448 research outputs found

    Rheological Behavior of Precursor PPV Monolayers

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    The rheological behavior of different precursor poly(p-phenylene vinylene) (prec-PPV) monolayers at the air-water interface was investigated using an interfacial stress rheometer (ISR). This device nicely reveals a transition of the precursor poly(2,5-dimethoxy-1,4 phenylene vinylene) (prec-DMePPV) monolayer from Newtonian to elastic behavior with increasing surface pressure. The transition is accompanied by an increase in the modulus. This behavior coincides with the coagulation of different 2D condensed domains as revealed by Brewster angle microscopy (BAM). However, partly converted prec-DMePPV monolayers show elastic behavior even at low surface pressures, although a sudden increase of the moduli does occur. This phenomenon is attributed to enhanced hydrophobic interactions between the conjugated moieties in the partly converted polymers. The latter also explains the stretching behavior of the partly converted prec-DMePPV upon transfer in Langmuir-Blodgett-type vertical dipping. The increase of the moduli which is observed is much more gradual in the precursor poly(2,5-dibutoxy-1,4-phenylene vinylene), prec-DBuPPV, a monolayer which is in agreement with the expected expanded state of the latter monolayer.

    Transcription analysis of apple fruit development using cDNA microarrays

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    The knowledge of the molecular mechanisms underlying fruit quality traits is fundamental to devise efficient marker-assisted selection strategies and to improve apple breeding. In this study, cDNA microarray technology was used to identify genes whose expression changes during fruit development and maturation thus potentially involved in fruit quality traits. The expression profile of 1,536 transcripts was analysed by microarray hybridisation. A total of 177 genes resulted to be differentially expressed in at least one of the developmental stages considered. Gene ontology annotation was employed to univocally describe gene function, while cluster analysis allowed grouping genes according to their expression profile. An overview of the transcriptional changes and of the metabolic pathways involved in fruit development was obtained. As expected, August and September are the two months where the largest number of differentially expressed genes was observed. In particular, 85 genes resulted to be up-regulated in September. Even though most of the differentially expressed genes are involved in primary metabolism, several other interesting functions were detected and will be presented

    To a better risk analysis and validation of E-health applications in health care and prevention

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    Bestaande methodieken voor risico-inschatting van medische hulpmiddelen worden ingehaald door de snelle opkomst en beschibaarheid van apps, serious games en online e-health applicaties. Er is gebrek aan transparantie voor eindgebruikers (consumenten, patienten, zorgprofessionals en –bemiddelaars en zorgverzekeraars) over de status, werking en effectiviteit van deze nieuwe middelen. Tegelijkertijd leiden bestaande filters voor risico-inschatting van medische hulpmiddelen voor vaak onterecht tot (te) zware validatie-eisen aan deze nieuwe middelen, wat hun mogelijke bijdrage aan betere en betaalbare zorg voor de patiĂ«nt belemmert. Ook werpt het barriĂšres op voor nieuwe ondernemende toetreders tot de zorgmarkt en hun innovatieve ideeĂ«n. Van groot belang bij een verbeterd systeem is een zo kort mogelijke doorlooptijd van deze vorm van kwaliteitszorg gezien de snelheid van technologische ontwikkelingen in zowel de technische platformen als de daarop draaiende applicaties (critical time-to-market) zodat producten niet hun waarde verliezen voor ze op de markt hebben kunnen komen

    Grondprijskaarten 1998-2008

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    Dit rapport is onderdeel van het project ‘Actualisatie Grondprijs- en Eigendomskaart’. Het geeft grondprijskaarten voor de jaren 1998, 2000, 2002, 2004, 2006 en 2008 weer. Daarnaast geeft het rapport inzicht in de grondmobiliteit (per grondmarktsegment) alsmede in de lange termijnontwikkeling van de grondprijs

