Genetic Characterization of the Tick-Borne Orbiviruses

The International Committee for Taxonomy of Viruses (ICTV) recognizes four species of tick-borne orbiviruses (TBOs): Chenuda virus, Chobar Gorge virus, Wad Medani virus and Great Island virus (genus Orbivirus, family Reoviridae). Nucleotide (nt) and amino acid (aa) sequence comparisons provide a basis for orbivirus detection and classification, however full genome sequence data were only available for the Great Island virus species. We report representative genome-sequences for the three other TBO species (virus isolates: Chenuda virus (CNUV); Chobar Gorge virus (CGV) and Wad Medani virus (WMV)). Phylogenetic comparisons show that TBOs cluster separately from insect-borne orbiviruses (IBOs). CNUV, CGV, WMV and GIV share low level aa/nt identities with other orbiviruses, in 'conserved' Pol, T2 and T13 proteins/genes, identifying them as four distinct virus-species. The TBO genome segment encoding cell attachment, outer capsid protein 1 (OC1), is approximately half the size of the equivalent segment from insect-borne orbiviruses, helping to explain why tick-borne orbiviruses have a ~1 kb smaller genome

Avert the Dirt:On the Design of Scalable Antifouling Polymer Coatings

Whether it be your house, clothes, phone, or precious record collection; everything gets dirty eventually. While we can simply hop in the shower or clean most of our belongings using basic cleaning supplies, the same does not apply to medical, marine, and industrial devices. Here, the uncontrollable and unwanted adhesion of all kinds of material, generally known as fouling, leads to serious complications related to health risks, pollution, and financial losses, which cannot be easily solved by the mere power of detergent. As a response, we strived to develop a novel antifouling coating, specifically designed for large-scale underwater applications. This protective layer consists of polymers: very long and flexible molecules. By attaching these individual polymers or polymer clusters to a surface one by one, a brush is formed, also known as a polymer brush. By repeating this adsorption step, but with a different type of polymer (cluster), the density of the brush is increased. Because of the high brush density and the used polymers’ antifouling character, fouling particles are unable to adhere to the coated surface and the surface remains clean. This simple two-step adsorption strategy has enabled the formation of an effective and reversible antifouling layer, which should allow the straightforward coating and protection of large-scale (underwater) applications. This way, we hope to contribute to a cleaner and more sustainable future

Dynamics of liquid crystalline domains in magnetic field

We study microscopic single domains nucleating and growing within the coexistence region of the Isotropic (I) and Nematic (N) phases in magnetic field. By rapidly switching on the magnetic field the time needed to align the nuclei of sufficiently large size is measured, and is found to decrease with the square of the magnetic field. When the field is removed the disordering time is observed to last on a longer time scale. The growth rate of the nematic domains at constant temperature within the coexistence region is found to increase when a magnetic field is applied.Comment: 10 pages, 5 figures, unpublishe

Linear magnetoresistance in a quasi-free two dimensional electron gas in an ultra-high mobility GaAs quantum well

We report a magnetotransport study of an ultra-high mobility ($\bar{\mu}\approx 25\times 10^6$\,cm$^2$\,V$^{-1}$\,s$^{-1}$) $n$-type GaAs quantum well up to 33 T. A strong linear magnetoresistance (LMR) of the order of 10$^5$ % is observed in a wide temperature range between 0.3 K and 60 K. The simplicity of our material system with a single sub-band occupation and free electron dispersion rules out most complicated mechanisms that could give rise to the observed LMR. At low temperature, quantum oscillations are superimposed onto the LMR. Both, the featureless LMR at high $T$ and the quantum oscillations at low $T$ follow the empirical resistance rule which states that the longitudinal conductance is directly related to the derivative of the transversal (Hall) conductance multiplied by the magnetic field and a constant factor $\alpha$ that remains unchanged over the entire temperature range. Only at low temperatures, small deviations from this resistance rule are observed beyond $\nu=1$ that likely originate from a different transport mechanism for the composite fermions

Manipulating quantum Hall edge channels in graphene through Scanning Gate Microscopy

We show evidence of the backscattering of quantum Hall edge channels in a narrow graphene Hall bar, induced by the gating effect of the conducting tip of a Scanning Gate Microscope, which we can position with nanometer precision. We show full control over the edge channels and are able, due to the spatial variation of the tip potential, to separate co-propagating edge channels in the Hall bar, creating junctions between regions of different charge carrier density, that have not been observed in devices based on top- or split-gates. The solution of the corresponding quantum scattering problem is presented to substantiate these results, and possible follow-up experiments are discussed.Comment: 10 pages, 12 figure

