Techniques Used by Elite Women Gymnasts Performing the Handspring Vault at the 1987 Pan American Games

1990 ◽  
Vol 6 (1) ◽  
pp. 29-55 ◽  
Author(s):  
Yoshiaki Takei
Keyword(s):  
Vertical Velocity ◽  
Large Change ◽  
Great Distance ◽  
Successful Performance ◽  
Factors Associated ◽  
Long Time ◽  
Mechanical Factors ◽  
Pan American ◽  
Female Gymnasts ◽  
Short Time

The purposes of this study were (a) to determine the mechanical factors associated with successful performance of women’s handspring vault and (b) to contrast the findings to those of men to gain insight for improvement of performance. The subjects were 24 female gymnasts in the 1987 Pan American Games. Significant correlations indicated that the following were important determinants for successful results: (a) large horizontal velocity (VH) and distance of hurdle; (b) large vertical velocity (Vv) at touchdown (TD) on board, a large change of Vv on board, and a short time of board contact; (c) large VH and Vv at takeoff (TO) from board; (d) short time of horse contact; (e) large VH and Vv at TO from horse; (f) high body CG at TO from horse; and (g) great distance and height and a long time of postflight. Comparisons revealed that women had significantly smaller VH and Vv at TD on horse and departed from it with significantly smaller VH and Vv than men. This resulted in significantly less height and distance as well as a shorter time of postflight for women even after adjusting for horse height and subject physique.

Techniques Used in Performing the Handspring and Salto Forward Tucked Vault at the 1988 Olympic Games

1990 ◽  
Vol 6 (2) ◽  
pp. 111-138 ◽  
Author(s):  
Yoshiaki Takei ◽  
Eay Jin Kim
Keyword(s):  
Vertical Velocity ◽  
Olympic Games ◽  
Large Change ◽  
Great Distance ◽  
Horizontal Velocity ◽  
Additional Insight ◽  
Factors Associated ◽  
Long Time ◽  
The Usa ◽  
Mechanical Factors

The purposes of this study were to (a) determine the mechanical factors associated with successful performance of the handspring and salto forward vault at the 1988 Olympic Games, and (b) contrast the findings in this study to those from the 1986 USA Championships to gain additional insight for the improvement of performance. The subjects were 51 male gymnasts in the 1988 Olympic Games. Significant correlations indicated that the following were important determinants for successful results: (a) large horizontal velocity (VH) at takeoff (TO) from floor and board resulting from a fast sprint in the approach run; (b) a large change of vertical velocity (Vv) during the horse contact by means of blocking with arms and shoulders; and (c) large VH and Vv at TO from horse, which ensures great distance and height and a long time of postflight, which the judges are seeking. Comparison of the techniques between the two groups revealed that the Olympic gymnasts achieved significantly greater horizontal velocity in preflight, change of vertical velocity while on horse, and vertical velocity at takeoff from horse, which resulted in a significantly longer time of postflight than for the USA gymnasts. An analysis of the aspect of form in postflight, possibly by means of mechanical variables, should be conducted because it may provide additional insight for improvement for performance of this vault.

Techniques Used by Elite Male Gymnasts Performing a Handspring Vault at the 1987 Pan American Games

1989 ◽  
Vol 5 (1) ◽  
pp. 1-25 ◽  
Author(s):  
Yoshiaki Takei
Keyword(s):  
Angular Momentum ◽  
Deterministic Model ◽  
Optical Axis ◽  
Significant Negative Correlation ◽  
Vertical Force ◽  
Relative Height ◽  
Breaking Force ◽  
Successful Performance ◽  
Mechanical Factors ◽  
Pan American

The purpose of this study was to determine mechanical factors, through development of the deterministic model, that govern successful performance of the handspring vault. The subjects were 40 elite male gymnasts participating in the 1987 Pan American Games. A motion-picture camera placed with its optical axis at right angles to the runway was used to record the subjects’ performances. Significant correlations indicated that the following were important determinants for success: (a) large horizontal velocity and angular momentum at takeoff from board, (b) shorter time of preflight and smaller relative height of takeoff in preflight, (c) large horizontal breaking force and large vertical force exerted as well as a large loss of angular momentum during horse contact, and (d) large vertical velocity of takeoff from horse. Significant correlation of “on-horse” factors with the judges’ scores indicated that the more the gymnast focused on horse contact and the more vertical the direction of his effort at takeoff, the better the final result. A significant negative correlation revealed that the less the height of CG at touchdown on mat, the more points awarded by judges. This relationship was almost entirely a consequence of the landing angle.

