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An investigation of links between metabolic rate and feed efficiency in European sea bass Dicentrarchus labrax
No full textFeed efficiency (FE) is the amount of body weight gain for a given feed intake. Improving FE through selective breeding is key for sustainable finfish aquaculture but its evaluation at individual level is technically challenging. We therefore investigated whether individual routine metabolic rate (RMR) was a predictor of individual FE in the European sea bass Dicentrarchus labrax, a major species in European mariculture. The European sea bass has three genetically distinct populations across its geographical range, namely Atlantic Ocean (AT), West Mediterranean (WM) and East Mediterranean (EM). We compared FE and RMR of fish from these three populations at 18°C or 24°C. We held 200 fish (62 AT, 66 WM and 72 EM) in individual aquaria and fed them from ad libitum down to fasting. Feed efficiency was assessed for an ad libitum feeding rate and for a fixed restricted ration (1% of metabolic body weight.day -1, with metabolic body weight = body weight 0.8). After being refed 12 weeks in a common tank, individual RMR was measured over 36h by intermittent flow respirometry. There was a significant effect of temperature whereby fish at 18°C had greater mean FE (P 0.05). Therefore, although the results provide evidence of an association between metabolic rate and FE, RMR was not a predictor of individual FE, for reasons that require further investigation
Pulmonary therapy podcast-COVID-19: Research and real-world experiences from the Editorial Board
No full textThe Editorial Board have prepared a podcast describing their experiences over the past year of the COVID-19 pandemic. The Editorial Board describe how COVID-19 impacted their research and how the initial clinical response changed over the course of the year in terms of treatment, personal protective equipment (PPE), and policy changes. The podcast and transcript can be viewed below the abstract of the online version of the manuscript. Alternatively, the podcast and transcript can be downloaded here: https://doi.org/10.6084/m9.figshare.1440229
Exploring the α2-adrenergic receptors with alkyl substituted bis-guanidinium diaryl derivatives
No full textThe burden of mental health conditions is on the rise globally. It is well documented that noradrenaline has a key role in memory, attention, stress, and regulation of emotions. The α2-adrenergic receptors (α2-ARs) are an attractive biological target for therapies for neurological conditions. Thus, α2-AR antagonists would block the activation of this autoreceptor potentially operating as therapeutic antidepressant agent. In a ligand-based drug design strategy we have investigated the effects on the binding affinity and ligand-receptor functional activity when releasing the rigid 2-aminoimidazolium moiety of lead compound 1, thus affecting steric and lipophilic properties. This aim will be achieved via computational studies, synthesis, and pharmacological evaluation. Due to their relevance in depression, three inactive α2A-AR receptor templates were used in the docking study: a homology model developed by Prof. Olivella, and two crystal structures recently reported, one complexed with a partial agonist and another with an antagonist. Compounds 1 (lead, symmetric), 15 (asymmetric), 16 (asymmetric), 18 (symmetric) and 22c (symmetric) were used as ligands for standard rigid receptor and fit-induced docking studies. All docked compounds were orientated based on the ionic interaction with the aspartate residue D1133.32, a known critical anchoring interaction with the α2-AR binding sites. Agonists 15 and 18 show interactions with S2005.42, a known residue involved in agonist activity, Moreover, the interaction between the ligand and E942.65 is common to the two known antagonists 16 and 22c and this could assist in directing the ligand away from TM5, avoiding receptor activation. A new synthesis of di-Boc-protected mono-substituted thioureas was developed utilizing Mitsunobu reaction conditions. Additionally, five new compounds were prepared, characterised using 1H and 13C NMR, IR, and HRMS. The α2-AR binding affinities of these compounds were measured in human prefrontal cortex tissue using a competitive assay with the α2-AR selective radioligand [3H]RX821002. When the ligands showed α2-AR affinity with Ki < 100 nM, functional [35S]GTPγS assays were used to determine their activity (i.e. antagonist, agonist or inverse agonist). Encouragingly, one of the five newly synthesised compounds (22c) displayed a binding affinity of 95.50 nM (best of substituted bis-guanidinium ligands to date) and antagonist activity. Considering past and present results with compounds 1, 16, 17 and 22c, a derivative containing both an imidazolium moiety and an ethyl-substituted guanidinium could be a very promising high affinity antagonist
Highly Selective Non-Covalent On-Chip Functionalization of Layered Materials
No full textNon-covalent functionalization of layered 2D materials is an essential tool
to modify and fully harness their optical, electrical, and chemical properties.
