Kinetic and Mechanistic Studies on Compounds With Strained Rings

A theory explaining the stabilisation of carbonium ion intermediates, termed "vertical stabilisation", has been put forward by T. G. Traylor and co-workers. Vertical stabilisation has been defined as that stabilisation in Y-CH2+ or Y-CH2- which is afforded while the internal geometry of Y and the Y-C bond length remain essentially as they were in the reactant. Traylor suggests that vertical stabilisation is a form of sigma-pi conjugation (hyperconjugation) and that it may be determined whether a group acts to stabilise a positive charge by internal nucleophilic displacement or by sigma-pi conjugation by studying the effect of that group in a vertical process. The reaction studied by Traylor was the charge transfer between substituted benzenes and a standard acceptor, tetracyanoethylene (T. C. N. E.). A relationship has been shown by various workers to exist between ionisation potentials and reactivity, i. e. sigma+, in another vertical process, gas-phase removal of an electron. Traylor believes that as the absorption frequencies of the charge transfer complexes are directly related to ionisation potentials then a relationship should be apparent between charge transfer frequency and sigma+. Evidence is given by Traylor for a linear correlation between absorption frequency and reactivity and it is postulated that a method of directly estimating the sigma+ constant for a particular substituent is possible by determining the charge transfer absorption frequency for the respective substituted benzene - T. C. N. E. complex. In particular, Traylor has suggested that strained cyclic substituents should exhibit vertical stabilisation in reactions involving carbonium ion formation. Traylor has attempted to demonstrate this theory of stabilisation by comparing the rates of solvolysis of various cyclic substituted carbinyl derivatives relative to the neopentyl derivative with the charge transfer frequencies of their respective substituted benzene - T. C. N. E. complexes. A plot of log relative rate of solvolysis against charge transfer frequency obtained by Traylor is shown. Using this plot Traylor has predicted the rate of solvolysis of the 1-norcaryl-and homocubyl-carbinyl systems. The scope of the present work has been to test this theory by determining the kinetics of electrophilic aromatic substitution of these cyclic substituted benzenes to see if, in fact, the rates predicted by Traylor are correct. Also, the homocubyl carbinyl compound was synthesised and the kinetics of solvolysis of the 3,5-dinitrobenzoate derivative in aqueous acetone were determined. Finally, the charge transfer absorption spectra of the cyclic substituted benzenes were recorded to see how accurately the absorption frequency could be determined for a particular substituent and to corroborate Traylor's results. The results obtained in this work suggest that Traylor's hypothesis of a method of estimating reaction rates by measuring the absorption maxima of the charge transfer complexes with T. C. N. E. needs to be taken with a great deal of reservation for several reasons. Firstly the inability to estimate accurately enough the exact position of the charge transfer absorption maxima. Secondly, the fact that the results of the electrophilic aromatic substitution reaction studied in this work, i. e. nitration, do not corroborate Traylor's theory. Finally, the rate of solvolysis of the homocubyl carbinyl system is much slower than that predicted by Traylor

Practical Implementation of Multiple Model Adaptive Estimation Using Neyman-Pearson Based Hypothesis Testing and Spectral Estimation Tools

This study investigates and develops various modifications to the Multiple Model Adaptive Estimation (MMAE) algorithm. The standard MMAE uses a bank of Kalman filters, each based on a different model of the system. Each of the filters predict the system response, based on its system model, to a given input and form the residual difference between the prediction and sensor measurements of the system response. Model differences in the input matrix, output matrix, and state transition matrix, which respectively correspond to an actuator failure, sensor failure, and an incorrectly modeled flight condition for a flight control failure application, were investigated in this research. An alternative filter bank structure is developed that uses a linear transform on the residual from a single Kalman filter to produce the equivalent residuals of the other Kalman filters in the standard MMAE. A Neyman Pearson based hypothesis testing algorithm is developed that results in significant improvement in failure detection performance when compared to the standard hypothesis testing algorithm. Hypothesis testing using spectral estimation techniques is also developed which provides superior failure identification performance at extremely small input levels

Failure Identification using Multiple Model Adaptive Estimation for the LAMBDA Flight Vehicle