Techniques Used by Elite Gymnasts in the 1992 Olympic Compulsory Dismount from the Horizontal Bar

1999 ◽  
Vol 8 (3) ◽  
pp. 207-232 ◽  
Author(s):  
Yoshiaki Takei ◽  
Hiroshi Nohara ◽  
Mamoru Kamimura
Keyword(s):  
Optical Axis ◽  
Body Position ◽  
The Body ◽  
Successful Performance ◽  
Extended Body ◽  
Body Style ◽  
Axis Parallel ◽  
Long Time ◽  
Mechanical Factors ◽  
Bonus Points

The purpose of this study was to identify the mechanical factors that are crucial to a successful double salto backward tucked dismount from thehorizontal bar. The subjects were 35 American and 43 Japanese gymnasts competing in their respective 1990 national gymnastics championships. A 16-mm camera, placed with its optical axis parallel to the horizontal bar and operating at 100 Hz, was used to record the performances of the subjects. Significant correlations indicated that a large vertical velocity at bar release, which ensures great height and long time of flight, is important. Successful performance is also likely when efforts are made to (a) achieve the tightest tuck position during the salto backward near the peak of flight, (b) extend the body rapidly and fully early in rotation before the vertical body position is reached well above the bar, (c) maintain the extended body position during the remainder of the flight to display body style for virtuosity bonus points, and (d) simultaneously prepare for a controlled landing on the mat.

Short-Time Tests for Long-Time Endurance

1923 ◽  
Vol 128 (4) ◽  
pp. 264-264
Author(s):  
J. W. Harsch
Keyword(s):  
Long Time ◽  
Short Time

Effect of Vial shaking on Loading Time of Epirubicin into Drug-Eluting Bead

2015 ◽  
Vol 5 (3) ◽  
Author(s):  
Kenji Ikeda ◽  
Yusuke Kawamura ◽  
Masahiro Kobayashi ◽  
Taito Fukushima ◽  
Yushi Sorin ◽  
...  
Keyword(s):  
Antitumor Agent ◽  
Loading Rates ◽  
Vortex Mixer ◽  
Long Time ◽  
Group A ◽  
Drug Eluting ◽  
Large Hepatocellular Carcinoma ◽  
Group B ◽  
Time Required ◽  
Short Time

Background: Although DC Bead has been useful in treatment of multiple and large hepatocellular carcinoma, loading time of doxorubicin into the DC Bead takes a long time of 30-120 minutes. Epirubicin is also used as an antitumor agent together with DC Bead, but its loading efficiency was not sufficiently elucidated. Methods: To shorten loading time of epirubicin into DC Bead (100-300µm, 300-500µm, 500-700µm), we examined the following three methods after mixing the drug: (a) let stand in room temperature, (b) agitated for 30 seconds with Vortex mixer, and (c) sonicated for 30 seconds with ultrasonic cleaner. After loading of epirubicin by each method, supernatant concentration for epirubicin was assayed at 5, 10, 30, 60, and 120 minutes. Results: Epirubicin loading rates for small bead (100-300µm) at 5 minutes were 82.9 % in group a, 93.8% in group b, and 79.9 % in group c. Similarly, medium bead (300-500µm), 40.1% in group a, 65.7% in group b and 45.5% in group c, respectively. In large-sized bead (500-700µm), loaded rates of epirubicin were 38.8% in group a, 59.0% in group b and 48.0% in group c. Agitation of mixture of epirubicin and DC Bead with Vortex mixer significantly shortened the loading time, but sonication did not affect the time required. Microscopic examination did not lead to any morphological change of microspheres in all the methods. Conclusions: Short time of agitation with Vortex mixer reduced the necessary time for loading of epirubicin in every standard of DC Bead.

Robust Test Method of TSOP PEMs for Space Application

2019 ◽  
Author(s):  
Yasunobu Iwai ◽  
Koichi Shinozaki ◽  
Daiki Tanaka
Keyword(s):  
Evaluation Method ◽  
Low Cost ◽  
Reliability Evaluation ◽  
Test Method ◽  
Thermal Shock Test ◽  
Space Application ◽  
Space Applications ◽  
Limit Test ◽  
Long Time ◽  
Short Time

Abstract Compared with space parts, consumer parts are highly functional, low cost, compact and lightweight. Therefore, their increased usage in space applications is expected. Prior testing and evaluation on space applicability are necessary because consumer parts do not have quality guarantees for space application [1]. However, in the conventional reliability evaluation method, the test takes a long time, and the problem is that the robustness of the target sample can’t be evaluated in a short time. In this report, we apply to the latest TSOP PEM (Thin Small Outline Package Plastic Encapsulated Microcircuit) an evaluation method that combines preconditioning and HALT (Highly Accelerated Limit Test), which is a test method that causes failures in a short time under very severe environmental conditions. We show that this method can evaluate the robustness of TSOP PEMs including solder connections in a short time. In addition, the validity of this evaluation method for TSOP PEM is shown by comparing with the evaluation results of thermal shock test and life test, which are conventional reliability evaluation methods.

