Biomedical subjects
Publications and source records attributed to C E Williams.
Gas permeable rigid lens materials offer the opportunity to reevaluate contact lens design. This paper presents the rationale and procedures followed in the development of a design concept for the Polycon lens material.
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High-quality tape recordings were constructed of single, double, and triple word test items from the six monosyllabic work lists of the Modified Rhyme Test (MRT), a multiple-choice intelligibility test. The test workd were incorporated in a carrier phrase somewhat analogous to typical aircraft radio messages. The recorded lists were mixed with shaped noise and played back to a group of listeners at three speech-to-noise ratios. The regular closed-response format of the MRT was utilized for all three types of test items. There was little difference in overall listener performance for the single, double, and triple word test items. Because of their more representative message length and decreased testing time, the triple word test items will be utilized in subsequent data-gathering studies directed toward the development of an efficient reliable test for assessing the ability of aircrew personnel to hear speech in their operational environments.
An in vitro serum bactericidal test was developed to assess the efficacy of Campylobacter fetus bacterins. Four experimental monovalent bacterins (either serotype C or A-2) and 2 commercial bivalent bacterins (a "suspect" and an "efficacious" bacterin) with aluminum hydroxide adjuvant were administered to sheep and rabbits from which antiserums were then prepared. The different vaccines were evaluated by comparing the in vitro bactericidal activity of the sheep and rabbit antiserums. Results of the in vitro tests were compared to the protection induced in vaccinated ewes which were orally exposed to C fetus. The sheep and the rabbit antiserums after they were heated at 56 C for 30 minutes were unable to exert a killing effect on C fetus cells. Addition of a fresh homologous complement source to the heated antiserums was necessary to demonstrate the in vitro bactericidal capacity. In the comparison of the suspect and the efficacious commercial bacterins, which both reportedly contain serotype C cells, there was a statistically significant difference in bactericidal activities for serotype C cells of antiserums from sheep 14 days after the 2nd vaccination. There was a corresponding significant difference in the antiserums from rabbits 14 days after the 2nd vaccination. Proportionally, more abortions and stillbirths were observed in the ewes vaccinated with the suspect bacterin and then orally exposed to C fetus-serotype C cells than in those vaccinated with the efficacious bacterin. The results indicated that the ability of vaccinated sheep to overcome infection is reflected in the in vitro bactericidal capacity of antiserum from the animal. Since 89% of the variation in sheep antiserums from 14 days after 2nd vaccination can be accounted for by rabbit antiserums from 14 days after 2nd vaccination, the in vitro bactericidal capacity of rabbit antiserums probably provides a reliable index of the protective effect of bacterins containing serotype C for ewes exposed to the homologous serotype.
This investigation was part of a larger study conducted by Memphis State University. This laboratory's portion of the study focused on administering conventional audiometry (manual and self-recording), high-frequency audiometry (4 kHz-18 kHz), and a speech intelligibility test in noise to 108 Naval Aviation Officer Candidates prior to and following primary flight training in T-34 aircraft. Hearing protection consisted of either the APH-6C or APH-6D flight helmet. Cockpit noise levels in the T-34 range from 96-115 dBA; during cruise the noise level is approximately 100 dBA. Results indicate no significant change in hearing sensitivity or speech discrimination that could be attributed to noise exposure during primary flight training. Pre- and postprimary hearing levels obtained for the high frequencies compare favorably with high-frequency hearing levels obtained by Northern et al. (1968) for males in the age range 20-29 years. Questionnaire data indicated that a considerable number of the subjects had been exposed to potentially harzardous noise before entry into military service.
This study was designed to discover the knowledge, attitudes, and practices of a selected group of undergraduate college students relative to individual venereal disease protective/preventive measures. A population of 373 students were drawn from two large, state-supported universities in the midwest. The investigation was conducted to provide base line data for medical personnel and health educators to consider when educating young adults about the prevention of venereal disease infection. The findings revealed the existence of desirable, as well as undesirable knowledge, attitudes, and practices with implications for education.
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