Made available in DSpace on 2014-10-09T12:32:46Z (GMT). No. of bitstreams: 0 / Made available in DSpace on 2014-10-09T14:08:48Z (GMT). No. of bitstreams: 1 03362.pdf: 1393147 bytes, checksum: 01489b7356e00847fe76c389e08056f8 (MD5) / Dissertacao (Mestrado) / IPEN/D / Instituto de Pesquisas Energeticas e Nucleares - IPEN/CNEN-SP

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Made available in DSpace on 2014-10-09T12:29:58Z (GMT). No. of bitstreams: 0 / Made available in DSpace on 2014-10-09T14:10:00Z (GMT). No. of bitstreams: 1 00719.pdf: 1100089 bytes, checksum: 52bcccbf50c4b3fe75b7220f72710e78 (MD5) / Dissertacao (Mestrado) / IEA/D / Instituto de Energia Atomica - IEA

Indiana University-Purdue University Indianapolis (IUPUI) / This clinical study investigated the efficacy of the new LED LCU technology when compared to that of the QTH LCU by evaluating retention and wear of Clinpro (3M ESPE) sealant material over six months of function. This study was designed as a split mouth, randomized clinical study. Sealants were placed and polymerized on contralateral teeth of 35 patients, 33 of which successfully completed the study. The sealants were evaluated for clinical retention at baseline, three months, and six months by two evaluators. For the wear analysis, the area of the sealant wear at six months is reported. Nine pairs of molars and 22 pairs of premolar teeth were used. This sample size is smaller than the original sample used for clinical evaluation, because a number of the baseline impressions had to be discarded due to poor impression quality. Subsequent impressions were taken at three months, and six months. Epoxy replicas were made from the impressions and the occlusal surface of each replica was digitized using SigmaScan software. A cummulative legit model was applied to the clinical data, and a linear model was applied to the wear analysis. The results for clinical retention over the six months of function were as follows. At Baseline, for the QTH, 97.3 percent of the teeth received an Alpha score; 2.7 percent received a score of B. For the LED, 87.7 percent received a score of A; 12.3 percent received a score of B. At three months follow-up, for the QTH, 93.1 percent received a score of A; 6.9 percent received a score of B. For the LED, 86.1 percent received a score of A; 12.5 percent received a score of B, and 1.14 percent received a score of C. At six months follow-up, for QTH; 91.7 percent received a score of A; 8.3 percent received a score of B. For the LED, 83.3 percent received a score of A; 15.3 percent received a score of B, and 1.14 percent received a score of C. The hypothesis was that there would be no significant difference in clinical retention and wear of Clinpro's sealant polymerized with the QTH or the LED light sources over six months of function. Based on the results of this clinical study, the following conclusions can be made: 1) At baseline, Clinpro's sealant polymerized with QTH light source showed marginally significant better retention than LED light source (p-value 0.05001). 2) There was no significant difference between light sources for sealant clinical retention at three-month and six-month follow up visits. 3) Wear analysis resulted in marginally significant more wear for molar sealants polymerized with LED LCU (p-value 0.0755). 4) Wear analysis showed no significant difference for premolar sealants polymerized with either light source.

Recent technologies enable wireless communication devices to become physically smaller in size. Antenna size is obviously a major factor that limits miniaturization. In the past few years, new designs of low-profile antennas for handheld wireless devices have been developed. The major drawback of many low-profile antenna designs is their narrow impedance bandwidth. Furthermore, the market trend of personal wireless devices is moving toward a universal system that can be used anywhere and rapid expansion of the wireless communication industry has created a need for connectivity among various wireless devices using short-range wireless links in the Bluetooth operating band to get rid of the cable connections. This requires therefore multiple frequency band operation. In summary, physically small size, wide bandwidth, and high efficiency are the desired characteristics of antennas in mobile systems. This dissertation presents a comprehensive analysis of a new wide-bandwidth compact antenna, called WC J-pole antenna, covering 50 % impedance fractional bandwidth. A set of guidelines is also provided for a bandwidth-optimized design at any frequency. A few design variations of the proposed antenna are also presented for existing commercial wireless applications. Efficiency is perhaps the most important characteristic of small antennas for mobile systems. An extension of the Wheeler cap method to moderate-length and wideband antennas is developed to measure quickly efficiency. The dissertation also provides a review of human operator interaction with handset antennas. Since the proposed antenna is intended to be used in the proximity of human body and in a casing, coupling effects of human body and casing on the antenna characteristics and radio frequency (RF) energy absorption into the human body are investigated. / Ph. D.

In this report, we evaluate the role of visual areas responsive to motion in the human brain in the perception of stimulus speed. We first identified and localized V1, V3A, and V5/MT+ in individual participants on the basis of blood oxygenation level-dependent responses obtained in retinotopic mapping experiments and responses to moving gratings. Repetitive transcranial magnetic stimulation (rTMS) was then used to disrupt the normal functioning of the previously localized visual areas in each participant. During the rTMS application, participants were required to perform delayed discrimination of the speed of drifting or spatial frequency of static gratings. The application of rTMS to areas V5/MT and V3A induced a subjective slowing of visual stimuli and (often) caused increases in speed discrimination thresholds. Deficits in spatial frequency discrimination were not observed for applications of rTMS to V3A or V5/MT+. The induced deficits in speed perception were also specific to the cortical site of TMS delivery. The application of TMS to regions of the cortex adjacent to V5/MT and V3A, as well as to area V1, produced no deficits in speed perception. These results suggest that, in addition to area V5/MT+, V3A plays an important role in a cortical network that underpins the perception of stimulus speed in the human brain.

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Made available in DSpace on 2014-10-09T12:43:21Z (GMT). No. of bitstreams: 0 / Made available in DSpace on 2014-10-09T13:58:04Z (GMT). No. of bitstreams: 1 06428.pdf: 6304808 bytes, checksum: 564076d766d1209b8ce5d2f96ff4876b (MD5) / Tese (Doutoramento) / IPEN/T / Instituto de Pesquisas Energeticas e Nucleares - IPEN/CNEN-SP