A computational analysis of lower bounds for big bucket production planning problems

In this paper, we analyze a variety of approaches to obtain lower bounds for multi-level production planning problems with big bucket capacities, i.e., problems in which multiple items compete for the same resources. We give an extensive survey of both known and new methods, and also establish relationships between some of these methods that, to our knowledge, have not been presented before. As will be highlighted, understanding the substructures of difficult problems provide crucial insights on why these problems are hard to solve, and this is addressed by a thorough analysis in the paper. We conclude with computational results on a variety of widely used test sets, and a discussion of future research

Clara Cell 10-kDa Protein Gene Transfection Inhibits NF-κB Activity in Airway Epithelial Cells

Clara cell 10-kDa protein (CC10) is a multifunctional protein with anti-inflammatory and immunomodulatory effects. Induction of CC10 expression by gene transfection may possess potential therapeutic effect. Nuclear factor κB (NF-κB) plays a key role in the inflammatory processes of airway diseases.To investigate potential therapeutic effect of CC10 gene transfection in controlling airway inflammation and the underlying intracellular mechanisms, in this study, we constructed CC10 plasmid and transfected it into bronchial epithelial cell line BEAS-2B cells and CC10 knockout mice. In BEAS-2B cells, CC10's effect on interleukin (IL)-1β induced IL-8 expression was explored by means of RT-PCR and ELISA and its effect on NF-κB classical signaling pathway was studied by luciferase reporter, western blot, and immunoprecipitation assay. The effect of endogenous CC10 on IL-1β evoked IL-8 expression was studied by means of nasal explant culture. In mice, CC10's effect on IL-1β induced IL-8 and nuclear p65 expression was examined by immunohistochemistry. First, we found that the CC10 gene transfer could inhibit IL-1β induced IL-8 expression in BEAS-2B cells. Furthermore, we found that CC10 repressed IL-1β induced NF-κB activation by inhibiting the phosphorylation of IκB-α but not IκB kinase-α/β in BEAS-2B cells. Nevertheless, we did not observe a direct interaction between CC10 and p65 subunit in BEAS-2B cells. In nasal explant culture, we found that IL-1β induced IL-8 expression was inversely correlated with CC10 levels in human sinonasal mucosa. In vivo study revealed that CC10 gene transfer could attenuate the increase of IL-8 and nuclear p65 staining in nasal epithelial cells in CC10 knockout mice evoked by IL-1β administration.These results indicate that CC10 gene transfer may inhibit airway inflammation through suppressing the activation of NF-κB, which may provide us a new consideration in the therapy of airway inflammation

Combined ship routing and inventory management in the salmon farming industry

We consider a maritime inventory routing problem for Norway's largest salmon farmer both producing the feed at a production factory and being responsible for fish farms located along the Norwegian coast. The company has bought two new ships to transport the feed from the factory to the fish farms and is responsible for the routing and scheduling of the ships. In addition, the company has to ensure that the feed at the production factory as well as at the fish farms is within the inventory limits. A mathematical model of the problem is presented, and this model is reformulated to improve the efficiency of the branch-and-bound algorithm and tightened with valid inequalities. To derive good solutions quickly, several practical aspects of the problem are utilized and two matheuristics developed. Computational results are reported for instances based on the real problem of the salmon farmer

JPN Guidelines for the management of acute pancreatitis:surgical management

Acute pancreatitis represents a spectrum of disease ranging from a mild, self-limited course to a rapidly progressive, severe illness. The mortality rate of severe acute pancreatitis exceeds 20%, and some patients diagnosed as mild to moderate acute pancreatitis at the onset of the disease may progress to a severe, life-threatening illness within 2–3 days. The Japanese (JPN) guidelines were designed to provide recommendations regarding the management of acute pancreatitis in patients having a diversity of clinical characteristics. This article sets forth the JPN guidelines for the surgical management of acute pancreatitis, excluding gallstone pancreatitis, by incorporating the latest evidence for the surgical management of severe pancreatitis in the Japanese-language version of the evidence-based Guidelines for the Management of Acute Pancreatitis published in 2003. Ten guidelines are proposed: (1) computed tomography-guided or ultrasound-guided fine-needle aspiration for bacteriology should be performed in patients suspected of having infected pancreatic necrosis; (2) infected pancreatic necrosis accompanied by signs of sepsis is an indication for surgical intervention; (3) patients with sterile pancreatic necrosis should be managed conservatively, and surgical intervention should be performed only in selected cases, such as those with persistent organ complications or severe clinical deterioration despite maximum intensive care; (4) early surgical intervention is not recommended for necrotizing pancreatitis; (5) necrosectomy is recommended as the surgical procedure for infected pancreatic necrosis; (6) simple drainage should be avoided after necrosectomy, and either continuous closed lavage or open drainage should be performed; (7) surgical or percutaneous drainage should be performed for pancreatic abscess; (8) pancreatic abscesses for which clinical findings are not improved by percutaneous drainage should be subjected to surgical drainage immediately; (9) pancreatic pseudocysts that produce symptoms and complications or the diameter of which increases should be drained percutaneously or endoscopically; and (10) pancreatic pseudocysts that do not tend to improve in response to percutaneous drainage or endoscopic drainage should be managed surgically

Relaxations for two-level multi-item lot-sizing problems

We consider several variants of the two-level lot-sizing problem with one item at the upper level facing dependent demand, and multiple items or clients at the lower level, facing independent demands. We first show that under a natural cost assumption, it is sufficient to optimize over a stock-dominant relaxation. We further study the polyhedral structure of a strong relaxation of this problem involving only initial inventory variables and setup variables. We consider several variants: uncapacitated at both levels with or without start-up costs, uncapacitated at the upper level and constant capacity at the lower level, constant capacity at both levels. We finally demonstrate how the strong formulations described improve our ability to solve instances with up to several dozens of periods and a few hundred products. © 2013 Springer-Verlag Berlin Heidelberg and Mathematical Optimization Society