ヒト歯根膜細胞伸展刺激による抗炎症性エクソソーム分泌誘導：マクロファージNF-κBシグナル制御を介したIL-1β発現抑制

要約のみTohoku University山田聡課

Novel Covalent Organic Frameworks (COFs) for Electrochemical Energy Storage and Conversion

Covalent Organic Frameworks (COFs) are a new type of crystalline porous organic materials composed of covalently linked organic molecular modules. They possess the advantages of ordered channels, nano-scale pore structures, large specific surface areas and high crystallinity. Meanwhile, unlike traditional linear polymerization leading to uncontrolled product structures, COFs can be designed to form highly regular structures in two or even three dimensions. In addition, rigid structures can provide excellent stability for COFs. Furthermore, the designable structure allows functional groups to be introduced into COFs to meet the specific requirements of devices. As a result, COFs have been widely used in various fields. In particular, COFs have been found to be suitable for electrochemical energy conversion and storage applications. In this thesis, I present two conceptual applications of COFs as electrochemical active material in supercapacitors for energy storage and as electrocatalysts bearing the metal-nitrogen-carbon single-atom structure for the oxygen reduction reaction. The results demonstrated in this thesis represent the specific applications of COFs in electrochemistry, offering further possibilities and new ideas for developing novel materials for electrochemical energy storage and conversion

Photocatalytic Methane Conversion to C1 Oxygenates over Palladium and Oxygen Vacancies Co-Decorated TiO_{2}

Direct methane conversion to value-added chemicals through photocatalysis is promising but still has great challenges in both efficient activation of C–H bonds and suppression of over-oxidation. Herein, palladium nanoparticles and oxygen vacancies (OVs) co-modified TiO_{2} photocatalysts are prepared and employed for photocatalytic CH_{4} conversion at room temperature. Under optimized conditions with O_{2} and water as the oxidants, a high yield of liquid oxygenates, e.g., 54 693 μmol g^{−1} h^{−1} with a nearly 100% selectivity has been achieved. Mechanism investigations reveal that Pd and OVs synergistically promote charge separation, with Pd and OVs acting as hole and electron acceptors, respectively. Isotopic experiments elucidate that both H_{2}O and O_{2} are oxygen sources for oxygenate production, where O_{2} is the predominant one

Unraveling the pH-Dependent Oxygen Reduction Performance on Single-Atom Catalysts: From Single- to Dual-Sabatier Optima

M-N-C single-atom catalysts (SACs) have emerged as a potential substitute for the costly platinum-group catalysts in oxygen reduction reaction (ORR). However, several critical aspects of M-N-C SACs in ORR remain poorly understood, including their pH-dependent activity, selectivity for 2- or 4-electron transfer pathways, and the identification of the rate-determining steps. Herein, analyzing >100 M-N-C structures and >2000 sets of energetics, we unveil for the first time a pH-dependent evolution in ORR activity volcanos from a single-peak in alkaline media to a double-peak in acids. We found that this pH-dependent behavior in M-N-C catalysts fundamentally stems from their moderate dipole moments and polarizability for O* and HOO* adsorbates, as well as unique scaling relations among ORR adsorbates. To validate our theoretical discovery, we synthesized a series of molecular M-N-C catalysts, each characterized by well-defined atomic coordination environments. Impressively, the experiments matched our theoretical predictions on kinetic current, Tafel slope, and turnover frequency in both acidic and alkaline environments. These new insights also refine the famous Sabatier principle by emphasizing the need to avoid an "acid trap" while designing M-N-C catalysts for ORR or any other pH-dependent electrochemical applications.Comment: 24 pages, 5 Figure

Cyclic Fatigue Resistance and Force Generated by OneShape Instruments during Curved Canal Preparation.

