Transient experiments from the thermal-hydraulic ADS lead bismuth loop (TALL) and comparative TRAC/AAA analysis

TALL is a medium-size experimental facility constructed at KTH, to study the steady-state and transient thermal-hydraulics performance of LBE-cooled reactors, with the primary purpose of supporting the European transmutation demonstration (ETD) using LBE-cooled accelerator-driven systems (ADS). This paper presents the results of transient experiments performed on the TALL test facility, whose aim is to provide a data base for validation of computer codes which may be used for the analysis of the safety of those systems. This paper also presents the results of the post-test calculations, carried out at PSI, using the TRAC/AAA code. The transient experiments performed include the loss of heat sink, the loss of pump, the loss of both primary and secondary flows, overpower, overcooling, heater trip, and the operational transients of start-up and shut-down. The experimental results show the excellent natural circulation performance of a LBE-cooled system which should contribute to a good safety performance. The TRAC/AAA calculations provide results which agree well with the experimental data.     

3D printing hybrid organometallic polymer‐based biomaterials via laser two‐photon polymerization

Materials with microscale structures are gaining increasing interest due to their range of technical and medical applications. Additive manufacturing approaches to such objects via laser two‐photon polymerization, also known as multiphoton fabrication, enable the creation of new materials with diverse and tunable properties. Here, we investigate the properties of 3D structures composed of organometallic polymers incorporating aluminium, titanium, vanadium and zirconium. The organometallic polymer‐based materials were analysed using a variety of techniques including SEM, energy‐dispersive X‐ray spectroscopy, X‐ray photoelectron spectroscopy analysis and contact angle measurements and their biocompatibility was tested in vitro. Cell viability and mode of death were determined by 3‐(4,5‐dimethyl‐2‐thiazolyl)‐2,5‐diphenyl‐2H‐tetrazolium bromide (MTT) assay and acridine orange/ethidium bromide staining. Polymers incorporating Al, Ti and Zr supported cell adhesion and proliferation, and showed low toxicity in vitro, whereas the organometallic polymer incorporating V was shown to be cytotoxic. Inductively coupled plasma optical emission spectrometry suggested that leaching of the V from the organometallic polymer is the likely cause of this. The preparation of the organometallic polymers is straightforward and both simple 2D and complex 3D structures can be fabricated with ease. Resolution tests of the newly developed organometallic polymer incorporating Al show that suspended lines with widths down to 200 nm can be fabricated. We believe that the materials described in this work show promising properties for the development of objects with sub‐micron features for biomedical applications (e.g. biosensors, drug delivery devices, tissue scaffolds etc.). © 2019 The Authors. Polymer International published by John Wiley & Sons Ltd on behalf of Society of Chemical Industry.     

Verification of the TRACE code against the MEGAPIE transient data

Megawatt pilot target experiment (MEGAPIE) is an international project aimed at demonstrating the feasibility of a liquid lead–bismuth target for spallation facilities at a maximum beam power level of 1 MW. The thermal-hydraulics data measured during the MEGAPIE experiment was used for the TRACE code qualification for transient analysis of liquid metal cooled systems.     

Production and Characterization of Peptide Antibodies to the C-Terminal of Frameshifted Calreticulin Associated with Myeloproliferative Diseases

Myeloproliferative Neoplasms (MPNs) constitute a group of rare blood cancers that are characterized by mutations in bone marrow stem cells leading to the overproduction of erythrocytes, leukocytes, and thrombocytes. Mutations in calreticulin (CRT) genes may initiate MPNs, causing a novel variable polybasic stretch terminating in a common C-terminal sequence in the frameshifted CRT (CRTfs) proteins. Peptide antibodies to the mutated C-terminal are important reagents for research in the molecular mechanisms of MPNs and for the development of new diagnostic assays and therapies. In this study, eight peptide antibodies targeting the C-terminal of CRTfs were produced and characterised by modified enzyme-linked immunosorbent assays using resin-bound peptides. The antibodies reacted to two epitopes: CREACLQGWTE for SSI-HYB 385-01, 385-02, 385-03, 385-04, 385-07, 385-08, and 385-09 and CLQGWT for SSI-HYB 385-06. For the majority of antibodies, the residues Cys¹, Trp⁹, and Glu¹¹ were essential for reactivity. SSI-HYB 385-06, with the highest affinity, recognised recombinant CRTfs produced in yeast and the MARIMO cell line expressing CRTfs when examined in Western immunoblotting. Moreover, SSI-HYB 385-06 occasionally reacted to CRTfs from MPN patients when analysed by flow cytometry. The characterized antibodies may be used to understand the role of CRTfs in the pathogenesis of MPNs and to design and develop new diagnostic assays and therapeutic targets.     

