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Biomedical subjects

S C Tong

Publications and source records attributed to S C Tong.

5 recordsLinked to original sources
PubMed2001

Comparison of MB/BacT system and agar proportion method in drug susceptibility testing of Mycobacterium tuberculosis.

The drug susceptibilities of 105 isolates/strains of Mycobacterium tuberculosis (101 clinical isolates and four control strains from the American Type Culture Collection) were assessed by the MB/BacT system and conventional agar proportion method. The agreement rates between the two methods were 99.0% for streptomycin, 95.2% for isoniazid and 100% for rifampin. The mean times to detection for drug-resistant isolates were 4.7 days (range: 2.5-13.7 days) using the MB/BacT system and 14.8 days (range: 14-21 days) using the agar proportion method. For drug-susceptible isolates, the times to detection were 10.8 days (mean) and 21 days respectively. Thus, these data have demonstrated that the automated, non-radiometric MB/BacT system is an efficient, accurate and reliable method for assessing drug susceptibilities of M. tuberculosis compared with the conventional agar proportion method.

Antibiotics, Antitubercular↗
PubMed1996

Effects of pinna position on head-related transfer functions in the cat.

To measure the effects of the pinna position on spectral sound localization cues, the head-related transfer function (HRTF) from the free-field to a point in the ear canal was measured for anesthetized cats with their pinnae in three positions: the relaxed, anesthetized position; pulled forward into an approximation of the "alert cat" posture; and pulled back. The general features of HRTFs are not changed by moving the pinna, although the mapping of particular HRTF features onto directions in space is changed. As an approximation, the pinna behaves like a fixed-shaped sound collector, so that HRTFs shift with the pinna when it moves; however, pinna movement changes some quantitative details of HRTFs beyond what is predicted by this approximation. When viewed as directional gain, pinna movements serve to optimize listening conditions. However, when considering sound localization, pinna movements lead to ambiguities regarding source location. If pinna position is not incorporated into the computation, and spectral cues alone are used for localization, the ambiguity is about 60 degrees in azimuth and 30 degrees in elevation. Pinna movements produce similar azimuthal ambiguity in interaural level differences. Interaural time difference cues could be used to reduce the ambiguity in azimuth, but a knowledge of pinna position seems to be necessary to resolve ambiguities in elevation.

Animals↗
PubMed1975

Elemental analysis of honey as an indicator of pollution. Forty-seven elements in honeys produced near highway, industrial, and mining areas.

Nineteen samples of honey taken from grocery shelves, near zinc mines, adjacent to an industrial area, and near a major highway, and one sample collected in 1899 were subjected to spark source mass spectrometry to determine the concentration of most of 47 elements in the honey. Certain samples of honey produced by bees in the vicinity of the New York State Thruway appeared to contain elevated levels of certain elements known to be emitted by traffic, such as aluminum, barium, calcuim, copper, magnesium, nickel, palladium, and silicon, but the true source of these elements was uncertain. Honey that had come into contact with metal containers in processing contained the greatest amounts of zinc and tin.

Air Pollution↗