279 research outputs found
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
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
Een voortgezet onderzoek naar een on-line voertuigklassifikatie met behulp van een PDP-11 minicomputer en twee lusdetektoren per rijstrook
No full textEen systeem voor on-line voertuigklassifikatie, dat gebruik maakt van een PDP-11 minicomputer en twee lusdetektoren per rijstrook, is verbeterd. Bij dit systeem wordt de klasse bepaald door de lengte van het voertuig en de vorm van de "handtekening". De handtekening wordt bemonsterd en genormeerd op snelheid. Daarna wordt afhankelijk van de lengte een vormfaktor berekend. De kombinatie van lengte en vormfaktor deelt de auto in bij éên van de vijf gebruikte klassen.Electrical Engineering, Mathematics and Computer ScienceAutomatische Verkeerssysteme
An International Expert Consensus Survey for A Treatment Versus Observation Strategy of Newly Diagnosed Patients with NF1 Associated Optic Pathway Glioma
No full textBackground/Objectives: Optic pathway glioma (OPG) develop in 15-20% of children with neurofibromatosis type 1 (NF-1), threatening vision loss but not survival. There is no consensus about the most appropriate strategy for selecting newly diagnosed patients with NF-1 for treatment or observation.
Design/Methods: 25 representative case scenarios, derived from a risk-adapted matrix of newly diagnosed children with NF-1 OPG, previously entered the SIOP LGG 2004 trial, were used for a strategy selection consensus survey. The respondents were 98 multi-disciplinary specialists for the first survey (10 cases) and 46 for the second survey (15 cases) from an international multi-professional expert group. Respondents
selected cases for initial observation (O) initial treatment (T) or randomisation between the two (R), justifying their selection with free text comments. A qualitative analysis of the free text comments describing reasoning was carried out by two reviewers and a mediator, following the grounded theory approach, allocating reasons to 8 themes, developed inductively.
Results: Greater than 70% agreement between survey respondents occurred for initial observation in 4/25 cases, initial treatment in 10/25 cases, less than 70% consensus occurred in 11/25 cases. The associated 808 free text comments justifying selection for O: 173; T: 426 and R: 209 were allocated by 2 reviewers to 8 themes (agreement; k: 0.762). Consensus selection for: observation was justified by risk of progression
(39%) and visual function (33%); for treatment by visual function (39%); for randomization by visual function (31%), risk of progression (22%), site/dimension of tumour (15%) and age and gender (12%).
Conclusions: This survey and its qualitative analysis identifies a new consensus of justified criteria for initial observation versus treatment, in 11/25 scenarios no consensus was reached. These criteria are proposed as eligibility criteria for future trials where a randomised trial of indications for initial management could be included.
on behalf of the SIOPE NF-1 OPG Nottingham, UK, Workshop (Participating centers: Berlin, Copenhagen, GOS, Hamburg, Leeds, Nottingham, Padua, Paris, Vienna
Expression of the zebrafish intermediate neurofilament Nestin in the developing nervous system and in neural proliferation zones at postembryonic stages-2
No full text<p><b>Copyright information:</b></p><p>Taken from "Expression of the zebrafish intermediate neurofilament Nestin in the developing nervous system and in neural proliferation zones at postembryonic stages"</p><p>http://www.biomedcentral.com/1471-213X/7/89</p><p>BMC Developmental Biology 2007;7():89-89.</p><p>Published online 25 Jul 2007</p><p>PMCID:PMC1950091.</p><p></p> and in the spinal cord reveals expression in major proliferative zones The relative rostrocaudal levels of each section are indicated in T and U. (A-I): sections at levels of forebrain and midbrain as well as midbrain-hindbrain boundary. (J-Q): sections at the level of HB and SC, showing expression in the cranial ganglia and the HB, MO, SC. (R): cross section through the eye of a 4 dpf embryo, is expressed in the CMZ; (S): cross section of a 4 dpf embryo at the level of the ethmoid plate, is expressed in the craniofacial mesenchyme adjacent to developing cartilage tissue. (T, U): scheme of a 2 dpf (T) and a 4 dpf (U) zebrafish embryo, the levels of the cross sections shown in A-S are indicated by blue lines. Ad: Aorta dorsalis; ALLG: anterior lateral line ganglion; CeP: cerebellar plate; Ch: chorda dorsalis; cm: craniofacial mesenchyme; CMZ: ciliary marginal zone; DiV: diencephalic ventricle; DT: dorsal thalamus; eg: enteric ganglia; eth: ethmoid plate; FG: facial ganglion; FP: Floor plate; g: gut; Ha: habenula; Hc: caudal hypothalamus; Hi: intermediate hypothalamus; hm: head mesenchyme; MHB: midbrain hindbrain boundary; MO: medulla oblongata; OC: otic capsule; OE: olfactory epithelium; OG: octaval ganglion; pc: parachordal cartilage; pq: palatoquadrate; Po: preoptic region; Pr: pretectum; PTv: ventral part of the posterior tuberculum; S: subpallium; SC: spinal cord; som: somites; T: midbrain tegmentum; TeO: optic tectum; TG: trigeminal ganglion; TS: torus semicircularis; VG: vagal ganglion. Scale bars: 100 μm
Switch Stand.
