Ion mobility spectrometry of gas-phase ions from laser ablation of solids in air at ambient pressure.

A mobility spectrometer was used to characterize gas-phase ions produced from laser ablation of solids in air at 100 degrees C and at ambient pressure with a beam focused to a diameter of

Student performance and perceptions of a lecture-based course compared with the same course utilizing group discussion.

BACKGROUND AND PURPOSE: Self-directed learning is believed to be an important aspect of the reflective clinical practitioner. This study was a comparison of student learning and student perceptions of course and instructor effectiveness, course difficulty, and amount learned between the active learning and lecture sections of a course. SUBJECTS: Participants in this study were 170 physical therapist students in 3 sections of a physiology course in the first year of their professional program. METHODS: Course grades and the results of teacher-course evaluations were compared between a lecture section and an active learning section. The students in the original active learning section were reassessed 1 year later to determine their perceptions of the course. The differences were analyzed using Kruskal-Wallis and Mann-Whitney U tests. RESULTS: Course grades were higher in both active learning sections than in the lecture section. However, the students in both active learning sections perceived that they had learned less than students in the lecture section. Students' perceptions of course and instructor effectiveness were lower in the active learning sections than in the lecture section. There were no differences between the lecture and active learning sections on the students' perceptions of course difficulty. CONCLUSION AND DISCUSSION: Although they did better in the active learning environment, physical therapist students in a basic sciences course (physiology) in the first year of their professional program perceived that they had learned less in active learning courses. They also had lower perceptions of course and instructor quality.

Sample preparation for high throughput accurate mass analysis by matrix-assisted laser desorption/ionization time-of-flight mass spectrometry.

An automated sample preparation for high throughput accurate mass determinations by matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOFMS) has been developed. Sample preparation was performed with an automated workstation and automated mass analyses were performed with a commercial MALDI-TOF mass spectrometer. The method was tested with a 41-sample library. MALDI-TOFMS was found to give the needed sensitivity, accurate mass measurement, and soft ionization necessary for structure confirmation, even of mixtures. A mass accuracy of 5 ppm or less was obtained in over 80% of known compound measurements. A mass accuracy better than 10 ppm was obtained for all measurements of known compounds. Analyses of parallel synthesis products resulted in 77% of the measurements with a mass accuracy of 5 ppm or better.

Peer tutoring improves student performance in an advanced physiology course.

Effectiveness of a peer tutoring system developed for an advanced physiology course was assessed in terms of academic performance and perceived value. Forty-five students took the course without the peer tutoring system, and sixty-nine students took the course with peer tutoring. Grades from both groups of students were compared with grades earned in an introductory physiology course. Tutored students were asked how much they valued the peer tutoring. There was a decline in grades received by the students in the advanced physiology course compared with their scores in the introductory physiology course in both tutored and untutored groups. However, the decline in the tutored group was significantly (P = 0.015) less than that in the untutored group of students. Tutored students reacted very favorably to the tutoring sessions and expressed a desire to see tutoring expanded to other courses. This was the first demonstration of the effectiveness of peer tutoring in college science teaching. Peer tutoring appears to be effective in enhancing student performance as well as being perceived as beneficial by the students.

Neuromuscular electrical stimulation. An overview and its application in the treatment of sports injuries.

In sports medicine, neuromuscular electrical stimulation (NMES) has been used for muscle strengthening, maintenance of muscle mass and strength during prolonged periods of immobilisation, selective muscle retraining, and the control of oedema. A wide variety of stimulators, including the burst-modulated alternating current ('Russian stimulator'), twin-spiked monophasic pulsed current and biphasic pulsed current stimulators, have been used to produce these effects. Several investigators have reported increased isometric muscle strength in both NMES-stimulated and exercise-trained healthy, young adults when compared to unexercised controls, and also no significant differences between the NMES and voluntary exercise groups. It appears that when NMES and voluntary exercise are combined there is no significant difference in muscle strength after training when compared to either NMES or voluntary exercise alone. There is also evidence that NMES can improve functional performance in a variety of strength tasks. Two mechanisms have been suggested to explain the training effects seen with NMES. The first mechanism proposes that augmentation of muscle strength with NMES occurs in a similar manner to augmentation of muscle strength with voluntary exercise. This mechanism would require NMES strengthening protocols to follow standard strengthening protocols which call for a low number of repetitions with high external loads and a high intensity of muscle contraction. The second mechanism proposes that the muscle strengthening seen following NMES training results from a reversal of voluntary recruitment order with a selective augmentation of type II muscle fibres. Because type II fibres have a higher specific force than type I fibres, selective augmentation of type II muscle fibres will increase the overall strength of the muscle. The use of neuromuscular electrical stimulation to prevent muscle atrophy associated with prolonged knee immobilisation following ligament reconstruction surgery or injury has been extensively studied. NMES has been shown to be effective in preventing the decreases in muscle strength, muscle mass and the oxidative capacity of thigh muscles following knee immobilisation. In all but one of the studies, NMES was shown to be superior in preventing the atrophic changes of knee immobilisation when compared to no exercise, isometric exercise of the quadriceps femoris muscle group, isometric co-contraction of both the hamstrings and quadriceps femoris muscle groups, and combined NMES-isometric exercise. It has also been reported that NMES applied to the thigh musculature during knee immobilisation improves the performance on functional tasks.(ABSTRACT TRUNCATED AT 400 WORDS)

Ethanol increases rate of isolated atria.

Ethanol has a positive chronotropic and negative inotropic effect on isolated spontaneously beating rabbit atria. Both effects increased with increasing ethanol concentrations in the bathing medium. This response is apparently a direct action of ethanol on the myocardium and is not due to the release of catecholamines, acetylcholine, or acetaldehyde produced by the oxidative metabolism of ethanol. Ethanol is one of the few pharmacologic agents having opposite actions on heart rate and force of contraction.