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1.
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. 相似文献
2.
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. 相似文献
3.
Koji Murofushi Shinji Sakurai Koji Umegaki Junji Takamatsu 《Sports biomechanics / International Society of Biomechanics in Sports》2013,12(3):301-314
Ground reaction force and wire tensile force were measured during test throws by three hammer throwers: the Asian record holder, who had a personal best of 83.47 m at the time of the investigation, and two university athletes, with personal bests of 59.95 m and 46.30 m respectively. They were filmed using three high-speed video cameras (250 Hz). The displacements of the hammer head and the athletes' centres of mass were calculated using three-dimensional analysis procedures. The Asian record holder's centre of mass and the hammer head on the final two turns exhibited approximate conjunctions of the hammer high point and the thrower's low point and vice versa about the hammer's azimuth angle. It is conjectured that the reason why the thrower's movement is asynchronous with the hammer's movement by approximately half a turn is to accelerate the hammer head in a manner similar to the way that the amplitude of a pendulum increases when it is pulled upward by a string against the downward movement of the swinging weight. 相似文献
4.
Murofushi K Sakurai S Umegaki K Takamatsu J 《Sports biomechanics / International Society of Biomechanics in Sports》2007,6(3):301-314
Ground reaction force and wire tensile force were measured during test throws by three hammer throwers: the Asian record holder, who had a personal best of 83.47 m at the time of the investigation, and two university athletes, with personal bests of 59.95 m and 46.30 m respectively. They were filmed using three high-speed video cameras (250Hz). The displacements of the hammer head and the athletes' centres of mass were calculated using three-dimensional analysis procedures. The Asian record holder's centre of mass and the hammer head on the final two turns exhibited approximate conjunctions of the hammer high point and the thrower's low point and vice versa about the hammer's azimuth angle. It is conjectured that the reason why the thrower's movement is asynchronous with the hammer's movement by approximately half a turn is to accelerate the hammer head in a manner similar to the way that the amplitude of a pendulum increases when it is pulled upward by a string against the downward movement of the swinging weight. 相似文献
5.
Direction of spin axis and spin rate of the pitched baseball 总被引：1，自引：0，他引：1
Jinji T Sakurai S 《Sports biomechanics / International Society of Biomechanics in Sports》2006,5(2):197-214
In this study, we aimed to determine the direction of the spin axis and the spin rate of pitched baseballs and to estimate the associated aerodynamic forces. In addition, the effects of the spin axis direction and spin rate on the trajectory of a pitched baseball were evaluated. The trajectories of baseballs pitched by both a pitcher and a pitching machine were recorded using four synchronized video cameras (60 Hz) and were analyzed using direct linear transform (DLT) procedures. A polynomial function using the least squares method was used to derive the time-displacement relationship of the ball coordinates during flight for each pitch. The baseball was filmed immediately after ball release using a high-speed video camera (250 Hz), and the direction of the spin axis and the spin rate (omega) were calculated based on the positional changes of the marks on the ball. The lift coefficient was correlated closely with omegasinalpha (r = 0.860), where alpha is the angle between the spin axis and the pitching direction. The term omegasinalpha represents the vertical component of the velocity vector. The lift force, which is a result of the Magnus effect occurring because of the rotation of the ball, acts perpendicularly to the axis of rotation. The Magnus effect was found to be greatest when the angular and translational velocity vectors were perpendicular to each other, and the break of the pitched baseball became smaller as the angle between these vectors approached 0 degrees. Balls delivered from a pitching machine broke more than actual pitcher's balls. It is necessary to consider the differences when we use pitching machines in batting practice. 相似文献
6.
