Exploring optimal current stimuli that provide membrane voltage tracking in a neuron model.

Studying neurons from an energy efficiency perspective has produced results in the research literature. This paper presents a method that enables computation of low energy input current stimuli that are able to drive a reduced Hodgkin-Huxley neuron model to approximate a prescribed time-varying reference membrane voltage. An optimal control technique is used to discover an input current that optimally minimizes a user selected balance between the square of the input stimulus current (input current 'energy') and the difference between the reference voltage and the membrane voltage (tracking error) over a stimulation period.

Parental decision making regarding treatment of hypoplastic left heart syndrome.

Parents of children diagnosed with a complex congenital heart anomaly such as hypoplastic left heart syndrome (HLHS) are faced with the challenge of choosing the best treatment option for their children. Parents must decide among options of compassionate care, palliative reconstructive surgery, or neonatal cardiac transplantation, and additionally with antenatal diagnosis must decide regarding continuation of pregnancy. With improved survival rates yet persistent morbidities following the Norwood surgical approach for HLHS, controversy remains whether parents should be counseled on all treatment options as evidenced by research that articulates the varied opinions of health care providers.

Expression and characterization of ras mRNAs from Saccharomyces cerevisiae.

The cellular homologs of the Harvey and Kirsten murine sarcoma virus oncogenes comprise a multigene family, ras, that displays striking evolutionary conservation. We recently reported [DeFeo-Jones et al., Nature (London) 306:707-709, 1983] the cloning of two ras homologs from the yeast Saccharomyces cerevisiae.

Chromosomal transplantation. The nuclear transplantation of colchicine-treated cells.

Dissociated cells of middle-to-late blastulae were exposed to 0.1 mg colchicine/ml and achieved 92% metaphase arrest. These cells contained a haploid set of Bombina maxima (Anura:Discoglossidae) chromosomes.

Amphibian cell culture: established fibroblastic line from embryos of the discoglossid frog, Bombina orientalis.

A new amphibian cell line, Bor II, is described. It was initiated from Stage 20 embryos of the discoglossid frog, Bombina orientalis. In early passages the cell line had an epithelioid morphology.