401 research outputs found
Customer Rosa Driever at teller window in Muenster State Bank
No full textPhotograph shows teller J. M. Wemzaysfel (left) helping Rosa Driever as bank president John W. Meurer stands nearby
ANALYSIS AND SELECTIVE TARGETING OF PANCREATIC BETA CELL REPLICATION BY GENERATION OF A TRANSGENIC ZEBRAFISH EXPRESSING THYMIDINE KINASE-GFP UNDER THE INSULIN PROMOTER
No full textPancreas development in zebrafish: early dispersed appearance of endocrine hormone expressing cells and their convergence to form the definitive islet.
No full textpeer reviewedTo begin to understand pancreas development and the control of endocrine lineage formation in zebrafish, we have examined the expression pattern of several genes shown to act in vertebrate pancreatic development: pdx-1, insulin (W. M. Milewski et al., 1998, Endocrinology 139, 1440-1449), glucagon, somatostatin (F. Argenton et al., 1999, Mech. Dev. 87, 217-221), islet-1 (Korzh et al., 1993, Development 118, 417-425), nkx2.2 (Barth and Wilson, 1995, Development 121, 1755-1768), and pax6.2 (Nornes et al., 1998, Mech. Dev. 77, 185-196). To determine the spatial relationship between the exocrine and the endocrine compartments, we have cloned the zebrafish trypsin gene, a digestive enzyme expressed in differentiated pancreatic exocrine cells. We found expression of all these genes in the developing pancreas throughout organogenesis. Endocrine cells first appear in a scattered fashion in two bilateral rows close to the midline during mid-somitogenesis and converge during late-somitogenesis to form a single islet dorsal to the nascent duodenum. We have examined development of the endocrine lineage in a number of previously described zebrafish mutations. Deletion of chordamesoderm in floating head (Xnot homolog) mutants reduces islet formation to small remnants, but does not delete the pancreas, indicating that notochord is involved in proper pancreas development, but not required for differentiation of pancreatic cell fates. In the absence of knypek gene function, which is involved in convergence movements, the bilateral endocrine primordia do not merge. Presence of trunk paraxial mesoderm also appears to be instrumental for convergence since the bilateral endocrine primordia do not merge in spadetail mutants. We discuss our findings on zebrafish pancreatogenesis in the light of evolution of the pancreas in chordates
Functional Architecture of an Optic Flow-Responsive Area that Drives Horizontal Eye Movements in Zebrafish
No full textSummaryAnimals respond to whole-field visual motion with compensatory eye and body movements in order to stabilize both their gaze and position with respect to their surroundings. In zebrafish, rotational stimuli need to be distinguished from translational stimuli to drive the optokinetic and the optomotor responses, respectively. Here, we systematically characterize the neural circuits responsible for these operations using a combination of optogenetic manipulation and in vivo calcium imaging during optic flow stimulation. By recording the activity of thousands of neurons within the area pretectalis (APT), we find four bilateral pairs of clusters that process horizontal whole-field motion and functionally classify eleven prominent neuron types with highly selective response profiles. APT neurons are prevalently direction selective, either monocularly or binocularly driven, and hierarchically organized to distinguish between rotational and translational optic flow. Our data predict a wiring diagram of a neural circuit tailored to drive behavior that compensates for self-motion
A comprehensive analysis of olig genes expression, regulation and function in zebrafish CNS development.
