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Development of methods for a 2-carbon extension of fatty acids under mild conditions
No full textPolyunsaturated fatty acids (PUFAs) play important roles in the human body in preventing and treating diverse diseases which includes Alzheimer's disease, cancers, cardiovascular diseases, epilepsy, inflammatory diseases and many others. Eicosapentaenoic acid (EPA) and Docosahexaenoic acid (DHA) sourced from marine fish are beneficial for vision and brain development. However, polyunsaturated fatty acids cannot be synthesized by the body and are obtained from dietary sources such as fish oils, nuts, seeds and dairy products. Extending the chain of polyunsaturated fatty acids by 2 carbons results in rare lipids for biological evaluation, which cannot be obtained in large quantities from plant and animal sources and is therefore the aim of this study. The objective was to develop methods of a 2-carbon chain elongation of the polyunsaturated fatty acids under mild conditions using Meldrum’s acid under basic conditions. Furthermore, ring opening of the Meldrum’s acid under different reaction conditions led to the synthesis of the esters of the 2-carbon extended fatty acids.The optimisations were first investigated using a model compound, 4-methoxyphenylacetic acid, which were then employed to the fatty acids of interest. 4-methoxyphenylacetic acid in the acylation and reduction steps with carbonyldiimidazole obtained a yield of 54% and ethyl ester yield of 49%. The esterification of the fatty acids occurred under acid-free (basic) conditions and shorter reaction times. The 5-alkyl Meldrum’s acid derivatives of oleic acid and dihomo--linolenic acid yielded very low quantities of 2% and 7% respectively. Nevertheless, the longer chain fatty acids did not yield desired results which could be attributed to non-enzymatic oxidation.In conclusion, rare lipids were synthesized in a 3-step reaction under basic conditions and shorter reaction time with Meldrum’s acid as a precursor and a coupling agent, but antioxidants are necessary for longer chain fatty acids to prevent oxidative degradation
Localised geomorphic response to channel-spanning leaky wooden dams
Get PDFThe introduction of leaky wooden dams (or engineered log jams or LDs) into river corridors in low-order steams in upper catchments has recently become a popular form of natural flood management, particularly in NW Europe. LDs are designed to emulate processes such as those of naturally occurring large wood in river systems, aiming to reduce downstream flood risk through the attenuation of water during higher flows, decreasing in-channel velocities and increasing channel–floodplain connectivity. LDs effectively act as channel roughness agents that disrupt the fluvial and hydrological regime and attenuate the peaks in high river flows, thus mitigating downstream flood risk. Despite their widespread installation, there is a paucity of data and understanding concerning the longer-term fluvial geomorphological response to LD installation. Here we present a detailed quantification of both the geomorphic and sedimentary response to the installation of two LDs in a catchment in Dalby Forest (North Yorkshire, UK) using high-resolution terrestrial laser scanning and detailed bathymetric surveys over a 2.5-year period. This period included two major storms with a recurrence interval of 3.9 and 3.4 years, and a further four smaller storm events (1.22–2.3 years). Results show that when LDs are engaged by the river flow, local topographic complexity significantly increases as sediment transport pathways are perturbed. The flow field complexity additionally changes the channel bed grain-size distribution, with trends of fining upstream and coarsening downstream of the structure observed. The LD was also observed to generate scour pools downstream of the structure, and coarsen the armour layer through the winnowing of fines. Monthly observations reveal that channel topography and bed sediment patterns self-organise in response to sustained low flows and are perturbed by higher flow events. The findings highlight how frequent monitoring of different LD designs and structures under various flow conditions is vital to understand their longer-term impacts. Moreover, it is critical that such observations are extended over longer-term periods in order to fully assess the efficacy of the structures as the channels respond to installations and the evolution of the geomorphic response. Finally, additional work is also required to better consider how individual LDs influence local geomorphology and alter sediment transport connectivity throughout the catchment
The longitudinal relationships between the built and natural environment, air pollution, noise and dementia: results from two UK-based cohort studies
