Plasmonic hot-electron transfer and nanofabrication

Localized surface plasmon resonance (LSPR) of plasmonic nanoparticles and nanostructures has attracted wide attention because the nanoparticles exhibit a strong near-field enhancement through interaction with visible light, enabling subwavelength optics and sensing at the single-molecule level. The extremely fast LSPR decays have raised doubts that such nanoparticles have use in photochemistry and energy storage. Recent studies have demonstrated the capability of such plasmonic systems in producing LSPR-induced hot electrons that are useful in energy conversion and storage when combined with electron-accepting semiconductors. Due to the femtosecond timescale, hot-electron transfer is under intense investigation to promote ongoing applications in photovoltaics and photocatalysis. Concurrently, hot-electron decay results in photothermal responses or plasmonic heating. Importantly, this heating has received renewed interest in photothermal manipulation, despite the developments in optical manipulation using optical forces to move and position nanoparticles and molecules guided by plasmonic nanostructures. To realize plasmonic heating-based manipulation, photothermally generated flows, such as thermophoresis, the Marangoni effect and thermal convection, are exploited. Plasmon-enhanced optical tweezers together with plasmon-induced heating show potential as an ultimate bottom-up method for fabricating nanomaterials. We review recent progress in two fascinating areas: solar energy conversion through interfacial electron transfer in gold-semiconductor composite materials and plasmon-induced nanofabrication

Flow-Induced Transport via Optical Heating of a Single Gold Nanoparticle

Optothermal trapping has gained increasing popularity in manipulation such as selecting, guiding, and positioning submicron objects because of a few mW laser power much lower than that required for optical trapping. The optotothermal trapping uses thermal gradient-induced phoretic motions, but the underlying physics of driving force has not been fully understood. In this study, we performed optotothermal trapping of 500-nm-diameter colloidal silica via a continuous laser illumination of a single gold nanoparticle from the bottom in a closed chamber. Under illumination, the tracer particles were attracted to the gold nanoparticle and trapped. Notably, the direction of migrating particles was always to hot gold nanoparticle regardless of the configuration of gold nanoparticle placed at two opposite sides of the chamber, on the bottom surface of an upper substrate (ceiling) or on the top surface of a lower substrate (floor). The previous interpretation based on thermal convective flow from the bottom to the top and circulating inside the chamber was only applicable to floor configuration and failed to explain our observation for ceiling. Instead, temperature-induced Marangoni effect at the water/superheated water interface is likely to play a role. This study promoted a better understanding of the driving mechanism in optothermal trapping. Moreover, as an application of the single-particle platform, we showed the photothermal phase separation-induced microdroplet formation of thermoresponsive polymers and the coating of non-thermoresponsive polymers on nanoparticles

Generation of monkey iPS cell-derived cartilage lacking MHC class I molecules on the cell surface

