of metabolic disorders including obesity on the levels of functional gastroesophageal reflux by videoesophagography. METHODS: Twenty-one patients with GERD-associated symptoms were examined by videoesophagography. On their initial visit, all patients completed the Japanese version of the Carlsson-Dent self-administered questionnaire (QUEST). The findings of videoesophagography were evaluated by the X-ray severity scores for gastroesophageal reflux (XRSS), which were defined for the total diagnosis of functional gastroesophageal reflux. Correlation between XRSS scores and physical or metabolic markers was evaluated. RESULTS: The mean XRSS in the QUEST-positive group (4.7+/-0.6) was significantly higher than that in the QUEST-negative group (3.3+/-0.5, P<0.05). XRSS correlated positively with BMI (P<0.05) and waist circumference (P<0.05), but negatively with high-density lipoprotein-cholesterol (P<0.05), serum adiponectin (P<0.05) and active ghrelin (P<0.05). In the multivariate analysis, serum adiponectin level, BMI and triglyceride independently affected the XRSS. CONCLUSION: Videoesophagography is a useful diagnostic modality for the evaluation of patients with GERD symptoms. Functional gastroesophageal reflux is seen in obese patients, especially with decreased levels of adiponectin.