“All-on-Four”コンセプトに基づいて即時荷重を適用したインプラントの力学解析

PURPOSE: The purpose of this study was to investigate the biomechanical behavior of immediately loaded implants in an edentulous mandible according to the "All-on-Four" concept. METHODS: A 3D-finite element model of an edentulous mandible was constructed. Four implants were placed between the bilateral mental foramen according to "All-on-Four" concept. A framework made of titanium or acrylic resin between the bilateral first molars was modeled. Immediate loading and a delayed loading protocol were simulated. A vertical load of 200N was applied at the cantilever or on the abutments region of the distal implants, simulating the absence of a cantilever. RESULTS: The peak principal compressive strains in the immediate loading models resulted in 24.0-35.8% and 26.4-39.0% increases compared with the delayed loading models under non-cantilever loading and cantilever loading, respectively. The loading position greatly affected the principal compressive and tensile strain values. The peak principal compressive strains in non-cantilever loading resulted in a 45.3-52.6% reduction compared with those in cantilever loading. The framework material did not influence the peak compressive and tensile strain. The maximum micromotion at the bone-implant interface in the immediate loading models was 7.5-14.4μm. CONCLUSIONS: Mandibular fixed full-arch prostheses without cantilevers may result in a favorable reduction of the peri-implant bone strain during the healing period, compared with cantilevers. The maximum micromotion was within the acceptable limits for uneventful implant osseointegration in the immediate loading models. Framework material did not play an important role in reducing the peri-implant bone strain and micromotion at the bone-implant interface.博士（医学）・乙第1398号・平成29年3月15日Copyright © 2016 Japan Prosthodontic Society. Published by Elsevier Ltd. All rights reserved

Reduction in Flux Loss of an Nd-Fe-B Bonded Ring Magnet for an SPM Motor

We have previously proposed a simulation method of an initial flux loss in permanent magnets using finite element method, and confirmed that predicted flux loss of an Nd-Fe-B boned ring magnet showed good agreement with measured flux loss. In this paper, we applied our proposed method to an Nd-Fe-B boned ring magnet in an SPM motor. We modeled a rotor composed of an Nd-Fe-B bonded ring magnet and a soft magnetic core made from silicon steels, and carried out the simulations for magnetizing process and prediction process of the flux loss. From the simulation results, we found that the inner side of the ring magnet has large flux loss. In order to reduce in flux loss, we enhanced the coercivity in the inner side of the ring magnet by partial replacement with another bonded magnet with high coercivity. Consequently, we found that the ring magnet with locally enhanced coercivity is effective to reduce in the flux loss

腓骨皮弁による下顎骨再建術術後のインプラント周囲軟組織における治療方法の検討

In maxillofacial reconstruction implant treatment, unsatisfactory soft tissue treatment of the area around the implant may lead to inflammation. As a result, appropriate soft tissue treatment is critical. To the best of our knowledge, there are no studies that compare the different tissue treatment methods available. Hence, in this study, we compare three soft tissue treatment methods around implants after mandibular reconstruction is achieved with a fibula-free flap. Out of 33 patients who underwent mandible reconstruction using fibula-free flaps between 2006 and 2015, 5 were selected for this study. A total of 17 implants were used for treatment by the final prosthetics of the five patients. Three soft tissue treatment methods with free gingival graft (FGG) were evaluated, namely, installing a splint in a modified abutment to protect the wounded area during a palatal mucosa transplant (method 1), installing a splint or dentures to a locator abutment (method 2), and the use of screw-in fixed dentures (method 3). The method that could guarantee the widest keratinized mucosa was the screw-in fixed denture method. The results of our study indicated that employing screw-in fixed dentures for FGG may be a useful soft tissue treatment for mandible reconstruction implants.博士（医学）・乙第1491号・令和2年12月24日Copyright © 2020 by the authors. Licensee MDPI, Basel, Switzerland. This article is an open access article distributed under the terms and conditions of the Creative Commons Attribution (CC BY) license (http://creativecommons.org/licenses/by/4.0/)

Importance of feeding status evaluation in older patients undergoing hemodialysis

