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Glacier forelands reveal fundamental plant and microbial controls on short-term ecosystem nitrogen retention
No full text1. Human activities have massively increased the amount of reactive nitrogen in the biosphere, which is leading to increased nitrogen (N) inputs in terrestrial ecosystems. The retention of N is a crucial ecosystem function of both managed and natural ecosystems, and there is a long history of experimental, observational, and conceptual studies identifying its major controls. Yet, the plant and soil microbial controls on the retention of added N remain elusive.2. Here, we used three ecosystem chronosequences in front of retreating glaciers in the European Alps to test our hypothesis that the retention of added reactive 15N increases as succession proceeds, and to identify the plant and microbial controls on ecosystem N retention.3. We found that the uptake and retention of N did not change during succession, despite consistent changes in plant, soil, and microbial properties with increasing time since deglaciation. Instead, we found that plant and microbial properties that remained constant during succession controlled 15N uptake and retention: low root and microbial C/N ratios, as well as high root biomass, increased plant and microbial uptake of added N. In addition, high soil concentrations of nitrate and ammonium reduced the uptake of N in microbes and roots, respectively.4. Synthesis Our results demonstrate that plant and microbial N demand, as well as soil N availability, drive the short-term retention of added N during succession in glacier forelands. This finding represents an advance in our understanding of the fundamental controls on ecosystem N retention and the role of plant-microbial interactions in this process. Such understanding is crucial for predicting and mitigating the response of terrestrial ecosystems to the ever-increasing amounts of reactive N in the biosphere
Risk of suicide in patients who present to hospital after self-cutting according to site of injury: findings from the Multicentre Study of Self-harm in England
No full textBackground: We compared the risk of death by suicide following hospital presentation for self-harm according to site of self-cut/stab.Method: We included 54,999 self-harm presentations (involving 31,419 individuals) to hospitals in the Multicentre Study of Self-harm in England (1/1/2004-31/12/2014), with mortality follow-up to 31/12/2019. Information on method of self-harm was obtained through monitoring in hospitals. Information about mortality was obtained through linkage with NHS Digital. We assessed the association of site of self-cut with death by suicide using mixed effect models. Results: 10,790 (19.6%) hospital presentations involved self-cutting/stabbing, 7,489 of which (69.4%) were due to laceration to the arm/wrist alone, 1,846 episodes (17.1%) involved cutting elsewhere on the body, and 1,455 (13.5%) were due to laceration to unknown site. Controlling for confounders, presentation to hospital following self-cut/stab to bodily parts other than wrist/arm was associated with greater chance of subsequent suicide relative to presentation after self-poisoning alone [adjusted odds ratio (aOR) 1.75, 95% confidence interval (CI) 1.03-2.96, P=0.038]. The likelihood of suicide after presentation for cutting/stabbing the wrist/arm alone was comparable to that of patients who had self-poisoned alone. Presentations after laceration involving the neck were associated with a 4-fold greater chance of subsequent suicide relative to self-poisoning (aOR 4.09, 95% CI 1.80-9.30, p=0.001). Conclusions: Patients who attend hospital after self-cutting/stabbing are a heterogeneous group in terms of characteristics, methods of cutting/stabbing and risk of subsequent suicide. Risk of suicide is greater in individuals who self-cut/stab to parts of the body other than the wrist or arm, especially the neck
Impact of shift working on the potential for self-powering via kinetic energy harvesting in wearable devices
No full textWearable devices are having a transformative impact on personalised monitoring and care. However, they frequently have limited battery life, requiring charging every few days; a major source of user frustration. Kinetic energy harvesting may help overcome this, collecting energy from the user’s motion to allow the device to self-charge. While there are many works which have investigated wearable energy harvesting potential, none have incorporated socio-economic factors which affect activity, such as occupation type, on energy harvesting potential. We use the UK Biobank free-living accelerometer dataset to investigate the impact of occupational patterns on energy harvesting potential for the first time. We identify that those following shift patterns have a different distribution of when power is available, with those who work shifts having the most power intense period spread over a longer period of the day compared to controls. When stratifying into day or night shift work, we identify that those who work night shifts have a large variation between participants, as their most energy dense period is spread over the entire 24-hour period. This is compared to day shift workers who have the most power concentrated within a substantially smaller window, typically in the morning. Considering these socio-economic factors may affect system design of wearable energy harvesters
