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1.
Yuta Suzuki Michiyoshi Ae Shunsuke Takenaka Norihisa Fujii 《Sports biomechanics / International Society of Biomechanics in Sports》2014,13(2):144-153
The purpose of this study was to investigate differences in the support leg joint moment and moment power between side-step (SS) and cross-step (CS) cutting techniques with a prescribed 90° cutting angle. Ground reaction forces (1,000 Hz) and three-dimensional kinematics (250 Hz) of SS and CS cutting techniques were collected from 20 male college athletes. Normalised peak knee extension moment was larger in the SS technique than in the CS technique (0.40 ± 0.10 in SS; 0.26 ± 0.08 in CS). In the SS technique, the knee extensors ( ? 0.10 ± 0.06 in SS; ? 0.02 ± 0.04 in CS) and ankle plantarflexors ( ? 0.12 ± 0.05 in SS; ? 0.07 ± 0.03 in CS) did significantly more negative work (normalised). The direction change angle (40.5 ± 8.7° in SS; 33.0 ± 6.8° in CS) and the decrease in horizontal velocity of the centre of mass ( ? 0.63 ± 0.23 m/s in SS; ? 0.31 ± 0.23 m/s in CS) were significantly larger in the SS technique. These results suggest that the SS technique is an effective means of changing running direction at the expense of velocity of the centre of mass and that the CS technique is better for minimising the reduction in horizontal velocity of the centre of mass. 相似文献
2.
Linda Desbois Adrien Padirac Shohei Kaneda Anthony J. Genot Yannick Rondelez Didier Hober Dominique Collard Teruo Fujii 《Biomicrofluidics》2012,6(4)
Water-in-oil microdroplets offer microreactors for compartmentalized biochemical reactions with high throughput. Recently, the combination with a sol-gel switch ability, using agarose-in-oil microdroplets, has increased the range of possible applications, allowing for example the capture of amplicons in the gel phase for the preservation of monoclonality during a PCR reaction. Here, we report a new method for generating such agarose-in-oil microdroplets on a microfluidic device, with minimized inlet dead volume, on-chip cooling, and in situ monitoring of biochemical reactions within the gelified microbeads. We used a flow-focusing microchannel network and successfully generated agarose microdroplets at room temperature using the “push-pull” method. This method consists in pushing the oil continuous phase only, while suction is applied to the device outlet. The agarose phase present at the inlet is thus aspirated in the device, and segmented in microdroplets. The cooling system consists of two copper wires embedded in the microfluidic device. The transition from agarose microdroplets to microbeads provides additional stability and facilitated manipulation. We demonstrate the potential of this method by performing on-chip a temperature-triggered DNA isothermal amplification in agarose microbeads. Our device thus provides a new way to generate microbeads with high throughput and no dead volume for biochemical applications. 相似文献
3.
Naoto Fujii Hiroki Hara Yasushi Enomoto Satoru Tanigawa 《European Journal of Sport Science》2019,19(3):336-344
We tested the hypothesis that work-matched supramaximal intermittent warm-up improves final-sprint power output to a greater degree than submaximal constant-intensity warm-up during the last 30?s of a 120-s supramaximal exercise simulating the final sprint during sports events lasting approximately 2?min. Ten male middle-distance runners performed a 120-s supramaximal cycling exercise consisting of 90?s of constant-workload cycling at a workload corresponding to 110% maximal oxygen uptake (VO2max) followed by 30?s of maximal-effort cycling. This exercise was preceded by 1) no warm-up (Control), 2) a constant-workload cycling warm-up at a workload of 60%VO2max for 6?min and 40?s, or 3) a supramaximal intermittent cycling warm-up for 6?min and 40?s consisting of 5 sets of 65?s of cycling at a workload of 46%VO2max?+?15?s of supramaximal cycling at a workload of 120%VO2max. By design, total work was matched between the two warm-up conditions. Supramaximal intermittent and submaximal constant-workload warm-ups similarly increased 5-s peak (590?±?191 vs. 604?±?215W, P?=?0.41) and 30-s mean (495?±?137 vs. 503?±?154W, P?=?0.48) power output during the final 30-s maximal-effort cycling as compared to the no warm-up condition (5-s peak: 471?±?165W; 30-s mean: 398?±?117W). VO2 during the 120-s supramaximal cycling was similarly increased by the two warm-ups as compared to no-warm up (P?≤?0.05). These findings show that work-matched supramaximal intermittent and submaximal constant-workload warm-ups improve final sprint (～30?s) performance to similar extents during the late stage of a 120-s supramaximal exercise bout. 相似文献
4.
Teruo Sato 《Prospects》1979,9(2):216-222
Japan is in a unique position regarding the question of education for international understanding: it participated actively in the Second World War, which is lost through the tragic events of which we are all aware. This dual heritage, from the war and then the post-war period, is clear in the two following articles which describe from very different viewpoints the role of eduction for international understanding in the national context. Reading them, in either order, should in our point of view not so much open a debate (who is against peace?) as on the contrary, stimulate thought on future action. The first article describes the evolution and current status of education for international understanding within the official school system. The second, theoretical, puts forth the point of view of those who work within the peace movement in Japan and who feel something more and different is needed from the formal school system. Such contrast, even tension, between two attitudes equally but differently aiming towards the same goal, is an excellent illustration of the fact that even though education for international understanding and peace, through its efforts, its successer or its inadequacies, is more than ever a question of foremost importance, it is one that no educational system can pretend to have definitively settled. 相似文献
5.
