A laminated, flex structure for electronic transport and hybridization of DNA.

We have developed the first prototypes of a three-dimensional, electrophoretically driven microlaboratory for the analysis of proteins and DNA. By selecting the appropriate spacing and geometrical configuration, oligonucleotides were transported, in a controlled, rapid fashion, by electrophoresis in free-space. Transport efficiencies over 2 mm distances exceeded 70%. Electrodes of similar design were combined with an electronically addressed DNA hybridization chip to form a fully electrophoretic microlaboratory. In this instance, gold-plated copper electrodes were patterned on a 2 mil thick polyimide substrate. This polyimide layer was stiffened with 20 mil of polyimide to provide support for flip-chip bonding of our standard 100-site Nanochip. This composite structure illustrated three-dimensional transport of target oligonucleotides, through a via in the polyimide, along a series of electrodes and onto the diagnostic chip. Upon reaching the diagnostic chip, electronic hybridization was performed for a competitive reverse dot blot assay. The electronic assay showed a specific to nonspecific ratio in excess of 20:1. These results suggested that this type of structure might be of practical consequence with the development of a microlaboratory for biowarfare applications.

Using 'found' data to augment a probability sample: Procedure and case study.

While probability sampling has the advantage of permitting unbiased population estimates, many past and existing monitoring schemes do not employ probability sampling. We describe and demonstrate a general procedure for augmenting an existing probability sample with data from nonprobability-based surveys ('found' data). The procedure, first proposed by Overton (1990), uses sampling frame attributes to group the probability and found samples into similar subsets. Subsequently, this similarity is assumed to reflect the representativeness of the found sample for the matching subpopulation. Two methods of establishing similarity and producing estimates are described: pseudo-random and calibration. The pseudo-random method is used when the found sample can contribute additional information on variables already measured for the probability sample, thus increasing the effective sample size. The calibration method is used when the found sample contributes information that is unique to the found observations. For either approach, the found sample data yield observations that are treated as a probability sample, and population estimates are made according to a probability estimation protocol. To demonstrate these approaches, we applied them to found and probability samples of stream discharge data for the southeastern US.

Deposition of sulfuric acid mists in the respiratory tract of beagle dogs.

Beagle dogs were exposed to 35S-labeled sulfuric acid mists. The size range of the mist droplets was 0.4-1.1 micrometer mass median aerodynamic diameter (MMAD), and the external relative humidity was 20 or 80%. Immediate isolation of the respiratory tract and measurement of radioactivity in specified portions allowed determination of regional deposition. It was found that inhaled sulfuric acid mists in the size ranges studied had deposition patterns similar to those for dry aerosols. The effect of hygroscopicity for these aerosols was not dominant in determining the site of deposition.

Research in the prehistory of central Western iran.

The archeological sequence in the Bisitun and Kangovar valleys promises to fill a number of gaps in the prehistory of this part of southwestern Asia. Ghar-i Khar should yield data concerning the degree of cultural continuity or discontinuity in the Upper Pleistocene and early Holocene ranges of prehistory. This cave site should also be helpful in gaining further insight into the climatic conditions during these times, and in particular on the prevalent fauna and flor (and the human use of them) at the close of the Pleistocene, when some groups may already have been leading ways of life foreshadowing the Neolithic. Ganj-i Dareh offers the opportunity of examining in detail what seems to be an early farming community at or very near the beginning of an important shift in methods of subsistence. The geographical position of this latter site may also be of unusual significance in studying the spread of the Neolithic; located as it is near the traditional route across the Zagros Mountains into Iraq, this site, as well as others in the region, may have played an important role in the diffusion of the new elements and methods to other parts of the mountainous zone. That is, within the broad "natural habitat zone" it may be useful to distinguish optimum areas of development and diffusion during the early phases of the Neolithic. Comparison with small sites like Tepe Asiab in the Kermanshah Valley (considered to have been a temporary encampment of clam collectors) (7) may place such sites in their proper perspective as seasonally occupied satellites of more permanent villages such as Ganj-i Dareh; the same possibility is open for the later ceramic Neolithic phase now that the oldest level of Godin Tepe shows a community to which nearby sites on this time horizon can probably be related. However, it will require an intimate study of the two valleys as microenvironments, and comparison of them with each other and with the Kermanshah and Hulailan valleys, in order to reach a fuller understanding of the interrelationships of the various aceramic and ceramic Neolithic sites from the 9th to the 6th millennium. Again, only further exploration in the region will reveal whether the absence of recognizable farming-community sites in the Zagros region during the 8th millennium reflects a genuine hiatus or simply insufficient investigation (21). A broader clearance of Period VII at Godin Tepe itself will enable us better to define the period during which material from Period VII is found stratigraphically associated with later material. Through the horizontal clearance of one of the six small sites in the Kangovar-Bisitun area where similar materials in the pottery Neolithic period are found on or near the surface, by sounding perhaps one other such site, and by plotting all the sites in the region that date to this period, we should be able to reconstruct a reasonably complete picture of this valley at the time of Godin VII. One of these small sites in the neighborhood may yet yield evidence on the relationship between the aceramic and pottery phases of the Neolithic. Godin, of course, provides us an excellent opportunity to examine the relationship between the pottery of the Neolithic and subsequent cultural periods in western Iran, since there appears to be no major break in the developmental sequence between Godin VII and VI. For the periods after the pottery Neolithic in western Iran we have had only the more or less stratified sequence of tombs excavated at Tepe Giyan on which to base our understanding of the developmental sequence from the 6th to the 1st millennium B. C. Even the evidence from our preliminary testing of Godin Tepe indicates how sketchy that understanding has been, since previously we had only suspected the presence of the Uruk culture in the area and had no evidence at all that the culture defined at Yanik Tepe near Tabriz, which has strong links with eastern Anatolia and the Caucasus, ever spread as far south as the central Zagros. Continued research at Godin will shed light on these new problems as well as on many of the long-standing issues that have puzzled archeologists concerned with the Bronze and Iron ages in western Iran.