Rule-based data mining for yield improvement in semiconductor manufacturing

We describe an automated system for improving yield, power consumption and speed characteristics in the manufacture of semiconductors. Data are continually collected in the form of a history of tool usage, electrical and other real-valued measurements—a dimension of tens of thousands of features. Unique to this approach is the inference of patterns in the form of binary regression rules that demonstrate a significantly higher or lower performance value for tools relative to the overall mean for that manufacturing step. Results are filtered by knowledge-based constraints, increasing the likelihood that empirically validated rules will prove interesting and worth further investigation. This system is currently installed in the IBM 300 mm fab, manufacturing game chips and microprocessors. It has detected numerous opportunities for yield and performance improvement, saving many millions of dollars.     

Searching for momentum enhancement in hypervelocity impacts

In conjunction with the Los Alamos National Laboratory hypervelocity microparticle impact (HMI) team effort to produce higher impact velocities and to understand the physics of crater formation and momentum transfer, we have implemented a low noise microphone as a momentum detector on both the 6 MV Van de Graaff and 85 KV “test stand” particle accelerators. Calculations are presented showing that the impulse response of a circular membrane. When used as a momentum impulse detector, the microphone theoretically may detect impulses as small as 8.8 × 10⁻¹⁵ N s. Sensitivity of the microphone in this application is limited by the noise threshold of the electronic amplifiers and the ambient microphonic vibration of the system. Calculations lead us to anticipate detection of particles over the full range of the Van de Graaff acceleration capability and up to 7 km/s on the test stand. We present momentum enhancement data in the velocity range between 10 km/s and 20 km/s. Preliminary work is presented on momentum impulse calibration of the microphone using laser-pulse photon momentum as an impulse source.     

Diameter-Controlled Synthesis of Polyaniline Nanofibers

Summary  Various diameters of polyaniline (PANI) nanofibers were easily made by varying the sweep rate in the electrochemical polymerization of the aniline monomer. At a sweep rate of 5 mV/s, the PANI nanofibers have an average diameter of 450 nm with a median of 440 nm. The fibers are short, on the order of a few microns in length, and exhibit a branched geometry. Increasing the sweep rate to 50 mV/s produced longer nanofibers with a smaller average diameter of 200 nm. Nanofibers synthesized at 100 mV/s were noted to be smaller with an average and median diameter of 100 nm. These results illustrate the ease in which the morphology of nanostructured PANI can be altered and indicate that the method has the potential to create multi-diameter fibers or mixed-morphology materials.     

Leaf Surface Compounds and Oviposition Preference of Turnip Root Fly Delia floralis: The Role of Glucosinolate and Nonglucosinolate Compounds

The role of leaf surface compounds influencing the oviposition of the turnip root fly, Delia floralis, was investigated using bioassays and fractionation of leaf surface extracts from four Brassica genotypes. Polar leaf surface extracts contained between 65 and 175 nM/g leaf equivalent of glucosinolates. However, following fractionation it was found that nonglucosinolates were the major stimuli for D. floralis oviposition. Electrophysiological studies of leaf surface extracts and their fractions were performed by using D. radicum, the cabbage root fly, as an analytical tool. The most behaviorally active fractions contained stimulatory compound(s) that had an activity profile identical to that previously described for recently discovered nonglucosinolate compounds. The role of leaf surface chemicals in influencing antixenotic resistance to D. floralis is discussed.     

Transfection of a reporter plasmid into cultured cells by sonoporation in vitro

Cultured Chinese hamster ovary cells were exposed to 2.25-MHz ultrasound in sterile 4.5-mL polyethylene chambers and tested for cell lysis, sonoporation and DNA transfection. Ten percent of Albunex, a gas-body-based ultrasound contrast agent, was added to ensure cavitation nucleation, and the chambers were rotated at 60 rpm to promote cavitation activity during the 1-min exposures. Uptake of large fluorescent dextran molecules by some cells was observed for spatial peak pressure amplitudes as low as 0.1 MPa, which indicates transient permeabilization and resealing, i.e., sonoporation, of these cells during exposure. Significant lysis occurred for 0.2 MPa, and increased rapidly for exposures above the apparent cavitation threshold (using the H2O2 production test) of about 0.4 MPa spatial peak pressure amplitude. In the DNA transfection tests, 20 micrograms/mL luciferase reporter plasmid was added to the suspension during exposure, and cells were assayed for proliferation ability and luciferase gene expression 2 days after exposure. Cell proliferation was greatly reduced above the cavitation threshold. Luciferase production was significant for 0.20-MPa exposure, and reached 0.33 ng per 10(6) cells at 0.8-MPa exposure. The luciferase production was great for cells exposed in medium supplemented with serum than for cells exposed in serum-free medium. Cells harvested for exposure either in the log phase or in the stationary phase of culture gave similar proliferation and transfection results. The effects essentially disappeared when the Albunex was omitted from the suspension and the tube was not rotated. Thus, sonoporation by ultrasonic cavitation in the rotating tube system yields plasmid transfection with subsequent transient gene expression.     

Compartment-ablation studies of GLUT4 distribution in adipocytes: evidence for multiple intracellular pools

The available data suggest that GLUT4 does populate the recycling endosomal system to some extent, but that a large proportion of the intracellular GLUT4 resides in a compartment that is devoid of transferrin receptors and may have properties more akin to specialized secretory vesicles. The study of the nature and biogenesis of this compartment will provide important insight into the mechanism by which insulin stimulates glucose transport. Further study of the role of the synaptobrevins in these distinct subcellular compartments will probably shed further light on the mechanism by which insulin stimulates GLUT4 translocation.     

Diagnostic accuracy of a rural live video telepathology system

Accuracy of diagnoses rendered using a live video telepathology network was assessed for permanent sections of surgical pathology specimens. To determine accuracy, telepathology diagnoses were compared with those obtained by directly viewing the glass slide using a standard microscope. A total of 294 cases were read via both telepathology and glass slide by attending pathologists at a tertiary care medical center. Overall accuracy was defined as exact concordance between diagnoses. Clinically insignificant differences in diagnoses were excluded to determine clinically significant accuracy. For the 285 cases with complete data, the overall accuracy for telepathology was 0.912 (95% confidence interval [CI], 0.872-0.941), whereas the overall accuracy for glass slide readings was 0.968 (95% CI, 0.939-0.985). This difference is statistically significant (p = 0.009). When focusing on clinically significant discrepancies, where the difference in diagnosis might affect therapeutic decisions, the video accuracy was only slightly less than the glass slide accuracy (0.965 [95% CI, 0.934-0.982] vs. 0.982 [95% CI, 0.957-0.994], respectively), but this difference is not statistically significant (p = 0.302). Most of the cases with clinically significant differences involved lesions with inherently high interobserver variation. Certainty of diagnosis did not differ between video and glass slide readings (p = 0.911), but there was an association between certainty of diagnosis and diagnostic accuracy for video (p = 0.003 for clinically significant accuracies). Based on these findings, we recommend when using this telepathology system that only preliminary diagnoses should be given in the following situations: for diagnostic areas with known high interobserver variability; when the consultant has any degree of uncertainty about the presence or absence of the lesion in question; and when there is insufficient experience using telepathology as a diagnostic medium.