Publications by authors named "Niven J"

Background: Immunometabolism is a crucial determinant of immune cell function, influencing cellular activation and differentiation through metabolic pathways. The intricate interplay between metabolism and immune responses is highlighted by the distinct metabolic programs utilized by immune cells to support their functions. Of particular interest is the pentose phosphate pathway (PPP), a key metabolic pathway branching out of glycolysis that plays a pivotal role in generating NADPH and pentose sugars crucial for antioxidant defense and biosynthesis.

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T cells play a key role in driving autoimmunity, with alterations in metabolism powering their effector function. In the July 11 issue of Cell Metabolism, Jenkins et al. describe how a type 2 diabetes drug, canagliflozin, can be repurposed for the treatment of autoimmune disorders through metabolic reprogramming of the T cell response.

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The negative effects of artificial lighting at night (ALAN) on insects are increasingly recognised and have been postulated as one possible cause of declines in insect populations. Yet, the behavioural mechanisms underpinning ALAN effects on insects remain unclear. ALAN interferes with the bioluminescent signal female glow-worms use to attract males, disrupting reproduction.

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Wood ants are excellent navigators, using a combination of innate and learnt navigational strategies to travel between their nest and feeding sites. Visual navigation in ants has been studied extensively, however, we have little direct evidence for the underlying neural mechanisms. Here, we perform lateralized mechanical lesions in the central complex (CX) of wood ants, a midline structure known to allow an insect to keep track of the direction of sensory cues relative to its own orientation and to control movement.

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High rates of postgraduate researchers (PGRs) terminate their studies early. This attrition can have detrimental personal consequences, and results in a loss of productivity, and research and innovation for the higher education sector and society as a whole. PGRs are vulnerable to the experience of mental health problems; a factor that appears to be increasing attrition amongst students in the UK.

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Introduction: Multidomain interventions to address modifiable risk factors for dementia are promising, but require more cost-effective, scalable delivery. This study investigated the feasibility of the "Active Brains" digital behavior change intervention and its trial procedures.

Materials And Methods: Active Brains aims to reduce cognitive decline by promoting physical activity, healthy eating, and online cognitive training.

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The movements of animal appendages are determined by extrinsic and intrinsic forces. Extrinsic forces include gravity or friction, whereas intrinsic forces are generated by active muscle contraction or passive musculoskeletal elements. For lightweight appendages, such as insect limbs, movements depend more upon intrinsic than extrinsic forces.

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Western diet (WD), high in sugar and fat, promotes obesity and associated chronic low-grade pro-inflammatory environment, leading to impaired immune function, reprogramming of innate and adaptive immune cells, and development of chronic degenerative diseases, including cardiovascular disease. Increased concentrations of circulating and tissue ceramides contribute to inflammation and cellular dysfunction common in immune metabolic and cardiometabolic disease. Therefore, ceramide-lowering interventions have been considered as strategies to improve adipose tissue health.

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Background: Individuals within the same species often differ in their metabolic rates, which may covary with behavioural traits (such as exploration), that are consistent across time and/or contexts, and morphological traits. Yet, despite the frequent occurrence of sexual dimorphisms in morphology and behaviour, few studies have assessed whether and how sexes differ in metabolic trait covariances.

Methods: We investigated sex-specific relationships among resting or active metabolic rate (RMR and AMR, respectively) with exploratory behaviour, measured independently of metabolic rate in a novel environment, body size and body mass, in ground beetles.

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Insects can navigate efficiently in both novel and familiar environments, and this requires flexiblity in how they are guided by sensory cues. A prominent landmark, for example, can elicit strong innate behaviours (attraction or menotaxis) but can also be used, after learning, as a specific directional cue as part of a navigation memory. However, the mechanisms that allow both pathways to co-exist, interact or override each other are largely unknown.

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Background: By 2050, worldwide dementia prevalence is expected to triple. Affordable, scalable interventions are required to support protective behaviours such as physical activity, cognitive training and healthy eating. This paper outlines the theory-, evidence- and person-based development of 'Active Brains': a multi-domain digital behaviour change intervention to reduce cognitive decline amongst older adults.

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Background: Cardiothoracic surgical outcomes are poorer in people with diabetes compared with those without diabetes. There are two important uncertainties in the management of people with diabetes undergoing major surgery: (1) how to improve diabetes management in the weeks leading up to an elective procedure and (2) whether that improved management leads to improved postoperative outcomes. The aim of this study was to develop and pilot a specialist diabetes team-led intervention to improve surgical outcomes in people with diabetes.

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Species' ranges are dynamic, changing through range shifts, contractions, and expansions. Individuals at the edge of a species' shifting range often possess morphological traits that increase movement capacity, that are not observed in individuals farther back within the species' range. Although morphological traits that increase in proportion toward the range edge may differ between the sexes, such sex differences are rarely studied.