Get PDFObjective: Recent epidemiological studies have investigated a variety of environmental risk factors for dementia. However, most existing studies have focused on single environmental factors and reported mixed results. The aim of this study is to examine the interrelationships between multiple environment factors and their joint associations with cognitive health in later life. Methods: This study was based on the Cognitive Function and Ageing Study II and Wales, two population-based cohort studies of 11,055 people aged ≥65 across five urban and rural areas in the UK. Using geospatial data, a wide range of environmental variables were generated for the participants and integrated into five domains through a latent approach, including the built environment, natural environment, noise, air pollution and deprivation. Multistate modelling was used to investigate their longitudinal associations with dementia and death adjusting for individual sociodemographic factors. Results: The effect sizes of joint associations between the built environment (HR: 1.00; 95 %CI: 0.66, 1.52), natural environment (HR: 0.95; 95 %CI: 0.66, 1.36), air pollution (HR: 0.91; 95 %CI: 0.78, 1.07), deprivation (HR: 1.02; 95 %CI: 0.96, 1.09) and incident dementia were generally small. The strongest association was found in noise, where a high level of exposure was associated with an increased risk of incident dementia (HR: 1.22; 95 %CI: 0.97, 1.54). However, the confidence intervals were wide. Conclusions: The joint associations between multiple environmental factors and incident dementia were found to be modest. Given mixed results in this field, future research should address methodological challenges and enhance evidence for population-level interventions on dementia risk factors
Tsunami Risk to UK Offshore Wind: Paleo-evidence and numerical model simulation
No full textThe UK produces over 45% of its energy through renewable means, the majority of this through wind power. The mainstay of this capacity is located offshore in the North Sea, a region and capacity which is set to significantly expand in the coming years. Given the increasing importance of offshore wind generation for UK energy security and net zero goals, it is becoming ever more vital that all stages of this generation method be risk assessed to ensure that no single event can cripple the nation’s energy supply.High Magnitude, Low Frequency events (HMLF), such as tsunamis, are often overlooked during risk assessments due to their infrequent nature. This thesis locates and analyses sedimentological evidence of one such HMLF event, the Storegga tsunami, and shows that such events have propagated through the North Sea and impacted upon the eastern coast of the UK. Specifically, sedimentological evidence for the Storegga tsunami is located in cores from Howick Burn in Northumberland.Using this data as a baseline, this thesis then uses inverse and forwards analysis models to determine the possible extent and severity of a Storegga-scale tsunami event in the present day. Inundation maps are utilised to assess potential damage to land-based assets of the offshore wind industry and national grid as a whole, and these suggest that a tsunami of a similar magnitude to Storegga could lead to a loss of between 9.1 and 10.3 GW of power generation, which amounts to 39% of UK power generation. About half of this loss is through the impacts upon offshore wind infrastructure, especially due to the damage to onshoring cabling sites and Operations and Maintenance (O&M) bases.This thesis therefore concludes that the risk from tsunami to offshore wind infrastructure is currently overlooked. Given the increasing importance of offshore wind to UK energy production, and the vulnerability of some stages of this generation method, it is important that more consideration is given to the protection of this infrastructure against the impacts of a tsunami
Negative pressure wound therapy versus usual care in patients with surgical wound healing by secondary intention in the UK (SWHSI-2): an open-label, multicentre, parallel-group, randomised controlled trial
Get PDFBackground: Surgical wound healing by secondary intention (SWHSI) presents a substantial management and financial challenge. Negative pressure wound therapy (NPWT) has increasingly been used as a treatment despite an absence of comparative evidence of effectiveness. We evaluated the effectiveness of NPWT compared with usual care for improving time to wound healing in patients with an SWHSI. Methods: We did a pragmatic, open-label, multicentre, parallel-group, randomised controlled trial in 29 UK National Health Service Trusts. Participants aged 16 years or older with an SWHSI appropriate for both study treatments (NPWT or usual care) were randomly assigned (1:1) by a centralised web-based system. Randomisation was stratified by wound location, wound area, and study centre. Participants were followed up for 12 months. Participants and clinical and research teams could not be masked to treatment. Assessors