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Biomedical subjects

S S Hall

Publications and source records attributed to S S Hall.

At least 19 recordsLinked to original sources
PubMed2006

The acquisition of stimulus equivalence in individuals with fragile X syndrome.

BACKGROUND: Few studies have employed stimulus equivalence procedures to teach individuals with intellectual disabilities (IDs) new skills. To date, no studies of stimulus equivalence have been conducted in individuals with fragile X syndrome (FXS), the most common known cause of inherited ID. METHOD: Five adolescents with FXS were taught basic math and geography skills by using a computerized stimulus equivalence training programme administered over 2 days in 2-h sessions. RESULTS: Four of the five participants learned the math relations, with one participant demonstrating stimulus equivalence at post-test. Three of the five participants learned the geography relations, with all three of these participants demonstrating stimulus equivalence at post-test. CONCLUSIONS: These data indicate that computerized stimulus equivalence procedures, conducted in time-limited sessions, may help individuals with FXS learn new skills. Hypotheses concerning the failure of some participants to learn the training relations and to demonstrate stimulus equivalence at post-test are discussed.

Adolescent↗
PubMed2001

The principal components of response strength.

As Skinner (1938) described it, response strength is the "state of the reflex with respect to all its static properties" (p. 15), which include response rate, latency, probability, and persistence. The relations of those measures to one another was analyzed by probabilistically reinforcing, satiating, and extinguishing pigeons' key pecking in a trials paradigm. Reinforcement was scheduled according to variable-interval, variable-ratio, and fixed-interval contingencies. Principal components analysis permitted description in terms of a single latent variable, strength, and this was validated with confirmatory factor analyses. Overall response rate was an excellent predictor of this state variable.

Animals↗
PubMed1983

Structure-activity relationships of synthetic antibiotic analogues of anisomycin.

A general synthetic sequence was used to synthesize a series of analogues of anisomycin, and the biological activities of the new synthetic analogues as antiprotozoals, antifungals, and antibacterials were evaluated. The synthetic antibiotics included 3 beta-acetoxy-4 alpha-hydroxy-2 beta-(p-methylbenzyl)pyrrolidine (1b), 3 beta-acetoxy-2 beta-benzyl-4 alpha-hydroxypyrrolidine (1c), 3 beta-acetoxy-4 alpha-hydroxy-2 beta-(m-methoxybenzyl)pyrrolidine (1d), 3 beta-acetoxy-4 alpha-hydroxy-2 beta-(o-methoxybenzyl)pyrrolidine (1e), 3 beta-acetoxy-4 alpha-hydroxy-2 beta-(alpha-methyl-p-methoxybenzyl)pyrrolidine (1f), and 3 beta-acetoxy-4 alpha-hydroxy-2 beta-(alpha-phenyl-p-methoxybenzyl)pyrrolidine (1g). The anisomycin analogues showed activity against protozoa and fungi, but this activity was restricted primarily to the p-methylbenzyl and benzyl analogues 1b and 1c. The activities dropped dramatically as the methoxy substituent was moved to the meta or ortho positions of the benzyl group (1d and 1e) or a methyl or phenyl group was attached at the alpha-benzyl carbon (1f and 1g).

Animals↗
PubMed1977

Synthesis and evaluation of alpha-hydroxythiol esters as antitumor agents and glyoxalase I inhibitors.

Synthesis of a series of alpha-hydroxythiol esters made available, for the first time, product-like molecules that were evaluated as inhibitors of the enzyme glyoxalase I and as potential antitumor agents. All the alpha-hydroxythiol esters tested were competitive inhibitors of the enzyme, albeit weak; however, the relative [I]50 values suggested information about the active site. Antileukemic activity in L1210 lymphoid leukemia indicated no significant activity by these alpha-hydroxythiol esters.

Animals↗