Blood transfusion and hepatitis viruses

Transmission of hepatitis viruses has been recognised as an undesirable effect of blood transfusion since the 1940s, when large outbreaks occurred following inoculation with a yellow fever vaccine which contained pooled human plasma. Further reports followed of jaundice occurring several months after transfusions with blood or plasma. It was also noted in studies in the UK that the incidence of icteric hepatitis increased relative to the number of units transfused.After the discovery of the Australia antigen in 1965, its recognition as a marker of hepatitis B virus (HBV) infection and its association with post-transfusion hepatitis (PTH), the subsequent introduction of screening tests for this antigen in the early 1970s led to a marked decrease in the incidence of PTH. However, despite increasingly sensitive testing methods for hepatitis B surface antigen (HBsAg), as it subsequently became designated, viral hepatitis was still considered the commonest lethal complication of blood transfusion. It was clear that there were still a number of cases of PTH that were due neither to hepatitis A virus nor to HBV, and the term 'non-A, non-B hepatitis' (NANBH) was coined.The introduction of molecular techniques enabled clones to be derived from the genome of an agent associated with transfusion-transmitted NANBH, and the proteins derived from these clones were then used to develop nn enzyme linked immunosorbent assay (ELISA) to detect antibodies to this virus, now termed hepatitis C virus (HCV). This ELlSA is now used in most developed countries to screen for HCV antibodies

In situ fracture behavior of single crystal LiNi0.8Mn0.1Co0.1O2 (NMC811)

Single crystal particle morphologies have become highly desirable for next generation cathode materials, removing grain boundary fracture and thereby reducing the surface area exposed to electrolyte. The intrinsic mechanical behavior of single crystal layered oxides, however, is poorly understood. Here, faceted single crystal LiNi0.8Mn0.1Co0.1O2 (NMC811) particles are compressed in situ in a scanning electron microscope (SEM), to determine mechanical deformation mechanisms as a function of crystallographic orientation. In situ, the dynamical deformation sequence observed is initial cracking at the compression zone, followed by accelerated transparticle crack propagation and concurrent (0001) slip band formation. The greatest loads and contact pressure at fracture, non-basal cracking, and activation of multiple basal slip systems in larger (>3 μm) particles, occur for compression normal to the (0001) layered structure. Loading on {012} preferentially activates basal fracture and slip at lower loads. Regardless of particle orientation, non-basal slip systems are not observed, and non-basal cracking and particle rotation occur during compression to compensate for this inability to activate dislocations in 3-dimensions. Crystallographic dependent mechanical behaviour of single crystal NMC811 means that particle texture in cathodes should be monitored, and sources of localised surface stress in cathodes, e. g. particle-to-particle asperity contacts during electrode manufacture, should be minimised

Ultra-High Energy Neutrino Fluxes and Their Constraints

Applying our recently developed propagation code we review extragalactic neutrino fluxes above 10^{14} eV in various scenarios and how they are constrained by current data. We specifically identify scenarios in which the cosmogenic neutrino flux, produced by pion production of ultra high energy cosmic rays outside their sources, is considerably higher than the "Waxman-Bahcall bound". This is easy to achieve for sources with hard injection spectra and luminosities that were higher in the past. Such fluxes would significantly increase the chances to detect ultra-high energy neutrinos with experiments currently under construction or in the proposal stage.Comment: 11 pages, 15 figures, version published in Phys.Rev.

Fracture testing of lithium‐ion battery cathode secondary particles in‐situ inside the scanning electron microscope

Fracture of cathode secondary particles is a critical degradation mechanism in lithium-ion batteries. The microindentation strength of LiNi0.8Mn0.1Co0.1O2 secondary particles is measured in situ in the scanning electron microscope (SEM), enabling dynamical imaging of fracture. Crack propagation is intergranular between primary particles when induced by compressing between flat platens (analogous to calendaring), and with a cono-spherical indenter (representing particle-particle contact). Fracture occurs directly beneath the cono-spherical tip and at the centre of secondary particles when compressed between flat platens. Finite element modelling of stress states provides insight into the dependence of fracture load upon cohesive strength and particle toughness. Secondary particle indentation strength decreases with increasing secondary particle size, with cycling, and with increasing state of charge. The indentation strength decrease is greatest in earlier stages of delithiation. The novel microindentation technique allows assessment of strength and toughness of different cathode morphologies, aiding prediction of optimal particle structure and processing conditions

Hippocampus, Amygdala and Basal Ganglia Based Navigation Control

In this paper we present a novel robot navigation system aimed at testing hypotheses about the roles of key brain areas in foraging behavior of rats. The key components of the control network are: 1. a Hippocampus inspired module for spatial localization based on associations between sensory inputs and places; 2. an Amygdala inspired module for the association of values with places and sensory stimuli; 3. a Basal Ganglia inspired module for the selection of actions based on the evaluated sensory inputs. By implementing this Hippocampus-Amygdala-Basal Ganglia based control network with a simulated rat embodiment we intend to test not only our understanding of the individual brain areas but especially the interaction between them. Understanding the neural circuits that allows rats to efficiently forage for food will also help to improve the ability of robots to autonomously evaluate and select navigation targets

