Ryosuke Kondo

A six-carbazole-decorated cyclophosphazene as a host with high triplet energy to realize efficient delayed-fluorescence OLEDs

A high triplet energy (ET) host material, hexakis(9H-carbazol-9-yl)cyclotriphosphazene (PzCz), is used in high-efficiency organic light-emitting diodes (OLEDs). PzCz (ET = 3.00 eV) functions as an effective host for thermally activated delayed fluorescence (TADF) molecules. Highest external electroluminescence quantum efficiencies over 15% and 18% are achieved for blue-green and green TADF-OLEDs, respectively.

Soft tissue sealing around dental implants based on histological interpretation

PURPOSE The aim of this study was to provide an overview on the biology and soft tissue sealing around dental implants and teeth. STUDY SELECTION This is a narrative review performed through scientific articles published between 1977 and 2014, indexed in MEDLINE and PubMed databases. The study selected articles that focused on epithelial sealing around dental implant or teeth with cell biology and histology of soft tissue. RESULTS Implant therapy has been widely applied in dental rehabilitation for many years, with predictable long-term results. The longevity and functionality of dental implants is dependent on both osseointegration around the implant body and the establishment of a soft tissue barrier that protects the underlying hard tissue structures and the implant itself. The health and stability of the peri-implant mucosa also affects the esthetics of the implant. The healing and maintenance of the epithelial and connective tissues around implants are increasingly recognized as being fundamental to implant success. However, there has been little research into the function or formation of the soft tissue seal around dental implants, and the roles of this unique mucosal interface remain unclear. CONCLUSIONS This narrative review explores the extent of the current knowledge of soft tissue barriers around implants from both a basic and clinical perspective, and aims to consolidate this knowledge and highlight the most pertinent questions relating to this area of research.

Highly luminescent π-conjugated dithienometalloles: photophysical properties and their application in organic light-emitting diodes

We have disclosed the photophysical and electroluminescent properties of a series of hetero-annulated π-conjugated dithieno[3,2-b:2′,3′-d]metallole derivatives incorporating Ge, Si, P, and S atoms as a bridging center. The influence of the hetero-annulated structures on their photophysical properties has been investigated systematically by UV/vis and photoluminescence (PL) spectroscopy, transient PL measurements, and DFT calculations. All these compounds show bright fluorescence with high quantum yields both in solutions and in doped thin films with a host matrix. Furthermore, the OLEDs employing the dithienometallole emitters exhibit high external quantum efficiencies of ∼6% at a practical brightness.

Effects of CaCl2 hydrothermal treatment of titanium implant surfaces on early epithelial sealing.

Improvement of oral epithelial adhesion to titanium (Ti) may significantly enhance the efficacy of dental implants. We aimed to investigate whether calcium chloride (CaCl2) hydrothermally treated (HT) Ti could promote sealing of the peri-implant epithelium (PIE) around the implant. Right maxillary first molars were extracted from rats and replaced with either CaCl2-HT implants (Ca-HT group), distilled water-HT implants (DW-HT group), or untreated implants (Cont group). After 4 weeks, the implant-PIE interface of the Ca-HT group exhibited a band of immunoreactive laminin-332, similar to the tooth-junctional epithelium interface, which was absent in the Cont and DW-HT groups at the upper portion. We also investigated the effect of Ca-HT on the attachment of rat oral epithelial cells (OECs). OEC adherence onto Ca-HT Ti plates was stronger with higher expression levels of adhesion proteins compared with Cont and DW-HT groups. These results indicate that HT with CaCl2 improves the integration of soft tissue cells with the Ti implant at 4 weeks after implantation, which might facilitate the development of a soft tissue barrier around the implant.

Therapeutic interaction of systemically-administered mesenchymal stem cells with peri-implant mucosa

Objectives The objective of this study was to investigate the effect of systemically transplanted mesenchymal stem cells (MSCs) on the peri-implant epithelial sealing around dental implants. Materials and Methods MSCs were isolated from bone marrow of donor rats and expanded in culture. After recipient rats received experimental titanium dental implants in the bone sockets after extraction of maxillary right first molars, donor rat MSCs were intravenously transplanted into the recipient rats. Results The injected MSCs were found in the oral mucosa surrounding the dental implants at 24 hours post-transplantation. MSC transplantation accelerated the formation of the peri-implant epithelium (PIE)-mediated mucosa sealing around the implants at an early stage after implantation. Subsequently, enhanced deposition of laminin-332 was found along the PIE-implant interface at 4 weeks after the replacement. We also observed enhanced attachment and proliferation of oral mucous epithelial cells. Conclusion Systemically transplanted MSCs might play a critical role in reinforcing the epithelial sealing around dental implants.

Developing a Face Monitoring Robot for a Desk Worker

We have developed an autonomous mobile robot which monitors the face of a desk worker. The robot uses three kinds of information observed with its Kinect to search for the desk worker and adjusts its position for monitoring. The monitoring is based on incremental clustering of the faces. Our experiments revealed that not only Animation Units (AUs) features, which represent deviations from the neutral face, but also the pitch angle of the face normalized in a new way are necessary for a valid clustering under specific conditions. Our robot lost sight of a desk worker only once in experiments for 8 persons for about 50 minutes. The resulting clusters correspond to “yawning”, “smiling”, and “reading” for a half of the desk workers with high NMI (normalized mutual information), which is an evaluation measure often used in clustering.

Expression of Integrin alpha-3 and beta-4 subunits on the process of peri-implant epithelium formation

Integrin, a component of the hemidesmosome, plays a role for epithelial cell migration and adhesion. This study investigated the process of peri-implant epithelium (PIE) formation after implantation, and compared it to the process of oral mucosa healing after tooth extraction. At the healing site of extraction socket without implant, the original junctional epithelium (JE) had disappeared at week 2, and the oral epithelium (OE) with integrin-α3 positive basal cells extending from the sides of the wound, then joined in the middle of the extraction socket. On the other hand in implant group, newly formed epithelium with integrin-α3 positive cells from the OE extended apically 1 week after implantation. After 3 weeks, basal cells of the new epithelium consisted of those with integrin-α3 positive but β4 negative. Finally, after 4 weeks, integrin-β4 was expressed at the implant-PIE interface. These findings suggest that integrin α3β1 plays a role in cell migration during PIE formation from OE. Furthermore, after the completion of PIE constitution, integrin α6β4 contributes to the attachment to titanium.