Linear polymers to target Vibrio cholerae adhesion and physiology

A key stage in bacterial pathogenesis is the ability of bacteria to adhere strongly and specifically to the host. Bacterial adhesion to host cells is a prerequisite for infection and disease, and with this in mind, synthetic polymers rationally designed to incorporate side-chain functionality targeting bacterial adhesion mechanisms have been reported to cluster bacteria via specific and non-specific multivalent interactions. Targeting bacteria in this way may have therapeutic value towards controlling drug resistant pathogens. However, progress in this area has been slow due to an incomplete understanding of polymer-bacteria interactions as well as technical difficulties in screening large libraries of polymers efficiently under standardised chemical and biological conditions in order to assess structure-activity relationships of these macromolecules. Here, poly(acryloyl hydrazide) is employed as a polymer scaffold capable of undergoing highly efficient post-polymerisation modifications of the side-chain under physiologically relevant conditions to facilitate the synthesis and in situ screening of a range of unexplored polymer chemistries towards sequestering V. cholerae. In particular, it was found that imidazole-functionalised polymers dramatically sequestered V. cholerae at sub-inhibitory concentrations, and suppressed the production of the Cholera toxin (Chapter 2), while glycopolymers resulted in accelerated biofilm production in a sugar-dependent manner (Chapter 3). Lastly, improved RAFT polymerisation of poly(Boc-acryloyl hydrazide) by choice of polymerisation temperature is reported (Chapter 1), as well as a synthetic route towards controlled end group fluorescent labelling (Chapter 4)

Caught in the act of an insider attack: detection and assessment of insider threat

The greatest asset that any organisation has are its people, but they may also be the greatest threat. Those who are within the organisation may have authorised access to vast amounts of sensitive company records that are essential for maintaining competitiveness and market position, and knowledge of information services and procedures that are crucial for daily operations. In many cases, those who have such access do indeed require it in order to conduct their expected workload. However, should an individual choose to act against the organisation, then with their privileged access and their extensive knowledge, they are well positioned to cause serious damage. Insider threat is becoming a serious and increasing concern for many organisations, with those who have fallen victim to such attacks suffering significant damages including financial and reputational. It is clear then, that there is a desperate need for more effective tools for detecting the presence of insider threats and analyzing the potential of threats before they escalate. We propose Corporate Insider Threat Detection (CITD), an anomaly detection system that is the result of a multi-disciplinary research project that incorporates technical and behavioural activities to assess the threat posed by individuals. The system identifies user and role-based profiles, and measures how users deviate from their observed behaviours to assess the potential threat that a series of activities may pose. In this paper, we present an overview of the system and describe the concept of operations and practicalities of deploying the system. We show how the system can be utilised for unsupervised detection, and also how the human analyst can engage to provide an active learning feedback loop. By adopting an accept or reject scheme, the analyst is capable of refining the underlying detection model to better support their decisionmaking process and significant reduce the false positive rate

Automated insider threat detection system using user and role-based profile assessment

© 2007-2012 IEEE. Organizations are experiencing an ever-growing concern of how to identify and defend against insider threats. Those who have authorized access to sensitive organizational data are placed in a position of power that could well be abused and could cause significant damage to an organization. This could range from financial theft and intellectual property theft to the destruction of property and business reputation. Traditional intrusion detection systems are neither designed nor capable of identifying those who act maliciously within an organization. In this paper, we describe an automated system that is capable of detecting insider threats within an organization. We define a tree-structure profiling approach that incorporates the details of activities conducted by each user and each job role and then use this to obtain a consistent representation of features that provide a rich description of the user's behavior. Deviation can be assessed based on the amount of variance that each user exhibits across multiple attributes, compared against their peers. We have performed experimentation using ten synthetic data-driven scenarios and found that the system can identify anomalous behavior that may be indicative of a potential threat. We also show how our detection system can be combined with visual analytics tools to support further investigation by an analyst