No full textPatent for a switch-stand for railroads with a vertically movable crank bar that is easily locked into position and a cam lever. The invention is operated more easily than other switch-stands
c-myc expression in medulloblastoma and its prognostic value
No full textTo identify prognostic factors in medulloblastoma, a common malignant brain tumor of childhood, expression of the oncogene c-myc was examined at the mRNA level by in situ hybridization. c-myc mRNA expression was observed in 30 of 72 tumors (42%), The c-myc gene copy number was determined by quantitative PCR from genomic DNA of paraffin-embedded tumors. c-myc gene amplification was present in 5 of 62 cases (8.3%), Therefore, c-myc amplification was obviously not the cause of c-myc mRNA expression in most samples, Kaplan-Meier estimation revealed a significant correlation between c-myc mRNA expression and survival (total mean follow-up 4.6 +/- 3.6 years, log-rank p = 0.02), Multivariate logistic regression analysis including sex, age, histological type, degree of surgical resection and expression of synaptophysin, GFAP and c-myc, was carried out on 54 patients who received both radiotherapy and chemotherapy. The analysis identified expression of c-myc as an independent predictive factor of death from disease. (C) 2000 Wiley-Liss, Inc
Cug2 is essential for normal mitotic control and CNS development in zebrafish.
No full textBackground:
We recently identified a novel oncogene, Cancer-upregulated gene 2 (CUG2), which is essential for kinetochore formation and promotes tumorigenesis in mammalian cells. However, the in vivo function of CUG2 has not been studied in animal models.
Results:
To study the function of CUG2 in vivo, we isolated a zebrafish homologue that is expressed specifically in the proliferating cells of the central nervous system (CNS). Morpholino-mediated knockdown of cug2 resulted in apoptosis throughout the CNS and the development of neurodegenerative phenotypes. In addition, cug2-deficient embryos contained mitotically arrested cells displaying abnormal spindle formation and chromosome misalignment in the neural plate.
Conclusions:
Therefore, our findings suggest that Cug2 is required for normal mitosis during early neurogenesis and has functions in neuronal cell maintenance, thus demonstrating that the cug2 deficient embryos may provide a model system for human neurodegenerative disorders
DEVELOPING RISK-BASED SELECTION CRITERIA FOR THE NEXT SIOP TRIAL OF "SIGHT-SAVING THERAPY" FOR CHILDREN WITH NF1-ASSOCIATED VISUAL PATHWAY GLIOMA (NF1-VPG) - A QUALITATIVE ANALYSIS OF A CONSENSUS SURVEY
No full textIntroduction
A consensus survey involving 98 multi-disciplinary specialists for the first survey (10 cases) and 46 for the second survey (15 cases) in SIOP-E brain tumour group, European NF1 society and the Optic Pathway Glioma Working Group in North America were asked to identify case-based criteria for primary observation, treatment or randomisation in 25 representative, newly diagnosed, NF1-VPG childhood cases which had been the subject of a consensus workshop as part of the SIOP-LGG 2004 trial. Respondents provided justifying statements for their selection of preferred strategy which are the focus for this report
Methods
Qualitative analysis following grounded theory, using the comparative method categorized 808 comments to: 173 for primary observation, 426 for primary treatment and 209 for primary randomization. These were grouped into 8 themes by two reviewers and compared with the kappa statistic. The themes were: 1) risk of progression, 2) visual function, 3) age and sex, 4) site/dimension of tumour, 5) other symptoms, 6) inconclusive comments, 7) equipoise and 8) parental consent. The themes were analysed by strategy selected for each case.
Result
Good agreement was achieved for theme allocation between reviewers (k: 0.762). Comments selected for observation were supported by responses categorised as: unknown risk of progression (32%), good vision function (25%); for treatment as poor vision and intention to preserve-improve vision (38%); for randomization as unknown risk of progression (15%), tumour site/dimension (13%) and stable vision (12%).
Conclusion
This survey and its qualitative analysis identified sufficient uncertainty to propose a randomised trial design for observation versus treatment in a subgroup of newly diagnosed NF1-VPG. A pilot cohort with vision assessment date, site of tumour and age is needed to conduct a power calculation to design a future international randomised trial to study risk of progression and response to new treatments. Collaborations would be welcome
- …