Herein, a facile method enabling the selective formation of self-assembled
monolayers (SAMs) of perylene bisimide (PBI) on transition metal dichal-
cogenides (TMDs), directly on the growth substrate (on-chip), is presented.
Laterally-resolved infrared atomic force microscopy (AFM-IR) and time-of-
flight secondary ion mass spectrometry (TOF-SIMS) are applied as superior
techniques to gain detailed information beyond traditional surface analysis
techniques, such as Raman spectroscopy and AFM, on TMD/PBI structures.
The highly selective functionalization conducted in organic solution on MoS
and WSe
opens up a pathway to controllable, versatile functionalization of
layered materials, which is highly sought after for its potential in passiva-
tion, tuning of properties and applications in optics, electronics, and (bio-)
sensing
The Personalization of Electoral Rules: How Shifting Influence From Selectors to Voters Affects Party Unity
No full textHow does making electoral systems more candidate-centered affect party unity? Using a principal-agent perspective, this study makes three contributions to the literature on this topic. Conceptually, it suggests thinking about the incentives due to personalization as arising from a shift in electoral impact from party selectors to voters. Theoretically, it incorporates this notion into a spatial model of parliamentary voting that also considers principals’ monitoring capacities. From the resulting framework follows a rich set of observable implications, notably that candidate-centered electoral systems facilitate rather than undermine collective action within parliamentary parties under certain conditions. Empirically, this study then analyzes the 2010 reform of Sweden’s flexible-list proportional representation system, which changed the preference vote threshold. As expected, I find that when extreme (district-based) selectors disagree with the moderate bills supported by the party group leadership, personalized rules incentivize politicians to support these policies and vote in unison.German Research Foundatio
Spherical silica particle production by combined biomimetic-Stöber synthesis using renewable sodium caseinate without petrochemical agents
No full textSpherical silica particles are typically made via Stöber processes. However, these processes are environmentally unsustainable. Here, we report a process to synthesise spherical silica particles in a more sustainable way using sodium caseinate. Initial experiments showed that sodium caseinate can replace the typical industrial structural directing agents used to produce spherical particles. Particles of 124 nm in size were produced with 200 mg L−1 sodium caseinate and 81 µL sodium silicate, and particles with a bimodal size distribution (258 and 1432 nm) were produced with 400 mg L−1 sodium caseinate and 81 µL sodium silicate. Particles with multimodal size distributions between 363–1588 nm and 342–860 nm where produced with 200 mg L−1 sodium caseinate and 162 µL sodium silicate and 200 mg L−1 sodium caseinate and 810 µL sodium silicate, respectively. Higher concentrations of sodium caseinate and low concentrations of sodium silicate promoted Ostwald ripening. Low concentrations of sodium caseinate and high concentrations of sodium silicate promoted coalescence. Subsequent optimisation of the monodispersity using a statistical design of experiments yielded size-monodisperse silica particles with a narrower size distribution between 172 and 340 nm using sodium caseinate, calcium chloride, sodium silicate, and acetate buffer. Analysis of variance (ANOVA) and regression analyses were used to determine and quantify the relationship between reagent concentrations and particle size. A regression equation was calculated, which predicts particle size based on reagent concentration. Predicted particle sizes (189.6, 197.1, 204.6, and 212.1 nm) and experimentally determined particle sizes (200, 190, 184, and 196 nm) showed good agreement. The possibility of producing spherical silica particles sustainably is shown
The breaking bad effect: priming with an antihero increases sensation seeking
No full textAntiheroes are characters that share features with both heroes and villains, typified as selfish and rule breakers, but who end up doing something good for society. In this research, we examined how priming people with antiheroes (vs. heroes) affected their sensation seeking. We reason that antiheroes (vs. heroes) are more associated with temporally close (vs. past and future) events. Given that sensation seeking is related to being focused on the present (vs. past or future), we hypothesized that if people are primed with antiheroes (vs. heroes) they are more likely to seek sensation. Findings from a series of five experimental studies provide insights into the effect of priming with an antihero on people’s sensation seeking, providing directions for future research in psychology and practical applications in the areas of marketing strategy and consumer behaviour.ACCEPTEDpeer-reviewe
