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  • 1
    Electronic Resource
    Electronic Resource
    Minimizing Mean Flow Time with Error Constraint (1998)
    Springer
    Algorithmica 20 (1998), S. 101-118 
    Details
    ISSN: 1432-0541
    Keywords: Key words. Real-time system, NP-hard, Pseudopolynomial time, Polynomial time, Ready time, Deadline, Imprecise computation, Mean flow time, Average error, Nonpreemptive scheduling, Preemptive scheduling.
    Source: Springer Online Journal Archives 1860-2000
    Topics: Computer Science , Mathematics
    Notes: Abstract. We consider the problem of minimizing mean flow time for the Imprecise Computation Model introduced by Lin et al. A task system TS=({T i },{r(T i )},{d(T i )},{m(T i )},{o(T i )}) consists of a set of n independent tasks, where r(T i ),d(T i ),m(T i ) , and o(T i ) denote the ready time, deadline, execution time of the mandatory part, and execution time of the optional part of T i , respectively. Given a task system TS and an error threshold K , our goal is to find a preemptive schedule on one processor such that the average error is no more than K and the mean flow time of the schedule is minimized. Such a schedule is called an optimal schedule. In this article we show that the problem of finding an optimal schedule is NP-hard, even if all tasks have identical ready times and deadlines. A pseudopolynomial-time algorithm is given for a set of tasks with identical ready times and deadlines, and oppositely ordered mandatory execution times and total execution times (i.e., there is a labeling of tasks such that m(T i )≤ m(T i+1 ) and m(T i )+o(T i )≥ m(T i+1 )+o(T i+1 ) for each 1≤ i〈n ). Finally, polynomial-time algorithms are given for (1) a set of tasks with identical ready times, and similarly ordered mandatory execution times and total execution times and (2) a set of tasks with similarly ordered ready times, deadlines, mandatory execution times, and total execution times.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/PL00009185
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  • 2
    Electronic Resource
    Electronic Resource
    Enzyme action in glycoprotein synthesis (1998)
    Springer
    Cellular and molecular life sciences 54 (1998), S. 223-252 
    Details
    ISSN: 1420-9071
    Keywords: Key words. Glycosyltransferase; biosynthesis; processing; inhibition; oligosaccharide; carbohydrate; cloning.
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Abstract. Just a few decades ago, the saccharides bound to glycoproteins were considered little more than an irritation. They increased the difficulty of purifying and characterizing proteins, making proteins run as several bands on gels and smearing them on columns. They were considered a nuisance and were typically cleaved away to reveal the ‘important part’, the protein moiety, for structural (e.g. via X-ray crystallography or nuclear magnetic resonance) and functional studies. We now realize that the saccharide is often as important as the protein itself, and that glycosylation can have many effects on the function, structure, physical properties and targeting of a protein. There are a myriad of reviews and books on this subject, reflecting the nearly overwhelming number of articles in print discussing saccharide structures, glycoprotein processing enzymes and the biological implications of glycosylation. This review discusses, in turn, the extent and biological relevance of glycosylation; the structures observed; how glycosylated proteins are formed in vivo; the clinical relevance of glycosylation, in terms of the correlations between disease states and unusual glycosylation patterns; and, finally, the molecules, both natural and synthetic, that can be used to study the roles of carbohydrates in glycoprotein structure and function or to disrupt various carbohydrate recognition processes and enzymatic reactions in the glycoprotein synthetic pathway.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/s000180050146
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  • 3
    Electronic Resource
    Electronic Resource
    Comparison of bone single-photon emission tomography and planar imaging in the detection of vertebral metastases in patients with back pain (1998)
    Springer
    European journal of nuclear medicine 25 (1998), S. 635-638 
    Details
    ISSN: 1619-7089
    Keywords: Key words: Vertebral metastases ; Bone scan ; Single-photon emission tomography ; Planar imaging
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract. Bone scan has long been considered to be an important diagnostic test in searching for bone metastases. However, considerable difficulty is encountered in the vertebral region due to the complexity of structures and the fact that other benign lesions, especially degenerative changes, are very common there. Single-photon emission tomography (SPET) has been reported to be useful in the differentiation of benign from malignant conditions. Here we report our experience with bone SPET in the diagnosis of vertebral metastases. This is a retrospective study of technetium-99m methylene diphosphonate (MDP) bone scans in 174 consecutive patients who were referred for the investigation of back pain in our department. MDP planar and SPET images were obtained. Of teh 174 patients, 98 had a known history of malignant tumours. The diagnosis of vertebral metastasis was made on the basis of the patients’ clinical histories and the findings with other imaging techniques such as magnetic resonance imaging, computed tomography or follow-up bone scan. We found that the presence of pedicle involvement as seen on SPET was an accurate diagnostic criterion of vertebral metastasis. SPET had a sensitivity of 87%, a specificity of 91%, a positive predictive value of 82%, a negative predictive value of 94% and an accuracy of 90%. On the other hand, planar study had a sensitivity of 74%, a specificity of 81%, a positive predictive value of 64%, a negative predictive value of 88% and an accuracy of 79% in diagnosing vertebral metastasis. Except with regard to the negative predictive value, SPET performed statistically better than planar imaging. Only 9/147 (6.4%) lesions involving the vertebral body alone and 3/49 (6.1%) lesions involving facet joints alone were subsequently found to be metastases. We conclude that bone SPET is an accurate diagnostic test for the detection of vertebral metastases and is superior to planar imaging in this respect.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/s002590050266
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    Paper (German National Licenses)
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  • 4
    Electronic Resource
    Electronic Resource
    Study of hydration of OPC/PFA blend with various activators using microwave technique (1998)
    Springer
    Journal of materials science 33 (1998), S. 4191-4199 
    Details
    ISSN: 1573-4803
    Source: Springer Online Journal Archives 1860-2000
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Notes: Abstract The early hydration of ordinary Portland cement (OPC) pulverized fly ash (PFA) blends with various PFA proportions was investigated using microwave technique and conduction calorimeter. It is found that PFA acts as almost inert filler in the OPC/PFA blends during the first 40 h of hydration, thus it retards the early hydration of the blends. To accelerate the pozzolanic hydration of the PFA, three different additives were studied. It is found that both Ca(OH)2 and Na2SO4 can accelerate the early hydration of the OPC/PFA blends, but Na2SO4 is more effective than Ca(OH)2, whereas NaOH is not suitable for the acceleration of the early hydration of the OPC/PFA blend. © 1998 Kluwer Academic Publishers
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1023/A:1004473723621
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    Paper (German National Licenses)
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