Multiple immune reactions when transplanting cartilage into monkeys. 京都大学プレスリリース. 2021-07-07.Due to the poor capacity for articular cartilage to regenerate, its damage tends to result in progressively degenerating conditions such as osteoarthritis. To repair the damage, the transplantation of allogeneic human induced pluripotent stem cell (iPSC)-derived cartilage is being considered. However, although allogeneic cartilage transplantation is effective, immunological reactions can occur. One hypothetical solution is to delete the expression of MHC class I molecules in order to reduce the immunological reactions. For this purpose, we deleted the β2 microglobulin (B2M) gene in a cynomolgus monkey (crab-eating monkey (Macaca fascicularis)) iPS cells (cyiPSCs) to obtain B2M⁻/⁻ cyiPSCs using the CRISPR/Cas9 system. Western blot analysis confirmed B2M⁻/⁻ cyiPSCs lacked B2M protein, which is necessary for MHC class I molecules to be transported to and expressed on the cell surface by forming multimers with B2M. Flow cytometry analysis revealed no B2M⁻/⁻ cyiPSCs expressed MHC class I molecules on their surface. The transplantation of B2M⁻/⁻ cyiPSCs in immunodeficient mice resulted in teratoma that contained cartilage, indicating that the lack of MHC class I molecules on the cell surface affects neither the pluripotency nor the chondrogenic differentiation capacity of cyiPSCs. By modifying the chondrogenic differentiation protocol for human iPSCs, we succeeded at differentiating B2M⁺/⁺ and B2M⁻/⁻ cyiPSCs toward chondrocytes followed by cartilage formation in vitro, as indicated by histological analysis showing that B2M⁺/⁺ and B2M⁻/⁻ cyiPSC-derived cartilage were positively stained with safranin O and expressed type II collagen. Flow cytometry analysis confirmed that MHC class I molecules were not expressed on the cell surface of B2M⁻/⁻ chondrocytes isolated from B2M⁻/⁻ cyiPSC-derived cartilage. An in vitro mixed lymphocyte reaction assay showed that neither B2M⁺/⁺ nor B2M⁻/⁻ cyiPSC-derived cartilage cells stimulated the proliferation of allogeneic peripheral blood mononuclear cells. On the other hand, osteochondral defects in monkey knee joints that received allogeneic transplantations of cyiPSC-derived cartilage showed an accumulation of leukocytes with more natural killer (NK) cells around B2M⁻/⁻ cyiPSC-derived cartilage than B2M⁺/⁺ cartilage, suggesting complex mechanisms in the immune reaction of allogeneic cartilage transplanted in osteochondral defects in vivo

Generation of Monkey Induced Pluripotent Stem Cell-Derived Cartilage Lacking Major Histocompatibility Complex Class I Molecules on the Cell Surface

Due to the poor capacity for articular cartilage to regenerate, its damage tends to result in progressively degenerating conditions such as osteoarthritis. To repair the damage, the transplantation of allogeneic human induced pluripotent stem cell (iPSC)-derived cartilage is being considered. However, although allogeneic cartilage transplantation is effective, immunological reactions can occur. One hypothetical solution is to delete the expression of major histocompatibility complex (MHC) class I molecules to reduce the immunological reactions. For this purpose, we deleted the β2 microglobulin (B2M) gene in a cynomolgus monkey (crab-eating monkey [Macaca fascicularis]) iPS cells (cyiPSCs) to obtain B2M−/− cyiPSCs using the CRISPR/Cas9 system. Western blot analysis confirmed B2M−/− cyiPSCs lacked B2M protein, which is necessary for MHC class I molecules to be transported to and expressed on the cell surface by forming multimers with B2M. Flow cytometry analysis revealed no B2M−/− cyiPSCs expressed MHC class I molecules on their surface. The transplantation of B2M−/− cyiPSCs in immunodeficient mice resulted in teratoma that contained cartilage, indicating that the lack of MHC class I molecules on the cell surface affects neither the pluripotency nor the chondrogenic differentiation capacity of cyiPSCs. By modifying the chondrogenic differentiation protocol for human iPSCs, we succeeded at differentiating B2M+/+ and B2M−/− cyiPSCs toward chondrocytes followed by cartilage formation in vitro, as indicated by histological analysis showing that B2M+/+ and B2M−/− cyiPSC-derived cartilage were positively stained with safranin O and expressed type II collagen. Flow cytometry analysis confirmed that MHC class I molecules were not expressed on the cell surface of B2M−/− chondrocytes isolated from B2M−/− cyiPSC-derived cartilage. An in vitro mixed lymphocyte reaction assay showed that neither B2M+/+ nor B2M−/− cyiPSC-derived cartilage cells stimulated the proliferation of allogeneic peripheral blood mononuclear cells. On the contrary, osteochondral defects in monkey knee joints that received allogeneic transplantations of cyiPSC-derived cartilage showed an accumulation of leukocytes with more natural killer cells around B2M−/− cyiPSC-derived cartilage than B2M+/+ cartilage, suggesting complex mechanisms in the immune reaction of allogeneic cartilage transplanted in osteochondral defects in vivo.Okutani Y., Abe K., Yamashita A., et al. Generation of Monkey Induced Pluripotent Stem Cell-Derived Cartilage Lacking Major Histocompatibility Complex Class I Molecules on the Cell Surface. Tissue Engineering - Part A 28, 94 (2022); https://doi.org/10.1089/ten.tea.2021.0053

