Adipose tissue is an important endocrine and secretory organ. There is growing evidence that adipocytes from different fat depots have distinct functional properties. Epicardial adipose tissue has been shown to produce inflammatory mediators, but the functional properties of isolated epicardial adipocytes (EA) have not been studied. We characterized human EA isolated from freshly harvested hearts, along with subcutaneous and perirenal adipocytes from the same donors. Differentiation from preadipocytes was associated with greatly increased adipokine and proinflammatory cytokine expression; of note, the proinflammatory mediator CD14 was expressed at 50-fold higher levels by EA compared to preadipocytes. EA have substantial cyclooxygenase and epoxide hydrolase activity. The major COX metabolite is PGE2, which plays an important role in angiogenesis and inflammation. LPS caused increased expression of adiponectin, VEGF, and CD14 in both epicardial adipose tissue explants and cultured EA. Conditioned medium from EA (but not control medium or medium from epicardial preadipocytes or subcutaneous adipocytes) strongly promoted growth and tubule formation by human coronary artery endothelial cells. These findings suggest that EA may play an important role in promoting coronary artery inflammation and growth of vasa vasorum and collateral coronary vessels in ischemia. (Supported by NIH HL70860 [NLW])

An integrated microfluidic device capable of performing a variety of genetic assays has been developed as a step towards building systems for widespread dissemination. The device integrates fluidic and thermal components such as heaters, temperature sensors, and addressable valves to control two nanoliter reactors in series followed by an electrophoretic separation. This combination of components is suitable for a variety of genetic analyses. As an example, we have successfully identified sequence-specific hemagglutinin A subtype for the A/LA/1/87 strain of influenza virus. The device uses a compact design and mass production technologies, making it an attractive platform for a variety of widely disseminated applications.

An active microvalve that uses a meltable piston in place of a conventional solid material to obstruct fluid flow in a microfluidic channel has been developed. This phase change valve is simple to operate and requires no additional fabrication steps. The valve is inherently latched, reusable, and leak-proof (to at least 250 psi) and can be electronically addressed using resistive heaters. The valve has been characterized for a range of operational parameters that will serve as a design guide. For the designs tested, piston displacements of 5 mm or more in 1 s have been achieved. Valves 1.4 mm in length in a 50 microm x 200 microm channel have been integrated on a biochemical reaction device, and successful DNA amplification using PCR has been achieved. The phase change valve can be easily implemented in an array format that can be used to realize complex microfluidic circuits.

A toroidal inductor has been developed that confines flux and eliminates eddy currents. A printed circuit and micromachined RFIC-compatible implementations of the inductor are presented.

The relative abundance and species richness of herpetofauna was investigated to assess the impact of recent logging operations in 47 forest stands in northeastern Pennsylvania during 1996 and 1997. Stands including nonindustrial private forestlands and public lands that have received some type of harvesting within the last 8 yr ranged from near complete overstory tree cover to complete removal of overstory cover. Stands included the two dominant forest types in the region: northern hardwood (Betula, Fagus, Prunus, Acer, and Tsuga spp.) and oak-hickory/(Quercus and Carya spp.). A total of 8,181 individuals of 26 species (12 salamander, 7 snake, 6 frog, and 1 toad species) were observed in the study stands. The relative abundance and species richness of salamanders increased significantly with increasing retention of tree basal area. Forest stands containing > 15 m²/ha live tree basal area appeared to be a threshold level for high salamander abundance. Snake species abundance and richness increased significantly with increasing removal of tree basal area. The abundance of anuran species showed no significant relationship with amount of tree basal area removal, but the relative abundance and species richness of anurans depended on the presence of water within or bordering the stands. Forest type did not change the overall response of herpetofauna community composition to forest harvesting, although salamanders were more abundant in northern hardwood stands, and snakes were more abundant in oak-hickory stands. Patterns and threshold levels of abundance and species richness of herpetofauna determined in this study may be used to maintain the abundance and richness of selected species when harvesting forest stands. For. Sci. 46(1):139-146.

Seeing and conserving wildlife are among the most important management objectives for nonindustrial private landowners in the eastern United States. Landowners want profitable timber harvests but also want to know how harvesting will affect their wildlife. The study examined associations between stand characteristics and wildlife abundance on 40 stands receiving different logging intensities in northeastern Pennsylvania and found that landowners have some choices when harvesting their stands for retaining or attracting different types of wildlife.

Understanding harvesting impacts on non-industrial private forestlands is important, since they represent 75% of all commercial forestlands in the State of Pennsylvania, as well as a large percentage of most of the eastern United States. This study measured species composition, richness, and diversity of herb- and shrub-layer plant communities on a total of 40 non-industrial private forest stands in northeastern Pennsylvania. These northern hardwood and oak–hickory stands had been recently harvested at different intensities. Remaining basal area was used as an indicator of harvest intensity. Species richness and diversity were not significantly related to basal area for summer or vernal herb understory plant communities for either forest type, although there was some evidence of a weak negative relationship between plant species richness and remaining basal area on more intensively harvested northern hardwood stands. Summer plant-species richness and diversity were related to percent litter cover and percent slope on northern hardwood stands, and percent Vaccinium cover and percent slope on oak–hickory stands. Ground- and shrub-layer cover significantly increased with increasing harvest intensity. Species composition of vernal herb communities did not vary in stands with differing amounts of basal area. Species composition of summer forest-floor communities differed with amount of basal area remaining, but only for northern hardwood stands. Shade-intolerant ruderal species dominated northern hardwood stands with low basal area, while more shade-tolerant plants dominated northern hardwood stands with high basal area. Summer plant understories of northern hardwood stands were generally dominated by fern and/or Rubus spp. (blackberry and raspberry), while oak–hickory stands were dominated by Vaccinium (blueberry) species. Litter cover, Vaccinium cover, fern cover, total ground cover, and forest type were significant variables related to species composition of vernal herb communities. Based on these results, forest landowners in this region should not expect significant short-term changes in vernal herbaceous or summer understory plant richness or diversity on their lands, regardless of the intensity of logging. However, short-term changes in vegetation structure (increased growth of forest-floor and shrub layers) should be expected for both oak–hickory and northern hardwood stands and a slight shift in species composition should be anticipated with intensive harvesting of northern hardwood stands.

