Steady-State and Ultrafast Fluorescence Depolarisation in Rigid-Rod Conjugated Polymers

Polarised spectroscopic techniques were used to investigate the underlying physics of steady-state and ultrafast fluorescence depolarisation in conjugated polymers. Depolarisation is due to fluorescence anisotropy: the angular difference between the absorption and emission transition dipole moments of a molecule. Polarised spectroscopy results from a polymer with a flexible backbone, poly (9,9-di(ethylhexyl)fluorene) were compared with those from two rigid backbone polymers: methyl-substituted ladder-type poly (para-phenylene) and the newly synthesised naphthylene ladder-type polymer (2,6-NLP). This revealed that there is an intrinsic anisotropy directly associated with the molecular backbone. This work is the first reported on 2,6-NLP. Fluorescence anisotropy was shown to be dependent upon the conjugation length; the transition dipole moments show larger angles for short lengths, tending to a minimum as the length increases. For rigid-rod polymers, this behaviour is replicated at each vibronic position. In the flexible polymer, planarisation of the backbone elongates the excited state over more conjugated bonds, changing the angle between the transition dipole moments, whereas in rigid-rod polymers, such elongation can only be electronic. Linear dichroism results obtained for all the polymers has shown the angle between the absorption transition dipole moment and the molecular backbone is large and that the emission transition dipole moment is aligned with the backbone. “Off-chain” to “on-chain” transition dipole moments arise from transitions from localised to delocalised states suggesting that the excited state in conjugated polymers is delocalised. Time-dependent measurements show that the main fluorescence depolarisation mechanism occurs in under 5 ps for both flexible and rigid polymers. The ultrafast timescale and the similarity of the two systems requires the process to be electronic in origin and not linked to a physical deformation. This work proposes that ultrafast fluorescence depolarisation is a result of the delocalisation of the electronic state as the conjugation length extends over more of the polymer

Nutritional and Phytochemical Content of High-Protein Crops

The authors acknowledge support from the Scottish Government’s Rural and Environment Science and Analytical Services Division (RESAS) via their strategic research and partnership programs.Peer reviewedPostprin

An evaluation of how digitised periodicals serve academic research in a New Zealand Context

Research problem This research investigates how researchers from humanities backgrounds research print periodicals that have been digitised. It investigates how New Zealand digitised periodical resources facilitate that research. How do these resources represent the periodical as an object, not just textual content? Methodology This research project is mixed methods in design combining two qualitative approaches of content analysis and a self-reporting survey comprised of mainly open-ended questions. These approaches facilitated exploration of rich data interspersed with some quantitative data to help interpret some of the findings. Both methods were undertaken simultaneously after an initial pilot study of one online source. The content analysis focused on four New Zealand digitised periodicals sources and there were nineteen responses to the survey. Results The findings indicated humanities researchers are using content and paratexts in their research. They require context from the digitised periodicals they use and they want good quality images and readable text. Researchers call for refinement of search results into component categories and want good browsing functionality. New Zealand digitised resources are inconsistent, fulfilling only some of these requirements and not delivering on others. Implications A better understanding of paratexts in periodicals and how they are used in research will address some of the assumptions in library practice that lead to incomplete digitisation and/or limited accessibility. The importance of consultation with targeted research communities during the planning of digitisation projects is highlighted

Patterns of organelle ontogeny through a cell cycle revealed by whole cell reconstructions using 3D electron microscopy

The major mammalian bloodstream form of the African sleeping sickness parasite Trypanosoma brucei multiplies rapidly, and it is important to understand how these cells divide. Organelle inheritance involves complex spatiotemporal re-arrangements to ensure correct distribution to daughter cells. Here, serial block face scanning electron microscopy (SBF-SEM) was used to reconstruct whole individual cells at different stages of the cell cycle to give an unprecedented temporal, spatial and quantitative view of organelle division, inheritance and abscission in a eukaryotic cell. Extensive mitochondrial branching occurred only along the ventral surface of the parasite, but the mitochondria returned to a tubular form during cytokinesis. Fission of the mitochondrion occurred within the cytoplasmic bridge during the final stage of cell division, correlating with cell abscission. The nuclei were located underneath each flagellum at mitosis and the mitotic spindle was located along the ventral surface, further demonstrating the asymmetric arrangement of cell cleavage in trypanosomes. Finally, measurements demonstrated that multiple Golgi bodies were accurately positioned along the flagellum attachment zone, suggesting a mechanism for determining the location of Golgi bodies along each flagellum during the cell cycle

Hemp and Buckwheat are valuable sources of dietary amino acids, beneficially modulating gastrointestinal hormones and promoting satiety in healthy volunteers

Acknowledgements: The authors are grateful to all the volunteers for their participance in this human study. The authors also are thankful for the assistance from Karen Taylor, Jean Bryce and Mel Hudson for the preparation of the study diets and Sylvia Stephen and Lorna Hermitage for their support in the Human Nutrition Unit. Furthermore, the authors would like to thank Dr Richard Herriot and Mrs Denise Mullen from Immunology Department, Aberdeen Royal Infirmary Hospital Foresterhill for performing the food allergy testing. Declarations Funding: The Rowett Institute and Biomathematics and Statistics Scotland are grateful for funding from The Scottish Government's Rural and Environment Science and Analytical Services Division (RESAS) via their strategic research and partnership programmes. Open Access via the Springer Compact AgreementPeer reviewedPublisher PD

‘It’s been a massive struggle’: Exploring the experiences of young people leaving care during COVID-19

This paper explores the experiences of young people leaving state careduring COVID-19. Twenty-one young people, predominantly from Wales, engaged in semi-structured interviews and / or contributed poems and artwork conveying their experiences of the pandemic. The data generated offered insights into young people’s daily lives, including their routines and relationships, as well as access to resources and services. The study found stark disparity in young people’s experiences, with some reassured by support responses, and others feeling neglected and forgotten. As an already disadvantaged group, the challenges presented by COVID19 further hinder young people’s transitions to adulthood. The ‘massive struggles’ faced by some young people reflect immediate difficulties which also have the potential for longer-term impacts. The recommendations of the study, informed by care-experienced young people, seek to positively influence policy and practice

Environmental Sensor Placement with Convolutional Gaussian Neural Processes

Environmental sensors are crucial for monitoring weather conditions and the impacts of climate change. However, it is challenging to maximise measurement informativeness and place sensors efficiently, particularly in remote regions like Antarctica. Probabilistic machine learning models can evaluate placement informativeness by predicting the uncertainty reduction provided by a new sensor. Gaussian process (GP) models are widely used for this purpose, but they struggle with capturing complex non-stationary behaviour and scaling to large datasets. This paper proposes using a convolutional Gaussian neural process (ConvGNP) to address these issues. A ConvGNP uses neural networks to parameterise a joint Gaussian distribution at arbitrary target locations, enabling flexibility and scalability. Using simulated surface air temperature anomaly over Antarctica as ground truth, the ConvGNP learns spatial and seasonal non-stationarities, outperforming a non-stationary GP baseline. In a simulated sensor placement experiment, the ConvGNP better predicts the performance boost obtained from new observations than GP baselines, leading to more informative sensor placements. We contrast our approach with physics-based sensor placement methods and propose future work towards an operational sensor placement recommendation system. This system could help to realise environmental digital twins that actively direct measurement sampling to improve the digital representation of reality.Comment: In review for the Climate Informatics 2023 special issue of Environmental Data Scienc