Kobayashi Y Takeuchi T Hosoi T Yoshizaki H Loeppky JA 《Research quarterly for exercise and sport》2005,76(4):450-455
The objective of this study was to determine the effect of a marathon run on serum lipid and lipoprotein concentrations and serum muscle enzyme activities and follow their recovery after the run. These blood concentrations were measured before, immediately after, and serially after a marathon run in 15 male recreational runners. The triglyceride level was significantly elevated postrace, then fell 30% below baseline 1 day after the run, and returned to baseline after 1 week. Total cholesterol responded less dramatically but with a similar pattern. High-density lipoprotein cholesterol remained significantly elevated and low-density lipoprotein cholesterol was transiently reduced for 3 days after the run. The total cholesterol/high-density cholesterol ratio was significantly lowered for 3 days. Serum lactate dehydrogenase activity significantly doubled postrace and then declined but remained elevated for 2 weeks. Serum creatine kinase activity peaked 24 hr after the run, with a 15-fold rise, and returned to baseline after 1 week. The rise of these enzymes reflects mechanically damaged muscle cells leaking contents into the interstitial fluid. It is concluded that a prolonged strenuous exercise bout in recreational runners, such as a marathon, produces beneficial changes in lipid blood profiles that are significant for only 3 days. However, muscle damage is also evident for 1 week or more from the dramatic and long-lasting effect on enzyme levels. Laboratory values for these runners were outside normal ranges for some days after the race. 相似文献
6.
In this study, we propose a microfluidic cell culture device mimicking the microscopic structure in liver tissue called hepatic cords. The cell culture area of the device was designed to align hepatocytes in two lines in a similar way to hepatic cords. Thanks to the structural design together with a cell seeding procedure, rat primary hepatocytes were successfully aligned in two lines and cultured under perfusion condition. It is shown that aligned hepatocytes gradually self-organize and form bile canaliculi along the hepatic cord-like structure. The present technique to culture hepatocytes with functional bile canaliculi could be used as an alternative to animal testing in the field of drug discovery and toxicological studies, and also be beneficial to tissue engineering applications. 相似文献
7.
Keisuke Fujii Shinsuke Yoshioka Tadao Isaka Motoki Kouzaki 《Sports biomechanics / International Society of Biomechanics in Sports》2013,12(1):28-44
We previously demonstrated the relationship between sidestepping performance and the preparatory state of ground reaction forces (GRFs). The present study investigated the effect of the preparatory state of GRFs on defensive performance in 1-on-1 subphase of basketball. Ten basketball players participated in 1-on-1 dribble game of basketball. The outcomes (penetrating and guarding) and the preparatory state of GRFs (non-weighted and weighted states, i.e. vertical GRFs below and above 120% of body weight, respectively) were assessed by separating the phases. In the non-weighted state and the weighted state to determine the outcome, the probability of successful guarding was 78.8% and 29.6%, respectively. The non-weighted state prevented delay of the defensive step in the determination phase. Both the non-weighted and weighted states, immediately before the determination phase, were likely to change to the weighted state in the determination phase; during this time, the defender's preparatory state would be destabilised, presumably by the dribbler's movement. These results revealed that the preparatory GRFs before the defensive step help to explain the outcome of the 1-on-1 subphase, and suggest a better way to prevent delaying initiation of the defensive step and thereby to guard more effectively against a dribbler. 相似文献
8.
Interest in single-cell analysis has increased because it allows to understand cell metabolism and characterize disease states, cellular adaptation to environmental changes, cell cycles, etc. Here, the authors propose a device to electrically trap and lyse single-bacterial cells in an array format for high-throughput single-cell analysis. The applied electric field is highly deformed and concentrated toward the inside of the microwell structures patterned on the planar electrode. This configuration effectively generates dielectrophoretic force to attract a single cell per well. The microwell has a comparable size to the target bacterial cell making it possible to trap single cells by physically excluding additional cells. Inducing highly concentrated electric potential on the cell membrane can also effectively lyse the trapped single-bacterial cells. The feasibility of the authors' approach was demonstrated by trapping and lysing Escherichia coli cells at the single-cell level. The present microwell array can be used as a basic tool for individual bacterial cell analysis. 相似文献
9.
The processing of intellectual property documents, such as patents, has been important to the industry, business, and law communities. Recently, the importance of patent processing has also been recognized in academic research communities, particularly by information retrieval and natural language processing researchers. In addition, large test collections that include patents have recently become available, to enable the systematic evaluation of methodologies from a scientific point of view. In the light of these activities, this special issue is intended to collect advanced research papers on patent processing. As an introduction to the special issue on patent processing, this paper surveys the relevant literature and outlines the papers selected for the special issue. 相似文献
10.
Kazumichi Ae Sekiya Koike Norihisa Fujii Michiyoshi Ae Takashi Kawamura 《Sports biomechanics / International Society of Biomechanics in Sports》2017,16(3):283-296
The purpose of this study was to investigate effects of the ground reaction forces on the rotation of the body as a whole and on the joint torques of the lower limbs associated with trunk and pelvic rotation in baseball tee batting. A total of 22 male collegiate baseball players participated in this study. Three-dimensional coordinate data were acquired by a motion capture system (250 Hz), and ground reaction forces of both legs were measured with three force platforms (1,000 Hz). Kinetic data were used to calculate the moment about the vertical axis through the body’s centre of mass resulting from ground reaction forces, as well as to calculate the torque and mechanical work in the lower limb joints. The lateral/medial ground reaction force generated by both legs resulted in the large whole body moment about its vertical axis. The joint torques of flexion/extension of both hips, adduction of the stride hip and extension of the stride knee produced significantly larger mechanical work than did the other joint torques. To obtain high bat-head speed, the batter should push both legs in the lateral/medial direction by utilising both hips and stride knee torques so as to increase the whole body rotation. 相似文献