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Evaluates a collaborative program in which high achieving biology students participate in genetics research under the guidance and supervision of a geneticist. Reviews the impact of their participation on college and career choices as well as understanding of science methodology, genetics, agricultural science, and product development. (SOE)

Many attempts have been made to address the problem of teenage premarital sexual activity in order to reduce the number of pregnancies and sexually transmitted diseases. The authors review some of those efforts and attempt to identify effective approaches. Implications for research are also presented. (Author)

To understand the mechanisms of neuronal [Zn.sup.2+] homeostasis better, experimental data obtained from cultured cortical neurons were used to inform a series of increasingly complex computational models. Total metals (inductively coupled plasma-mass spectrometry), resting metallothionein, [sup.65][Zn.sup.2+] uptake and release, and intracellular free [Zn.sup.2+] levels using ZnAF-2F were determined before and after neurons were exposed to increased [Zn.sup.2+], either with or without the addition of a [Zn.sup.2+] ionophore (pyrithione) or metal chelators [EDTA, clioquinol (CQ), and N,N,N',N'-tetrakis(2-pyridylmethyl)ethylenediamine]. Three models were tested for the ability to match intracellular free [Zn.sup.2+] transients and total [Zn.sup.2+] content observed under these conditions. Only a model that incorporated a muffler with high affinity for [Zn.sup.2+], trafficking [Zn.sup.2+] to intracellular storage sites, was able to reproduce the experimental results, both qualitatively and quantitatively. This 'muffler model' estimated the resting intracellular free [Zn.sup.2+] concentration to be 1.07 nM. If metallothionein were to function as the exclusive cytosolic [Zn.sup.2+] muffler, the muffler model predicts that the cellular concentration required to match experimental data is greater than the measured resting concentration of metallothionein. Thus [Zn.sup.2+] buffering in resting cultured neurons requires additional high-affinity cytosolic metal binding moieties. Added CQ, as low as 1 [micro]M, was shown to selectively increase [Zn.sup.2+] influx. Simulations reproduced these data by modeling CQ as an ionophore. We conclude that maintenance of neuronal [Zn.sup.2+] homeostasis, when challenged with [Zn.sup.2+] loads, relies heavily on the function of a high-affinity muffler, the characteristics of which can be effectively studied with computational models. muffler; zinc buffering; computational model; metal ion transport and homeostasis; metallothionein