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Biomedical subjects

B Roy

Publications and source records attributed to B Roy.

At least 127 records · Page 7Linked to original sources
PubMed1984

[Geometric and dynamic characteristics of hockey sticks in regard to their performance].

The hockey stick can be used for numerous tasks such as shooting, dribbling, receiving and executing passes, stick handling, etc. The purpose of this study was to evaluate the geometrical and dynamic characteristics of hockey sticks in order to identify those which contribute most significantly to its longevity and durability. The characteristics of 14 models of hockey sticks were measured according to the procedure describes by Roy and Doré (1975). To evaluate the longevity of the stick, 45 Midget AA were selected. Each one was given two sample sticks selected randomly. They were to use those sticks in practices and in game situations. Fifteen adult players were selected to evaluate the durability of the stick. Each one received four sample sticks. They had to execute as many slap shots as they could until the stick broke. This work confirmed a previous study of Roy and Doré 1975) which demonstrated a high level of homogeneity in the geometrical characteristics, but a high heterogeneity in their dynamic characteristics. This study revealed also that the longevity and durability measures showed a high level of variability. Through a multiple regression analysis, it was shown that the width and thickness of the handle as well as the rupture coefficient and the module of rigidity of the handle (in a plane parallel to the blade) were four variables contributing significantly to the longevity of the stick.

Adolescent↗
PubMed1984

[Kinematics and kinetics of sprint acceleration].

The kinematic and dynamic characteristics of the sprint of ten (10) male athletes are presented. A Kistler force plate was used to record the following dynamic variables: force, impulse and their duration. A Photosonic, cinecamera was used to obtain the following parameters: stride length and frequency, duration of the different phases and trunk angular measures during certain phases of the running stride. This study has shown that the majority of the kinematic and kinetic factors measured are closely associated with the variation of velocity during the first 18 strides of a sprint. Moreover, two factors account for 80% of the variance in running velocity, the first one being related to the breaking phase and the second to the duration of the support phase. It was also found that the modification of sprint velocity was especially influenced by stride length and frequency. However sprint acceleration was mostly sensitive to the relative duration of the support phase.

Biomechanical Phenomena↗
PubMed1982

Free erythrocyte protoporphyrin, zinc protoporphyrin and blood lead in newly re-exposed smelter workers: a prospective study.

The relationship between blood lead and free erythrocyte protoporphyrin (FEP) or zinc protoporphyrin (ZPP) was evaluated prospectively for 50 weeks in a group of workers who were removed from occupational lead exposure for 10 weeks. FEP or ZPP continued to fall in spite of a rising blood lead upon re-exposure. Although statistically significant relationships between square root FEP or ZPP and blood lead were found, wide confidence limits prevent meaningful predictions of blood lead from FEP or ZPP for an individual. Blood lead is a better index of exposure than FEP or ZPP, especially when exposure is not stable.

Environmental Exposure↗
PubMed1982

[Comparative study of the performance of leather and plastic skate boots].

The authors have tried to demonstrate the influence of leather skate boots and plastic boots on the performance of Atome hockey players. Speed tests and joint flexibility tests by means of rotentgenograms showed that besides the speed tests where the leather boot appeared to perform a little better than the plastic boot, no significant difference could be found between both types of boots. It seems to be more a matter of individual choice and adaptation.

Equipment Design↗
PubMed1982

[Biomechanical characteristics of endurance running].

Over the years, running as a means of locomotion has raised the scientific curiosity of man (Amar, 1920). The advent of modern techniques of investigation such as high speed cinematography and force plates makes the analysis of the data more efficient. The last decade has been particularly fruitful in that respect. The purpose of this study was to measure the biomechanical variations associated with an increase in running speed. The most significant factors related to the increase of running speed were also studied. Twenty subjects of both sexes were selected for the study. They were required to run at seven different velocities, ranging between 12.1 and 19.3 km/h. Cinematographic and force platform data were collected as the subjects were running at prescribed speed, around a 200 m track. This study has shown that three variables related to the running cycle accounted for 90% of the variance in running velocity. A factorial analysis revealed also that two factors made up exclusively of temporal variables accounted for more than 60% of the variance; a third factor, saturated with the dynamic variables accounted for over 25% of the variance.

Biomechanical Phenomena↗
PubMed1980

Time-action characteristics of regular and NPH insulin in insulin-treated diabetics.

