193 research outputs found
Building Decision Support Systems in Excel for Production and Distribution Planning: A Case Study
We develop a decision support system in Microsoft Excel that integrates production and distribution for a manufacturer of natural fiber-based products in North America. The production and distribution of the company’s products were optimized using a linear programming model, implemented in Excel. The spreadsheet dynamically adjusts the formulation to reflect the user’s current requirements, solves the optimization model in the background, and generates detailed managerial reports. In addition, it allows users to conduct what-if analyses by varying the number of plants and warehouses. It demonstrates the ability of a Linear Programming Model run on an Excel platform to provide the firm with an optimized production plan resulting in significant, cost savings since implementation
Recommended from our members
Heuristic solution techniques for a spatial harvest scheduling problem involving wildlife habitat and timber income
Three heuristic techniques: simulated annealing (SA), tabu search (TS), and tabu search with strategic oscillation (TSSO), were used to schedule silvicultural activities designed to accelerate development of older forest structure at both stand and landscape scales over a 2450 acre forest located in northwestern Oregon. Goals for the forest over a 100-year planning horizon included reaching at least 500 acres of older forest structure with at least one contiguous 200-acre (or larger) block as soon as possible. The configuration and location, but not the amounts, of the older forest structure acres and the contiguous block were then free to move about the forest through time while best meeting the goal of producing a high, steady revenue flow over the entire planning horizon subject to restrictions on maximum clearcut patch size. The heuristic techniques were able to provide feasible tactical schedules fulfilling the strategic goals over the entire horizon in ways which traditional forest planning tools cannot. Of the three techniques examined, TSSO produced schedules with the best, most consistent objective function values. SA yielded a wider range of values which were always slightly worse but required only a fraction of the computing time. Straightforward TS produced relatively poor objective function values, most likely because of its inability to search the infeasible regions of the diverse solution space. Estimation of the globally optimal objective function value using Weibull distributions suggested that all TSSO solutions were within 1.8% of the optimum, the best being within .03%, while all SA solutions were within 7.6%, the best being within 1 .7%. However, 95% confidence intervals of the Weibull location parameter estimates for the SA and TSSO distributions did not overlap, despite the fact that both distributions of results failed to be rejected as fitting a Weibull distribution. This disparity again suggests that statistical inference by itself of global optima for heuristic results may be an inadequate means of assessing how "good" a heuristic is
Cystic fibrosis presenting as recurrent pancreatitis in a young child with a normal sweat test and pancreas divisum: a case report
<p>Abstract</p> <p>Introduction</p> <p>Pancreatitis is a rare manifestation of cystic fibrosis (CF) and may rarely be the presenting symptom in adolescent or adult patients with CF. We report a case of a 4 year-old female who initially presented with recurrent pancreatitis, a normal sweat test, and a diagnosis of pancreas divisum. She was subsequently diagnosed with cystic fibrosis at the age of 6 years, despite normal growth and no pulmonary symptoms, after nasal potential difference measurements suggested possible CF and two known CF-causing mutations (ΔF508 and L997F) were detected.</p> <p>Case Presentation</p> <p>An otherwise healthy 4 year-old female developed chronic pancreatitis and was diagnosed with pancreas divisum. Sphincterotomy was performed without resolution of her pancreatitis. Sweat test was negative for cystic fibrosis, but measurement of nasal potential differences suggested possible cystic fibrosis. These results prompted extended Cystic Fibrosis Transmembrane Regulator Conductance (CFTR) mutational analysis that revealed a compound heterozygous mutation: ΔF508 and L997F.</p> <p>Conclusion</p> <p>CFTR mutations should be considered in cases of chronic or recurrent pancreatitis despite a negative sweat test and the presence of pancreas divisum. Children with CFTR mutations may present with recurrent pancreatitis, lacking any other signs or symptoms of cystic fibrosis. It is possible that the combination of pancreas divisum and abnormal CFTR function may contribute to the severity and frequency of recurrent pancreatitis.</p
BART Inhibits Pancreatic Cancer Cell Invasion by PKCα Inactivation through Binding to ANX7