To evaluate the cyclic fatigue resistance and the force generated by OneShape files during preparation of simulated curved canals.Six OneShape files (the test) and six ProTaper F2 files (the control) were subject to the bending ability test. Another thirty files of each type were used to prepare artificial canals (n = 60), which were divided into 3 groups according to respective curvatures of the canals (30°, 60°, and 90°). The numbers of cycles to fatigue (NCF) as well as the positive and negative forces that were generated by files during canal preparation were recorded. The scanning electron microscopy was applied to detect the fracture surfaces.Compared with ProTaper F2 files, the bending loads of OneShape files were significantly lower at deflections of 45°(P < .05), 60° (P < .05) and 75° (P < .01). No significant difference was found at 30°. OneShape files presented a higher NCF in both 60° and 90° canals than the control (P < .01). No significant difference of NCF was found between OneShape and ProTaper files in 30° canals. During the preparation of 30° canals by both files, the negative forces were dominant. With the increase of the curvature, more positive forces were observed. When the OneShape Files were compared with the control, significant different forces were found at D3 and D2 (P < .05) in 30° canals, at D2 (P < .05), D1 (P < .01) and D0 (P < .01) in 60° canals, and at D4 and D3 (P < .01) in 90° canals.OneShape files possessed a reliable flexibility and cyclic fatigue resistance. According to the assessments of the forces generated by files, OneShape instruments performed in a more fatigue-resistant way during curved canal preparation, compared with the ProTaper F2 files

The flexibility evaluation of OneShape files.

<p>Compared with ProTaper files (the control), OneShape files presented significantly lower bending values at deflections of 45° (<i>P</i> < .05), 60° (<i>P</i> < .05) and 75° (<i>P</i> < .01) (A). OneShape files presented a higher NCF in both 60° and 90° canals than the control (P < .01). No significant difference of NCF was found between OneShape and ProTaper files in 30° canals. (B).</p

The force generated by OneShape and ProTaper instruments during simulated canal preparation.

<p>In group of 30° canals, the negative force generated by OneShape was significantly higher at D3 and D2 (<i>P</i> < .05) (A). In group of 60°, the negative force generated by OneShape was significantly higher at D2 (<i>P</i> < .05), D1 and D0 (<i>P</i> < .01), while the positive force generated by ProTaper F2 was significantly higher at D1 and D0 (<i>P</i> < .01) (B). In group of 90°, the negative force generated by OneShape was significantly higher at D4 and D3 (<i>P</i> < .01), while the positive force generated by ProTaper F2 was significantly higher at D4 and D3 (<i>P</i> < .01) (C). (*: <i>P</i> < .05, **: <i>P</i> < .01)</p

SEM images of the fracture surfaces.

<p>The crack initiation areas were pointed by the arrows and the fast fracture zones were surrounded by black dots.</p

Incidence Rate of Type 2 Diabetes Mellitus after Gestational Diabetes Mellitus: A Systematic Review and Meta-Analysis of 170,139 Women

Objective. The reported incidence of type 2 diabetes mellitus (T2DM) after gestational diabetes (GDM) varies widely. The purpose of this meta-analysis was to define the incidence rate of T2DM among women with a history of GDM and to examine what might modulate the rate. Research Design and Methods. We searched PubMed and Embase for terms related to T2DM after GDM up to January 2019. Large cohort studies with sample size ≥300 and follow-up duration of at least one year were included. Data from selected studies were extracted, and meta-analysis was performed using the random-effects model. Subgroups analyses were based on the sample size of gestational diabetes, geographic region, maternal age, body-mass index, diagnostic criteria, and duration of follow-up. Results. Twenty-eight studies involving 170,139 women with GDM and 34,627 incident cases of T2DM were identified. The pooled incidence of T2DM after GDM was 26.20 (95% CI, 23.31 to 29.10) per 1000 person-years. Women from Asia and those with older age and higher body mass index seem to experience higher risk of developing T2DM. The incidence rate of T2DM was lowest when applying IADPSG (7.16 per 1000 person-years) to diagnose GDM. The risk of developing T2DM after GDM increased linearly with the duration of follow-up. The increments per year of follow-up were estimated at 9.6‰. The estimated risks for T2DM were 19.72% at 10 years, 29.36% at 20 years, 39.00% at 30 years, 48.64% at 40 years, and 58.27% at 50 years, respectively. Conclusions. The findings of very high incidence of T2DM after GDM add an important insight into the trajectory of the development of T2DM in the long-term postpartum periods, which could provide evidence for consultant and might motivate more women with GDM to screen for T2DM. This trial is registered with PROSPERO identifier CRD42019128980