Messenger RNA delivery by hydrazone-activated polymers

This is the Accepted Manuscript of the following article: Juanes, M., Creese, O., Fernández-Trillo, P., & Montenegro, J. (2019). Messenger RNA delivery by hydrazone-activated polymers. Medchemcomm, 10(7), 1138-1144. doi: 10.1039/c9md00231fThe intracellular delivery of DNA and RNA therapeutics requires the assistance of vectors and/or nucleotide modifications to protect the nucleic acids against host nucleases and promote cellular internalization and release. Recently, messenger RNA (mRNA) has attracted much attention due to its transient activity and lack of genome permanent recombination and persistent expression. Therefore, there is a strong interest in the development of conceptually new non-viral vectors with low toxicity that could improve mRNA transfection efficiency. We have recently introduced the potential of polyhydrazones and the importance of the degree of polymerization for the delivery of siRNA and plasmid DNA. Here, we demonstrate that this technology can be easily adapted to the more interesting complexation and delivery inside living cells of mRNA. The polyplexes resulting from the combination of the amphiphilic polyhydrazone were characterized and the transfection efficiency and cell viability were studied for a discrete collection of functionalized polyhydrazones. The results obtained demonstrated the versatility of these polymeric vectors as excellent candidates for the delivery of mRNA and validate the easy adaptability of the technology to more sensitive and therapeutically relevant nucleic acidsThis work has received financial support from Spanish Agencia Estatal de Investigación (AEI) [CTQ2014-59646-R, SAF2017-89890-R], the Xunta de Galicia (ED431C 2017/25, 2016-AD031 and Centro singular de investigación de Galicia accreditation 2016–2019, ED431G/09) and the European Union (European Regional Development Fund - ERDF). M.J. received a F.P.I. fellowship from MINECO (CTQ2014-59646- R). J.M. received a Ramón y Cajal (RYC-2013-13784), an ERC Starting Investigator Grant (DYNAP- 677786) and a Young Investigator Grant from the Human Frontier Science Research Program (RGY0066/2017). F.F.T. thanks the Birmingham Science City and the European Regional Development Fund, and the University of Birmingham (John Evans Fellowship). O.C. thanks the Midlands Integrative Biosciences Training Partnership (MIBTP) for the PhD scholarshipS

Poly(acryloyl hydrazide), a versatile scaffold for the preparation of functional polymers: synthesis and post-polymerisation modification

Here we present the synthesis and post-polymerisation modification of poly(acryloyl hydrazide), a versatile scaffold for the preparation of functional polymers: poly(acryloyl hydrazide) was prepared from commercially available starting materials in a three step synthesis on a large scale, in good yields and high purity. Our synthetic approach included the synthesis of a Boc-protected acryloyl hydrazide, the preparation of polymers via RAFT polymerisation and the deprotection of the corresponding Boc-protected poly(acryloyl hydrazide). Post-polymerisation modification of poly(acryloyl hydrazide) was then demonstrated using a range of conditions for both hydrophilic and hydrophobic aldehydes. These experiments demonstrate the potential of poly(acryloyl hydrazide) as a scaffold in the synthesis of functional polymers, in particular those applications where in situ screening of the activity of the functionalised polymers may be required (e.g. biological applications)This work was supported by the Royal Society, U.K (IE130688) and the Wellcome Trust (177ISSFPP). F. F.-T. thanks the Birmingham Science City and the European Regional Development Fund, the Royal Society (RG140273), and the University of Birmingham (John Evans Fellowship). J. M. thanks funding from MINECO (CTQ2014-59646-R, RYC-2013-1378) the Xunta de Galicia (ED431G/09 and 2016-AD031) and the ERC (Stg-DYNAP-677786)S

Poly(Boc-acryloyl hydrazide):the importance of temperature and RAFT agent degradation on its preparation