Can tax payments complement high environmental, social, and governance reputational risk?

[Purpose] This study aims to investigate firms’ tax payment motivation from the point of corporate social responsibility by dissecting samples into firms with high, low, and no environmental, social, and governance (ESG)-related reputational risk. [Design/methodology/approach] This paper is an empirical study using 3,981 firm-year observations from 31 countries from OECD countries through 2017 to 2019. We construct panel data and use the fixed-effects model to control unobserved firm heterogeneity. To capture legal tax avoidance, we use two types of tax avoidance measurements. [Findings] We find that paying taxes can complement the high reputational risk of ESGs. However, if ESG-related reputational risk is not large, tax payments do not affect ESG risk. Our results indicate that tax payment is a matter of firms’ ESG-related reputational risk. This paper contributes to providing evidence to show that the relationship between ESG and tax avoidance is different depending on an individual firm’s level of ESG-related reputational risk. [Originality] We create a reputation-based ESG risk data set that addresses the endogeneity associated with the manager’s decision and simultaneity bias to determine the relationship between ESG and tax avoidance. Also, this is one of few studies that examine the relationship between CSR and tax avoidance internationally

先新第三系中の鉛直回転軸を持つ摺曲（屈曲）

Various folds (bends) with subvertical/vertical axes are widely developed in the pre-Neogene terranes of Southwest Japan. They are variable in shape, conical folds, accordion folds, megakink bands and so on, and some of them are associated with strike-slip faults. Their size ranges from several meters to 10km or more in half-wavelength. Their deformation style indicate that they were produced under a brittle condition in a shallow level of the crust. They are superimposed on the pre-existing structures, and are regarded to have been formed mostly during the Middle Miocene contemporaneously at the time of the clockwise-rotation of Southwest Japan. The presence of them, thus, suggests that the upper crust of island arc is easily deformable around subvertical/vertical rotation axes to form various folds (bends) and locally strike-slip faults during its rotation

Lack of effect of bone marrow transplantation on airway hyperresponsiveness in an asthmatic

ABSTRACTBronchial asthma has been recognized as an inflammatory disorder in this past decade. This leads to an assumption that perfect control of inflammatory cells may cure this disease. However, herein we report on an asthmatic whose airway hyperresponsiveness (AHR) did not change after bone marrow transplantation (BMT). The concentrations of acetylcholine to produce a 20% fall in forced expiratory volume in 1 s 15 days before and 98 days after BMT were 900 and 480 μg/mL, respectively. Asthma treatment with beclo-methasone dipropionate and theophylline was continued before and after BMT and a conventional supporting therapy for BMT with cyclosporine A and methylprednisolone, followed by oral administration of tacrolimus hydrate alone inhibited graft-versus-host disease. Plasma interleukin (IL)-4, IL-5 and IgE, but not interferon-γ, levels decreased after BMT. Note that the second measurement of airway sensitivity was performed under systemic administration of tacrolimus. The presented case suggests that replacement of bone marrow-derived inflammatory cells is not enough to reverse once-established AHR. Hence, AHR and airway inflammation may develop independently in some part, but both need to be present for asthma to be present in this asthmatic

Engraftment of allogeneic iPS cell-derived cartilage organoid in a primate model of articular cartilage defect

