New approaches to robotics

In order to build autonomous robots that can carry out useful work in unstructured environments new approaches have been developed to building intelligent systems. The relationship to traditional academic robotics and traditional artificial intelligence is examined. In the new approaches a tight coupling of sensing to action produces architectures for intelligence that are networks of simple computational elements which are quite broad, but not very deep. Recent work within this approach has demonstrated the use of representations, expectations, plans, goals, and learning, but without resorting to the traditional uses of central, abstractly manipulable or symbolic representations. Perception within these systems is often an active process, and the dynamics of the interactions with the world are extremely important. The question of how to evaluate and compare the new to traditional work still provokes vigorous discussion.     

New approaches to surface structure determinations

Progress in understanding the many scientifically interesting and technologically important processes that occur at surfaces has been slowed by the absence of basic structural information. A variety of new techniques are being developed to attack this central problem in surface science. With the new surface probes it is now possible to quantitatively determine the arrangement of atoms in the first monolayers of a solid. This provides the basis for exciting advances in surface science.     

A siting policy for an acceptable nuclear future

A nuclear siting policy leading to a few, large concentrated sites, it is argued, is preferable in the long run to the present policy which could lead to many dispersed sites. Such a policy could be implemented incrementally if requirements for new nuclear generating capacity were met by adding reactors to the existing 100-odd sites. Such a concentrated nuclear siting policy would, to some extent, isolate nuclear activities while augmenting the strengths of the institutions responsible for managing them. Additionally, it would confer an element of permanence on the sites and thereby open new options fer managing low level wastes and reactor decommissioning. These actions may improve the public acceptability of nuclear energy in the United States as well as lead to a more rational contained nuclear system in the long run.     

New approaches in economic analysis

The level of detail of economic models has until recently been limited by the availability of computational capability. At present, the constraint is the systematic compilation of detailed and comprehensive economic and technical data and the ability to manipulate them. The effective use of enhanced data processing capabilities will have to proceed hand in hand with a concerted effort to develop the economic database and with the shift from analytic approaches based on aggregative data to those that can take advantage of detailed information.     

Uranium power and horizontal proliferation of nuclear weapons

Only a few nonnuclear weapons states with uranium-fueled power plants have kept the weapons option open, and none has evidenced activities intended for diverting fissionable material from its civilian system. Analysis of alternative strategies shows that acquisition of nuclear weapons material would probably depend on military production facilities rather than diversion. Horizontal proliferation is primarily a political issue and is related only marginally to uranium power development. Restrictions of the Nuclear Non-Proliferation Act on the supply of equipment and fuel by the United States appear to have induced, in some nonnuclear weapons states, the building of small-scale facilities that can be modified for production of weapons material. More attention should be given to the international political, economic, and military factors that persuade such states to abjure nuclear weapons.     

Immunotherapeutic approaches to Alzheimer's disease

Although neurodegenerative diseases such as Alzheimer's disease are not classically considered mediated by inflammation or the immune system, in some instances the immune system may play an important role in the degenerative process. Furthermore, it has become clear that the immune system itself may have beneficial effects in nervous system diseases considered neurodegenerative. Immunotherapeutic approaches designed to induce a humoral immune response have recently been developed for the treatment of Alzheimer's disease. These studies have led to human trials that resulted in both beneficial and adverse effects. In animal models, it has also been shown that immunotherapy designed to induce a cellular immune response may be of benefit in central nervous system injury, although T cells may have either a beneficial or detrimental effect depending on the type of T cell response induced. These areas provide a new avenue for exploring immune system-based therapy of neurodegenerative diseases and will be discussed here with a primary focus on Alzheimer's disease. We will also discuss how these approaches affect microglia activation, which plays a key role in therapy of such diseases.     

Therapeutic approaches to bone diseases

The strength and integrity of our bones depends on maintaining a delicate balance between bone resorption by osteoclasts and bone formation by osteoblasts. As we age or as a result of disease, this delicate balancing act becomes tipped in favor of osteoclasts so that bone resorption exceeds bone formation, rendering bones brittle and prone to fracture. A better understanding of the biology of osteoclasts and osteoblasts is providing opportunities for developing therapeutics to treat diseases of bone. Drugs that inhibit the formation or activity of osteoclasts are valuable for treating osteoporosis, Paget's disease, and inflammation of bone associated with rheumatoid arthritis or periodontal disease. Far less attention has been paid to promoting bone formation with, for example, growth factors or hormones, an approach that would be a valuable adjunct therapy for patients receiving inhibitors of bone resorption.     

Requirement of nuclear prolactin for interleukin-2--stimulated proliferation of T lymphocytes

Prolactin (PRL) is necessary for the proliferation of cloned T lymphocytes in response to interleukin-2 (IL-2). Translocation of PRL into the nucleus occurs during IL-2--stimulated mitogenesis. Therefore, the function of intranuclear PRL in T cell proliferation was tested. Eukaryotic expression vectors were prepared to express wild-type PRL [PRL(WT)], PRL that lacks the signal sequence for translocation into the endoplasmic reticulum [PRL(ER-)], and chimeric PRL in which the signal peptide was replaced with the sequence that directs the nuclear translocation of the SV40 large T antigen [PRL(NT+)]. Expression of these constructs in a T cell line (Nb2) responsive to PRL and IL-2 resulted in localization of PRL in the extracellular milieu, cytoplasm, or nucleus, respectively. Stimulation with IL-2 alone resulted in a five- to tenfold increase in the incorporation of [3H]thymidine by cells expressing PRL(NT+) or PRL(WT) as compared to PRL(ER-) or the parental Nb2 cells. Only the PRL(NT+) clone proliferated continuously with IL-2 stimulation in the presence of antiserum to PRL. These results demonstrate that nuclear PRL is necessary for IL-2--stimulated proliferation and suggest that a peptide hormone can function in the nucleus without binding to its cell surface receptor.