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Biomedical subjects

A Villaseñor

Publications and source records attributed to A Villaseñor.

12 recordsLinked to original sources
PubMed2006

Recoil effect of the ice hockey stick during a slap shot.

The purpose of this study was to examine the "recoil" effect of the ice hockey stick shaft during a stationary slap shot. Nine male adult subjects (four elite and five recreational) were tested. Their performances were evaluated by simultaneously recording stick movement and internal bending from high-speed digital video (1,000 Hz) and puck acceleration from a triaxial accelerometer positioned inside the puck. In addition, an electrical circuit measured blade-puck contact time. Data were analyzed with a one-way MANOVA for several dependent variables, including final puck velocity, puck acceleration, maximum stick shaft bending (angle and distance deflection), stick shaft angular velocities, blade-puck contact time, and corresponding time events. The results indicate the following. First, blade-puck contact time was greater for the elite than for recreational players (38 +/- 9 ms and 27 +/- 5 ms); however, measures for puck acceleration were essentially the same (63.8 g +/- 9.9 and 61.8 g +/- 19.5). Two, the elite players were able to generate greater puck velocities (120 +/- 18 km/h and 80.3 +/- 11.6 km/h). Three, the recoil timing was found to be reater for elite players (59.8% of blade-puck contact).

Acceleration↗
PubMed1998

Educational outcomes of an otitis media workshop for primary care providers in Latin America.

Otitis media is a prevalent condition that can be diagnosed and treated by primary care providers skilled in otoscopy. Previous analysis demonstrated that brief, intensive instruction at one site in rural Mexico improved the test scores of health care providers and changed long-term practices (Eavey R, et al. Otolaryngol Head Neck Surg 1993; 109:895-8). We wanted to confirm these test score findings at other sites. A didactic course on otitis media with a practical otoscopy workshop was conducted at six Mexican locations and in one Venezuelan city by an interdisciplinary group of physicians. The same coded test was given immediately before and after the course. The Wilcoxon test for significance of intrasubject performance before and after intervention was used as a nonparametric assessment. At all seven sites (n = 190 subjects), test scores demonstrated statistically significant improvement (range = p < 0.001 to p < 0.0001). We conclude that this educational method consistently improved short-term knowledge of otitis media and that further teaching efforts and a longer term practice-impact study are warranted.

Child↗
PubMed1997

The structure of mammalian 15-lipoxygenase reveals similarity to the lipases and the determinants of substrate specificity.

Here we report the first structure of a mammalian 15-lipoxygenase. The protein is composed of two domains; a catalytic domain and a previously unrecognized beta-barrel domain. The N-terminal beta-barrel domain has topological and sequence identify to a domain in the mammalian lipases, suggesting that these domains may have similar functions in vivo. Within the C-terminal domain, the lipoxygenase substrate binding site is a hydrophobic pocket defined by a bound inhibitor. Arachidonic acid can be docked into this deep hydrophobic pocket with the methyl end extending down into the bottom of the pocket and the acid end tethered by a conserved basic residue on the surface of the enzyme. This structure provides a unifying hypothesis for the positional specificity of mammalian lipoxygenases.

Animals↗
PubMed1986

Four-incision radial keratotomy for low to moderate myopia.

The first 112 consecutive eyes (75 patients) to undergo four-incision radial keratotomy (RK) performed by four surgeons were evaluated retrospectively. The preoperative myopia (spherical equivalent) ranged from -1.12 to -7.00 D (95% between -1.12 and -4.25 D). The preoperative uncorrected visual acuity was 20/100 or worse in 95% of the eyes. A six-month follow-up was achieved in 95% of the eyes and 45% were followed over one year. Following four incision RK, 79% of the eyes achieved 20/40 or better vision and 82% were corrected to within 1 D of emmetropia. Following repeat RK in 15 eyes (13%), 82% had uncorrected visual acuity of 20/40 or better, and 90% were corrected to within 1 D of emmetropia. Only 3.5% of the eyes were overcorrected by more than 1 D and only one eye had induced astigmatism greater than 1 D. For eyes with preoperative myopia up to -4.25 D over 90% achieved uncorrected visual acuity of 20/40 or better and were within 1 D of emmetropia following primary four incision RK and a second four incisions in 13 eyes (12%). Only 3.5% of the eyes in this group were overcorrected by more than 1 D. There were no serious complications.

Adult↗
PubMedDate not supplied

Comparison of two ultrasonic cleaning units for deterioration of cutting edges and debris removal on dental burs.

The effects of two ultrasonic cleaning units on surface deterioration and cleaning effectiveness of dental burs were compared in this study. The units tested were the Dextrex Model L 503B (Dextrex Chemical Industries, Inc., Bowling Green, KY) industrial ultrasonic unit and a conventional dental ultrasonic unit L & R T-21 B (L & R Manufacturing Co., Kearny, NJ). SEM photomicrographs of the burs were made before cleaning; and burs were processed for 10 min in each unit. Forty-eight new burs (24 #1/2A diamond and 24 #330 carbide) contaminated with human blood and 48 burs contaminated with tooth debris following cavity preparation were used to evaluate cleanliness. To assess deterioration, 48 new burs were evaluated for changes in the number of diamond chips or pits (carbide burs) and color changes following ultrasonic cleaning. Neither unit sufficiently cleaned the burs, as evidenced by remnants of remaining blood and debris on the burs. The loss of diamond chips was statistically significant for the burs processed in the Dextrex unit (P < 0.001) as well as for burs processed in the L & RT 21-B unit (P < 0.01). The mean number of pits was significant in carbide burs processed in both units as well (Dextrex unit: P < 0.01; L & RT-21 B unit: P < 0.001). No differences were noted in color changes for any of the burs in either unit. These data showed that the industrial-type unit was no more effective in cleaning dental burs than the conventional unit, though both units caused significant amounts of deterioration in the cutting surfaces.

Carbon↗