No full textDistinct delta and jagged genes control sequential segregation of pancreatic cell types from precursor pools in zebrafish
No full textThe different cell types of the vertebrate pancreas arise asynchronously during organogenesis. Beta-cells producing insulin, alpha-cells producing glucagon, and exocrine cells secreting digestive enzymes differentiate sequentially from a common primordium. Notch signaling has been shown to be a major mechanism controlling these cell-fate choices. So far, the pleiotropy of Delta and Jagged/Serrate genes has hindered the evaluation of the roles of specific Notch ligands, as the phenotypes of knock-out mice are lethal before complete pancreas differentiation. Analyses of gene expression and experimental manipulations of zebrafish embryos allowed us to determine individual contributions of Notch ligands to pancreas development. We have found that temporally distinct phases of both endocrine and exocrine cell type specification are controlled by different delta and jagged genes. Specifically, deltaA knock-down embryos lack alpha cells, similarly to mib (Delta ubiquitin ligase) mutants and embryos treated with DAPT, a gamma secretase inhibitor able to block Notch signaling. Conversely, jagged1b morphants develop an excess of alpha-cells. Moreover, the pancreas of jagged2 knock-down embryos has a decreased ratio of exocrine-to-endocrine compartments. Finally, overexpression of Notch1a-intracellular-domain in the whole pancreas primordium or specifically in beta-cells helped us to refine a model of pancreas differentiation in which cells exit the precursor state at defined stages to form the pancreatic cell lineages, and, by a feedback mediated by different Notch ligands, limit the number of other cells that can leave the precursor state
Warmteintegratie van een BTX hydrogenerings- en ontzwavelingsinstallatie
No full textDocument uit de collectie Chemische ProcestechnologieDelftChemTechApplied Science
Moleculaire Dynamica
No full textDe huidige vloeistof-damp evenwichts berekeningen van een binair systeem voldoen goed zolang de componenten niet te veel in grootte verschillen. Worden de verschillen van de beide componenten groter, dan kunnen de berekeningen, met behulp van binaire interactie-parameters, binnen een redelijke nauwkeurigheid gebracht warden. In een systeem als methaan-decaan aan bij de berekeningen grote verschillen optreden. Bij deze berekeningen wordt meestal uitgegaan van een van der Waals achtige toestandsvergelijking. Deze vergelijkingen gaan echter in principe uit van moleculen die bolvormig zijn. In het geval van het mengsel methaan-decaan kan voor decaan daarvan geen sprake zijn. Dit is een van de redenen waarom deze methode voor dit soort systemen niet voldoende nauwkeurig is. Ontwikkelingen op het gebied van de toestandsvergelijkingen vinden op drie gebieden plaats: - Simulatie techniek. - Storingstechniek (Perturbation theorie.) - Integraal vergelijkingen. De Moleculaire Dynamica (MD) is een simulatie techniek, die uitgaande van een interactiepotentiaal de snelheden, posities en richtingen van elk individueel molecuul berekent. Hieruit kunnen statistisch temperatuur, druk en mol.volume worden afgeleid. Het doel van deze scriptie is een overzicht te geven op welke wijze Moleculaire Dynamica kan bijdragen tot het berekenen van vloeistofdamp evenwichten.Applied SciencesScheikundige Technologi
Driever, Bernard (Death, 1877-08-14)
No full textAddress: St. Mary's HospitalAge at death: 35 yrsPg 48/1877/211/M W WR/Germany/Dr. Wenning/Ackerman/St. Joseph's OldOriginal record filed in drawer labeled 'DRAH-DUGAN'
Improving the reproducibility of BOLD rs-fMRI signal by selective data elimination
No full textConnectivity mapping with resting state functional magnetic resonance imaging (rs-fMRI) is rapidly developing and has shown great promise for clinical applications. Before successful implementation in clinical setting, it is key to evaluate the long-term reproducibility of the functional connectivity profiles. To this end, the reproducibility of rs-fMRI data is studied in this work. The main research question revolves around the improvement of the overall reproducibility by selectively omitting single components (either nodes or elements) from BOLD rs-fMRI connectivity matrices (CM’s). The scans of the subjects are parcellated using four different schemes, which are all analysed throughout this work. A reproducibility study is carried out on a dataset of 37 subjects that are scanned twice within 2 weeks on average. The inter-subject intraclass correlation coefficient (ICC) is used to quantify component reproducibility within the dataset. An algorithm is designed to quantify which component has the lowest inter-subject ICC, which is then eliminated from all CM’s in the dataset. After every single component elimination, the intra-subject ICC is computed for every subject to quantify the reproducibility, and a matching accuracy (MA) test is performed on the set to quantify the distinctive power of the CM’s.The order in which components are eliminated and its effect on the overall reproducibility is tested by applying this to a larger test set of longitudinal data. To this end, a dataset of 521 subjects is used to quantify the reproducibility of the CM’s after iteratively removing components in the order that is found in the reproducibility study. This larger dataset of 521 subjects is analysed, along with 4 subsets, namely: sex based, age based, interscan time based and based on the grounds for exclusion. The latter is a subset where the quality of the rs-fMRI scans could not be assured due to pathologies or excessive motion during image acquisition. No significant difference is found within the sex-based subsets, and no relation between the reproducibility and the interscan time (within the range that is assessed in this work, namely 5 years) is found. Significantly lower intra-subject ICC’s are found for the subjects whose scan quality was subpar, due to excessive motion or pathology. For the age-based subset analysis, it is reported that reproducibility decreases with age.The node removal algorithm clearly outperforms the element removal algorithm when looking at the intra-subject ICC. As the element removal algorithm can increase the intra-subject ICC by roughly 0.1, whereas the node removal algorithm manages to increase the intra-subject ICC of roughly 0.3. The MA, which is used as to quantify the distinguishing power between various CM’s, is seen to increase from 82.4% to the maximum of 98.7% correctly matched subjects for the RSS100 parcellation scheme within the reproducibility study. Aside from the element removal within the reproducibility study, the matching accuracy is not improved for any of the other analyses. The component elimination algorithm can increase the intra-subject ICC’s of the subjects of the longitudinal set. The MA is not found to increase with the component elimination algorithm
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