Superior oxygen and glucose supply in perfusion cell cultures compared to static cell cultures demonstrated by simulations using the finite element method

Oxygen and glucose supply is one of the important factors for the growth and viability of the cells in cultivation of tissues, e.g., spheroid, multilayered cells, and three-dimensional tissue construct. In this study, we used finite element methods to simulate the flow profile as well as oxygen and glucose supply to the multilayered cells in a microwell array chip for static and perfusion cultures. The simulation results indicated that oxygen supply is more crucial than glucose supply in both static and perfusion cultures, and that the oxygen supply through the wall of the perfusion culture chip is important in perfusion cultures. Glucose concentrations decline with time in static cultures, whereas they can be maintained at a constant level over time in perfusion cultures. The simulation of perfusion cultures indicated that the important parameters for glucose supply are the flow rate of the perfusion medium and the length of the cell culture chamber. In a perfusion culture chip made of oxygen-permeable materials, e.g., polydimethylsiloxane, oxygen is hardly supplied via the perfusion medium, but mainly supplied through the walls of the perfusion culture chip. The simulation of perfusion cultures indicated that the important parameters for oxygen supply are the thickness of the flow channel and the oxygen permeability of the walls of the channel, i.e., the type of material and the thickness of the wall.     

Scaffold fabrication in a perfusion culture microchamber array chip by O(2) plasma bonding of poly(dimethylsiloxane) protected by a physical mask

Extracellular matrix (ECM) proteins are required for cell culture. In this paper, we report the use of O(2) plasma bonding to fabricate a perfusion culture microchamber array chip with identical-size ECM spots in the isolated microchambers. The chip was fabricated by assembly of two poly(dimethylsiloxane) (PDMS) layers, a microfluidic network layer, and an ECM array layer, which were aligned and then bonded by O(2) plasma oxidation with protection of the ECM microarray with a physical mask made from PDMS. We successfully cultivated Chinese hamster ovary K1 cells in the microchambers with fibronectin. In the fibronectin microchambers, the cells adhered and extended after 12 h of static culture and then grew over the course of 1 d of perfusion culture.     

Specific types of sports and exercise group participation and socio-psychological health in older people

ABSTRACT

Older people who engage in sports and exercise in a group render greater benefits for socio-psychological aspects compared to exercising alone. The aim of this study was to identify the prevalence of specific types of sports and exercise groups and the association with self-rated health, depressive symptoms, and frequency of laughter among community-dwelling older people. We used cross-sectional data from the 2016 Japan Gerontological Evaluation Study and analysed 63,465 males and 68,497 females aged ≥65 years. The top three most popular types among males were golf (11.3%), walking (8.4%), and ground golf (6.3%). Among females, the top three were fitness exercises (13.8%), walking (8.3%), and weight exercises (6.2%). After adjusting for potential confounders, engaging in golf with a group was significantly related with excellent self-rated health (prevalence ratio, PR, 1.31 in male and 1.78 in female), low depressive symptoms (PR, 0.70 and 0.71), and a high frequency of laughter (PR, 1.12 and 1.13). Among females, walking displayed a significant relationship with all three characteristics (PR, 1.23, 0.79, and 1.06, respectively). Golf in older males and walking in older females might be the first choice for an effective programme to spread sports and exercise groups within the older Japanese community.     

Beliefs, practices, and interactions of teachers in a Japanese high school English department

This study reveals the school culture and the teachers’ professional development activities in a Japanese high school learning environment. Furthermore, it documents the relationships among the context, teachers’ beliefs, practices, and interactions. Using multiple data sources including interviews, observations, and documents of teachers from an English department, this yearlong study revealed these English as a Foreign Language teachers lacked many teacher learning opportunities in their context. The study revealed that teacher collaboration only reinforced existing practices, eroding teachers’ motivation to learn to teach in this specific context. The study provides evidence to teacher educators about inservice teachers and their learning environment and the significance of the relationships between the two entities.     

Inverting microwell array chip for the cultivation of human induced pluripotent stem cells with controlled aggregate size and geometrical arrangement

We present a novel cell culture chip, namely, “inverting microwell array chip,” for cultivation of human induced pluripotent stem cells. The chip comprises a lower hydrogel microwell array and an upper polystyrene culture surface. We demonstrate the formation of uniform cellular aggregates in the microwell array, and after inversion, a culture with controlled aggregate size and geometrical arrangement on the polystyrene surface. Here, we report effects of cell concentrations on a cultivation sequence in the chip.     

Hierarchically porous monoliths based on low-valence transition metal (Cu,Co, Mn) oxides: gelation and phase separation

Hierarchically porous monoliths based on copper (Cu), cobalt (Co) and manganese (Mn) oxides with three-dimensionally (3D) interconnected macropores and open nanopores were prepared using metal bromides as precursors via a sol–gel process accompanied by phase separation. The difficulty of gelation for low-valence metal cation was overcome by introducing a highly electronegative Br atom near to the metal atom to control the rates of hydrolysis and polycondensation. The 3D interconnected macropores were obtained using appropriate polymers to induce phase separation. The domain sizes of macropores and skeletons can be controlled by reaction parameters such as concentration and/or average molecular weight of polymers, and the amount of hydrochloric acid. The crystalline metal oxide monoliths with their 3D interconnected macroporous structure preserved were obtained after heat treatment in air.