masked to treatment reviewed wound photography to verify the outcome. The primary outcome was time to wound healing (days from randomisation to complete epithelial cover), analysed via intention to treat using Kaplan–Meier survival curves and a proportional hazards Cox regression model. The trial was registered with ISRCTN, ISRCTN26277546. Findings: Between May 15, 2019, and Jan 13, 2023, 686 participants with an SWHSI were randomly assigned to receive NPWT (n=349) or usual care (n=337). All participants were included in the primary analysis. Most participants were diabetic (n=549, 80·0%) and had a single SWHSI (n=622, 90·7%), located on the foot or leg (n=620, 90·4%), arising after vascular surgery (n=619, 90·2%). There was no clear evidence that NPWT reduced the time to wound healing compared with usual care (hazard ratio 1·08 [95% CI 0·88–1·32], p=0·47). There were 448 adverse events, of which 14 were serious (nine participants in the NPWT group and five participants in the usual care group); 124 were deemed potentially related to treatment. NPWT was found not to be cost-effective compared with usual care. Interpretation: In patients with a lower limb SWHSI, including those with complications of diabetes, there is no clear evidence that NPWT reduced the time to wound healing compared with standard dressings. These findings do not support the use of NPWT to augment SWHSI healing. Funding: National Institute for Health Research Health Technology Assessment Programme
Transformer-Driven Active Transfer Learning for Cross-Hyperspectral Image Classification
Get PDFHyperspectral image (HSI) classification presents inherent challenges due to high spectral dimensionality, significant domain shifts, and limited availability of labeled data. To address these issues, we propose a novel Active Transfer Learning (ATL) framework built upon a Spatial-Spectral Transformer (SST) backbone. The framework integrates multistage transfer learning with an uncertainty-diversity-driven active learning mechanism that strategically selects highly informative and diverse samples for annotation, thereby significantly reducing labeling costs and mitigating sample redundancy. A dynamic layer freezing strategy is introduced to enhance transferability and computational efficiency, enabling selective adaptation of model layers based on domain shift characteristics. Furthermore, we incorporate a self-calibrated attention mechanism that dynamically refines spatial and spectral weights during adaptation, guided by uncertainty-aware feedback. A diversity-promoting sampling strategy ensures broad spectral coverage among selected samples, preventing overfitting to specific classes. Extensive experiments on benchmark cross-domain HSI datasets demonstrate that the proposed SST-ATL framework achieves superior classification performance compared to conventional approaches
‘Official’ Histories of the End of Empire
Get PDFThe study of the end of empire through the production of official histories has been a challenging undertaking due to the sensitivities and controversies that accompanied imperial deconstruction. The choice of editors also affected the ways in which the demission of empire was reflected. Although the quasi-official British Documents on the End of Empire represented a progression from previous official histories by incorporating documents drawn from a wider range of Whitehall departments, its shortcomings were exposed by the revelation that thousands of files, the so-called ‘migrated files’, generated by the colonial administrations themselves, had been clandestinely held by the FCO
Reconfiguring Resource Orchestration via Social Capital: A Processual View of Blockchain in Supply Chains
Get PDFPurpose – This study examines how social capital's cognitive and relational dimensions enable effective resource orchestration for blockchain implementation in global supply chains. It reconceptualizes blockchain implementation as a dynamic, cyclical process shaped by evolving interorganizational trust and collaboration. Design/methodology/approach – Adopting an abductive, multi-case qualitative methodology, this study examines data collected from a UK-based food manufacturer and nine of its suppliers from developing economies. Primary data, along with secondary documents, is analyzed using social capital theory as the primary lens and resource orchestration theory as a secondary lens. Findings – Findings reveal that while structural capital is foundational, advanced cognitive and relational capital are vital for successful blockchain implementation. Features of blockchain, like immutability and automated verification, enable trust to shift from interpersonal to system-based. Challenging linear models, the study shows a recursive loop where blockchain reinforces social capital, enabling ongoing collaboration and capability building. Practical implications – Managers should approach blockchain not merely as a technological upgrade but as a relational transformation. Successful implementation requires phased trust-building, capability alignment and tailored orchestration strategies suited to the digital maturity of supply chain partners. Originality/value – This research contributes a novel integrative framework linking social capital and resource orchestration in a digitally mediated context, a perspective largely overlooked in the existing literature. It challenges deterministic blockchain implementation models by introducing a co-evolutionary perspective grounded in trust dynamics