Electron-phonon coupling in the two phonon mode ternary alloy Al0.25In0.75As/Ga0.25In0.75AsAl_{0.25}In_{0.75}As/Ga_{0.25}In_{0.75}As quantum well

We have investigated the infrared transmission of a two-dimensional (2DEG) electron gas confined in a $Al_{0.25}In_{0.75}As/Ga_{0.25}In_{0.75}As$ single quantum well in order to study the electron optical phonon interaction in a two phonon mode system. Infrared transmission experiments have been performed in both the perpendicular Faraday (PF) and tilted Faraday (TF) configurations for which the growth axis of the sample is tilted with respect to the incident light propagation direction and to the magnetic field direction. The experimental results lead to question the validity of the concept of polaron mass in a real material.Comment: 7 pages, 3 figure

An Unusual Anterior Neck Injury [Cut Throat]: A Case Report

Introduction –The Neck is prone to injuries that are life threatening due to the presence of vital structures that lie within the neck. Cut throat injuries are located on the anterior neck classically, with dangers to the aero digestive tract and the vascular structures. Case Presentation-A 40 year old farmer presented with injuries on the lateral sides of the neck with an island of normal tissue anteriorly two days after the incidence from a rural hospital, fig 1. Examination revealed an anaemic, dehydrated young man that was not in any respiratory distress. There was complete avulsion of the epiglottis at the base; and the eyes were also plucked. Patient had blood transfusion, tracheostomy, fig 2 and subsequent repair with favourable outcome. Conclusion-Cut throat injuries are relatively uncommon in our environment, but on the increase due to violence in the society (insurgency, ritual killings, armed robbery etc).Prompt identification and referral to the specialist for proper management will reduce morbidity and mortality. Keywords: unusual, anterior neck, injury DOI: 10.7176/JHMN/63-06 Publication date:June 30th 2019

Lifting of the Landau level degeneracy in graphene devices in a tilted magnetic field

We report on transport and capacitance measurements of graphene devices in magnetic fields up to 30 T. In both techniques, we observe the full splitting of Landau levels and we employ tilted field experiments to address the origin of the observed broken symmetry states. In the lowest energy level, the spin degeneracy is removed at filling factors $\nu=\pm1$ and we observe an enhanced energy gap. In the higher levels, the valley degeneracy is removed at odd filling factors while spin polarized states are formed at even $\nu$. Although the observation of odd filling factors in the higher levels points towards the spontaneous origin of the splitting, we find that the main contribution to the gap at $\nu= -4,-8$, and $-12$ is due to the Zeeman energy.Comment: 5 pages, 4 figure

Transport Gap in Suspended Bilayer Graphene at Zero Magnetic Field

We report a change of three orders of magnitudes in the resistance of a suspended bilayer graphene flake which varies from a few k$\Omega$s in the high carrier density regime to several M$\Omega$s around the charge neutrality point (CNP). The corresponding transport gap is 8 meV at 0.3 K. The sequence of appearing quantum Hall plateaus at filling factor $\nu=2$ followed by $\nu=1$ suggests that the observed gap is caused by the symmetry breaking of the lowest Landau level. Investigation of the gap in a tilted magnetic field indicates that the resistance at the CNP shows a weak linear decrease for increasing total magnetic field. Those observations are in agreement with a spontaneous valley splitting at zero magnetic field followed by splitting of the spins originating from different valleys with increasing magnetic field. Both, the transport gap and $B$ field response point toward spin polarized layer antiferromagnetic state as a ground state in the bilayer graphene sample. The observed non-trivial dependence of the gap value on the normal component of $B$ suggests possible exchange mechanisms in the system.Comment: 8 pages, 5 figure

Transport and thermoelectric properties of the LaAlO3_3/SrTiO3_3 interface

The transport and thermoelectric properties of the interface between SrTiO$_3$ and a 26-monolayer thick LaAlO$_3$-layer grown at high oxygen-pressure have been investigated at temperatures from 4.2 K to 100 K and in magnetic fields up to 18 T. For $T>$ 4.2 K, two different electron-like charge carriers originating from two electron channels which contribute to transport are observed. We probe the contributions of a degenerate and a non-degenerate band to the thermoelectric power and develop a consistent model to describe the temperature dependence of the thermoelectric tensor. Anomalies in the data point to an additional magnetic field dependent scattering.Comment: 7 pages, 4 figure