This study develops and investigates the performance of a Multiple Model Adaptive Estimator (MMAE) to detect and identify control surface and sensor failures on the LAMBDA flight vehicle (a URV developed by Wright Laboratories). The MMAE uses a bank of Kalman filters that predict the aircraft response to a given input, with each filter model based on a different failure hypothesis, and then forms the residual difference between the prediction and sensor measurements for each filter. The MMAE uses these residuals to determine the probabilities of the failures that are modeled by the Kalman filters. Initially the MMAE identified all these failures within 4 seconds of onset. Various performance improvement techniques were researched and the identification time was reduced to less than 2 seconds after failure onset. This improvement was mostly due to an increase in the penalty for measurement differences, and through returning of the Kalman filters. The MMAE performance was tested at the boundaries of the LAMBDA flight envelope, with good performance found at points close to the design flight condition. The performance at points that were far from the design flight condition indicates that gain scheduling is required to provide adequate performance across the entire envelope

Long-term condition management in adults with intellectual disability in primary care: a systematic review

Background: Adults with intellectual disabilities have higher morbidity and earlier mortality than the general population. Access to primary health care is lower, despite a higher prevalence of many long-term conditions. Aim: To synthesise the evidence for the management of long-term conditions in adults with intellectual disabilities and identify barriers and facilitators to management in primary care. Design & setting: Mixed-methods systematic review. Method: Seven electronic databases were searched to identify both quantitative and qualitative studies concerning identification and management of long-term conditions in adults with intellectual disability in primary care. Both the screening of titles, abstracts, and full texts, and the quality assessment were carried out in duplicate. Findings were combined in a narrative synthesis. Results: Fifty-two studies were identified. Adults with intellectual disabilities are less likely than the general population to receive screening and health promotion interventions. Annual health checks may improve screening, identification of health needs, and management of long-term conditions. Health checks have been implemented in various primary care contexts, but the long-term impact on outcomes has not been investigated. Qualitative findings highlighted barriers and facilitators to primary care access, communication, and disease management. Accounts of experiences of adults with intellectual disabilities reveal a dilemma between promoting self-care and ensuring access to services, while avoiding paternalistic care. Conclusion: Adults with intellectual disabilities face numerous barriers to managing long-term conditions. Reasonable adjustments, based on the experience of adults with intellectual disability, in addition to intervention such as health checks, may improve access and management, but longer-term evaluation of their effectiveness is required

Systematic review and meta-analysis of the sero-epidemiological association between Epstein-Barr virus and rheumatoid arthritis

Acknowledgements The authors would like to thank Cynthia Fraser for helping run the literature search, Dr Neil Basu for providing advice on search terms for rheumatoid arthritis and to Xueli Jia, Katie Bannister and Kubra Boza for their help with foreign language papers. The authors would also like to thank the University of Aberdeen librarians at the Foresterhill medical library for their help in locating articles used for this systematic review and meta-analysis.Peer reviewedPublisher PD

Waring's Problem in Finite Rings

In this paper we obtain sharp results for Waring's problem over general finite rings, by using a combination of Artin-Wedderburn theory and Hensel's lemma and building on new proofs of analogous results over finite fields that are achieved using spectral graph theory. We also prove an analogue of S\'ark\"ozy's theorem for finite fields.Comment: 34 page

Influence of Sediment Nutrients on Growth of Emergent Hygrophila

Hygrophila ( Hygrophila polysperma (Roxb.) T. Anderson) is a plants which forms serious aquatic weed problems. Both submerged and emergent growth forms occur. Nutritional studies with a controlled release fertilizer and sediments collected from hygrophila-infested areas were conducted with the emergent growth habit to provide insights into growth of this introduced plant. Plant dry weights for experimental 16- week culture periods with low average temperatures were associated with low amounts of hygrophila biomass as compared to culture periods with high average temperatures. Hygrophila cultured in sand rooting media with the controlled release fertilizer produced as much as 20 times more dry weight than plants cultured in sediments only. First-degree linear regression statistics showed hygrophila dry weights were highly related to ammonia nitrogen, magnesium, sodium, and pH values in the sediments. These findings show the close relationship of the emergent growth habit of hygrophila to sediment nutrients. Analyses for certain sediment characteristics may provide an indication of the potential growth that may be expected for weed infestations of this plant. Hygrophila grows year round in south Florida; however, visual observations of canals and other bodies of water indicate that lower amounts of hygrophila plants occur during the cooler months of year than during the summer season. These findings show the seasonal growth of emergent hygrophila occurs with biomass dependent on both sediment nutrients and temperature

