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Milton Keynes, United Kingdom

Huusom J.K.,DK | Poulsen N.K.,Technical University of Denmark | Jorgensen S.B.,DK
Brazilian Journal of Chemical Engineering

Iterative Feedback Tuning is a purely data driven tuning algorithm for optimizing control parameters based on closed loop data. The algorithm is designed to produce an unbiased estimate of the performance cost function gradient for iteratively improving the control parameters to achieve optimal loop performance. This tuning method has been developed for systems based on a transfer function representation. This paper presents a state feedback control system with a state observer and its transfer function equivalent in terms of input output dynamics. It is shown how the parameters in the closed loop state space system can be tuned by Iterative Feedback Tuning utilizing this equivalent representation. A simulation example illustrates that the tuning converges to the known analytical solution for the feedback control gain and to the Kalman gain in the state observer. In case of parametric uncertainty, different choices of tuning parameters are investigated. It is shown that the data driven tuning method produces optimal performance for convex problems when it is the model parameter estimates in the observer that are tuned. Source

Sand A.,Bioinformatics Research Center | Holt M.K.,DK | Johansen J.,DK | Brodal G.S.,DK | And 3 more authors.

TqDist is a software package for computing the triplet and quartet distances between general rooted or unrooted trees, respectively. The program is based on algorithms with running time for the triplet distance calculation and for the quartet distance calculation, where n is the number of leaves in the trees and d is the degree of the tree with minimum degree. These are currently the fastest algorithms both in theory and in practice. © 2014 The Author 2014. Source

Wustner D.,DK | Landt Larsen A.,DK | Faergeman N.J.,DK | Brewer J.R.,University of Southern Denmark | Sage D.,Ecole Polytechnique Federale de Lausanne

The nematode Caenorhabditis elegans is a genetically tractable model organism to investigate sterol transport. In vivo imaging of the fluorescent sterol, dehydroergosterol (DHE), is challenged by C. elegans' high autofluorescence in the same spectral region as emission of DHE. We present a method to detect DHE selectively, based on its rapid bleaching kinetics compared to cellular autofluorescence. Worms were repeatedly imaged on an ultraviolet-sensitive wide field (UV-WF) microscope, and bleaching kinetics of DHE were fitted on a pixel-basis to mathematical models describing the intensity decay. Bleach-rate constants were determined for DHE in vivo and confirmed in model membranes. Using this method, we could detect enrichment of DHE in specific tissues like the nerve ring, the spermateca and oocytes. We confirm these results in C. elegans gut-granule-loss (glo) mutants with reduced autofluorescence and compare our method with three-photon excitation microscopy of sterol in selected tissues. Bleach-rate-based UV-WF imaging is a useful tool for genetic screening experiments on sterol transport, as exemplified by RNA interference against the rme-2 gene coding for the yolk receptor and for worm homologues of Niemann-Pick C disease proteins. Our approach is generally useful for identifying fluorescent probes in the presence of high cellular autofluorescence. © 2010 John Wiley & Sons A/S. Source

Akiyama S.,DK | Kikuchi D.,DK | Mitani T.,DK | Fujii T.,DK | And 6 more authors.

Mucinous adenocarcinoma (MC) is a unique pathological type of colorectal cancer (CRC). The development of MC is often associated with intestinal inflammation and/or microsatellite instability (MSI). Moreover, MC has clinicopathological characteristics that render making the correct diagnosis difficult such as extramural progression. Meanwhile, intestinal spirochetosis (IS) is a condition in which colonic epithelial cells are colonized and/or infected by spirochetes. Intestinal inflammation due to IS occurs by the destruction of colonic microvilli and induces chronic diarrhea. Recently, it was reported that the prevalence of IS tended to be high in patients with sessile serrated adenomas/polyps, the precursor of MSI-high CRC including MC. This study presents a case of MC in the setting of intestinal inflammation due to IS and tries to clarify the cause of MC development by performing immunohistochemical stain of resected specimen for DNA mismatch repair (MMR) proteins. This patient is a 63-year-old man with no symptoms who had a positive fecal occult blood test. Subsequent endoscopic findings and biopsy results revealed intestinal stricture of the transverse colon and chronic infective colitis associated with IS. Metronidazole therapy was initiated but was not effective. Although follow-up colonoscopy was performed repeatedly, intestinal perforation occurred 20 months later. Subtotal colectomy and ileostomy were performed. Pathological examination of resected specimens revealed MC with normal expression of MMR proteins, including MLH1, MSH2, MSH6, and PMS2. The histopathological classification was Union for International Cancer Control (UICC) IIIB and adjuvant chemotherapy was initiated. This is an interesting case of MC developing in the setting of chronic colitis associated with IS. It seemed that the cause of MC development was not MSI but intestinal inflammation. Besides, endoscopic diagnosis of MC in this case was difficult because of the extramural progression and lack of obvious atypical colonic glands in biopsy specimens. This report provides evidence for an association between neoplasm and IS-induced intestinal inflammation. Moreover, we suggest that making the diagnosis of MC could be difficult because of its unique clinicopathological characteristics. Source

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