Older hospitalized patients undergoing hemodialysis are increasingly experiencing malnutrition caused by dysphagia. However, only a few studies have focused on this problem. We used the Kuchikara Taberu Balance Chart (KTBC) to evaluate the patients’ feeding status and examined its association with their nutritional status and prognosis. This study included elderly patients undergoing hemodialysis who were hospitalized at Nagasaki Renal Center for > 3 days between June 2021 and February 2022. In total, 82 inpatients were included [mean age, 73.4 ± 10.0 years; men, 57.3%; median dialysis vintage, 79.0 months (interquartile range, 37.3–164.8)]. We classified patients with lower than the median KTBC score (57 points) as being at risk for dysphagia; 37 patients (45.1%) were at risk for dysphagia. Spearman’s rank correlation coefficient (ρ) elucidated that the KTBC total score was significantly associated with each nutritional indicator [serum albumin level (ρ = 0.505, p < 0.001); geriatric nutritional risk index (ρ = 0.600, p < 0.001); and nutritional risk index (ρ = -0.566, p < 0.001)]. The KTBC score was also closely associated with the body mass index (ρ = 0.228, p = 0.04). Patients with a lower KTBC score showed poor prognosis (log-rank test: p = 0.001), and age- and sex-adjusted Cox proportional analysis showed that the KTBC score was associated with life prognosis (hazard ratio, 0.90; 95% confidential interval, 0.86–0.94; p < 0.001). Therefore, we concluded that the patients at risk of dysphagia, identified using the KTBC score, were malnourished and had a poor prognosis. Hence, the evaluation of dysphagia using the KTBC is encouraged to prevent malnutrition in vulnerable older patients undergoing hemodialysis

Critical Temperature in Bulk Ultrafine-Grained Superconductors of Nb, V, and Ta Processed by High-Pressure Torsion

This overview describes the progressive results of the superconducting critical temperature in bulk nanostructured metals (niobium, vanadium and tantalum) processed by high-pressure torsion (HPT). Bulk nanostructured superconductors provide a new route to control superconducting property, because ultrafine-grain structures with a high density of grain boundaries, dislocations, and other crystalline defects modify the superconducting order parameter. The critical temperature Tc in Nb increases with the evolution of grain refinement owing to the quantum confinement of electrons in ultrafine grains. In V and Ta, however, Tc decreases at a certain HPT revolution number (i.e. at certain strain levels). The different behaviour of Tc in the three materials is explained by the competition effect between the quantum size effect and disorder effect; these effects are characterized by the parameters of grain size, electron mean free path, and superconducting coherence length

A Genome-Wide Association Study Identified AFF1 as a Susceptibility Locus for Systemic Lupus Eyrthematosus in Japanese

Systemic lupus erythematosus (SLE) is an autoimmune disease that causes multiple organ damage. Although recent genome-wide association studies (GWAS) have contributed to discovery of SLE susceptibility genes, few studies has been performed in Asian populations. Here, we report a GWAS for SLE examining 891 SLE cases and 3,384 controls and multi-stage replication studies examining 1,387 SLE cases and 28,564 controls in Japanese subjects. Considering that expression quantitative trait loci (eQTLs) have been implicated in genetic risks for autoimmune diseases, we integrated an eQTL study into the results of the GWAS. We observed enrichments of cis-eQTL positive loci among the known SLE susceptibility loci (30.8%) compared to the genome-wide SNPs (6.9%). In addition, we identified a novel association of a variant in the AF4/FMR2 family, member 1 (AFF1) gene at 4q21 with SLE susceptibility (rs340630; P = 8.3×10−9, odds ratio = 1.21). The risk A allele of rs340630 demonstrated a cis-eQTL effect on the AFF1 transcript with enhanced expression levels (P<0.05). As AFF1 transcripts were prominently expressed in CD4+ and CD19+ peripheral blood lymphocytes, up-regulation of AFF1 may cause the abnormality in these lymphocytes, leading to disease onset

Formal Nucleophilic Boryl Substitution of Organic Halides with Silylborane/Alkoxy Base System

Boryl substitution of organohalides with a silylborane and alkoxy bases is described. This reaction can be applied to various functionalized aryl halides. Alkyl and alkenyl halides, and even sterically congested aryl bromides also provided the corresponding borylated products in high yields. Mechanistic studies indicated that neither trace transition-metal impurities nor aryl radical species involved in this reaction

Proving Properties of Incremental Merkle Trees

This paper proves two basic properties of the model of a single attack point-free event ordering system, developed by NTT. This model is based on an incremental construction of Merkle trees, and we show the correctness of (1) completion and (2) an incremental sanity check. These are mainly proved using the theorem prover MONA; especially, this paper gives the first proof of the correctness of the incremental sanity check