Thesis (Ph.D.)--University of Missouri-Columbia, 2006. / The entire dissertation/thesis text is included in the research.pdf file; the official abstract appears in the short.pdf file (which also appears in the research.pdf); a non-technical general description, or public abstract, appears in the public.pdf file. Title from title screen of research.pdf file viewed on (February) Vita. Includes bibliographical references.

<p><font face="Times New Roman" size="4"><font face="Times New Roman" size="4"> <p align="left">The aim of this study is to investigate the repair bond strength of composite resin following micromechanical and chemical means of retention in improving the repair of composite resin specimens.</p> </font></font></p>

This study investigates the influence of ionic strength on the binding constant (KDOC) between benzo(h)quinoline (BHQ) and LHA by using fluorescence quenching method. Being a basic polycyclic aromatic hydrocarbon, BHQ is the dominated solute as the solution¡¦s pH value is higher than BHQ¡¦s pKb. In contrast, BHQ+ is the major species as the solution¡¦s pH value is lower than BHQ¡¦s pKb. In a salty neutral or basic LHA solution, the cation will bind with the acidic functional groups of LHA, then the conformation of LHA would be coiled up to be small in size. Due to that, leading to the decrease of the corresponding BHQ¡¦s KDOC. Furthermore, the charge density of cation is an important factor in control of the variation of BHQ¡¦s KDOC. The lower charge density of cation is, the less BHQ¡¦s KDOC varied. Besides, SO4 2- may suppress the binding affinity between Na+ and the acidic function groups of LHA, so that lower variation of BHQ¡¦s KDOC was observed than that of Cl- in a Na+ contained LHA solution. In an acidic solution, cation will also bind with the acidic functional groups of LHA, leading to the decrease of the binding sites of BHQ+ on LHA and the corresponding BHQ+¡¦s KDOC. Besides, Mg2+ could provide more binding sites for the acidic functional groups of LHA than Na+, so that the variation of BHQ+¡¦s KDOC with Mg2+ addition is higher than that with Na+ addition.

A strategy was proposed to the rule for paralyzed patients. One goal of the design is to reduce or avoid the occurrence of decubitus ulcer. The other goal is to reduce the decline of muscle strength of patient. The contents of the study include collection and system analysis. The issue is know how the burdens of muscles are affected by the locations and postures that sickbed supporting the body. To attack this issue, a simplified body model, which is consisted of 11 rigid bodies, is proposed. An analysis method, which adopts the optimization approach, is suggested to calculate the ¡§ relaxed burdens of muscles ¡¨. Apply the mathematical model of the optimization to acquire an analysis method of the relaxed burdens of muscles, modeling the concern of the support loading and burdens of muscles. According to the analysis answer of the mathematical model verified that a patient lay on the bed by the horizontal postures and variation postures, the best support locations resulted in the relaxed burdens of muscles and strengthen muscles. So, the rule of the logical thinking to reduce or avoid the occurrence of decubitus ulcer and the decline of muscle strength.

It is now generally accepted that strength training in pubertal children will increase strength, but it is unlikely to induce morphological changes. However research in this area is limited as most studies fail to control for the confounding effects of normal growth, or employ appropriate training programs. To overcome these limitations it is suggested that researchers should use a within-subject design employing an exercise regime of sufficient intensity. In adults, eccentric training has been shown to have the greatest effect on hypertrophy and strength. The purpose of the study was to examine the effects of eccentric training on muscle strength and development in children, using a one arm training model. Seventeen boys in grades 6, 7, and 8 participated in an eight week eccentric elbow flexion training program; three training sessions per week. The program consisted of 2 5 sets of 6 10 reps using progressive resistance. Pre and post test strength (Eccentric and concentric elbow flexion maximal strength by a Biodex System 3 Dynamometer and 1 RM with dumbbells) and bicep thickness measurements were performed. The change in biceps thickness was significantly greater in the training arm versus the non-training arm (7.3 +/- 8.3% vs. 0.7 +/- 7.5%) (p<0.05). No significant difference was found for isokinetic concentric strength gain between arms (p>0.05), but isokinetic eccentric strength gain in the training arm was significantly greater than the non-training arm (25.4 +/- 16.6% vs. 2.4% +/- 15.6%) (p<0.05). Training arm 1 RM isotonic strength significantly increased when compared to the non-training arm, both concentrically (35.0 +/- 15.8% vs. 14.8 +/- 13.1%) and eccentrically (45.0 +/- 16.1% vs. 21.8 +/- 8.0%) (p<0.05). Results from this study indicate eccentric strength training can increase muscle strength and hypertrophy in pubertal boys.

No description available.

