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We address the problem of scheduling a set of parts with given processing times and tool requirements on m identical parallel machines. The problem is to find an allocation of the machines to the parts, a proper sequence for the parts assigned to each machine, and a corresponding tool-switching plan for each machine so as to minimize the makespan. It is demonstrated that this problem is np-hard , and three heuristic procedures are proposed for solving it. The first procedure is a multi-start local improvement procedure, and various neighborhood structures and search strategies are discussed in this context. The second procedure is a variation of the list-processing routine that is commonly used for the parallel machine problem. Finally, the last procedure is an adaptation of a well-known constructive procedure for the k -travelling salesman problem. Results of a limited computational experiment are also presented in which the makespan obtained via each heuristic procedure is compared with a proposed lower bound and with other reference values.  相似文献   
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Evaluation of a variety of PDE4 inhibitors in a series of cellular and in vivo assays suggested a strategy to improve the therapeutic index of PDE4 inhibitors by increasing their selectivity for the ability to inhibit PDE4 catalytic activity versus the ability to compete for high affinity [3H]rolipram-binding sites in the central nervous system. Use of this strategy led ultimately to the identification of cis-4-cyano-4-[3-(cyclopentyloxy)-4-methoxyphenyl]cyclohexane-1-carboxyl ic acid (1, SB 207499, Ariflo), a potent second-generation inhibitor of PDE4 with a decreased potential for side effects versus the archetypic first generation inhibitor, (R)-rolipram.  相似文献   
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The ability of the second generation phosphodiesterase 4 inhibitor SB 207499 (Ariflo), [c-4-cyano-4-(3-cyclopentyloxy-4-methoxyphenyl)-r-l-cyclohexane carboxylic acid], to inhibit inflammatory cytokine production in vivo was evaluated and compared to that of rolipram, a first generation phosphodiesterase 4 inhibitor. To examine human tumor necrosis factor alpha (TNFalpha) production, human monocytes were adoptively transferred into Balb/c mice and challenged with lipopolysaccharide (LPS). In this model, SB 207499 inhibited human TNFalpha production with oral ED50 of 4.9 mg/kg. Similarly, R-rolipram inhibited human TNFalpha production with an ED50 of 5.1 mg/kg, p.o. In contrast to their equipotent activity against TNFalpha production, SB 207499 (ED50 = 2.3 mg/kg, p.o.) was 10-fold less potent than R-rolipram (ED50 = 0.23 mg/kg, p.o.) in reversing reserpine-induced hypothermia, a model of antidepressant activity. In time course studies, SB 207499 (30 mg/kg, p.o.) inhibited TNFalpha production for at least 10 hr; substantial plasma concentrations of SB 207499 were detected over the same interval. The ability of SB 207499 to modulate interleukin-4 production in vivo was assessed in a chronic oxazolone-induced contact sensitivity model in Balb/c mice. In this model, topical administration of SB 207499 (1000 microgram) inhibited intralesional concentrations of interleukin-4 (55%; P <.01). The results demonstrate that SB 207499 is a potent inhibitor of inflammatory cytokine production in a variety of settings in vivo. Moreover, although it is as potent as R-rolipram in inhibiting TNFalpha production, it has substantially less central nervous system activity. Thus SB 207499 represents an excellent candidate with which to evaluate the antiinflammatory potential of PDE4 inhibitors.  相似文献   
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Test Review.     
Reviews the American College Testing Program (1972 Edition) assessment device for the guidance of students enrolled in 2-year colleges and institutes. Issues addressed include testing mechanics, the Career Planning Program Profile (construction and content), reliability, predictive validity, concurrent validity, the Counselor's Manual, and the Student Booklet. It is concluded that the amount of information returned to the student is large and carefully planned, that interpretation of the profile by a guidance counselor would be imperative, and that the level of difficulty of the extensive material presented in the Handbook is high. (PsycINFO Database Record (c) 2010 APA, all rights reserved)  相似文献   
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The hydrophobic but hygroscopic nature of polydimethylsiloxane (PDMS) with quaternary ammonium cationic side chains adsorbed on a SiO(2) surface was investigated with sum frequency generation vibration spectroscopy (SFG) and attenuated total reflectance infrared spectroscopy (ATR-IR). PDMS with cationic side chains, named cationic polymer lubricant (CPL), forms a self-healing boundary lubrication film on SiO(2). It is interesting that CPL films are externally hydrophobic but internally hydrophilic. The comparison of SFG and ATR-IR data revealed that the methyl groups of the PDMS backbone are exposed at the film/air interface and the cationic side groups and counterions are embedded within the film. The hydrophobicity must originate from the surface CH(3) groups, while the ionic groups inside the film must be responsible for water uptake. The surface hydrophobicity can alleviate the capillary adhesion while the hygroscopic property enhances the mobility and self-healing capability of the CPL boundary lubrication film.  相似文献   
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375 questionnaire returns (73%) from the 563 psychology majors during the 10-year period 1948-58 were usable. 10% are teaching (elementary school to college levels), 14% are housewives, 16% are in the managerial-industrial area, 12% in the sales-advertising area, 9% are graduate students, 9% are professional psychologists, 8% are in social work, and 5% have MD degrees. Chiropodists, pharmacists, ministers, engineers, and nurses are also represented. Respondents were asked "if they were now advising a young person, or had it to do over again themselves, would they recommend psychology as an undergraduate major." 62% answered yes. From Psyc Abstracts 36:02:2AM84B. (PsycINFO Database Record (c) 2010 APA, all rights reserved)  相似文献   
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The concurrent validity of the MVII was investigated with over 1000 vocational high school boys in Grades 9 and 12 in Buffalo, New York, schools. Scores of boys in particular trade curricula were checked against relevant MVII scales. At Grade 12, the food, electrical, and printing trade choices were well predicted; students in building trade, machinist, and mechanical programs were not well spotted. Similar results, but less encouraging, were found for the Grade-9 sample. With 1 student sample only (electrical), aptitude test data were unrelated to MVII scores. Students with "high" academic or shop school averages earned higher MVII criterion scale scores than did others. (PsycINFO Database Record (c) 2010 APA, all rights reserved)  相似文献   
10.
This paper describes the direct deposition of hydrocarbon coatings with a static water contact angle higher than 150 using simple C6 hydrocarbons as a reactive gas in helium plasma generated in ambient air without any preroughening of the silicon (100) substrate. The film morphology and hydrophobicity are found to strongly depend on the structure of the reagent hydrocarbon. The films deposited with n-hexane and cyclohexane exhibited relatively smooth morphology and the water contact angle was only ~95°, similar to polypropylene. When benzene was used as a main reactive gas, the deposited film surface showed nanoscale textured morphology and superhydrophobicity with a water contact angle as high as 167°. Because the plasma is generated in air, all films show some degree of oxygen incorporation. These results imply that the incorporation of a small amount of oxygenated species in hydrocarbon films due to excitation of ambient air is not detrimental for superhydrophobicity, which allows the atmospheric rf plasma with the benzene precursor to produce rough surface topography needed for superhydrophobicity.  相似文献   
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