Baseline clinical factors associated with diabetes distress in dialysis patients: Insights from the ABCD audit data
No full textIntroduction: Diabetes is the leading cause of end-stage renal disease (ESRD) in the United Kingdom, accounting for one third of individuals starting renal replacement therapy (RRT). Data on the prevalence of diabetes distress (DD) in people with Diabetic Kidney Disease (DKD) on dialysis are scarce. Aim: To describe the prevalence of DD in people living with diabetes undergoing haemodialysis. Methods: We used baseline data from the Association of British Clinical Diabetologists nationwide audit of people with diabetes in the United Kingdom. Analysis was limited to people who were started on intermittently scanned continuous glucose monitoring (isCGM) who were undergoing haemodialysis. DD was assessed using the two-item diabetes distress scale (DDS-2). High DD was defined as a DDS score ≥3, while low DD was DDS score <3. Comparisons were made between patients with type 1 diabetes mellitus (T1DM) and type 2 diabetes mellitus (T2DM). Chi-square test was used to assess the difference between categorical variables, and a t test for continuous variables. Results: Eighty-six people with diabetes who were on haemodialysis were included in this study. Forty-eight had T1DM whereas thirty-eight had T2DM. Overall, 31 (36%) were female. The mean age was 60.7 years ± 15.5. The duration of diabetes was significantly shorter in the T2DM group (20.6 years ± 8.8) compared to the T1DM group (25.8 years ± 13.6) (p = 0.04). Overall, the average DDS score was 2.7 (±1.59). The prevalence of severe DD (DDS ≥ 3) was 42%. DD among those with T1DM was 43% compared to 40% in T2DM (p = 0.96). Body mass index was negatively correlated with high DD (p < 0.001). Conclusion: Diabetes distress is highly prevalent among individuals with diabetes on haemodialysis and appears to be influenced more by the challenges of dialysis than traditional diabetes-related factors. These findings highlight the need for routine screening and tailored psychological support for this vulnerable population to improve emotional well-being and overall care outcomes
pH Challenges in the Life of Pagurus bernhardus: Chemotaxis, Feeding, and Energy Allocation
Get PDFIt is established that decreasing ocean pH is adversely impacting marine organisms’ behaviour and physiology. In this thesis, I tested the hypothesis that challenges in the life of ocean acidification are not an isolated mechanism but an interplay between chemical communication, physiological shifts, and energy dynamics. Chemotactic traits were explored utilising pH-dependent signalling molecules at current and future predicted pH conditions to identify if chemoreceptive disruption is at the detection level or potentially physiological. The chemotactic traits in speed, acceleration, distance moved, and the average distance from chemicals were measured in individuals across pH treatments (7.7 and 8.2). The results show that ocean acidification negatively impacted chemotactic traits under the pH-sensitive chemical, which protonates more under reduced pH than the control, suggesting chemotaxis is altered by infodisruption and not energy conservation. During the chemotactic experiment, food ingestion rates of P.bernhardus were analysed at the same time at pH 8.2 and pH 7.7. Reduced pH increased the rate of food consumption immediately; these effects were exacerbated with pH exposure time. The scope for growth, or P.bernhardus was conducted in current pH (8.2), future pre-dicted pH (7.7), and extreme predicted intertidal pH (7.4) to identify the energy budget reserves of organisms.A reduced pH of 7.7 limits scope for growth potential, while a pH of 7.4 causes metabolic depression and increases SFG. Enzymatic and surface morphology analysis showed that reduced pH treatments can inflict energetic costs and potentially damage to the surface of the exoskeleton and sites of chemoreceptive organ anchorage (setae).The results obtained from this doctoral thesis provide substantiating evidence for the proposition that diminished pH constitutes a multifaceted stressor, capable of instigating both behavioural and physiological repercussions. The intricate interplay between these factors may give rise to extensive ramifications for intertidal populations in climate change scenarios