    Matrix theory of gravitation

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    A new classical theory of gravitation within the framework of general relativity is presented. It is based on a matrix formulation of four-dimensional Riemann-spaces and uses no artificial fields or adjustable parameters. The geometrical stress-energy tensor is derived from a matrix-trace Lagrangian, which is not equivalent to the curvature scalar R. To enable a direct comparison with the Einstein-theory a tetrad formalism is utilized, which shows similarities to teleparallel gravitation theories, but uses complex tetrads. Matrix theory might solve a 27-year-old, fundamental problem of those theories (sec. 4.1). For the standard test cases (PPN scheme, Schwarzschild-solution) no differences to the Einstein-theory are found. However, the matrix theory exhibits novel, interesting vacuum solutions.Comment: 24 page

    Awake craniotomy versus craniotomy under general anesthesia for the surgical treatment of insular glioma: choices and outcomes

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    Objective: To investigate differences in outcomes in patients who underwent surgery for insular glioma using an awake craniotomy (AC) vs. a craniotomy under general anesthesia (GA). Methods: Data from patients treated at our hospital between 2005 and 2015 were analyzed retrospectively. The preoperative, intraoperative, postoperative, and longer term follow-up characteristics and outcomes of patients who underwent surgery for primary insular glioma using either an AC or GA were compared. Results: Of the 52 identified patients, 24 had surgery using an AC and 28 had surgery under GA. The extent of resection was similar for the two anesthesia techniques: the median extent of resection was 61.4% (IQR: 37.8–74.3%) in the WHO grade <4 AC group vs. 50.5% (IQR: 35.0–71.2%) in the grade <4 GA group and 73.4

    Contemporary frameless intracranial biopsy techniques: Might variation in safety and efficacy be expected?

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    Background: Frameless stereotactic neuronavigation has proven to be a feasible technology to acquire brain biopsies with good accuracy and little morbidity and mortality. New systems are constantly i

    Monitoringsystemen voor plattelandsontwikkeling; Een actueel overzicht

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    Met 17 monitoringsystemen kunnen beleidsmakers, onderzoekers en anderen alle belangrijke thema's in het EU-plattelandsbeleid langjarig en goed onderbouwd volgen. Deze systemen leveren ook een grote bijdrage aan de invulling van de context-, resultaat- en impact-indicatoren die de Europese Commissie vraagt voor haar rapportage op het gebied van beleidsplanning, -monitoring en -evaluatie. Dit rapport bevat een actueel overzicht van alle bestaande en nieuw ontwikkelde monitoringsystemen rond de thema's en indicatoren die voor plattelandsontwikkeling relevant zijn

    Long-term follow-up of retrograde colonic irrigation for defaecation disturbances

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    Objective. Irrigation of the distal part of the large bowel is a nonsurgical alternative for patients with defaecation disturbance. In our institution, all patients with defaecation disturbances, not responding to medical treatment and biofeedback therapy, were offered retrograde colonic irrigation (RCI). This study is aimed at evaluating the long-term feasibility and outcome of RCI. Methods. Between 1989 and 2001, a consecutive series of 267 patients was offered RCI. All patients received instructions about RCI by one of our enterostomal therapists. Twenty-eight patients were lost to follow-up. A detailed questionnaire was sent by mail to 239 patients. The total response rate was 79% (190 patients). Based on the returned questionnaires it became clear the 21 (11%) patients never started RCI. The long-term feasibility and outcome of RCI was therefore assessed in the remaining group of 169 patients. Thirty-two patients were admitted with soiling, 71 patints with faecal incontinence, 37 patients with obstructed defaecation and 29 had defaecation disturbance after low anterior resection or pouch surgery. Results. According to the returned questionnaires, RCI was considered effective by 91 (54%) patients. Among patients with soling and faecal incontinence, RCI was found to be effective in, respectively, 47 and 41% of the subjects. Despite of the reported effectiveness, 10 (67%) patients with soiling and 5 (17%) patients with faecal incontinence decide to stop. Among patients with obstructed defaecation and those with defaecation disturbances after low anterior resection or pouch surgery the effectiveness of RCI was found to be 65 and 79%, respectively. None of these patients ceased their therapy. The overall succes-rate of long-term RCI was therefore 45%. Conclusions. Long-term RCI is beneficial for 45% of patients with defaecation disturbance. In the group of patients who considered RCI effective and beneficial, discontinuation of therapy was only observe among those with soiling and faecal incontinence
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