Activation of ß-catenin by TGF-ß1 promotes ligament-fibroblastic differentiation and inhibits cementoblastic differentiation of human periodontal ligament cells.

TGF-ß and Wnt/ß-catenin signaling pathways are known to be essential for the development of periodontal tissue. In this study, we examined the crosstalk between TGF-ß and Wnt/ß-catenin signaling in ligament-fibroblastic differentiation of human periodontal ligament cells (hPDLCs). TGF-ß1 treatment significantly increased the expression of ligament-fibroblastic markers, but such expression was preventing by treatment with SB431542, a TGF-ß type I receptor inhibitor. As well as phosphorylation of Smad3, TGF-ß1 increased ß-catenin activation. The depletion of ß-catenin reduced the expression of ligament-fibroblastic markers, suggesting that ß-catenin is essential for ligament differentiation. The effect of TGF-ß1 on ß-catenin activation did not seem to be much correlated with Wnt stimuli, but endogenous DKK1 was suppressed by TGF-ß1, indicating that ß-catenin activation could be increased much more by TGF-ß1. In addition to DKK1 suppression, Smad3 phosphorylation by TGF-ß1 facilitated the nuclear translocation of cytoplasmic ß-catenin. In contrast to ligament-fibroblastic differentiation, inhibition of TGF-ß1 signaling was needed for cementoblastic differentiation of hPDLCs. BMP7 treatment accompanied by inhibition of TGF-ß1 signaling had a synergistic effect on cementoblastic differentiation. In conclusion, ß-catenin activation by TGF-ß1 caused ligament-fibroblastic differentiation of hPDLCs, and the presence of TGF-ß1 stimuli basically determined whether hPDLCs are differentiated into ligament progenitor or cementoblasts.

Cell Surface Accumulation of Intracellular Leucine Proline-Enriched Proteoglycan 1 Enhances Odontogenic Potential of Human Dental Pulp Stem Cells.

Primary dental pulp cells can be differentiated into odontoblast-like cells, which are responsible for dentin formation and mineralization. Successful differentiation of primary dental pulp cells can be verified using a few markers. However, odontoblast-specific cell surface markers have not been fully studied yet. LEucine PRoline-Enriched Proteoglycan 1 (LEPRE1) is a basement membrane-associated proteoglycan. LEPRE1 protein levels are increased during odontoblastic differentiation of human dental pulp cells (hDPCs). Intracellular and cell surface accumulation of this protein completely disappeared during dentin maturation and mineralization. Cell surface binding of an anti-LEPRE1 monoclonal antibody that could recognize an extracellular region was gradually increased in the odontoblastic stage. Overexpression and knockdown experiments showed that accumulation of intracellular LEPRE1 could lead to inefficient odontoblastic differentiation and that the movement of LEPRE1 from intracellular region to the cell surface was required for odontoblastic differentiation. Indeed, when LEPRE1 already located on the cell surface was blocked by the anti-LEPRE1 monoclonal antibody, odontoblastic differentiation of hDPCs was inhibited. In this study, we looked at other aspects of LEPRE1 function as a cell surface molecule rather than its known intracellular hydroxylase activity. Our results indicate that this protein has potential as a specific cell surface marker in odontoblastic differentiation.

Chemical synthesis of Nd2Fe14B/Fe-Co nanocomposite with high magnetic energy product.

Nd2Fe14B is one of the most popular permanent magnets (PMs) possessing the best energy product (BH)max among the common PM materials. However, exchange-coupled nanocomposite magnets fabricated by embedding nanostructures of soft-phase magnetic materials into a hard-phase magnetic matrix manifest higher remanence and a higher energy product. Here we present the fabrication of exchange coupled Nd2Fe14B/Fe-Co magnetic nanocomposites using gel-combustion and diffusion-reduction processes. Pre-fabricated CoFe2O4 nanoparticles (NPs) of ∼5 nm diameter were incorporated into a Nd-Fe-B oxide matrix during its synthesis by gel-combustion. The obtained mixed oxide was further processed with oxidative annealing at 800 °C for 2 h and reductive annealing at 900 °C for 2 h to form a Nd2Fe14B/Fe-Co nanocomposite. Nanocomposites with different mol% of soft-phase were prepared and characterized by X-ray diffraction (XRD), transmission electron microscopy (TEM) and physical property measurement system (PPMS) to study their crystalline phase, morphology and magnetic behavior. Addition of 7.7 mol% of soft-phase was found to be optimum, producing a coercivity (H c) of 5.6 kOe and remanence (M r) of 54 emu g-1 in the nanocomposite.