Origins of the Ambient Solar Wind: Implications for Space Weather

The Sun's outer atmosphere is heated to temperatures of millions of degrees, and solar plasma flows out into interplanetary space at supersonic speeds. This paper reviews our current understanding of these interrelated problems: coronal heating and the acceleration of the ambient solar wind. We also discuss where the community stands in its ability to forecast how variations in the solar wind (i.e., fast and slow wind streams) impact the Earth. Although the last few decades have seen significant progress in observations and modeling, we still do not have a complete understanding of the relevant physical processes, nor do we have a quantitatively precise census of which coronal structures contribute to specific types of solar wind. Fast streams are known to be connected to the central regions of large coronal holes. Slow streams, however, appear to come from a wide range of sources, including streamers, pseudostreamers, coronal loops, active regions, and coronal hole boundaries. Complicating our understanding even more is the fact that processes such as turbulence, stream-stream interactions, and Coulomb collisions can make it difficult to unambiguously map a parcel measured at 1 AU back down to its coronal source. We also review recent progress -- in theoretical modeling, observational data analysis, and forecasting techniques that sit at the interface between data and theory -- that gives us hope that the above problems are indeed solvable.Comment: Accepted for publication in Space Science Reviews. Special issue connected with a 2016 ISSI workshop on "The Scientific Foundations of Space Weather." 44 pages, 9 figure

Randomized controlled field trial to assess the immunogenicity and safety of rift valley fever clone 13 vaccine in livestock

BACKGROUND:Although livestock vaccination is effective in preventing Rift Valley fever (RVF) epidemics, there are concerns about safety and effectiveness of the only commercially available RVF Smithburn vaccine. We conducted a randomized controlled field trial to evaluate the immunogenicity and safety of the new RVF Clone 13 vaccine, recently registered in South Africa. METHODS:In a blinded randomized controlled field trial, 404 animals (85 cattle, 168 sheep, and 151 goats) in three farms in Kenya were divided into three groups. Group A included males and non-pregnant females that were randomized and assigned to two groups; one vaccinated with RVF Clone 13 and the other given placebo. Groups B included animals in 1st half of pregnancy, and group C animals in 2nd half of pregnancy, which were also randomized and either vaccinated and given placebo. Animals were monitored for one year and virus antibodies titers assessed on days 14, 28, 56, 183 and 365. RESULTS:In vaccinated goats (N = 72), 72% developed anti-RVF virus IgM antibodies and 97% neutralizing IgG antibodies. In vaccinated sheep (N = 77), 84% developed IgM and 91% neutralizing IgG antibodies. Vaccinated cattle (N = 42) did not develop IgM antibodies but 67% developed neutralizing IgG antibodies. At day 14 post-vaccination, the odds of being seropositive for IgG in the vaccine group was 3.6 (95% CI, 1.5 - 9.2) in cattle, 90.0 (95% CI, 25.1 - 579.2) in goats, and 40.0 (95% CI, 16.5 - 110.5) in sheep. Abortion was observed in one vaccinated goat but histopathologic analysis did not indicate RVF virus infection. There was no evidence of teratogenicity in vaccinated or placebo animals. CONCLUSIONS:The results suggest RVF Clone 13 vaccine is safe to use and has high (>90%) immunogenicity in sheep and goats but moderate (> 65%) immunogenicity in cattle

The challenge to professionals of using social media: teachers in England negotiating personal-professional identities

Social media are a group of technologies such as Twitter, Facebook and LinkedIn which offer people chances to interact with one another in new ways. Teachers, like other members of society, do not all use social media. Some avoid, some experiment with and others embrace social media enthusiastically. As a means of communication available to everyone in modern society, social media is challenging teachers, as other professionals in society, to decide whether to engage with these tools and, if so, on what basis – as an individual (personally), or as a teacher (professionally). Although teachers are guided by schools and codes of practice, teachers as individuals are left to decide whether and how to explore social media for either their own or their students' learning. This paper analyses evidence from interviews with 12 teachers from England about their use of social media as to the challenges they experience in relation to using the media as professional teachers.. Teachers are in society’s spotlight in terms of examples of inappropriate use of social media but also under peer pressure to connect. This paper explores their agency in responding. The paper focuses on how teachers deal with tensions between their personal and professional use of social media. These tensions are not always perceived as negative and some teachers' accounts revealed a unity in their identities when using social media. The paper reflects on the implications of such teachers' identities in relation to the future of social media use in education