A novel function for the binder of Arl two (BART) molecule in pancreatic cancer cells is reported. BART inhibits invasiveness of pancreatic cancer cells through binding to a Ca2+-dependent, phosphorylated, guanosine triphosphatase (GTPase) membrane fusion protein, annexin7 (ANX7). A tumor suppressor function for ANX7 was previously reported based on its prognostic role in human cancers and the cancer-prone mouse phenotype ANX7(+/−). Further investigation demonstrated that the BART–ANX7 complex is transported toward cell protrusions in migrating cells when BART supports the binding of ANX7 to the protein kinase C (PKC) isoform PKCα. Recent evidence has suggested that phosphorylation of ANX7 by PKC significantly potentiates ANX7-induced fusion of phospholipid vesicles; however, the current data suggest that the BART–ANX7 complex reduces PKCα activity. Knocking down endogenous BART and ANX7 increases activity of PKCα, and specific inhibitors of PKCα significantly abrogate invasiveness induced by BART and ANX7 knockdown. These results imply that BART contributes to regulating PKCα activity through binding to ANX7, thereby affecting the invasiveness of pancreatic cancer cells. Thus, it is possible that BART and ANX7 can distinctly regulate the downstream signaling of PKCα that is potentially relevant to cell invasion by acting as anti-invasive molecules
Genetic Analyses of Heme Oxygenase 1 (HMOX1) in Different Forms of Pancreatitis
Contains fulltext :
107993.pdf (publisher's version ) (Open Access)BACKGROUND: Heme oxygenase 1 (HMOX1) is the rate limiting enzyme in heme degradation and a key regulator of inflammatory processes. In animal models the course of pancreatitis was ameliorated by up-regulation of HMOX1 expression. Additionally, carbon monoxide released during heme breakdown inhibited proliferation of pancreatic stellate cells and might thereby prevent the development of chronic pancreatitis (CP). Transcription of HMOX1 in humans is influenced by a GT-repeat located in the promoter. As such, HMOX1 variants might be of importance in the pathogenesis of pancreatitis. METHODS: The GT-repeat and SNP rs2071746 were investigated with fluorescence labelled primers and by melting curve analysis in 285 patients with acute pancreatitis, 208 patients with alcoholic CP, 207 patients with idiopathic/hereditary CP, 147 patients with alcoholic liver cirrhosis, and in 289 controls, respectively. GT-repeat analysis was extended to a total of 446 alcoholic CP patients. In addition, we performed DNA sequencing in 145 patients with alcoholic CP, 138 patients with idiopathic/hereditary CP, 147 patients with alcoholic liver cirrhosis, and 151 controls. Exon 3 screening was extended to additional patients and controls. RESULTS: S- and L-alleles of the GT-repeat, genotypes and alleles of SNP rs2071746 and non-synonymous variants detected by sequencing were found with similar frequencies in all groups. CONCLUSIONS: Although functional data implicate a potential influence of HMOX1 variants on the pathogenesis of pancreatitis, we did not find any association. As rare non-synonymous HMOX1 variants were found in patients and controls, it is rather unlikely that they will have functional consequences essential for pancreatitis development
Proton Magnetic Resonance Spectroscopy Reveals Neuroprotection by Oral Minocycline in a Nonhuman Primate Model of Accelerated NeuroAIDS
Background: Despite the advent of highly active anti-retroviral therapy (HAART), HIV-associated neurocognitive disorders continue to be a significant problem. In efforts to understand and alleviate neurocognitive deficits associated with HIV, we used an accelerated simian immunodeficiency virus (SIV) macaque model of NeuroAIDS to test whether minocycline is neuroprotective against lentiviral-induced neuronal injury. Methodology/Principal Findings: Eleven rhesus macaques were infected with SIV, depleted of CD8+ lymphocytes, and studied until eight weeks post inoculation (wpi). Seven animals received daily minocycline orally beginning at 4 wpi. Neuronal integrity was monitored in vivo by proton magnetic resonance spectroscopy and post-mortem by immunohistochemistry for synaptophysin (SYN), microtubule-associated protein 2 (MAP2), and neuronal counts. Astrogliosis and microglial activation were quantified by measuring glial fibrillary acidic protein (GFAP) and ionized calcium binding adaptor molecule 1 (IBA-1), respectively. SIV infection followed by CD8+ cell depletion induced a progressive decline in neuronal integrity evidenced by declining N-acetylaspartate/creatine (NAA/Cr), which was arrested with minocycline treatment. The recovery of this ratio was due to increases in NAA, indicating neuronal recovery, and decreases in Cr, likely reflecting downregulation of glial cell activation. SYN, MAP2, and neuronal counts were found to be higher in minocycline-treated animals compared to untreated animals while GFAP and IBA-1 expression were decreased compared to controls. CSF and plasma viral loads were lower in MN-treated animals. Conclusions/Significance: In conclusion, oral minocycline alleviates neuronal damage induced by the AIDS virus