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Resting metabolic rate (RMR) is a fundamental physiological measure linked to numerous aspects of organismal function, including lifespan. Although dietary restriction in insects during larval growth/development affects adult RMR, the impact of the nutritional composition of larval diets (i.e.

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Introduction: Cardiothoracic surgical outcomes are poorer in people with diabetes compared with those without diabetes. There are two important uncertainties in the management of people with diabetes undergoing major surgery: (1) how to improve diabetes management in the weeks leading up to an elective procedure and (2) whether that improved management leads to better postoperative outcomes. We previously demonstrated the feasibility of delivering the Optimising Cardiac Surgery ouTcOmes in People with diabeteS (OCTOPuS) intervention, an outpatient intervention delivered by diabetes healthcare professionals for people with suboptimally managed diabetes over 8-12 weeks before elective cardiac surgery.

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Obesity is considered a global epidemic developed in part as a consequence of the overconsumption of high fat diets. One of the main negative outcomes of obesity is the development of low-grade chronic systemic inflammation, induced by dysregulated immune responses, which can lead to multiple obesity-related diseases. Ceramides are a group of bioactive lipids known to be elevated in obesity and obesity-associated conditions, including cardiovascular disease and type II diabetes.

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Article Synopsis
  • Lymphatic endothelial cells (LECs) play a crucial role in inducing T cell tolerance and are the primary source of sphingosine-1-phosphate (S1P), which is important for T cell survival and movement from lymph nodes.
  • Research shows that while disrupting autophagy in LECs doesn't impact overall immune balance, it disrupts regulatory T cell populations in arthritic mice, potentially affecting how LECs present antigens.
  • Inflammation triggers autophagy in LECs that helps degrade Sphingosine kinase 1, leading to reduced S1P levels; this results in enhanced Th17 cell migration and worsens arthritis symptoms in mice lacking autophagy in LECs.
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The natural scale of insect navigation during foraging makes it challenging to study under controlled conditions. Virtual reality and trackball setups have offered experimental control over visual environments while studying tethered insects, but potential limitations and confounds introduced by tethering motivates the development of alternative untethered solutions. In this paper, we validate the use of a motion compensator (or 'treadmill') to study visually driven behaviour of freely moving wood ants ().

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Background: Increasing physical activity, improving diet, and performing brain training exercises are associated with reduced cognitive decline in older adults.

Objective: In this paper, we describe a feasibility trial of the Active Brains intervention, a web-based digital intervention developed to support older adults to make these 3 healthy behavior changes associated with improved cognitive health. The Active Brains trial is a randomized feasibility trial that will test how accessible, acceptable, and feasible the Active Brains intervention is and the effectiveness of the study procedures that we intend to use in the larger, main trial.

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Malpighian tubules, analogous to vertebrate nephrons, play a key role in insect osmoregulation and detoxification. Tubules can become infected with a protozoan, Malpighamoeba, which damages their epithelial cells, potentially compromising their function. Here we used a modified Ramsay assay to quantify the impact of Malpighamoeba infection on fluid secretion and P-glycoprotein-dependent detoxification by desert locust Malpighian tubules.

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Background: Data from studies with undergraduate and postgraduate taught students suggest that they are at an increased risk of having mental health problems, compared to the general population. By contrast, the literature on doctoral researchers (DRs) is far more disparate and unclear. There is a need to bring together current findings and identify what questions still need to be answered.

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Visual navigation in ants has long been a focus of experimental study [1-3], but only recently have explicit hypotheses about the underlying neural circuitry been proposed [4]. Indirect evidence suggests the mushroom bodies (MBs) may be the substrate for visual memory in navigation tasks [5-7], while computational modeling shows that MB neural architecture could support this function [8, 9]. There is, however, no direct evidence that ants require MBs for visual navigation.

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Artificial lighting at night (ALAN) is increasingly recognised as having negative effects on many organisms, though the exact mechanisms remain unclear. Glow worms are likely susceptible to ALAN because females use bioluminescence to signal to attract males. We quantified the impact of ALAN by comparing the efficacy of traps that mimicked females to attract males in the presence or absence of a white artificial light source (ALS).

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We present experiments to study the relaxation of a nanoscale cylindrical perturbation at one of the two interfaces of a thin viscous freestanding polymeric film. Driven by capillarity, the film flows and evolves toward equilibrium by first symmetrizing the perturbation between the two interfaces and eventually broadening the perturbation. A full-Stokes hydrodynamic model is presented, which accounts for both the vertical and lateral flows and which highlights the symmetry in the system.

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Predators must often employ flexible strategies to capture prey. Particular attention has been given to the strategies of visual predators that actively pursue their prey, but sit-and-wait predators have been largely overlooked, their strategies often characterized as stereotyped. Praying mantids are primarily sit-and-wait predators that often employ crypsis to catch their prey using a raptorial strike produced by their highly modified forelimbs.

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