The Spread of Pollutants from Harbour Sludge Depots

1984 ◽  
Vol 16 (3-4) ◽  
pp. 623-633
Author(s):  
M Loxham ◽  
F Weststrate
Keyword(s):  
Time Scales ◽  
Molecular Diffusion ◽  
Near Field ◽  
Parameter Analysis ◽  
Migration Patterns ◽  
Long Time ◽  
Dilution Effects ◽  
Short Time ◽  
Harbour Sludge

It is generally agreed that both the landfill option, or the civil techniques option for the final disposal of contaminated harbour sludge involves the isolation of the sludge from the environment. For short time scales, engineered barriers such as a bentonite screen, plastic sheets, pumping strategies etc. can be used. However for long time scales the effectiveness of such measures cannot be counted upon. It is thus necessary to be able to predict the long term environmenttal spread of contaminants from a mature landfill. A model is presented that considers diffusion and adsorption in the landfill site and convection and adsorption in the underlaying aquifer. From a parameter analysis starting form practical values it is shown that the adsorption behaviour and the molecular diffusion coefficient of the sludge, are the key parameters involved in the near field. The dilution effects of the far field migration patterns are also illustrated.

Alteration of intrapancreatic serotonin, homocysteine, TNF-α, and NGF levels as predisposing factors for diabetes following exposure to 900-MHz waves

2021 ◽  
pp. 074823372110226
Author(s):  
Gholamali Jelodar ◽  
Mansour Azimzadeh ◽  
Fatemeh Radmard ◽  
Narges Darvishhoo
Keyword(s):  
Cell Damage ◽  
Pancreatic Beta Cell ◽  
Predisposing Factors ◽  
Male Rats ◽  
Control Group ◽  
Predisposing Factor ◽  
Time Exposure ◽  
Tnf Α ◽  
Long Time ◽  
Short Time

Exposure to mobile phone radiation causes deleterious health effects on biological systems. The objects of this study were to investigate the effect of 900-MHz radiofrequency waves (RFW) emitted from base transceiver station antenna on intrapancreatic homocysteine (Hcy), tumor necrosis factor-α (TNF-α), and nerve growth factor (NGF) as predisposing factors involved in pancreatic beta cell damage. Thirty male rats (Sprague-Dawley, 200 ± 10 g) were randomly divided into the control (without any exposure) and exposed groups: short time (2 h/day), long time (4 h/day), and exposed to 900-MHz RFW for 30 consecutive days. On the last days of the experiment, animals were killed and pancreas tissue was dissected out for evaluation of serotonin, Hcy, TNF-α, and NGF. There was a significant decrease in the serotonin and NGF levels in the pancreatic tissue of exposed groups compared to the control group ( p < 0.05). Also, the levels of serotonin and NGF in the long-time exposure were significantly lower than the short-time exposure ( p < 0.05). However, levels of Hcy and TNF-α were significantly increased in the pancreas of exposed groups compared to the control groups ( p < 0.05). Exposure to 900-MHz RFW decreased pancreatic NGF and serotonin levels and increased the proinflammatory markers (Hcy and TNF-α), which can be a predisposing factor for type 2 diabetes.

scholarly journals Internal dosimetry in F-18 FDG PET examinations based on long-time-measured organ activities using total-body PET/CT: does it make any difference from a short-time measurement?

2021 ◽  
Vol 8 (1) ◽  
Author(s):  
Pengcheng Hu ◽  
Xin Lin ◽  
Weihai Zhuo ◽  
Hui Tan ◽  
Tianwu Xie ◽  
...  
Keyword(s):  
Effective Dose ◽  
Dynamic Model ◽  
Bladder Wall ◽  
Time Measurement ◽  
Post Injection ◽  
Time Activity ◽  
Pet Ct ◽  
Long Time ◽  
Total Body ◽  
Short Time