A device was developed that uses microfabricated fluidic channels, heaters, temperature sensors, and fluorescence detectors to analyze nanoliter-size DNA samples. The device is capable of measuring aqueous reagent and DNA-containing solutions, mixing the solutions together, amplifying or digesting the DNA to form discrete products, and separating and detecting those products. No external lenses, heaters, or mechanical pumps are necessary for complete sample processing and analysis. Because all of the components are made using conventional photolithographic production techniques, they operate as a single closed system. The components have the potential for assembly into complex, low-power, integrated analysis systems at low unit cost. The availability of portable, reliable instruments may facilitate the use of DNA analysis in applications such as rapid medical diagnostics and point-of-use agricultural testing.

The potential fate of polymeric materials in soils is important to environmental safety. This study validated highperformance gel permeation chromatography (HPGPC) to assess elution behavior of a commercially available, crosslinked, high molecular weight polyacrylate absorbent (PA) and a soluble low molecular mass (4500 Da), linear poly(acrylic acid) (LPA) in three types of columns prepared from sandy and loamy soils. HPGPC was used to monitor the elution of the soluble PA and LPA from the columns. The LPA represents the fraction (<4%) of the PA that is typically extractable in commercial PA material. Over 99% of the PA sample was found to be retained on a Borden sand test column. The amount that moved is probably related to the extractable polymer. A total of 92% of the non-cross-linked LPA was retained on a Borden sand column. Virtually all of the LPA was retained on the Fox loam column. PA mobility could not be studied bn the Fox loam soil; however, the high clay content of this soil is expected to make the PA less mobile than in Borden sand. Londo loam soil yielded high levels of background interferents for PA and LPA, preventing acquisition of definitive mobility data. However, LPA and PA are expected to be less mobile on Londo loam than on Borden sand due to the higher organic matter/clay contents. These results indicate that typical consumer product-grade PAs would not move appreciably through common soil types in or near landfills. The results also support the use of LPA as a model for studying movement of the soluble portion of commercially available PA through soils and demonstrate that HPGPC is suitable for quantifying soluble polyacrylates in synthetic groundwater effluents.

In recent years, there has been tremendous interest in developing a complete, high-volume, DNA analysis system using microfabrication techniques. Key to the success of such systems, is the development of a high-resolution separation and detection system for analyzing DNA reaction products. Over the past decade, many researchers have demonstrated that micromachined fluidic devices are capable of performing many of the required functions of such a device. However, all of these devices rely on expensive external fluorescence imaging systems that may limit the realization of a low cost, miniature DNA analysis chip. We have developed an on-chip fluorescent detection system and used it to detect individual DNA bands migrating in a microfabricated electrophoretic device. Fluorescence-based detection of DNA bands is achieved by incorporating a highly sensitive photodiode beneath the electrophoresis channel along with a thin film optical filter deposited above the diode. A miniaturized detection system, with sensitivity comparable to macroscale detection systems, could accelerate the realization of integrated 'lab-on-a-chip' systems.

The majority of hardwood forests in the northeastern United States are privately owned and harvested without the advice of a professional forester. For such sites, training and education programs for loggers and landowners have been identified as key tools for promoting sustainable and responsible forestry. The Procter & Gamble Company and the National Audubon Society have initiated a cooperative research project in northeastern Pennsylvania that will provide a scientifically-based training module for sustaining biodiversity and productivity on private forest lands of the region. This research will determine how harvesting affects wildlife habitat characteristics and the wildlife communties that depend upon them so that landowners and loggers may make informed decisions about wildlife when planning forest harvesting.

Photolithographic micromachining of silicon is a candidate technology for the construction of high-throughput DNA analysis devices. However, the development of complex silicon microfabricated systems has been hindered in part by the lack of a simple, versatile pumping method for integrating individual components. Here we describe a surface-tension-based pump able to move discrete nanoliter drops through enclosed channels using only local heating. This thermocapillary pump can accurately mix, measure, and divide drops by simple electronic control. In addition, we have constructed thermal-cycling chambers, gel electrophoresis channels, and radiolabeled DNA detectors that are compatible with the fabrication of thermocapillary pump channels. Since all of the components are made by conventional photolithographic techniques, they can be assembled into more complex integrated systems. The combination of pump and components into self-contained miniaturized devices may provide significant improvements in DNA analysis speed, portability, and cost. The potential of microfabricated systems lies in the low unit cost of silicon-based construction and in the efficient sample handling afforded by component integration.