A Simple Model Relating Gauge Factor to Filler Loading in Nanocomposite Strain Sensors
No full textConductive nanocomposites are often piezoresistive, displaying significant changes in resistance upon deformation, making them ideal for use as strain and pressure sensors. Such composites typically consist of ductile polymers filled with conductive nanomaterials, such as graphene nanosheets or carbon nanotubes, and can display sensitivities, or gauge factors, which are much higher than those of traditional metal strain gauges. However, their development has been hampered by the absence of physical models that could be used to fit data or to optimize sensor performance. Here we develop a simple model which results in equations for nanocomposite gauge factors as a function of both filler volume fraction and composite conductivity. These equations can be used to fit experimental data, outputting figures of merit, or predict experimental data once certain physical parameters are known. We have found these equations to match experimental data, both measured here and extracted from the literature, extremely well. Importantly, the model shows the response of composite strain sensors to be more complex than previously thought and shows factors other than the effect of strain on the interparticle resistance to be performance limiting
Decentralized coordinated beamforming for weighted sum energy efficiency maximization in multi-cell MISO downlink
No full textThe 3rd IEEE Conference on Signal & Information Processing, Orlando, Florida, United States of America, 14-16 December 2015We study energy-efficient decentralized coordinated beam-forming in multi-cell multiuser multiple-input single-output system. The problem of interest is to maximize the weighted sum energy efficiency subject to user-specific quality of service constraints. The original problem is iteratively approximated as a convex program according to successive convex approximation (SCA) principle. The convex problem at each iteration is then formulated as a general global consensus problem, which is solved via alternating direction method of multipliers (ADMM). This enables base stations to independently and in parallel optimize their beamformers relying only on local channel state information and limited backhaul information exchange. In addition to waiting for the ADMM to converge as conventionally when solving the approximate convex program, we propose a method where only one ADMM iteration is performed after each SCA update step. Numerical results illustrate the fast convergence of the proposed methods and show that performing only one ADMM iteration per each convex problem can significantly improve the convergence speed.Science Foundation IrelandFinnish Funding Agency for Technology and InnovationInfotech Oulu Doctoral ProgramHPY Research FoundationWalter Ahlström FoundationTauno Tönning FoundationKAUTE Foundatio
Efficient three-dimensional geometrically nonlinear analysis of variable stiffness composite beams using strong unified formulation
No full textThe use of composite laminates for advanced structural applications has increased recently, due in part to
their ability for tailoring material properties to meet specific requirements. In this regard, variable stiffness
(VS) designs have potential for improved performance over constant stiffness designs, made possible by
fibre placement technologies which permit steering of the fibre path to achieve variable in-plane orientation.
However, due to the expanded, large design space, computationally expensive routines are required to fully
explore the potential of VS designs. This computational requirement is further complicated when VS composites
are deployed for applications involving nonlinear large deflections which often necessitate complex 3D stress
predictions to accurately account for localised stresses. In this work, we develop a geometrically nonlinear
strong Unified Formulation (SUF) for the 3D stress analysis of VS composite structures undergoing large
deflections. A single domain differential quadrature method-based 1D element coupled with a serendipity
Lagrange-based 2D finite element are used to capture the kinematics of the 3D structure in the axial and cross sectional dimensions, respectively. Predictions from SUF compare favourably against those in the literature as
well as with those from ABAQUS 3D finite element models, yet also show significant enhanced computational
efficiency. Results from the nonlinear large deflection analysis demonstrate the potential of variable stiffness
properties to achieve enhanced structural response of composite laminates due to the variation of coupling
effects in different loading regimes