Experimental study on steel plate shear wall with composite frame
No full textIn order to improve the space utilization rate and seismic performance of high-rise buildings, a new seismic structural system, a buckling-restrained steel plate shear wall (SPSW) with concrete-filled L-shaped built-up section tube composite frame is proposed in this study. In this composite shear wall system, the columns in the frame arecomposed of hot-rolled carbon steel H-section members and carbon steel square hollow section tubes, which are connected by steel plates and filled with concrete, and the steel plate shear wall is comprised of an embedded steel plate and several pairs of cold-formed steel hat section buckling-restraining strips. In order to study the seismic performance of this new type of shear wall system, two specimens were prepared and tested subjected to the horizontal cyclic load. Test results show that the two specimens had great bearing capacity, good ductility and energy dissipation capacity. It is indicated that the new shear wall system is reliable and effective to resist lateral forces. The finite element models were established and validated against the experimental results. Based on the parametric analysis results, the coefficient η was proposed to be taken as 0.85 to modify the PFI theory, which could be used to calculate the bearing capacity of the buckling-restrained SPSW with concrete-filled L-shaped built-up section tube composite frame.Keywords: Buckling-restrained; Cold-formed steel; Concrete-filled built-up section tube composite frame; Cyclic shear; Steel plate shear wall (SPSW
The effects of transcranial alternating current stimulation on memory performance in healthy adults: A systematic review
No full textThe recent introduction of Transcranial Alternating Current stimulation (tACS) in research on memory modulation has yielded some exciting findings. Whilst evidence suggests small but significant modulatory effects of tACS on perception and cognition, it is unclear how effective tACS is at modulating memory, and the neural oscillations underlying memory. The aim of this systematic review was to determine the efficacy with which tACS, compared to sham stimulation, can modify working memory (WM) and long-term memory (LTM) performance in healthy adults. We examined how these effects may be moderated by specific tACS parameters and study/participant characteristics. Our secondary goal was to investigate the neural correlates of tACS’ effects on memory performance in healthy adults. A systematic search of eight databases yielded 11,413 records, resulting in 34 papers that included 104 eligible studies. The results were synthesised by memory type (WM/LTM) and according to the specific parameters of frequency band, stimulation montage, individual variability, cognitive demand, and phase. A second synthesis examined the correspondence between tACS’ effects on memory performance and the oscillatory features of electroencephalography (EEG) and magnetencephalography (MEG) recordings in a subset of 26 studies. The results showed a small-to-medium effect of tACS on WM and LTM performance overall. There was strong evidence to suggest that posterior theta-tACS modulates WM performance, whilst the modulation of LTM is achieved by anterior gamma tACS. Moreover, there was a correspondence between tACS effects on memory performance and oscillatory outcomes at the stimulation frequency. We discuss limitations in the field and suggest ways to improve our understanding of tACS efficacy to ensure a transition of tACS from an investigative method to a therapeutic tool
Efficacy of tumour-necrosis factor-inhibitor in moderate disease activity rheumatoid arthritis: sub-analysis of the ‘VEDERA’ trial
No full textOxidative dehalogenation of halophenols by high-valent nonheme iron(IV)-oxo intermediates
No full textMononuclear high-valent iron(IV)-oxo intermediates are excellent oxidants towards oxygenation reactions by heme and nonheme metalloenzymes and their model systems. One of the most important functions of these intermediates in nature is to detoxify various environmental pollutants. Organic substrates such as halogenated phenols are known to be water pollutants which can be degraded to their less hazardous forms through an oxidation reaction by iron(IV)-oxo complexes. Metalloproteins in the Nature utilize various types of second-coordination sphere interactions to anchor the substrate in the vicinity of the active site. This concept of substrate-binding is well-known for natural enzymes, but quite elusive for the relevant biomimetic model systems. Herein, we report the oxidative reactivity patterns of an iron(IV)-oxo intermediate, [FeIV(O)(2PyN2Q)]2+, (2PyN2Q = 1,1-di(pyridin-2yl)-N, N-bis(quinolin-2-ylmethyl)methanamine) with a series of mono-, diand tri-halophenols. A detailed experimental study shows that the dehalogenation reactions of the halophenols by such iron(IV)-oxo intermediates proceed via an initial hydrogen atom abstraction from the phenolic O-H group. Further, based on the size and nucleophilicity of the halophenol, an intermediate substrate-bound species forms , that is a phenolate adduct to the ferric species - which thereafter leads to the formation of the corresponding products.<br/
