Most previous workflow scheduling research focused on scheduling a single workflow on parallel systems. Recent researches show that utilizing idle time slots between scheduled tasks is a promising direction for efficient multiple workflow scheduling. Stavrinides and Karatza proposed a list scheduling approach to efficient utilization of the idle time slots through bin packing techniques. In this paper, we elaborate on this direction and develop a new approach to further improve multiple workflow scheduling performance through two techniques. The first, in contrast with the list scheduling approach, is clustering the tasks within workflows into groups before allocation. This can reduce inter-task communication cost and thus improve workflow execution performance. The second technique tries to make a balance between tasks' start time and the fitness of idle time slots when allocating task groups. The proposed approach has been evaluated with a series of simulation experiments and compared to the previous method. The results show that our approach outperforms the previous method significantly, up to 51% performance improvement in terms of average makespan.
BackgroundHerbochip® technology is a high throughput drug screening platform in a reverse screening manner, in which potential chemical leads in herbal extracts are immobilized and drug target proteins can be used as probes for screening process [BMC Complementary and Alternative Medicine (2015) 15:146]. While herbal medicines represent an ideal reservoir for drug screenings, here a molecular chaperone GRP78 is demonstrated to serve as a potential target for antiviral drug discovery.MethodsWe cloned and expressed a truncated but fully functional form of human GRP78 (hGRP781-508) and used it as a probe for anti-HBV drug screening on herbochips. In vitro cytotoxicity and in vitro anti-HBV activity of the herbal extracts were evaluated by MTT and ELISA assays, respectively. Finally, anti-HBV activity was confirmed by in vivo assay using DHBV DNA levels in DHBV-infected ducklings as a model.ResultsPrimary screenings using GRP78 on 40 herbochips revealed 11 positives. Four of the positives, namely Dioscorea bulbifera, Lasiosphaera fenzlii, Paeonia suffruticosa and Polygonum cuspidatum were subjected to subsequent assays. None of the above extracts was cytotoxic to AML12 cells, but P. cuspidatum extract (PCE) was found to be cytotoxic to HepG2 2.2.15 cells. Both PCE and P. suffruticosa extract (PSE) suppressed secretion of HBsAg and HBeAg in HepG2 2.2.15 cells. The anti-HBV activity of PSE was further confirmed in vivo.ConclusionWe have demonstrated that GRP78 is a valid probe for anti-HBV drug screening on herbochips. We have also shown that PSE, while being non-cytotoxic, possesses in vitro and in vivo anti-HBV activities. Taken together, our data suggest that PSE may be a potential anti-HBV agent for therapeutic use.Electronic supplementary materialThe online version of this article (doi:10.1186/s13020-017-0132-2) contains supplementary material, which is available to authorized users.
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