Semi-customized three-dimensional ultra-fine titanium meshes in guided bone regeneration for implant therapy in severe alveolar bone defect: a case report.

This case report provides a detailed description of a simple and fast bone regeneration procedure using a semi-customized three-dimensional ultra-fine titanium mesh. A 50-year-old male with a severe vertical and horizontal bone defect in the anterior mandible underwent implant treatment in a staged approach. The autologous bone was combined with a xenograft, and the mixture was grafted to augment the bone defect and covered with semi-customized ultra-fine titanium meshes, which were selected among its various types according to size and configuration of the bone defect, directly connected and immobilized on the tenting screws with minimal shaping. In a postoperative 6 months re-entry surgery, the performed titanium meshes were removed, implants were placed, and a bone core biopsy was obtained that demonstrated satisfactory new bone formation. Finally, two months later, the definitive prosthesis was installed. This semi-customized ultra-fine titanium mesh could help an implant clinician obtain more predictable results in the guided bone regeneration (GBR).

A Randomized Controlled Trial of Guided Bone Regeneration for Peri-Implant Dehiscence Defects with Two Anorganic Bovine Bone Materials Covered by Titanium Meshes.

The aim of this study is to compare two low-temperature sintered anorganic bovine bone materials (ABBMs), Bio-Oss (Geistlich, Wolhusen, Switzerland) and A-Oss (Osstem, Seoul, Korea), for GBR in dehiscence defects. A single implant was placed simultaneously with GBR in the buccal or bucco-proximal osseous defect by double-layering of inner allograft and outer ABBM, covered by a preformed ultrafine titanium mesh and an absorbable collagen membrane. Grafted volume changes were evaluated by cone-beam computed tomography, taken preoperatively (T0), immediately after implant surgery (T1), after re-entry surgery (T2), and after delivery of the final restoration (T3). The density of the regenerated bone was assessed by measuring the probing depth on the buccal mid-center of the mesh after removing the mesh at T2. Postoperative sequelae were also recorded. Grafted volume shrinkage of 46.0% (0.78 ± 0.37 cc) and 40.8% (0.79 ± 0.33 cc) in the Bio-Oss group (8 patients) and A-Oss group (8 patients), respectively, was observed at T3 (p < 0.001). There were no significant differences in grafted volume changes according to time periods or bone density between the two groups. Despite postoperative mesh exposure (3 patients), premature removal of these exposed meshes and additional grafting was not necessary, and all implants were functional over the 1-year follow-up period. Both ABBMs with titanium meshes showed no significant difference in the quantity and density of the regenerated bone after GBR for peri-implant defects.

Nucleolar GTPase NOG-1 regulates development, fat storage, and longevity through insulin/IGF signaling in C. elegans.

NOG1 is a nucleolar GTPase that is critical for 60S ribosome biogenesis. Recently, NOG1 was identified as one of the downstream regulators of target of rapamycin (TOR) in yeast. It is reported that TOR is involved in regulating lifespan and fat storage in Caenorhabditis elegans. Here, we show that the nog1 ortholog (T07A9.9: nog-1) in C. elegans regulates growth, development, lifespan, and fat metabolism. A green fluorescence protein (GFP) promoter assay revealed ubiquitous expression of C. elegans nog-1 from the early embryonic to the adult stage. Furthermore, the GFP-tagged NOG-1 protein is localized to the nucleus, whereas the aberrant NOG-1 protein is concentrated in the nucleolus. Functional studies of NOG-1 in C. elegans further revealed that nog-1 knockdown resulted in smaller broodsize, slower growth, increased life span, and more fat storage. Moreover, nog-1 over-expression resulted in decreased life span. Taken together, our data suggest that nog-1 in C. elegans may be an important player in regulating life span and fat storage via the insulin/IGF pathway.

Effect of needle-like silicon nanosurface on the charge storage characteristics of silicon nanocrystals embedded within silicon nitride matrix.

In this work, a metal-insulator-silicon (MIS) structure with a silicon nitride (SiNx) film, in which silicon nanocrystals (Si-NCs) are embedded as a gate insulator layer, was fabricated on needle-like silicon nanosurfaces. The MIS structure with Si-NCs embedded within the SiNx on the needle-like silicon nanosurface can be used to fabricate nonvolatile memory (NVM) devices with increased charge storage capacities compared to planar structures. In this study, as part of a strategy to overcome the technological and physical constraints involved in scaling down of NVM devices, the charge storage effects associated with the electronic properties of the MIS structure with a silicon substrate having a needle-like nanostructure were evaluated. For fabrication of the needle-like silicon nanosurfaces, polystyrene-block-polymethyl methacrylate (PS-b-PMMA) block copolymer composed of polystyrene (PS) and polymethyl methacrylate (PMMA) was used. The hysteresis width of the capacitance-voltage (C-V) characteristics of the MIS structures embedded with Si-NCs on the silicon substrates of the needle-like nanostructure was greater than that of the MIS structure embedded with Si-NCs fabricated on a planar structure. The interface trap density between the SiNx and uniform needle-like silicon nanosurface was also lower than that of the MIS structure fabricated on a planar structure. Therefore, NVM devices with increased charge storage capacity compared to those fabricated on a planar structure can be realized with a needle-like silicon nanosurface.

Fabrication of nanostructure and formation of nanocrystal for non-volatile memory.

In this work, we have demonstrated that the nanocrystal created by combining the self-assembled block copolymer thin film with regular semiconductor processing can be applicable to non-volatile memory device with increased charge storage capacity over planar structures. Self-assembled block copolymer thin film for nanostructures with critical dimensions below photolithographic resolution limits has been used during all experiments. Nanoporous thin film from PS-b-PMMA diblock copolymer thin film with selective removal of PMMA domains was used to fabricate nanostructure and nanocrystal. We have also reported about surface morphologies and electrical properties of the nano-needle structure formed by RIE technique. The details of nanoscale pattern of the very uniform arrays using RIE are presented. We fabricated different surface structure of nanoscale using block copolymer. We also deposited Si-rich SiNx layer using ICP-CVD on the silicon surface of nanostructure. The deposited films were studied after annealing. PL studies demonstrated nanocrystal in Si-rich SiNx film on nanostructure of silicon.