It is now generally accepted that strength training in pubertal children will increase strength, but it is unlikely to induce morphological changes. However research in this area is limited as most studies fail to control for the confounding effects of normal growth, or employ appropriate training programs. To overcome these limitations it is suggested that researchers should use a within-subject design employing an exercise regime of sufficient intensity. In adults, eccentric training has been shown to have the greatest effect on hypertrophy and strength. The purpose of the study was to examine the effects of eccentric training on muscle strength and development in children, using a one arm training model. Seventeen boys in grades 6, 7, and 8 participated in an eight week eccentric elbow flexion training program; three training sessions per week. The program consisted of 2 5 sets of 6 10 reps using progressive resistance. Pre and post test strength (Eccentric and concentric elbow flexion maximal strength by a Biodex System 3 Dynamometer and 1 RM with dumbbells) and bicep thickness measurements were performed. The change in biceps thickness was significantly greater in the training arm versus the non-training arm (7.3 +/- 8.3% vs. 0.7 +/- 7.5%) (p<0.05). No significant difference was found for isokinetic concentric strength gain between arms (p>0.05), but isokinetic eccentric strength gain in the training arm was significantly greater than the non-training arm (25.4 +/- 16.6% vs. 2.4% +/- 15.6%) (p<0.05). Training arm 1 RM isotonic strength significantly increased when compared to the non-training arm, both concentrically (35.0 +/- 15.8% vs. 14.8 +/- 13.1%) and eccentrically (45.0 +/- 16.1% vs. 21.8 +/- 8.0%) (p<0.05). Results from this study indicate eccentric strength training can increase muscle strength and hypertrophy in pubertal boys.

Abstract Aim: The aim of this study was to investigate how neural mechanisms operate during maximum strength training in the Quadriceps Femoris muscle group. One of the main objectives is to investigate the effects of five weeks unilateral maximum eccentric strength training on contralateral neural adaptations. The second is to investigate the effects of adding electromyographic (EMG) biofeedback into the training intervention.  Method: 20 healthy, recreationally active men and women had to undergo five weeks (three training sessions per week, resulting in 15 sessions in total) of maximum isokinetic unilateral eccentric strength training of the Quadriceps femoris muscle, with EMG biofeedback; FBG, n=10 five women and five men, or without EMG biofeedback; RTG n=10 five women and five men. The study was performed at the Laboratory of Biomechanics and Motor control, BMC Laboratory, Stockholm Sweden. Results: The results demonstrated an increase in concentric strength development in the trained leg; before 130 ± 43 Nm and after training 148 ± 46 Nm, (p=0.006). No significant increase in strength was detected for the untrained leg. Further, post hoc tests showed a tendency towards an increase in level of activation (LOA) of the trained leg in the FBG; from 69 ± 15 % before to 81 ± 13 % after training (p=0.097). No significant differences in the ecc:con EMG-ratio or in antagonist co-activation after the training intervention were shown. Conclusion: No significant difference in strength development was shown, whether training occurred with or without EMG biofeedback. However, eccentric training tended to induce transfer of neural activation to a maximum voluntary contraction (MVC) in the trained leg only in the group training with EMG biofeedback. In addition, the results revealed that eccentric strength training improved concentric strength in the trained leg but induced no transfer to the contralateral untrained leg. The benefits and prospects with incorporating feedback into training remains somewhat unknown and requires further research to obtain deeper understanding of the neural mechanisms affected by biofeedback.

Abstract In this paper, the mechanical properties of carbon-fiber reinforced polyether-ether ketone (PEEK) with and lay-up subject to impact and temperature reaction have been investigated.The drop-weight impact tests were performed by a 4mm diameter semi spherical nosed projectile. Incident impact height adopts 0.8m and 1.6m incident height. After impact testing, the static tension tests were performed to measure the ultimate strengths and elastic modulus at 25¢J¡B75¢J¡B125¢J¡B145¢J,so that the effects of stacking sequence and the damage mechanism subjected impact at elevated temperature was obtained. By the parametric study and research , there are very important results as follow: The destructive crack of AS4/PEEK laminates subject to impact were arised from the tension sides toward the pressure sides, and the lay-up was more serious than the lay-up. Although more excellent ultimate strength than the lay-up, the must be quantities of decay When the incident height increase as well as elevated temperature. Keywords: Composite, Impact, Temperature, Strength, Elastic Modulus, Fracture.

The joint strength and fracture surface of Sn80¢HAu20¢H and Sn20¢HAu80¢H solders in laser diode package under thermal aging testing were studied experimentally. The AuSn thin film solders were coated on the substrate by electro-plating technique. The Sn80¢HAu20¢H solder was melting point at 210¢J,while the Sn20¢HAu80¢Hsolder was melting point at 280¢J. During the processes of bonding substrate and Al2O3 together, the N2 and H2 gases were used to achieve the bonding. Then the specimens were aged at 150¢J for one, four, nine, sixteen, twenty-five, thirty-six and forty-nine days. We investigated the bonding strength, voids, IMC thickness and microstructure of the Sn80¢HAu20¢H and Sn20¢HAu80¢H solders. In addition, we also studied the comparison with the process of flux and fluxless. Under the forty-nine days of aging, the bonding strength of Sn80¢HAu20¢Hand Sn20¢HAu80¢H solders decreased from 34.3¢V to 26.0¢V and from 54.96¢V to 47.06¢V,respectively. Moreover,the IMC thickness of Sn80¢HAu20¢H and Sn20¢HAu80¢H solders increased from1.07£gm to 2.85£gm and from 0.83 £gm to 1.08 £gm, respectively. The Sn20¢HAu80¢H solders showed a better joint strength performance than Sn80¢HAu20¢H due to the less grown of IMC and superior mechanical properties of Au. The fluxless process exhibited the better joint strength performance due to the less grown of voids. In the study, by using the lead-free and fluxless process, the reliability of laser module package may be improved.