Poly(acryloyl hydrazide) is a versatile polymer scaffold readily functionalised through post-polymerisation modification with aldehydes to yield polymers for biological applications. However, its polymerisation is affected by nucleophilic degradation of the RAFT agent that leads to early termination, an issue often overlooked in the polymerisation of primary acrylamides. Here we report the effect of temperature on the RAFT polymerisation of N’-(tert-butoxycarbonyl)acryloyl hydrazide (1) and demonstrate that by carefully selecting this polymerisation temperature, a balance between rate of polymerisation and rate of degradation of the RAFT agent can be achieved. This way a greater control over the polymerisation process is achieved, allowing the synthesis of Boc-protected poly(acryloyl hydrazide) with higher degrees of polymerisation than those achieved previously, while still maintaining low dispersities. We believe our results should be of importance to those working on the RAFT polymerization of primary and secondary (meth)acrylamides and monomers with nucleophilic moieties. </p

Microglial activation, tau and amyloid deposition in TREM2 p.R47H carriers and mild cognitive impairment patients: a multi-modal/multi-tracer PET/MRI imaging study with influenza vaccine immune challenge

BACKGROUND: Microglia are increasingly understood to play an important role in the pathogenesis of Alzheimer's disease. The rs75932628 (p.R47H) TREM2 variant is a well-established risk factor for Alzheimer's disease. TREM2 is a microglial cell surface receptor. In this multi-modal/multi-tracer PET/MRI study we investigated the effect of TREM2 p.R47H carrier status on microglial activation, tau and amyloid deposition, brain structure and cognitive profile. METHODS: We compared TREM2 p.R47H carriers (n = 8; median age = 62.3) and participants with mild cognitive impairment (n = 8; median age = 70.7). Participants underwent two [18F]DPA-714 PET/MRI scans to assess TSPO signal, indicative of microglial activation, before and after receiving the seasonal influenza vaccination, which was used as an immune stimulant. Participants also underwent [18F]florbetapir and [18F]AV1451 PET scans to assess amyloid and tau burden, respectively. Regional tau and TSPO signal were calculated for regions of interest linked to Braak stage. An additional comparison imaging healthy control group (n = 8; median age = 45.5) had a single [18F]DPA-714 PET/MRI. An expanded group of participants underwent neuropsychological testing, to determine if TREM2 status influenced clinical phenotype. RESULTS: Compared to participants with mild cognitive impairment, TREM2 carriers had lower TSPO signal in Braak II (P = 0.04) and Braak III (P = 0.046) regions, despite having a similar burden of tau and amyloid. There were trends to suggest reduced microglial activation following influenza vaccine in TREM2 carriers. Tau deposition in the Braak VI region was higher in TREM2 carriers (P = 0.04). Furthermore, compared to healthy controls TREM2 carriers had smaller caudate (P = 0.02), total brain (P = 0.049) and white matter volumes (P = 0.02); and neuropsychological assessment revealed worse ADAS-Cog13 (P = 0.03) and Delayed Matching to Sample (P = 0.007) scores. CONCLUSIONS: TREM2 p.R47H carriers had reduced levels of microglial activation in brain regions affected early in the Alzheimer's disease course and differences in brain structure and cognition. Changes in microglial response may underlie the increased Alzheimer's disease risk in TREM2 p.R47H carriers. Future therapeutic agents in Alzheimer's disease should aim to enhance protective microglial actions

Understanding Insider Threat: A Framework for Characterising Attacks

The threat that insiders pose to businesses, institutions and governmental organisations continues to be of serious concern. Recent industry surveys and academic literature provide unequivocal evidence to support the significance of this threat and its prevalence. Despite this, however, there is still no unifying framework to fully characterise insider attacks and to facilitate an understanding of the problem, its many components and how they all fit together. In this paper, we focus on this challenge and put forward a grounded framework for understanding and reflecting on the threat that insiders pose. Specifically, we propose a novel conceptualisation that is heavily grounded in insider-threat case studies, existing literature and relevant psychological theory. The framework identifies several key elements within the problem space, concentrating not only on noteworthy events and indicators- technical and behavioural- of potential attacks, but also on attackers (e.g., the motivation behind malicious threats and the human factors related to unintentional ones), and on the range of attacks being witnessed. The real value of our framework is in its emphasis on bringing together and defining clearly the various aspects of insider threat, all based on real-world cases and pertinent literature. This can therefore act as a platform for general understanding of the threat, and also for reflection, modelling past attacks and looking for useful patterns