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Efficacy of tumour-necrosis factor-inhibitor in moderate disease activity rheumatoid arthritis: sub-analysis of the ‘VEDERA’ trial
No full textElectrolyte Salts and Additives Regulation Enables High Performance Aqueous Zinc Ion Batteries: a Mini Review
No full textAqueous zinc ion batteries (ZIBs) are regarded as one of the most ideally suited candidates for large-scale energy storage applications owning to their obvious advantages, i.e., low cost, high safety, high ionic conductivity, abundant raw material resources and eco-friendliness. Much effort has been devoted to the exploration of cathode materials design, cathode storage mechanisms, anode protection as well as failure mechanisms, while inadequate attentions are paid on the performance enhancement through modifying the electrolyte salts and additives. Herein, to fulfil a comprehensive aqueous ZIBs research database, a range of recently published electrolyte salts and additives researches are reviewed and discussed in this mini review. Furthermore, the remaining challenges and future directions of electrolytes in aqueous ZIBs are also suggested, which could provide insights to push ZIBs’ commercialization
Low Latency Broadband Internet Satellite Constellations – Technology, Risks and Global Impact
No full textTo achieve global network coverage and meet the demands for high-speed communications, technological improvements have to be made to the existing terrestrial network infrastructure. Low Earth orbit (LEO) satellite constellations have the potential to enable broadband access anywhere in the world and ensure short round-trip delays. This paper investigates the technology behind communication satellite networks in low Earth orbits and estimates the impact that high-speed and widely accessible broadband can have globally. The analytical design of an optimal LEO satellite configuration for continuous global coverage is presented. The results show that in case the users are separated by the orbital seam where the adjacent orbital planes are counter-rotating and inter-satellite links (ISLs) are not supported, the latency is significantly increased. Therefore, polar orbits are necessary to provide global coverage, but show low performance in terms of latency. The optimal solution would be a hybrid constellation: polar orbits to cover high-latitude regions and inclined orbits to meet the data demands in densely populated areas. The presented analyses are used to explore the technology behind communication satellite networks in LEOs and understand their advantages over the existing terrestrial network infrastructure. The crucial part of this paper is the evaluation of risks that LEO satellite networks raise and how, if at all, they can be mitigated. Two main concerns regarding LEO constellations have been investigated – space debris and the effects on astronomical observations. To better understand the severity of the risks, SpaceX’s measures towards risk mitigation are discussed. In summary, the aforementioned risks cannot be eliminated entirely; with today’s technology and the implementation of artificial intelligence, risk mitigation is promising. Nonetheless, the issue of space debris and effects on astronomical observations should not be trivialized. Satellite technology is currently the only way to provide global connectivity and bridge the digital divide. Taking careful mitigating measures, the benefits of such technology outweigh the risks, and in order to bridge the existent digital gap, those trade-offs areultimately worth making
The width of Herschel filaments varies with distance
No full textContext. Filamentary structures in nearby molecular clouds have been found to exhibit a characteristic width of 0.1 pc, as observed in dust emission. Understanding the origin of this universal width has become a topic of central importance in the study of molecular cloud structure and the early stages of star formation.Aims. We investigate how the recovered widths of filaments depend on distance from the observer, by using previously published results from the Herschel Gould Belt Survey.Methods. We obtain updated estimates on the distances to nearby molecular clouds observed with Herschel, by using recent results based on 3D dust extinction mapping and Gaia. We examine the widths of filaments from individual clouds separately, as opposed to treating them as a single population. We use these per-cloud filament widths to search for signs of variation amongst the clouds of the previously published study.Results. We find a significant dependence of the mean per-cloud filament width with distance. The distribution of mean filament widths for nearby clouds is incompatible with that of farther away clouds. The mean per-cloud widths scale with distance approximately as 4–5 times the beam size. We examine the effects of resolution by performing a convergence study of a filament profile in the Herschel image of the Taurus Molecular Cloud. We find that resolution can severely affect the shapes of radial profiles over the observed range of distances.Conclusions. We conclude that the data are inconsistent with 0.1 pc being the universal characteristic width of filaments
Studies of the Temperature-Dependence of the Structure and Magnetism of a Hexagonal Bipyramidal Dysprosium(III) Single-Molecule Magnet
No full textThe hexagonal-bipyramidal lanthanide(III) complex [Dy(OtBu)Cl(18-C-6)][BPh4] (18-C-6 = 1,4,7,10,13,16-hexaoxacycloocta-decane ether 1) displays an energy barrier for magnetization reversal (Ueff) of ca. 1000 K in zero DC field. Temperature dependent X-ray diffraction studies of 1 down to 30 K of compound reveal bending of the Cl-Ln-OtBu angle at low temperature. Using ab initio calculations, we show that the significant bending of the O-Dy-Cl angle upon cooling from 273 K to 100 K leads to a ca. 10% decrease in the energy of the excited electronic states. A thorough exploration of the temperature- and field-dependencies of the magnetic relaxation rate reveals that magnetic relaxation is dictated by five mechanisms in different regimes: Orbach, Raman-I, QTM and Raman-II, in addition to the observation of a phonon bottleneck effect