Pathways to Injury in Chronic Pancreatitis: Decoding the Role of the High-Risk SPINK1 N34S Haplotype Using Meta-Analysis
Background: The complex interactions between recurrent trypsin-mediated pancreatic injury, alcohol-associated pancreatic injury and SPINK1 polymorphisms in chronic pancreatitis (CP) are undefined. We hypothesize that CP occurs as a result of multiple pathological mechanisms (pathways) that are initiated by different metabolic or environmental factors (etiologies) and may be influenced differentially by downstream genetic risk factors. We tested this hypothesis by evaluating the differences in effect size of the high risk SPINK1 N34S haplotype on CP from multiple etiologies after combining clinical reports of SPINK1 N34S frequency using meta-analysis. Methods and Findings: The Pubmed and the Embase databases were reviewed. We studied 24 reports of SPINK1 N34S in CP (2,421 cases, 4,857 controls) using reported etiological factors as surrogates for pathways and multiple meta-analyses to determine the differential effects of SPINK1 N34S between alcoholic and non-alcoholic etiologies. Using estimates of between-study heterogeneity, we sub-classified our 24 studies into four specific clusters. We found that SPINK1 N34S is strongly associated with CP overall (OR 11.00; 95% CI: 7.59-15.93), but the effect of SPINK1 N34S in alcoholic CP (OR 4.98, 95% CI: 3.16-7.85) was significantly smaller than in idiopathic CP (OR 14.97, 95% C.I. = 9.09-24.67) or tropical CP (OR 19.15, 95% C.I. = 8.83-41.56). Studies analyzing familial CP showed very high heterogeneity suggestive of a complex etiology with an I2 = 80.95%. Conclusion: The small effect of SPINK1 N34S in alcoholic subjects suggests that CP is driven through a different pathway that is largely trypsin-independent. The results also suggest that large effect sizes of SPINK1 N34S in small candidate gene studies in CP may be related to a mixture of multiple etiologic pathways leading to the same clinical endpoint. © 2008 Aoun MD et al
Significant Effects of Antiretroviral Therapy on Global Gene Expression in Brain Tissues of Patients with HIV-1-Associated Neurocognitive Disorders
Antiretroviral therapy (ART) has reduced morbidity and mortality in HIV-1 infection; however HIV-1-associated neurocognitive disorders (HAND) persist despite treatment. The reasons for the limited efficacy of ART in the brain are unknown. Here we used functional genomics to determine ART effectiveness in the brain and to identify molecular signatures of HAND under ART. We performed genome-wide microarray analysis using Affymetrix U133 Plus 2.0 Arrays, real-time PCR, and immunohistochemistry in brain tissues from seven treated and eight untreated HAND patients and six uninfected controls. We also determined brain virus burdens by real-time PCR. Treated and untreated HAND brains had distinct gene expression profiles with ART transcriptomes clustering with HIV-1-negative controls. The molecular disease profile of untreated HAND showed dysregulated expression of 1470 genes at p<0.05, with activation of antiviral and immune responses and suppression of synaptic transmission and neurogenesis. The overall brain transcriptome changes in these patients were independent of histological manifestation of HIV-1 encephalitis and brain virus burdens. Depending on treatment compliance, brain transcriptomes from patients on ART had 83% to 93% fewer dysregulated genes and significantly lower dysregulation of biological pathways compared to untreated patients, with particular improvement indicated for nervous system functions. However a core of about 100 genes remained similarly dysregulated in both treated and untreated patient brain tissues. These genes participate in adaptive immune responses, and in interferon, cell cycle, and myelin pathways. Fluctuations of cellular gene expression in the brain correlated in Pearson's formula analysis with plasma but not brain virus burden. Our results define for the first time an aberrant genome-wide brain transcriptome of untreated HAND and they suggest that antiretroviral treatment can be broadly effective in reducing pathophysiological changes in the brain associated with HAND. Aberrantly expressed transcripts common to untreated and treated HAND may contribute to neurocognitive changes defying ART
International genome-wide meta-analysis identifies new primary biliary cirrhosis risk loci and targetable pathogenic pathways.
Primary biliary cirrhosis (PBC) is a classical autoimmune liver disease for which effective immunomodulatory therapy is lacking. Here we perform meta-analyses of discovery data sets from genome-wide association studies of European subjects (n=2,764 cases and 10,475 controls) followed by validation genotyping in an independent cohort (n=3,716 cases and 4,261 controls). We discover and validate six previously unknown risk loci for PBC (Pcombined<5 × 10(-8)) and used pathway analysis to identify JAK-STAT/IL12/IL27 signalling and cytokine-cytokine pathways, for which relevant therapies exist
- …