Induced pluripotent stem cells (iPSCs) are a promising resource for allogeneic cartilage transplantation to treat articular cartilage defects that do not heal spontaneously and often progress to debilitating conditions, such as osteoarthritis. However, to the best of our knowledge, allogeneic cartilage transplantation into primate models has never been assessed. Here, we show that allogeneic iPSC-derived cartilage organoids survive and integrate as well as are remodeled as articular cartilage in a primate model of chondral defects in the knee joints. Histological analysis revealed that allogeneic iPSC-derived cartilage organoids in chondral defects elicited no immune reaction and directly contributed to tissue repair for at least four months. iPSC-derived cartilage organoids integrated with the host native articular cartilage and prevented degeneration of the surrounding cartilage. Single-cell RNA-sequence analysis indicated that iPSC-derived cartilage organoids differentiated after transplantation, acquiring expression of PRG4 crucial for joint lubrication. Pathway analysis suggested the involvement of SIK3 inactivation. Our study outcomes suggest that allogeneic transplantation of iPSC-derived cartilage organoids may be clinically applicable for the treatment of patients with chondral defects of the articular cartilage; however further assessment of functional recovery long term after load bearing injuries is required

CHOROIDAL STRUCTURE IN RP

Purpose: To investigate the choroidal structures in the enhanced depth imaging optical coherence tomographic images in eyes with retinitis pigmentosa (RP) and to determine correlations between the choroidal structures and visual functions. Methods: The enhanced depth imaging optical coherence tomographic images of 100 eyes with typical RP and 60 age-, sex-, and axial length–matched normal eyes were binarized using ImageJ. The cross-sectional luminal and stromal areas of the inner and outer subfoveal choroid of 1,500-µm width were measured. The inner choroid included the choriocapillaris and medium vessel layer, and the outer choroid included the larger vessel layer. Results: In the inner choroid, the luminal area and the ratio of luminal/total choroidal area (L/C ratio) were significantly smaller in RP than in controls (P = 0.010, P < 0.001, respectively), whereas the stromal area was not significantly different (P = 0.114). The inner choroidal L/C ratio was significantly correlated with the best-corrected visual acuity, mean deviation, foveal sensitivity, width of the ellipsoid zone, and central foveal thickness in RP after adjusting for the axial length, age, and sex (all P < 0.005). Conclusion: The significant correlations between the inner choroidal structures and the visual functions and retinal structures indicate that the choroidal structures are altered in association with the progression of RP

Engraftment of allogeneic iPS cell-derived cartilage organoid in a primate model of articular cartilage defect

Induced pluripotent stem cells (iPSCs) are a promising resource for allogeneic cartilage transplantation to treat articular cartilage defects that do not heal spontaneously and often progress to debilitating conditions, such as osteoarthritis. However, to the best of our knowledge, allogeneic cartilage transplantation into primate models has never been assessed. Here, we show that allogeneic iPSC-derived cartilage organoids survive and integrate as well as are remodeled as articular cartilage in a primate model of chondral defects in the knee joints. Histological analysis revealed that allogeneic iPSC-derived cartilage organoids in chondral defects elicited no immune reaction and directly contributed to tissue repair for at least four months. iPSC-derived cartilage organoids integrated with the host native articular cartilage and prevented degeneration of the surrounding cartilage. Single-cell RNA-sequence analysis indicated that iPSC-derived cartilage organoids differentiated after transplantation, acquiring expression of PRG4 crucial for joint lubrication. Pathway analysis suggested the involvement of SIK3 inactivation. Our study outcomes suggest that allogeneic transplantation of iPSC-derived cartilage organoids may be clinically applicable for the treatment of patients with chondral defects of the articular cartilage; however further assessment of functional recovery long term after load bearing injuries is required.Abe K., Yamashita A., Morioka M., et al. Engraftment of allogeneic iPS cell-derived cartilage organoid in a primate model of articular cartilage defect. Nature Communications 14, 804 (2023); https://doi.org/10.1038/s41467-023-36408-0