Exchange-Coupling Interaction in Zero- and One-Dimensional Sm2Co17/FeCo Core-Shell Nanomagnets.

Rare-earth-based core-shell spring nanomagnets have been intensively studied in the permanent magnet industry. However, the inherent agglomeration characteristics of zero-dimensional (0-D) magnetic nanoparticles are an issue in practical fabrication of magnetic nanocomposites due to deterioration in exchange-coupling interactions, resulting in inferior magnetic performance. Here, with an aim to overcome the structural limitations, we report a new type of SmCo/FeCo core-shell nanomagnet with a well-dispersed one-dimensional (1-D) structure prepared by a combination of electrospinning and electroless plating processes. An FeCo layer with a tailored thickness on nanoscale SmCo was produced to achieve a sufficient exchange-coupling effect. The influence of electroless plating time on the microstructure of fibers was discussed, and comparisons were made as a function of the magnet shape. A 1-D SmCo/FeCo spring nanomagnet having a core diameter ranging from 150 to 200 nm and a shell thickness of 15-20 nm showed a potent exchange-coupling effect compared with its 0-D counterpart. This effectively reduced self-aggregation and further showed a remarkable enhancement in (BH)max (above 45.7%). We think that this novel structure marks a new era in the exchange-spring magnet industry and may overcome the limitations of traditional core-shell nanomagnets.

Synthesis and Magnetic Properties of τ-MnAlC Powders.

In order to improve the hard magnetic properties of MnAl alloy, it is critical to fabricate fine τ phase MnAl powders. In addition, a rapid cooling process and an addition of stabilization elements are required to fabricate a homogeneous phase because a τ phase is a metastable structure. In this study, τ-Mn54Al(46-x)C(x) (x = 0, 1, 2) powders were prepared by melt-spinning and subsequent annealing and milling processes. As a result, a main phase was revealed as a high temperature e phase in melt spun MnAI ribbons. And a subsequent annealing in the temperature range of 450-650 degrees C resulted in the formation of a τ phase. A maximum saturation magnetization (M(s)) value of 96.56 emu/g was obtained when the melt-spun τ-Mn54Al44C2 ribbons were annealed at 500 degrees C for 10 min. However, a milling process increased the coercivity up to 3804 Oe but simultaneously reduced M(s) down to 60.34 emu/g.

Enhancement of the Remanence Value of Bulk Strontium Ferrite by the Addition of AlNiCo.

Increasing the remanence value of bulk permanent magnets is a critical issue to increase their maximum energy product ((BH)(max)) value. Currently, the enhancement of magnetic alignment is known to come close to the engineering limit. In this study, we investigated the effect of a magnetic layered structure on the remanence value using strontium ferrite and AlNiCo. Through the thickness control of AlNiCo layers, the magnetic properties of the layered composite magnets were evaluated. As a result, the remanence value increased from 4.13 kG to 4.32 kG and the maximum energy product value increased from 3.90 MGOe to 4.23 MGOe with the 5 wt% addition of AlNiCo.

The stability following advancement genioplasty with biodegradable screw fixation.

The purpose of this study was to compare postoperative stability using biodegradable screws with that of metal plates for fixation of advancement genioplasty. We studied patients who had advancement genioplasty alone or at the same time as other orthognathic surgery including mandibular setback. We assessed the lateral cephalographs at different time points (preoperatively, and 7 days, 3 months, 6 months, and 12 months postoperatively). A total of 54 patients were enrolled and 27 patients were assigned to each group. The position of pogonion was stable 12 months postoperatively, and the amount of skeletal advancement was reflected in soft tissue close to 100%. There were no clinical differences between biodegradable screws and conventional metal plates used for fixation. Biodegradable fixation for advancement genioplasty is a good option for patients who would require a second operation for removal of the plates.