2015 researcher's mini-symposium

Postgraduate researchers from the Faculties of Science, Engineering, Medicine & Surgery and Health Sciences gathered for a forum to present their research interests. The symposium was held in the afternoon of 30 January 2015 in the Engineering Lecture Theatre. The symposium promoted multi-disciplinary networking between various university faculties. Participants were invited based on research topic diversity and gender balance.peer-reviewe

Sin nombre virus glycoprotein trafficking

AbstractSin Nombre virus (SNV) is a major representative of the New World hantaviruses and the most common cause of hantavirus pulmonary syndrome (HPS) with high mortality in North America. Unlike other members of the family Bunyaviridae which mature in the Golgi complex, New World hantaviruses have been previously reported to mature at the cell surface. For family Bunyaviridae viruses, retention of the viral glycoproteins at the Golgi complex is thought to be responsible for their Golgi maturation. In our studies, the majority of SNV glycoproteins, G1 and G2, was localized in the Golgi complex when expressed from a full-length GPC clone or in SNV-infected cells, in agreement with data for other members of the family Bunyaviridae, including the Old World hantaviruses. However, the SNV glycoproteins could also be detected at the cell surface at advanced posttransfection or postinfection time points. G1 expressed in the absence of G2 did not accumulate in the Golgi, but remained predominantly associated with the endoplasmic reticulum (ER). Overexpressed amounts of apparently misfolded G1 were aggregated in a subcellular compartment likely to represent the aggresome. Unexpectedly, an additional major pool of G1 was detected intracellularly in SNV-infected and GPC-expressing transfected cells, by using a SNV G1-specific Fab antibody. This pool of G1 is predominantly localized in late endosomes–lysosomes

Observation of audio-frequency edge magnetoplasmons in the classical two-dimensional electron gas

The electric admittance of a two-dimensional electron gas on liquid helium measured at audio frequencies ¿ is observed to oscillate as a function of magnetic field at strong magnetic fields. The oscillations can be attributed to the propagation of very-low-frequency (¿t~10-6, t scattering time; ¿/¿c~10-8, ¿c cyclotron frequency) edge magnetoplasmons. The directly determined dispersion relation agrees with theory and quantitatively with measurements in the collisionless regime (¿t»1). The attenuation, theoretically obtained by incorporating the screening in a simple local-capacitance model, agrees well with experiments

Eenvoudige elleboogluxaties in Nederland: Wat doen Nederlandse chirurgen?

Abstract: Er is weinig evidence voor de optimale behandeling van eenvoudige elleboogluxaties. Hoewel er aanwijzingen zijn dat eenvoudige elleboogluxaties niet te lang moeten worden geïmmobiliseerd en functioneel kunnen worden nabehandeld. Om een overzicht te krijgen over hoe eenvoudige elleboogluxaties in Nederland worden behandeld, verrichtten wij een enquête onder leden van de Nederlandse Vereniging van Traumatologie. Alle leden ontvingen een e-mail met het verzoek om een digitale vragenlijst over de behandeling van elleboogluxaties in te vullen. Het response percentage was 17% (n=90). Vijfendertig (39%) chirurgen verbinden geen consequenties aan stabiliteitsonderzoek van de elleboog na repositie. Drieënzestig procent van deze chirurgen behandelt de patiënten met een gipsverband gedurende gemiddeld 3.4 weken. Bij 55 (61%) van de 90 respondenten beïnvloed het stabiliteitsonderzoek wel de vorm van behandeling. Bij een stabiel gewricht wordt in ongeveer 64% van de gevallen een functionele behandeling voorgeschreven en bij een instabiel gewricht behandelen 24% van de respondenten functioneel met een functionele fixateur. De resultaten van de enquête onder Nederlandse chirurgen laat zien, dat de meeste ondervraagden immobilisatie verkiezen boven functionele behandelingAbstract Background: Randomised controlled trials and observational comparative studies show little proof for the optimal form of treatment for simple elbow dislocations. However, there is some evidence that functional treatment in simple elbow dislocations may lead to better functional outcome. To get an overview of how simple elbow dislocations are treated in the Netherlands we performed a survey among Dutch surgeons. Methods: All members of the Dutch Society of Traumatology received an e-mail with the request to fill out an electronic questionnaire. Results: The response rate was 17% (n=90) . Thirty vive (39%) of them stated that stability testing after reposition of the joint did not influence subsequent form of treatment. Sixty three percent of them treated patients with a above the elbow cast for a mean of 3.4 weeks. Fifty five (61%) responders used stability testing as a guide for treatment. joint is stable after reposition. In the case of a stabile joint 64% of these surgeons treat patients with functional treatment. When there is joint instability 24% prefer functional treatment with a hinged external fixator. Conclusion: The results of this inquiry among Dutch surgeons showed that the majority of simple elbow dislocations are treated with immobilisation and that functional treatment is not widespread

Iris Yellow Spot Virus in the Netherlands: Occurence in Onion and Confirmation of Transmission by Thrips tabaci

