Expands the basic concepts regarding the radiation chemistry of simple aqueous systems to more complex, but well defined, organized assemblies. Discusses the differences in behavior in comparison to simple systems. Reviews these techniques: pulse radiolysis, laser flash, photolysis, and steady state irradiation by gamma rays or light. (CS)

This study recalculates outdated values for thermochemical radii using more reliable and elaborate calculations of lattice energy and recently obtained ancillary thermodynamic data. (BT)

Describes a three-dimensional computer modeling system for biological molecules which is suitable for sixth-form teaching. Consists of the modeling program "RasMol" together with structure files of proteins, DNA, and small biological molecules. Describes how the whole system can be downloaded from various sites on the Internet.…

Discussed is the fundamental role that the favorable free energy of binding of the rate-determining transition state plays in catalysis. The principle that all of the catalytic factors discussed are realized by the use of this binding energy is reviewed. (CW)

Discussed is an analytical technique that uses photons from lasers to resonantly excite an electron from some initial state of a gaseous atom through various excited states of the atom or molecule. Described are the apparatus, some analytical applications, and the precision and accuracy of the technique. Lists 26 references. (CW)

Considered are the underlying ideas of nucleophilic substitution and some of the misconceptions regarding this topic. Discusses methods for teaching this topic and includes definitions for key ideas and terms. (Author/CW)

Discussed are the molecular electronic terms which can arise from a given electronic configuration. Considered are simple cases, molecular states, direct products, closed shells, and open shells. Two examples are provided. (CW)

Argues for including several key ideas in every introductory general chemistry course, including the phenomena of chemistry, the organization and classification of matter, atomic structure, molecular bonding and molecular structure, the language of chemistry, the mole, chemical reactions and reactivity, chemical kinetics, chemical equilibrium, and…

The study examines the effectiveness of visually enhanced instruction that emphasizes molecular representations. Instructional conditions were specified in terms of the visual elaboration level (static and dynamic) and the presentation mode (whole class and individual). Fifty-two eighth graders (age range 14-15 years) participated in one of the…

We report the development of a simplified procedure for restriction fragment length polymorphism (RFLP) analysis of mushrooms. We have adapted standard molecular techniques to be amenable to an undergraduate laboratory setting in order to allow students to explore basic questions about fungal diversity and relatedness among mushroom species. The…

The yeast "Saccharomyces cerevisiae" has been used by human beings since ancient times for its ability to convert sugar to alcohol. Continual exposure to glucose in the natural environment for innumerable generations has probably enabled "S. cerevisiae" to grow in fermentative mode on sugars by switching off the genes responsible for respiration…

A module that can be incorporated into chemistry or environmental science classes at the high school or undergraduate level is described. The module is divided into a series of segments, each of which incorporates several concepts and results in students making significant predictions about the behavior of organic xenobiotics.

If teachers decide to introduce the idea that the behaviour of matter ("stuff") can be explained by thinking about it as being made up of particles that exhibit particular properties, then they need to be aware of the learning difficulties involved. Before using this approach, therefore, more immediate consideration needs to be directed…

Mutations in the neuronal-specific microtubule-binding protein TAU are associated with several dementias and neurodegenerative diseases. However, the effects of elevated TAU accumulation on behavioral plasticity are unknown. We report that directed expression of wild-type vertebrate and "Drosophila" TAU in adult mushroom body neurons, centers for…

The [delta] subunit of the GABA[subscript [Alpha]] receptor (GABA[subscript [Alpha]]R) is highly expressed in the dentate gyrus of the hippocampus. Genetic deletion of this subunit reduces synaptic and extrasynaptic inhibition and decreases sensitivity to neurosteroids. This paper examines the effect of these changes on hippocampus-dependent trace…