Operations research in the high-level synthesis of integrated circuits

The acceptance of high-level synthesis tools and methodologies by the design engineers depends on their efficiency in producing circuits with small silicon areas and high operating speeds. This paper shows how this efficiency can be achieved through the use of several operations research techniques applied to the many optimization problems that must be solved. These include: shortest path algorithms, integer programming techniques applied to silicon area minimization, force directed scheduling to optimize the number of operators and cost/speed trade-offs of logical gates. This paper presents several examples providing an operations research solution to each of them.     

Plasma norepinephrine, epinephrine, and thyroid hormone interactions in severely burned patients

In this prospective study of thyroid catecholamine interactions, 15 severely burned patients were divided into two groups. Nine patients receiving 200 micrograms/day of triiodothyronine constituted the T3-treated group. Eight additional patients constituted the untreated group. Mean serum concentrations of T3 were significantly lower in the untreated group than in the treated group. Mean serum thyroxine (T4) concentrations were significantly higher in the untreated group than in the treated group. The mean plasma norepinephrine concentration in the untreated group was significantly greater than that of the treated group. In the untreated group, log plasma norepinephrine correlated inversely with serum T3. Similarly, in the untreated group, log plasma epinephrine correlated inversely with serum T3. Metabolic rates were not different between groups. These data suggest that a reciprocal relationship exists between plasma concentration of T3 and both norepinephrine and epinephrine in untreated burn patients and that treatment with the metabolically active hormone, triiodothyronine, does not alter the level of hypermetabolism accompanying thermal injury.     

Fixation of osteotomies using bioabsorbable screws in the canine femur

The purpose of this study was to compare the healing properties of femoral osteotomies fixed by bioabsorbable screws (20:80 polyglycolic copolylactic acid copolymer) to standard stainless steel screws of a similar design in a dog femoral model. Two osteotomies were used, the trephine osteotomy (10 mm diameter) in the metaphyseal lateral femoral condyle and in the femoral diaphysis, and a unilateral osteotomy in the lateral femoral condyle. Two months after the trephine osteotomies, the femurs that contained the polymer screws were not significantly different in mechanical strength from the femurs treated with the stainless steel screws, either in the diaphyseal or metaphyseal model. There was no histological difference in bone healing between the metallic and polymer screws for all periods (2, 9, and 17 months). There was no adverse inflammatory response to the polymeric or metallic screws. By month 17, the polymer screws were resorbed completely. All the diaphyseal screw tracks had healed with bone and areas of remodeling were evident in two specimens. For the femoral condyle osteotomy model at 2 months, the polymer screws were present and intact, and all osteotomies healed with no evidence of inflammation. By 9 months, only one specimen had polymeric material left in the screw track. At 15 months, the screw tracks still were present but no evidence of any polymer remained. The tracks were filled with fibrous and adipose connective tissue. All osteotomies stabilized with either bioabsorbable polymer screws or stainless steel screws did heal satisfactorily without any complications, inflammation, or osteolysis. The polyglycolic polylactic acid copolymer may have a clinical role as a bioabsorbable material without the concerns for the osteolysis, foreign body reaction, and sterile abscess formation that have occurred with bioabsorbable fixation methods in the past.     

Planar coincidence scintigraphy and PET in staging malignant melanoma

This study describes a comparison of simulated planar positron coincidence scintigraphy (PCS) with PET in the whole-body staging of patients with malignant melanoma using 2-18F-fluoro-2-deoxy-D-glucose (FDG). METHODS: In 55 patients with either known metastatic or newly diagnosed malignant melanoma, whole-body PET scanning was performed on a conventional full-ring dedicated PET tomograph, and multiaxial sections were obtained. Furthermore, anteroposterior projection images simulating images of a dual-head Anger camera operating in coincidence mode were obtained from the PET raw data. Each study was evaluated separately and blindly. Imaging findings were confirmed by biopsy or by at least one imaging modality in addition to PET. RESULTS: A total of 108 lesions were evaluated, of which 76 proved to be melanoma metastases. Whole-body PET correctly demonstrated 68 metastases, 6 lesions were classified as questionable metastases and 2 were missed. Whole-body PCS correctly demonstrated 14 metastases, 22 lesions were classified as questionable metastases and 40 metastases were missed. The sensitivities of whole-body PET and whole-body PCS were 89% and 18%, respectively. In PCS lesions in regions of high background activity, such as in the abdomen, were missed more often than in PET (p < 0.05). The tumor-to-background contrast was generally lower in PCS than in PET. A further decrease in PCS detection was found in lesions of < 22 mm in diameter. CONCLUSION: The lack of sensitivity precludes the clinical use of whole-body PCS in staging malignant melanoma.     