The time course of action of regular and NPH insulins injected sc was studied in 15 insulin-treated diabetics over a 24-h period during which they received a constant infusion of glucose. The blood glucose began to decline in 1.2 +/- 0.1 h (range, 0.5--2) and reached its nadir in 5.7 +/- 0.3 h (range, 4--8) after the sc injection of regular insulin. The peak effect of regular insulin usually persisted for several hours, and the total duration of action was 16.2 +/- 1.1 h (range, 9--24). Both the time of peak effect and the total duration of action were considerably prolonged compared to data provided in standard textbooks. Free insulin increased to a peak in 2.7 +/- 0.3 h (range, 1--4) after regular insulin injection and then returned to baseline by 8.8 +/- 0.96 h. Subcutaneous injection of NPH insulin decreased the blood glucose by 2.4 +/- 0.5 h (range, 1--7), with a maximal effect at 11.0 +/- 1.4 h (range, 5--19). The total duration of effect on blood glucose was 25.1 +/- 0.7 h (range, 20--29). These values are similar to those in standard textbooks. Although the total insulin levels increased after the injection of NPH insulin, there was very little if any elevation in free insulin. Recognition of the prolonged effect of regular insulin is important in establishing an insulin treatment regime for diabetic patients.

Adolescent↗
PubMed1980

Electroacupuncture elevates blood cortisol levels in naive horses; sham treatment has no effect.

It was hypothesized that electroacupuncture releases beta-endorphin and ACTH from the pituitary. Since ACTH induces the release of cortisol from the adrenal glands, blood cortisol level should be enhanced by electroacupuncture. The present result shows that the blood cortisol levels of horses are significantly increased after 30 min of electroacupuncture treatment while the sham treatment (control) shows an insignificant effect.

Acupuncture Therapy↗
PubMed1979

[Dynamic characteristics of hockey sticks and efficacy of shooting in ice hockey].

Previous studies have established that efficiency in shooting is influenced partly by the dynamic characteristics of the stick being used and partly by the morphology of the player. The purpose of the present study was therefore to verify the hypothesis stating that flexible sticks were superior to rigid ones in respect to the proficiency of shooting of pee-wee hockey players. This study has confirmed the superiority of the flexible stick over the rigid one in terms of speed and accuracy of shooting among pee-wee hockey players. Moreover morphological parameters and muscular strength were found to play a determining role in efficiency of shooting. In fact, it was suggested that the smaller and weaker the player the more advantageous is the use of a flexible stick. Through the use of strain gages fixed to the experimental hockey sticks, it was possible to determine that the speed of shooting is directly related to the acceleration imparted to the stick during the forward phase of the movement. It was also possible to demonstrate that for a given speed of the puck the more flexible stick required a smaller force than the rigid one.

Anthropometry↗
PubMed1978

Simultaneous production of two types of beta-lactamase in Escherichia coli and Providencia stuartii.

The production of beta-lactamase has been studied in two strains isolated from clinical samples: Providencia stuartii MULB 501 and Escherichia coli MULB 130. These strains were selected for their high resistance level to penicillins and cephalosporins. Determination and identification of beta-lactamase activity were achieved by combining several up-to-date methods including (i) neutralization by anti-beta-lactamase sera, (ii) purification by affinity chromatography on cephalosporin C linked Sepharose 4B, (iii) determination of substrate specificity and kinetic values (Km and Vmax) by a computerized microacidimetric method, and (iv) isoelectric focusing. The results clearly demonstrate that in these two strains there is a simultaneous production of different beta-lactamases: the first one is similar to the TEM penicillinase and the second one shares a typical cephalosporinase profile. This double beta-lactamase production is a relatively rare phenomenon.

Bacterial Infections↗
PubMed1977

Composition and enzyme activities of Spiroplasma citri membranes.

Spiroplasma citri was cultured in three different media that supplied cholesterol and fatty acids from: (i) horse serum, (ii) pleuropneumonia-like organism (PPLO) serum fraction, or (iii) bovine serum albumin-fatty acid-cholesterol. The ability of PPLO serum fraction to support growth varied by lot number. Neither PPLO serum fraction nor the bovine serum albumin medium supported growth as well as the horse serum medium. Analysis of cholesterol, lipid phosphorus, and membrane protein showed the horse serum- and PPLO-grown cells to be indistinguishable, but the bovine serum albumin-grown cells were deficient in lipid phosphorus. The three cultures did not show markedly different fatty acid compositions, but, in all cases, the cultures preferentially incorporated palmitic acid and discriminated against linoleic acid. Cultures grown for different times from logarithmic growth through a degenerative phase showed relatively constant ratios of cholesterol/protein and lipid phosphorus/protein. Fatty acid composition was also relatively constant at the different stages. Adenosine triphosphatase and p-nitrophenyl phosphatase were mainly associated with the membrane, whereas reduced nicotinamide adenine dinucleotide oxidase was either readily removed or not associated with the membrane. The reduced nicotinamide adenine dinucleotide oxidase was inactivated at temperatures above 35 degrees C.

Bacterial Proteins↗