Astrocytes and neurons communicate via a monocarboxylic acid shuttle

Since formulation of the Astrocyte-Neuron Lactate Shuttle (ANLS) hypothesis in 1994, the hypothesis has provoked criticism and debate. Our review does not criticise, but rather integrates experimental data characterizing proton-linked monocarboxylate transporters (MCTs) into the ANLS. MCTs have wide substrate specificity and are discussed to be in protein complex with a proton donor (PD). We particularly focus on the proton-driven transfer of L-lactic acid (L-lacH) and pyruvic acid (pyrH), were PDs link MCTs to a flow of energy. The precise nature of the PD predicts the activity and catalytic direction of MCTs. By doing so, we postulate that the MCT4•phosphoglycerate kinase complex exports and at the same time in the same astrocyte, MCT1•carbonic anhydrase II complex imports monocarboxylic acids. Similarly, neuronal MCT2 preferentially imports pyrH. The repertoire of MCTs in astrocytes and neurons allows them to communicate via monocarboxylic acids. A change in imported pyrH/L-lacH ratio in favour of L-lacH encodes signals stabilizing the transit of glucose from astrocytes to neurons. The presented astrocyte neuron communication hypothesis has the potential to unite the community by suggesting that the exchange of monocarboxylic acids paves the path of glucose provision

Process and progression: an investigation into provoking curiosity by challenging and extending perceptual engagement

Through the production of small objects I have developed strategies for extending a viewer’s perceptual engagement by provoking curiosity via ambiguity of form and challenging expectations through materiality. The process of creative development is embedded in both the content and production. The main aim of the project was to build objects that invite and reward acute attention to material nature and relationships between forms. My intention was to fabricate small jewellery scale objects in metal that are shaped by the progression and evolution within my creative processes against a backdrop of discourse on visual attention and perception. In particular this research focused on perception and attention to detail and their role in gain a deeper understanding of ‘cause and effect’ and its importance in the continued development and progress of idea/concept and also in relation to physical manual engagement and material control. Using insights into the manner of human visual perception I devised forms that explore the effects of variations in the scale, detail, structure and contrasts in materiality as a means to encourage and intensify curiosity and reward a viewer’s sensory attentiveness; in effect drawing parallels between the process of the artist and the viewers perceptions of the artworks that result

Burning Man’s Mathematical Underbelly

A math degree can take you to a lot of places, both physically and figuratively, and if you play your cards right, you too can argue counterfactual definiteness with a shaman. First in 2008, and several times since, a fellow math PhD and I traveled to the Burning Man art festival to sit in the desert and talk with the locals about whatever they happened to be curious about

Underactuated Attitude Control of a CubeSat Using Cold Gas Thrusters and Nonlinear Control Methods

Impulsive thrusters on small satellites, such as CubeSats, are typically used for attitude control. However, to become more agile, small CubeSats must also look to propulsion systems utilizing impulsive thrusters, such as cold-gas, for translational maneuvers. The combined thrust vector is often misaligned with the system\u27s center of mass resulting in a disturbance torque. This must be counteracted by either an attitude determination and control system (ADCS), additional thrusters, or a control method to keep the satellite\u27s attitude at or near equilibrium. Nonlinearities generated by the impulsive maneuvers are overcome via control techniques explored in this research to include on-off control, sliding mode control, and model reference adaptive control (MRAC). These methods were then compared to a baseline test without thruster modulation, where the reaction wheels must de-saturate prior to continuing the maneuver. For a 1.5 m/s delta-v maneuver, the nonlinear control techniques completed the maneuver nearly 100 times faster than the baseline, while improving pointing accuracy throughout the burn by up to 5%

Lived experiences of multimorbidity: an interpretative meta-synthesis of patients', general practitioners' and trainees' perceptions

OBJECTIVES: Multimorbidity is an increasing challenge. Better understanding of lived experiences of patients, general practitioners and trainees, may advance patient care and medical education. This interpretative meta-synthesis sought to (i) understand lived experiences of patients, general practitioners and trainees regarding multimorbidity, (ii) identify how similarities and differences in experiences should shape future solutions. METHODS: Empirical studies containing qualitative data and pertaining to lived experiences from our recent realist synthesis (PROSPERO 2013:CRD42013003862) were included. Following quality assessment, data were extracted from key studies to build an integrated analytic framework. Data from remaining studies were utilised to expand and refine the framework through thematic analysis of concepts within and between perspectives. RESULTS: Twenty-one papers were included in the meta-synthesis. Analysis of 70 concepts produced five themes: (1) goals of care and decision making, (2) complexity, (3) meeting expectations, (4) logistics and (5) interpersonal dynamics. The complexities of multimorbidity lead to shared feelings of vulnerability, uncertainty and enforced compromises. Barriers to optimal care-education included system constraints, inadequate continuity and role uncertainty. DISCUSSION: There was little evidence of shared discussion of these challenges. Addressing these issues and more explicit exploration of the experiences of each group during interactions may improve delivery and satisfaction in care and education

The basis of resilience in forest tree species and its use in adaptive forest management in Britain

Forest ecosystems face a range of challenges in the coming decades, of which climate change, pests and diseases are the most serious. These challenges will be overlaid on a background of historically modified and fragmented forests managed in a wide range of ways for different objectives. As northern temperate forests are species-poor in a global context, their resilience to these challenges is fundamentally dependent on the resilience of individual species. However, dealing with each new threat as it arises is unlikely to be cost effective and in any case, probably not practically feasible. A better strategy for establishing long term resilience would be to harness evolutionary processes, to maximise the capability of individual tree species to respond to new threats by the reorganisation of populations via natural selection; in other words, to be resilient. Such processes depend on the internal variability of species, their mechanisms of dispersal and their ability to recruit new genotypes to a population. In this paper we review the theoretical concept of resilience, examine how it might be applied to tree populations and assess the state of knowledge of Britain’s forests from this perspective