Transformation of mycosis fungoides: T-cell receptor beta gene analysis demonstrates a common clonal origin for plaque-type mycosis fungoides and CD30+ large-cell lymphoma

We investigated the consequences of Sr2+ binding to the transport sites of sarcoplasmic reticulum (SR) Ca(2+)-ATPase for two fluorescent conformational probes located in different regions of the ATPase. Using SR vesicles in which Lys-515 in the ATPase had been previously labeled with fluorescein 5'-isothiocyanate (FITC), we found that the Sr(2+)-induced a drop in the fluorescein fluorescence of this FITC-labeled ATPase shifted toward lower Sr2+ concentrations than the Sr(2+)-induced rise in Trp fluorescence for the same FITC-labeled ATPase. The curve describing the Sr(2+)-dependent rise in Trp fluorescence had a characteristic asymmetric shape, and the changes in Trp fluorescence occurred in parallel with the activation by Sr2+ of pNPP hydrolysis by the ATPase. Analysis of these results in terms of the simplest scheme describing the sequential binding of the two Sr2+ ions suggests that under the conditions of these experiments, i.e. at neutral pH in the presence of potassium, the Sr(2+)-induced rise in the Trp fluorescence mainly reflected the formation of ATPase with two ions bound to the transport sites, whereas the binding of a single Sr2+ ion was virtually sufficient to reduce the fluorescence of bound FITC to its minimal level.     

Ten-year linear trends in reproduction and wool production among inbred and noninbred lines of Rambouillet, Targhee, and Columbia sheep

To investigate the value of creating inbred lines for genetic improvement of sheep, 54 inbred, 1 randombred control, and 3 noninbred control lines were evaluated for lamb and wool production. Results were based on 19,438 dam and 23,625 lamb records from Rambouillet (R), Targhee (T), and Columbia (C) sheep collected over 9 yr (for T and C) and 10 yr (for R), starting in 1954. Average inbreeding in the inbred lines during the period was near 25% for lambs and 20% for ewes. The general trend in inbred lines for litter weight weaned (120 d) and number weaned (net reproductive rate), per ewe exposed to breeding, was downward as inbreeding increased. Trends in fleece weight generally also were down, regardless of concomitant increases in body weight. Declines were most pronounced in two lines developed by rapid inbreeding. Reproductive merit in the R and C noninbred controls also declined, but the declines were less than those for most inbred lines. Although the T noninbred control declined in fleece weight, trends for fleece weight in the R and C controls were positive and significantly different from the negative trends in the inbred lines. For the randombred control, slight downward trends in litter weight and number weaned were less (P < .05) than those for most inbred lines, indicating genetic declines in these traits for most inbred lines. Direct selection for an index of overall phenotypic merit, recurrent selection for combining ability for overall merit, and direct selection for body type, clean fleece weight, or staple length were all ineffective in preventing a decline in reproductive merit. Ending means (last 2 yr of production) revealed that litter weight weaned in the control groups of each breed was clearly superior to that in most inbred lines. Controls also were typically superior for fleece and body weight. Not one of the 54 inbred lines was superior (P < .05) to its respective noninbred control in weight of lamb weaned or net reproductive rate. Only four of the inbred lines were superior to the noninbred controls in fleece weight. These results, after at least 23 yr of development for most lines, reflect little encouragement for the costly development of many inbred lines for the purpose of improving lamb and wool production, especially when using the above selection criteria.