Biochemical Functionalization of Graphene Oxide for Directing Stem Cell Differentiation
No full textThe regeneration of peripheral nerve tissue is crucial in the treatment of peripheral nerve trauma. In recent years, there has been increased focus on biomaterial scaffolds which can deliver stem cells, direct differentiation to the desired lineage and guide tissue regeneration at the site of injury. Here, we report on a graphene oxide (GO) scaffold which has been chemically functionalised to direct the differentiation of adipose-derived mesenchymal stem cells towards the neuroglial lineage and maintain the viability of differentiated cells. A comparison is made between substrates of GO, reduced GO and a peptide (IKVAV) functionalised GO in comparison to standard tissue culture glass. Our results show that the graphene substrates are highly biocompatible, and the IKVAV functionalised substrates are more effective in directing stem cell differentiation towards neuroglial phenotypes compared to glass and other graphene substrates. Furthermore, GO-IKVAV substrates showed increased neuronal attachment and neurons grown on GO-IKVAV sprouted longer neurites. These results suggest that graphene can be rationally functionalised to direct stem-cell differentiation and that functionalised GO could provide a viable scaffold in regenerative therapies of peripheral nerve injuries and disorders
Optimisation of heat recovery from low-enthalpy aquifers with geological uncertainty using surrogate response surfaces and simple search algorithms
No full textOptimisation of doublet well spacing in low-enthalpy geothermal systems is ad dressed by defining a novel objective function that is based on the Coefficient of Performance (CoP) and energy sweep efficiency. The definition of objec tive function that separates performance–based criteria from economic factors, allows us to better observe the effects of heterogeneity on optimisation. A checkerboard pattern of two doublets (two injection wells diagonally placed and two production wells diagonally placed over corners of a rectangle) is considered for a range of homogeneous to heterogeneous (spatially correlated and fluvial) synthetic low enthalpy reservoirs. Optimal length and width of this rectangle are sought in order to (a) maximise heat recovery from a conventionally-chosen licence area around the rectangular domain, (b) minimise heat recovery from outside this licence area, and (c) maximise CoP. We define fixed (15 years and 30 years) and varying life times of operation (between 15 and 30 years). For optimisation, in addition to a simple-search procedure of optimisation across a mesh of simulation nodes, we also utilise a surrogate response surface model to computationally solve the optimisation problem. Our results consistently show that for a fixed life time of 15 years and a discharge rate of 250 m3/hr, 400 m is the optimal well/doublet spacing. Increasing the life time and the discharge rate will increase the optimal well/doublet spacing. The results show while CoP is sensitive to the heterogeneity, adding energy sweep to the objective function makes the distances found for the homogeneous cases also consistent solutions for the heterogeneous cases.Keywords: Doublets, Well spacing, Low-enthalpy geothermal systems,Optimisation, Coefficient of Performanc
Privacy-Enhancing Settlements Protocol in Peer-to-Peer Energy Trading Markets
No full textThis paper proposes a privacy-friendly billing and settlements system for use in peer-to-peer energy trading markets. More specifically, it proposes a privacy-enhancing settlements protocol (PESP) which makes use of a partial homomorphic encryption scheme to facilitate private processing and computation of smart grid users’ monthly energy bill by a semitrusted third party. In addition, it allows for minor financial penalties to users who participate in peer-to-peer trading but do not accurately predict their energy usage for each period and, as such, import or export varying amounts compared to the amount they have agreed to trade for initially. This encourages predictions to be accurate to help keep the trading fair and aiding suppliers tomake accurate predictions about the amount of electricity needed for each trading period. Our security analysis and performance evaluation demonstrate that PESP protects users’ privacy and isefficient in terms of computation and communication cost.Index Terms—Privacy, Peer-to-Peer, Energy Trading, Billing and Settlemen