Oestrogenic, anti-oestrogenic and fertility effects of some triphenylethanes and triphenylethylenes related to ethamoxytriphetol (MER 25)

The myocardial content of digoxin 60 min after intravenous administration in open-chest dogs correlated with heart rate controlled in individual dogs between 64 and 215 beats/min. In other dogs, increasing right ventricular mechanical work by constriction of the pulmonary artery resulted in greater right ventricular digoxin uptake. Increase in myocardial blood flow per se could not explain these findings since, in further dogs, increasing regional myocardial blood flow by adenosine infusion did not much affect digoxin uptake. Active uptake of cardiac glycosides is probably influenced by myocardial mechanical and metabolic activity.     

A Multipath Fading Channel Model for Terrestrial Digital Radio Systems

The frequency transfer function of a multipath fading channel is examined in terms of its effects on digital radio signals. The transfer function is expanded into a power series about the channel center frequency and the coefficients are related to the multipath structure. It is then shown that, in the channelized common carrier bands below 15 GHz, the first two (complex) terms of the power series are usually sufficient for characterizing multipath effects. This demonstration is based on a mean-square error-of-fit measure which is applied to the multipath fading response and evaluated under some worst-case assumptions.     

Psychomotor objectives in occupational therapy education

This article describes the role of educational objective taxonomies in facilitating the specification of intended learning outcomes and the apparent neglect of objectives directed toward psychomotor learning. A review of the literature indicates extensive material is available on motor learning and on the classification of psychomotor levels of behavior according to a systematic framework. Although many of the categories are functional for special areas, no one system has universal applicability. It is suggested that each discipline may need to draw on the literature to formulate its own taxonomic system, and a model taxonomy is offered for occupational therapy education in which levels of psychomotor performance are differentiated by the degree of individuation, the unique quality of performance introduced by the learner. Examples are given at each level and illustrative objectives combine expected behaviors with selected curriculum areas.     

Did the Price of the Internet Drop?

No statistic would seem as important to know as the price of the Internet. You might reasonably respond, How can the Internet have a price attached to it? As it turns out, there are many such prices. A particularly interesting one is the consumer price index (CPI) for Internet access, which focuses on the retail price of a household connection. This price index does not get enough attention because observers confuse future opportunity with recent history. One other thing motivates an examination of this index. There is a big debate in the US about whether the broadband market has been organized intelligently. Economic statistics can inform policy debates, that is, if they get interpreted the right way. However, and this is my point in this column, the index is easy to misinterpret. It is worth a close look.     

phnE and glpT genes enhance utilization of organophosphates in Escherichia coli K-12

Wild-type Escherichia coli K-12 strain JA221 grows poorly on low concentrations (< or = 1 mM) of diisopropyl fluorophosphate and its hydrolysis product, diisopropyl phosphate (DIPP), as sole phosphorus sources. Spontaneous organophosphate utilization (OPU) mutants were isolated that efficiently utilized these alternate sources of phosphate. A genomic library was constructed from one such OPU mutant, and two genes were isolated that conferred the OPU phenotype to strain JA221 upon transformation. These genes were identified as phnE and glpT. The original OPU mutation represented phnE gene activation and corresponded to the same 8-bp unit deletion from the cryptic wild-type E. coli K-12 phnE gene that has been shown previously to result in phnE activation. In comparison, sequence analysis revealed that the observed OPU phenotype conferred by the glpT gene was not the result of a mutation. PCR clones of glpT from both the mutant and the wild type were found to confer the OPU phenotype to JA221 when they were present on the high-copy-number pUC19 plasmid but not when they were present on the low-copy-number pWSK29 plasmid. This suggests that the OPU phenotype associated with the glpT gene is the result of amplification and overproduction of the glpT gene product. Both the active phnE and multicopy glpT genes facilitated effective metabolism of low concentrations of DIPP, whereas only the active phnE gene could confer the ability to break down a chromogenic substrate, 5-bromo-4-chloro-3-indoxyl phosphate-p-toluidine (X-Pi). This result indicates that in E. coli, X-Pi is transported exclusively by the Phn system, whereas DIPP (or its metabolite) may be transported by both Phn and Glp systems.