Abstract Purpose A 2-m axial field-of-view, total-body PET/CT scanner (uEXPLORER) has been recently developed to provide total-body coverage and ultra-high sensitivity, which together, enables opportunities for in vivo time-activity curve (TAC) measurement of all investigated organs simultaneously with high temporal resolution. This study aims at quantifying the cumulated activity and patient dose of 2-[F-18]fluoro-2-deoxy-D-glucose (F-18 FDG ) imaging by using delayed time-activity curves (TACs), measured out to 8-h post-injection, for different organs so that the comparison between quantifying approaches using short-time method (up to 75 min post-injection) or long-time method (up to 8 h post-injection) could be performed. Methods Organ TACs of 10 healthy volunteers were collected using total-body PET/CT in 4 periods after the intravenous injection of F-18 FDG. The 8-h post-injection TACs of 6 source organs were fitted using a spline method (based on Origin (version 8.1)). To compare with cumulated activity estimated from spline-fitted curves, the cumulated activity estimated from multi-exponential curve was also calculated. Exponential curve was fitted with shorter series of data consistent with clinical procedure and previous dosimetry works. An 8-h dynamic bladder wall dose model considering 2 voiding were employed to illustrate the differences in bladder wall dose caused by the different measurement durations. Organ absorbed doses were further estimated using Medical Internal Radiation Dose (MIRD) method and voxel phantoms. Results A short-time measurement could lead to significant bias in estimated cumulated activity for liver compared with long-time-measured spline fitted method, and the differences of cumulated activity were 18.38% on average. For the myocardium, the estimated cumulated activity difference was not statistically significant due to large variation in metabolism among individuals. The average residence time differences of brain, heart, kidney, liver, and lungs were 8.38%, 15.13%, 25.02%, 23.94%, and 16.50% between short-time and long-time methods. Regarding effective dose, the maximum differences of residence time between long-time-measured spline fitted curve and short-time-measured multi-exponential fitted curve was 9.93%. When using spline method, the bladder revealed the most difference in the effective dose among all the investigated organs with a bias up to 21.18%. The bladder wall dose calculated using a long-time dynamic model was 13.79% larger than the two-voiding dynamic model, and at least 50.17% lower than previous studies based on fixed bladder content volume. Conclusions Long-time measurement of multi-organ TACs with high temporal resolution enabled by a total-body PET/CT demonstrated that the clinical procedure with 20 min PET scan at 1 h after injection could be used for retrospective dosimetry analysis in most organs. As the bladder content contributed the most to the effective dose, a long-time dynamic model was recommended for the bladder wall dose estimation.

scholarly journals Inhibition of CCL7 derived from Mo-MDSCs prevents metastatic progression from latency in colorectal cancer

2021 ◽  
Vol 12 (5) ◽  
Author(s):  
Xiaoli Ren ◽  
Jianbiao Xiao ◽  
Wanning Zhang ◽  
Feifei Wang ◽  
Yongrong Yan ◽  
...  
Keyword(s):  
Colorectal Cancer ◽  
Suppressor Cells ◽  
Metastatic Progression ◽  
Ht29 Cells ◽  
Metastatic Cells ◽  
Long Time ◽  
Mice Liver ◽  
Short Time ◽  
Related Proteins

AbstractIn colorectal cancer (CRC), overt metastases often appear after years of latency. But the signals that cause micro-metastatic cells to remain indolent, thereby enabling them to survive for extended periods of time, are unclear. Immunofluorescence and co-immunoprecipitation assays were used to explore the co-localization of CCL7 and CCR2. Immunohistochemical (IHC) assays were employed to detect the characters of metastatic HT29 cells in mice liver. Flow cytometry assays were performed to detect the immune cells. Bruberin vivo MS FX Pro Imager was used to observe the liver metastasis of CRC in mice. Quantitative real-time PCR (qRT-PCR) and western blot were employed to detect the expressions of related proteins. Trace RNA sequencing was employed to identify differentially expressed genes in MDSCs from liver micro-M and macro-M of CRC in mice. Here, we firstly constructed the vitro dormant cell models and metastatic dormant animal models of colorectal cancer. Then we found that myeloid-derived suppressor cells (MDSCs) were increased significantly from liver micro-metastases to macro-metastases of CRC in mice. Moreover, monocytic MDSCs (Mo-MDSC) significantly promoted the dormant activation of micro-metastatic cells compared to polymorphonuclear MDSCs (PMN-MDSC). Mechanistically, CCL7 secreted by Mo-MDSCs bound with membrane protein CCR2 of micro-metastatic cells and then stimulated the JAK/STAT3 pathway to activate the dormant cells. Low-dose administration of CCL7 and MDSCs inhibitors in vivo could significantly maintain the CRC metastatic cells dormant status for a long time to reduce metastasis or recurrence after radical operation. Clinically, the level of CCL7 in blood was positively related to the number of Mo-MDSCs in CCR patients, and highly linked with the short-time recurrence and distant metastasis. CCL7 secreted by Mo-MDSCs plays an important role in initiating the outgrowth of metastatic latent CRC cells. Inhibition of CCL7 might provide a potential therapeutic strategy for the prevention of metastasis recurrence.

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