Radio frequency response of GaN-based SAW oscillator to UVillumination by the Sun and man-made source

A new solar-blind UV detector based on a GaN surface acoustic wave delay line oscillator is reported. The illumination by an artificial UV source in the presence of sunlight increased the RF spectral line width of the oscillator by almost an order of magnitude, which is attributed to the different noise spectra of these light sources. The output of this detector is a radio signal, which makes it especially attractive for remote sensing applications     

Automatic benthic imagery recognition using a hierarchical two-stage approach

The main objective of this work is to establish an automated classification system of seabed images. A novel two-stage approach to solving the image region classification task is presented. The first stage is based on information characterizing geometry, colour and texture of the region being analysed. Random forests and support vector machines are considered as classifiers in this work. In the second stage, additional information characterizing image regions surrounding the region being analysed is used. The reliability of decisions made in the first stage regarding the surrounding regions is taken into account when constructing a feature vector for the second stage. The proposed technique was tested in an image region recognition task including five benthic classes: red algae, sponge, sand, lithothamnium and kelp. The task was solved with the average accuracy of 90.11% using a data set consisting of 4589 image regions and the tenfold cross-validation to assess the performance. The two-stage approach allowed increasing the classification accuracy for all the five classes, more than 27% for the “difficult” to recognize “kelp” class.     

Signaling aptamers created using fluorescent nucleotide analogues

A new approach to creating fluorescent signaling aptamers using fluorescent nucleotide analogues is presented. The fluorescence quantum yield of nucleotide analogues such as 2-aminopurine strongly depends on base stacking interactions when incorporated into double or single stranded DNA. This property is used to generate a binding-specific fluorescence signal. Aptamers for human alpha-thrombin, immunoglobulin E, and platelet-derived growth factor B were modified with fluorescent nucleotide analogues in positions that undergo conformational changes. The resulting signaling aptamers show a specific, binding-induced increase in the fluorescence signal of up to 30-fold. Conformation-changing positions in these aptamers were identified by screening a set of modified aptamer sequences that each included a fluorescent nucleotide analogue at a different position. The positions for these modifications were estimated by modeling the aptamer secondary structure. It is likely that this approach to producing fluorescent signaling aptamers is of general use for protein-binding aptamers because of their "induced fit" binding mechanism.     

Guided-wave acousto-optic diffraction in Zn:LiNbO3

The acousto-optic control of light in Zn-diffused LiNbO₃ optical waveguides is demonstrated. The guided optical mode diffraction by the surface acoustic waves is consistent with the Klein and Cook model for the intermediate diffraction regime. The SAW induced refractive index change is 1.5times10^-4 at acoustic power 130 mW. The Zn-diffused lithium niobate waveguides appear to be good candidates for integrated light-control devices based on acousto-optic interaction     

Peptide Antibody Reactivity to Homologous Regions in Glutamate Decarboxylase Isoforms and Coxsackievirus B4 P2C

Two isoforms of the glutamate decarboxylase (GAD) enzyme exist, GAD65 and GAD67, which are associated with type 1 diabetes (T1D) and stiff-person syndrome (SPS), respectively. Interestingly, it has been reported that T1D patients seldom develop SPS, whereas patients with SPS occasionally develop T1D. In addition, coxsackievirus B4 (CVB4) has previously been proposed to be involved in the onset of T1D through molecular mimicry. On this basis, we aimed to examine antibody cross-reactivity between a specific region of GAD65 and GAD67, which has high sequence homology to the nonstructural P2C protein of CVB4 to determine potential correlations at antibody level. Monoclonal peptide antibodies generated in mice specific for a region with high similarity in all three proteins were screened for reactivity along with human sera in immunoassays. In total, six antibodies were generated. Two of the antibodies reacted to both GAD isoforms. However, none of the antibodies were cross-reactive to CVB, suggesting that antibody cross-reactivity between GAD65 and CVB, and GAD67 and CVB may not contribute to the onset of T1D and SPS, respectively.