A Study of the Production of Neutrons for Boron Neutron Capture Therapy using a Proton Accelerator

Boron Neutron Capture Therapy (BNCT) is a binary cancer therapy particularly well-suited to treating aggressive tumours that exhibit a high degree of infiltration of the surrounding healthy tissue. Such tumours, for example of the brain and lung, provide some of the most challenging problems in oncology. The first element of the therapy is boron-10 which is preferentially introduced into the cancerous cells using a carrier compound. Boron-10 has a very high capture cross-section with the other element of the therapy, thermal neutrons, resulting in the production of a lithium nucleus and an alpha particle which destroy the cell they are created in. However, a large flux of neutrons is required and until recently the only source used was a nuclear reactor. In Birmingham, studies of an existing BNCT facility using a 2.8 MeV proton beam and a solid lithium target have found a way to increase the beam power to a sufficient level to allow clinical trials, while maintaining the target solid. In this paper, we will introduce BNCT, describe the work in Birmingham and compare with other accelerator-driven BNCT projects around the World

Magnetic resonance imaging (MRI) of heavy-metal transport and fate in an artificial biofilm

Unlike planktonic systems, reaction rates in biofilms are often limited by mass transport, which controls the rate of supply of contaminants into the biofilm matrix. To help understand this phenomenon, we investigated the potential of magnetic resonance imaging (MRI) to spatially quantify copper transport and fate in biofilms. For this initial study we utilized an artificial biofilm composed of a 50:50 mix of bacteria and agar. MRI successfully mapped Cu2+ uptake into the artificial biofilm by mapping T2 relaxation rates. A calibration protocol was used to convert T2 values into actual copper concentrations. Immobilization rates in the artificial biofilm were slow compared to the rapid equilibration of planktonic systems. Even after 36 h, the copper front had migrated only 3 mm into the artificial biofilm and at this distance from the copper source, concentrations were very low. This slow equilibration is a result of (1) the time it takes copper to diffuse over such distances and (2) the adsorption of copper onto cell surfaces, which further impedes copper diffusion. The success of this trial run indicates MRI could be used to quantitatively map heavy metal transport and immobilization in natural biofilms

Doing racialized masculinities in Finnish schools: subjectivation and de/humanization

This paper focuses on Judith Butler’s theorisation of the performative subject and contemporary critiques to consider its relevance to the doing of racialized masculinities in Finnish schools. Recent postcolonial critique has indicated that, early work on performativity and subjectivation implicitly assumes a white and western, enlightenment subject and does not take the aftermath of slavery into account. While Butler’s work since then theorises inequalities including racism, it leaves untheorized the de/subjectivation of Black people and those from other minoritised ethnic groups as well as how racialisation and abjection is a systematic part of the subjectivation of white people. This paper draws on a study of the narratives of Finnish 12–15-year-olds in order to shed light on processes of subjectivation they do while doing racialized masculinities. The findings point to the need to extend Butler’s theory of subjectivation to take power-knowledge-affect-relations and de/humanization on board in ways that account for Black as well as white people’s performative subjectivation

Survey Instrument for Gender Based Violence

This is a proposal for the design of a survey on gender-based violence across Europe. It introduces the purpose of the survey, which shapes the priorities embedded in the proposed design. It identifies the major issues involved in operationalising the concept of gender-based violence for a survey. It identifies some technical issues and how they are best addressed. The focus is on the questionnaire, largely leaving to one side the design of the survey and its strategy for issues such as sampling. This proposal draws on experience of a wide range of surveys and draws on selected parts of the architecture and questionnaire of the Crime Survey for England and Wales (CSEW), modified to fit the present priorities

Understanding the friendship networks of older Black and Minority Ethnic people living in the United Kingdom

Older Black and Minority Ethnic (BME) people living in the United Kingdom (UK) are vulnerable to the experiences of social isolation and loneliness. Despite this, it is widely assumed that they adhere to traditional family practices and living arrangements that protect them from social isolation and loneliness. Such assumptions are problematic and can reify family networks as the main area of research for older BME people to the detriment of friendship networks which are also crucial. However, few researchers have explored this area. With the older BME population increasing at a faster rate than the older white population, further research is needed. Utilising data from Wave 6 of Understanding Society (N = 7,499, 4.3% of whom self-identified as BME), this study explores the ways in which the friendship networks of older BME people differ compared to older white people using logistic regression analyses. After controlling for potential confounding socio-demographic characteristics, older BME people were more likely to report having fewer close friends and fewer friends who live locally, suggesting that their friendship networks may be restricted in quantity and accessibility. Not only do these findings raise important questions about the varying needs of older minority ethnic people who have been largely overlooked in recent government policy, but they also highlight the continuing challenges of using large-scale surveys to research older BME people in the UK