Strategy effects on word searching in Japanese letter fluency tests: evidence from the NIRS findings
Takeshi Hatta Ayano Kanari Mitsuhito Mase Yuko Nagano Tatsuaki Shirataki Shinji Hibino 《Reading and writing》2009,22(9):1041-1052
Strategy effects on word searching in the Japanese letter fluency test were investigated using the Near-infrared Spectroscopy
(NIRS). Participants were given a Japanese letter fluency test and they were classified into two types of strategy users,
based on analysis of their recorded verbal responses. One group, AIUEO-order strategy users, employed sequential word searching
based upon the imagery of the AIUEO-table which they mastered when young, and the other group, semantic strategy users, searched
for the next word mainly based on semantic relations. The blood-flow volumes (OxyHb) measured of the AIUEO-order strategy
users were greater than for the semantic strategy users in the frontal parts of the brain, and the blood-flow was more active
in the right than in the left part of the brain. These different activation patterns suggest that the NIRS might be useful
new brain imaging technique for examination of psychological process in verbal behavior. 相似文献
7.
Sasakawa K Sakurai S 《Sports biomechanics / International Society of Biomechanics in Sports》2008,7(3):311-321
Joint angles of the throwing limb were examined from the acceleration phase up until release for the sidearm throwing motion when using a flying disc. 17 individuals (ten skilled, seven unskilled) threw a disc as far as possible ten times. Throwing motions were recorded using three-dimensional high-speed videography. The initial condition of disc release and joint angle kinematics of the upper limb during the throwing motion were obtained. Mean (+/- standard deviation) throwing distance and disc spin rate were significantly greater for skilled throwers (51.4 +/- 6.6 m, 12.9 +/- 1.3 rps) than for unskilled throwers (29.5 +/- 7.6 m, 9.4 +/- 1.3 rps), although there was no significant difference in initial velocity of the disc between the two groups (skilled: 21.7 +/- 1.7m/s; unskilled: 20.7 +/- 2.5m/s). A marked difference in motion of supination/pronation of the forearm before disc release was identified, with the forearm supinated in the final acceleration phase leading up to disc release for the unskilled participants, while the forearm was pronated in the same phase for the skilled participants. These differences in joint kinematics could be related to differences in disc spin rate, and thus led to the substantial differences in throwing distance. 相似文献
8.
9.
Shinya Sano Yasuo Ikegami Hiroyuki Nunome Tommy Apriantono Shinji Sakurai 《Journal of sports sciences》2013,31(4):381-391
Abstract A new method was established for the continuous measurement of force applied from a springboard to a gymnast in vaulting (board reaction force). Male gymnasts performed a handspring vault using a springboard mounted on force platforms. A high-speed video camera sampled the springboard motion at 500 Hz. The springboard was initially partitioned into 29 segments. The force due to the accelerative motion of the springboard was determined by summing the forces of the individual segments. The board reaction force acting on the gymnast was calculated by subtracting the force due to the accelerative motion of the springboard and weight from the force recorded by the force platform. The new method succeeded in illustrating transient changes of the board reaction force. The horizontal and vertical components of the peak values of the board reaction force were three and two times greater respectively than the average values. A series of tests was conducted to determine whether the number of segments of the springboard model could be reduced without affecting accuracy. A model consisting of only four segments produced almost the same accuracy as the 29-segment model. The simplified model is recommended as a more efficient method to measure board reaction force. 相似文献
10.
This article discusses the validity of the incorporation of online communication in language education classes as a practice free of power politics. By examining blog activities in an advanced‐level Japanese‐as‐a‐Foreign‐Language classroom at a university in the USA, we show that the blog’s postings and readers’ comments evoke certain modes of governmentality – practices that shape one’s conduct – and define the space of a particular blog. This article illustrates two kinds of space created in blogs: that of language education in which ‘native speakers’ dominate ‘non‐native speakers’; and that of information exchange with less fixed relations of dominance, although participants’ behavior is regulated nonetheless. We suggest involving students in analyzing blog comments so that they can understand, and respond to, how the mode of governmentality works outside the classroom and how to transform relations of dominance that manifest themselves in online spaces. 相似文献