Design of novel reaction-separation-recycle processes for the production of 4-hydroxybutyl acrylate
No full textTwo chemistry routes are known for 4-hydroxybutyl acrylate production: the direct esterification of acrylic acid with 1,4-butanediol, and the transesterification of methyl acrylate with 1,4-butanediol. However, very scarce information in the literature is available about industrial production, or design and operation of production processes. In this study, we propose three novel reaction–separation–recycle processes for 4-hydroxybutyl acrylate production by direct esterification based on solid catalyst. Use of solid catalysts may avoid well-known issues of the liquid catalysts like recovery and re-use of the catalyst, difficult product recovery and corrosion. Due to the nature of the chemical system and reactions conditions, the chemistry is not 100 % selective towards the acrylate, important amounts of diacrylate by-product being formed. All processes use fixed-bed tubular reactors to perform the reactions and distillation-based equipment to achieve the required separations. While all processes have a similar separation sequence, each has its key particularities: the RSR-A process accepts the loss of reactants due to formation and elimination from the process of the diacrylate, RSR-B converts the diacrylate into its reactants in the esterification reactor, while RSR-C converts the diacrylate in a dedicated hydrolysis reactor. A key element in the separation sequence is the use of pressure-swing distillation to make the difficult split of the alcohol/acrylate/diacrylate ternary mixture. All processes are capital and energy intensive. The economic analysis shows that the RSR-A process has the most favorable economics: a total annualized cost of 2 million /t of product. A control structure for the RSR-C process is presented, the dynamic simulations showing its efficiency in rejecting various disturbances
Rethinking the design of a 2-methoxy-2-methyl-heptane process by unraveling the true thermodynamics and kinetics
No full textAmong other fuel additives - such as MTBE, ETBE, or TAME - 2-methoxy-2-methyl heptane (MMH) can increase the fuel octane number and reduce the CO emission. MMH can be obtained through the exothermal etherification of 2-methyl-1-heptene and methanol. Lately, many researchers have developed more and more efficient processes considering the kinetics corresponding to an endothermal reaction. However, in this work we demonstrate that the reaction is actually quite exothermal, and this has strong impact on the designed process. Also, the vapor-liquid equilibrium data predicted by UNIQUAC model for 2-methoxy-2-methyl heptane and 2-methyl-2-heptanol mixture reveals that product purification is more difficult, and it requires more energy to recover and obtain MMH with high purity. Considering these aspects, the 54.87 ktpy process developed in this paper is more realistic and energy intensive (1.82 kWh/kg MMH), with a TAC of 5.3 M$/year. The controllability of the process is proven for ±20% changes of 2-methoxy-2-methyl-heptane production rate
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
EMMA-CAD: Design automation for synthetic mammalian constructs
No full textComputational design tools are the cornerstone of synthetic biology and have underpinned its rapid development over the past two decades. As the field has matured, the scale of biological investigation has expanded dramatically, with computational tools often relied upon by researchers to operate in the high-throughput investigational space. This is especially apparent in the modular design of DNA expression circuits, where complexity is accumulated rapidly. Alongside our automated pipeline for the high-throughput construction of Extensible Modular Mammalian Assembly (EMMA) expression vectors, we recognized the need for an integrated software solution for EMMA vector design. Here, we present EMMA-CAD (https://emma.cailab.org), a powerful, web-based computer-aided design tool for the rapid design of bespoke mammalian expression vectors. EMMA-CAD features a variety of functionalities, including a user-friendly design interface, automated connector selection underpinned by rigorous computer optimization algorithms, customization of part libraries, and personalized design spaces. Capable of translating vector assembly designs into human and machine readable protocols for vector construction, EMMA-CAD integrates seamlessly into our automated EMMA pipeline, hence completing an end-to-end design to production work flow
Investigation of fiber orientation and void content in bagasse fiber composites using image analysis technique
No full textIn this research work, a nondestructive technique of image analysis was explored to determine the fiber orientation and void content in Bagasse fiber reinforced composites. Fiber length, alkali treatment and fiber loading were studied as variables. The fiber orientation was irrespective of the variables of fiber length, fiber loading and alkali treatment. The void content and the size decreased with increases in fiber length and alkali treatment. The alkali treatment resulted in the removal of lignin, making the surface of the fibers rough. It also resulted in making the fiber count fine i.e. reduce the diameter of the fibers and thus presenting more fibers for interaction with resin. Both these phenomena resulted in slower flow of resin. The void content of bagasse fiber composites decreased with higher fiber loading because the higher number of fibers slows the resin flow. However the size i.e. area of the voids increased with the fiber loading from 20 to 30%, probably due to increased wetting difficulty