Security against eavesdropping in quantum cryptography

In this article we deal with the security of the BB84 quantum cryptography protocol over noisy channels using generalized privacy amplification. For this we estimate the fraction of bits needed to be discarded during the privacy amplification step. This estimate is given for two scenarios, both of which assume the eavesdropper to access each of the signals independently and take error correction into account. One scenario does not allow a delay of the eavesdropper's measurement of a measurement probe until he receives additional classical information. In this scenario we achieve a sharp bound. The other scenario allows a measurement delay, so that the general attack of an eavesdropper on individual signals is covered. This bound is not sharp but allows a practical implementation of the protocol.Comment: 11 pages including 3 figures, contains new results not contained in my Phys. Rev. A pape

Computational insights into the catalytic mechanism of Is-PETase : an enzyme capable of degrading poly(ethylene) terephthalate

This work was supported through a studentship from BBSRC in the EastBio doctoral training programme for E. S.-P.Is-PETase has become an enzyme of significant interest due to its ability to catalyse the degradation of polyethylene terephthalate (PET) at mesophilic temperatures. We performed hybrid quantum mechanics and molecular mechanics (QM/MM) at the DSD-PBEP86-D3/ma-def2-TZVP/CHARMM27//rev-PBE-D3/dev2-SVP/CHARMM level to calculate the energy profile for the degradation of a suitable PET model by this enzyme. Very low overall barriers are computed for serine protease-type hydrolysis steps (as low as 34.1 kJ mol-1). Spontaneous deprotonation of the final product, terephthalic acid, with a high computed driving force indicates that product release could be rate limiting.Publisher PDFPeer reviewe

Generation of long-living entanglement using cold trapped ions with pair cat states

With the reliance in the processing of quantum information on a cold trapped ion, we analyze the entanglement entropy in the ion-field interaction with pair cat states. We investigate a long-living entanglement allowing the instantaneous position of the center-of-mass motion of the ion to be explicitly time dependent. An analytic solution for the system operators is obtained. We show that different nonclassical effects arise in the dynamics of the population inversion, depending on the initial states of the vibrational motion. We study in detail the entanglement degree and demonstrate how the input pair cat state is required for initiating the long living entanglement. This long living entanglement is damp out with an increase in the number difference $q$. Owing to the properties of entanglement measures, the results are checked using another entanglement measure (high order linear entropy).Comment: 15 pages, 7 figures, Sub. Appl. Phys. B: Laser and Optic

Accumulation of entanglement in a continuous variable memory

We study the accumulation of entanglement in a memory device built out of two continuous variable (CV) systems. We address the case of a qubit mediating an indirect joint interaction between the CV systems. We show that, in striking contrast with respect to registers built out of bidimensional Hilbert spaces, entanglement superior to a single ebit can be efficiently accumulated in the memory, even though no entangled resource is used. We study the protocol in an immediately implementable setup, assessing the effects of the main imperfections.Comment: 4 pages, 3 figures, RevTeX

Optimum detection for extracting maximum information from symmetric qubit sets

We demonstrate a class of optimum detection strategies for extracting the maximum information from sets of equiprobable real symmetric qubit states of a single photon. These optimum strategies have been predicted by Sasaki et al. [Phys. Rev. A{\bf 59}, 3325 (1999)]. The peculiar aspect is that the detections with at least three outputs suffice for optimum extraction of information regardless of the number of signal elements. The cases of ternary (or trine), quinary, and septenary polarization signals are studied where a standard von Neumann detection (a projection onto a binary orthogonal basis) fails to access the maximum information. Our experiments demonstrate that it is possible with present technologies to attain about 96% of the theoretical limit.Comment: 10 pages, 11 figures, to be submitted to Phys. Rev. A Converted to REVTeX4 format, and a few other minor modifications according to the comments from PRA referre