Integrating Oxygen and 3D Cell Culture System: A Simple Tool to Elucidate the Cell Fate Decision of hiPSCs

Oxygen, as an external environmental factor, plays a role in the early differentiation of human stem cells, such as induced pluripotent stem cells (hiPSCs). However, the effect of oxygen concentration on the early-stage differentiation of hiPSC is not fully understood, especially in 3D aggregate cultures. In this study, we cultivated the 3D aggregation of hiPSCs on oxygen-permeable microwells under different oxygen concentrations ranging from 2.5 to 20% and found that the aggregates became larger, corresponding to the increase in oxygen level. In a low oxygen environment, the glycolytic pathway was more profound, and the differentiation markers of the three germ layers were upregulated, suggesting that the oxygen concentration can function as a regulator of differentiation during the early stage of development. In conclusion, culturing stem cells on oxygen-permeable microwells may serve as a platform to investigate the effect of oxygen concentration on diverse cell fate decisions during development.     

An asymptotically optimal policy for finite support models in the multiarmed bandit problem

In the multiarmed bandit problem the dilemma between exploration and exploitation in reinforcement learning is expressed as a model of a gambler playing a slot machine with multiple arms. A policy chooses an arm in each round so as to minimize the number of times that arms with suboptimal expected rewards are pulled. We propose the minimum empirical divergence (MED) policy and derive an upper bound on the finite-time regret which meets the asymptotic bound for the case of finite support models. In a setting similar to ours, Burnetas and Katehakis have already proposed an asymptotically optimal policy. However, we do not assume any knowledge of the support except for its upper and lower bounds. Furthermore, the criterion for choosing an arm, minimum empirical divergence, can be computed easily by a convex optimization technique. We confirm by simulations that the MED policy demonstrates good performance in finite time in comparison to other currently popular policies.     

Design and calibration of curved and see-through integral imaging 3D display

Virtual Reality - Heads-up displays that are ‘see-through’ and ‘curved’ and capable of displaying 3D contents are considered crucial for augmented reality-based navigation...     

Bio-Inspired Adhesive with Reset-On Demand,Reuse-Many (RORM) Modes

Development of tough, reusable adhesives is important, but remains a major challenge, especially in water. A tough reusable adhesive that resets entirely to its virgin condition when needed is reported using caffeic acid. Here, caffeic acid is employed as adhesive moiety to achieve such the functions due to its dual characteristics: an adhesive moiety from mussel-inspired catechol and a photo-reversible crosslink from cinnamic acid. Adhesion involves a two-step process. First, the caffeic acid-functionalized polymer is applied to the adherend, followed by UV irradiation (peak wavelength of light-emitting diode, λ_P: 365 nm) to form a durable pre-applied adhesive (PAA) layer through crosslinking among the caffeic acid moieties. Second, thermal activation of the PAA layer ensures repeated adhesion to a variety of adherends ( R euse- M any mode). The cyclic dimer of the caffeic acid moiety is de-crosslinked by UV irradiation at λ_P: 254 nm. This allows the complete removal of the adhesive residues from the adherends when the adhesive is no longer needed ( R eset- O n demand mode). Furthermore, using magnetic nanoparticles, the caffeic acid-functionalized polymer can be activated remotely under water by magnetic induction heating. This study paves the way for the rational design of bio-inspired adhesives that outperform nature using plant-derived raw materials.     

Recent trends of advanced ceramics industry and Fine Ceramics Roadmap 2050

Japan's fine ceramics (advanced ceramics) industry, which reached US$30 billion of production in 2018 (an annual growth rate of 6.3%), accounts for 40% of the global market. The mission of the Japan Fine Ceramics Association (JFCA), which consists of 116 corporate members related to fine ceramics, is to further promote the development of this industry. In this paper, we describe the recent trends of fine ceramics industry and the latest JFCA's activities, including the publication of the FC Roadmap 2050 (2021 edition). This roadmap addresses fine ceramics technologies and products that will meet increasingly diverse needs of society, market, and industry in the year 2050.     

Effect of natural biomass fillers on the stability,degradability, and elasticity of crop straws liquefied polyols-based polyurethane foams

Oilseed rape straw (OS), rice straw (RS), wheat straw (WS), and corn stover (CS) particles were used to reinforce bio-polyols based polyurethane (PU) foams. The influence of crop straws (XS) fillers on the stability in water, degradability in soil, thermal stability, and elasticity of foams were investigated. The incorporation of OS and CS particles in the PU matrix increased the stability of reinforced foams in water, while the addition of WS and RS particles made foams lower stability in water. PU foams reinforced by XS particles displayed mass reductions up to 53.8% after burying in soil for 250 days. The reinforced foams were more stable under heating but the enhancement of thermal stability trended to disappear after water immersion or soil burying. The reinforced foams showed better elasticity that incorporations of OS and CS made PU foams higher height recovery percentage, while RS and WS made the recovery percentage decline firstly and then enhance during three times compressions. All these four XS particles are suitable to modify bio-based PU foams, especially OS and CS particles appear to be more outstanding in preparing foams with higher stability in water, degradability in soil, thermal stability, and elasticity than RS and WS particles.