Interventions by healthcare professionals to improve management of physical long-term conditions in adults who are homeless: a systematic review protocol

Introduction People experiencing homelessness are at increased risk of, and have poorer outcomes from, a range of physical long-term conditions (LTCs). It is increasingly recognised that interventions targeting people who are homeless should be tailored to the specific needs of this population. This systematic review aims to identify, describe and appraise trials of interventions that aim to manage physical LTCs in homeless adults and are delivered by healthcare professionals. Methods and analysis Seven electronic databases (Medline, EMBASE, Cochrane Central Register of Controlled Trials, Assia, Scopus, PsycINFO and CINAHL) will be searched from 1960 (or inception) to October 2016 and supplemented by forward citation searching, handsearching of reference lists and searching grey literature. Two reviewers will independently review titles, abstract and full-texts using DistillerSR software. Inclusion criteria include (1) homeless adults with any physical LTC, (2) interventions delivered by a healthcare professional (any professional trained to provide any form of healthcare, but excluding social workers and professionals without health-related training), (3) comparison with usual care or an alternative intervention, (4) report outcomes such as healthcare usage, physical and psychological health or well-being or cost-effectiveness, (5) randomised controlled trials, non-randomised controlled trials, controlled before-after studies. Quality will be assessed using the Cochrane EPOC Risk of Bias Tool. A meta-analysis will be performed if sufficient data are identified; however, we anticipate a narrative synthesis will be performed. Ethics and dissemination This review will synthesise existing evidence for interventions delivered by healthcare professionals to manage physical LTCs in adults who are homeless. The findings will inform the development of future interventions and research aiming to improve the management of LTCs for people experiencing homelessness. Ethical approval will not be required for this systematic review as it does not contain individual patient data. We will disseminate the results of this systematic review via conference presentations, healthcare professional networks, social media and peer-reviewed publication

A systematic review of interventions by healthcare professionals to improve management of non-communicable diseases and communicable diseases requiring long-term care in adults who are homeless

Objective: Identify, describe and appraise trials of interventions delivered by healthcare professionals to manage non-communicable diseases (NCDs) and communicable diseases that require long-term care or treatment (LT-CDs), excluding mental health and substance use disorders, in homeless adults. Design: Systematic review of randomised controlled trials (RCTs), non-RCTs and controlled before–after studies. Interventions characterised using Effective Practice and Organisation of Care (EPOC) taxonomy. Quality assessed using EPOC risk of bias criteria. Data sources: Database searches (MEDLINE, Embase, PsycINFO, Scopus, Cumulative Index to Nursing and Allied Health Literature (CINAHL), Applied Social Sciences Index and Abstracts (ASSIA) and Cochrane Central Register of Controlled Trials), hand searching reference lists, citation searches, grey literature and contact with study authors. Setting: Community. Participants: Adults (≥18 years) fulfilling European Typology of Homelessness criteria. Intervention: Delivered by healthcare professionals managing NCD and LT-CDs. Outcomes: Primary outcome: unscheduled healthcare utilisation. Secondary outcomes: mortality, biological markers of disease control, adherence to treatment, engagement in care, patient satisfaction, knowledge, self-efficacy, quality of life and cost-effectiveness. Results: 11 studies were included (8 RCTs, 2 quasi-experimental and 1 feasibility) involving 9–520 participants (67%–94% male, median age 37–49 years). Ten from USA and one from UK. Studies included various NCDs (n=3); or focused on latent tuberculosis (n=4); HIV (n=2); hepatitis C (n=1) or type 2 diabetes (n=1). All interventions were complex with multiple components. Four described theories underpinning intervention. Three assessed unscheduled healthcare utilisation: none showed consistent reduction in hospitalisation or emergency department attendance. Six assessed adherence to specific treatments, of which four showed improved adherence to latent tuberculosis therapy. Three concerned education case management, all of which improved disease-specific knowledge. No improvements in biological markers of disease (two studies) and none assessed mortality. Conclusions: Evidence for management of NCD and LT-CDs in homeless adults is sparse. Educational case-management interventions may improve knowledge and medication adherence. Large trials of theory-based interventions are needed, assessing healthcare utilisation and outcomes as well as assessment of biological outcomes and cost-effectiveness