Since its first detection in the Netherlands in 1992, Iris yellow spot virus (IYSV, genus Tospovirus) has been reported worldwide in Allium crops, in a few ornamentals and in a small number of weeds. After recent findings of IYSV in Alstroemeria and Eustoma in the Netherlands, a number of neighbouring onion fields were surveyed. In 2005 and 2006, only few infected plants were found with obvious symptoms of IYSV. In 2007, after sampling and testing small leaf samples with various types of damage, including small brown-yellow colored spots and spots with thrips feeding damage, a high percentage of plants were found with positive IYSV scores in ELISA. Infection by IYSV could be confirmed in most ELISA-positive samples by RT-PCR. Under laboratory conditions, evidence was obtained that Thrips tabaci acts as a vector for this virus. Acquisition of the IYSV from infected Datura stramonium plants resulted in virus uptake and replication in over 60% of the thrips exposed, as determined by Western blotting and immunolocalisation of the virus in the foregut, and in epithelial and midgut muscle cells using antibodies against both the viral N and NSs proteins. Successful transmission of IYSV to seedlings of Emilia sonchifolia was observed, however, only at low frequency under the laboratory conditions used

Observation of novel edge excitations of a two-dimensional electron liquid on helium in a magnetic field

Low-frequency edge excitations in a magnetic field of the two-dimensional electron system on liquid helium are studied. It is found that, in addition to the conventional edge magnetoplasma resonances, novel resonances of smaller amplitude appear at lower frequencies at

Operative Treatment of Intra-Articular Distal Radius Fractures With versus Without Arthroscopy

__Background:__ In the past several years, an increase in open reduction and internal fixation (ORIF) for intra-articular distal radius fractures has been observed. This technique leads to a quicker recovery of function compared to non-operative treatment. However, some patients continue to have a painful and stiff wrist postoperatively. Arthroscopically assisted removal of intra-articular fracture haematoma and debris may improve the functional outcomes following operative treatment of intra-articular distal radius fractures. The purpose of this randomised controlled trial is to determine the difference in functional outcome, assessed with the Patient-Rated Wrist Evaluation (PRWE) score, after ORIF with and without an additional wrist arthroscopy in adult patients with displaced complete articular distal radius fractures. __Methods:__ In this multicentre trial, adult patients with a displaced complete articular distal radius fracture are randomised between ORIF with an additional wrist arthroscopy to remove fracture haematoma and debris (intervention group) and conventional fluoroscopic-assisted ORIF (control group). The primary outcome is functional outcome assessed with the PRWE score after three months. Secondary outcomes are wrist function assessed with the Disability of the Arm, Shoulder and Hand (DASH) score, postoperative pain, range of motion, grip strength, complications and cost-effectiveness. Additionally, in the intervention group, the quality of reduction, associated ligamentous injuries and cartilage damage will be assessed. A total of 50 patients will be included in this study. __Discussion:___ Although ORIF of intra-articular distal radi

Reanalysis of two eclipsing binaries: EE Aqr and Z Vul

We study the radial-velocity and light curves of the two eclipsing binaries EE Aqr and Z Vul. Using the latest version of the Wilson & Van Hamme (2003) model, absolute parameters for the systems are determined. We find that EE Aqr and Z Vul are near-contact and semi-detached systems, respectively. The primary component of EE Aqr fills about 96% of its 'Roche lobe', while its secondary one appears close to completely filling this limiting volume. In a similar way, we find fill-out proportions of about 72 and 100% of these volumes for the primary and secondary components of Z Vul respectively. We compare our results with those of previous authors.Comment: 13 pages, 8 figures, 10 table

Pulsar timing arrays and the challenge of massive black hole binary astrophysics

Pulsar timing arrays (PTAs) are designed to detect gravitational waves (GWs) at nHz frequencies. The expected dominant signal is given by the superposition of all waves emitted by the cosmological population of supermassive black hole (SMBH) binaries. Such superposition creates an incoherent stochastic background, on top of which particularly bright or nearby sources might be individually resolved. In this contribution I describe the properties of the expected GW signal, highlighting its dependence on the overall binary population, the relation between SMBHs and their hosts, and their coupling with the stellar and gaseous environment. I describe the status of current PTA efforts, and prospect of future detection and SMBH binary astrophysics.Comment: 18 pages, 4 figures. To appear in the Proceedings of the 2014 Sant Cugat Forum on Astrophysics. Astrophysics and Space Science Proceedings, ed. C.Sopuerta (Berlin: Springer-Verlag

Pulsar Timing and its Application for Navigation and Gravitational Wave Detection

Pulsars are natural cosmic clocks. On long timescales they rival the precision of terrestrial atomic clocks. Using a technique called pulsar timing, the exact measurement of pulse arrival times allows a number of applications, ranging from testing theories of gravity to detecting gravitational waves. Also an external reference system suitable for autonomous space navigation can be defined by pulsars, using them as natural navigation beacons, not unlike the use of GPS satellites for navigation on Earth. By comparing pulse arrival times measured on-board a spacecraft with predicted pulse arrivals at a reference location (e.g. the solar system barycenter), the spacecraft position can be determined autonomously and with high accuracy everywhere in the solar system and beyond. We describe the unique properties of pulsars that suggest that such a navigation system will certainly have its application in future astronautics. We also describe the on-going experiments to use the clock-like nature of pulsars to "construct" a galactic-sized gravitational wave detector for low-frequency (f_GW ~1E-9 - 1E-7 Hz) gravitational waves. We present the current status and provide an outlook for the future.Comment: 30 pages, 9 figures. To appear in Vol 63: High Performance Clocks, Springer Space Science Review