A Nematic to Nematic Transformation Exhibited by a Rod-Like Liquid Crystal

A novel, highly polar rod-like liquid crystal was found to exhibit two distinct nematic mesophases (N and Nx). When studied by microscopy and X-ray scattering experiments, and under applied electric fields, the nematic phases are practically identical. However, calorimetry experiments refute the possibility of an intervening smectic mesophase, and the transformation between the nematic phases was associated with a weak thermal event. Analysis of measured dielectric data, along with molecular properties obtained from DFT calculations, applying the Maier-Meier relationship allowed for the degree of antiparallel pairing of dipoles in both nematic phases to be quantified. Based on the results, we conclude that the onset of the lower temperature phase is driven by the formation of antiparallel molecular associations

Evaluation of 4-alkoxy-40-nitrobiphenyl liquid crystals for use in next generation scattering LCDs

We have prepared nine members of the 4-alkoxy-40-nitrobiphenyl family of liquid crystals and evaluated their thermal behaviour by a combination of polarised optical microscopy, differential scanning calorimetry and small angle X-ray scattering, as well as in single pixel scattering devices for use in backlight free liquid crystal displays (LCDs). Whereas homologues with shorter terminal aliphatic chains are nematogenic, those with longer aliphatic chain lengths exhibit an additional smectic A phase, identified as the subtype SmAD by SAXS with all materials having a D/L ratio (smectic layer spacing divided by molecular length) of 1.4. When doped with 0.1 wt% hexadecyltrimethylammonium perchlorate we observed that the SmAD phase of compound 9 could be switched with a relatively low voltage (58 VRMS, roughly half that required for the analogous nitrile). This apparent reduction in threshold voltage, which occurs as a consequence of switching from a nitrile- to a nitro- group, provides a new impetus to study alternative polar terminal groups when designing host materials for smectic A scattering devices

Experimental and molecular dynamics studies of anthraquinone dyes in a nematic liquid-crystal host: a rationale for observed alignment trends

Five anthraquinone dyes with bis(4-propylphenyl) substituents, connected via sulfide or amine linking groups at the 1,5-positions or directly at the 2,6-positions, have been studied as guests in the nematic liquid crystal host, E7. Polarized UV-visible absorption spectra of aligned samples were used to obtain experimental dichroic order parameters, which exhibit values in the range 0.51-0.74. Fully atomistic MD simulations of these guest-host systems were carried out, generally using default parameters but using new force constants derived here for the dyes containing flexible phenyl-sulfide and phenyl-amine linking groups. An analysis of the alignment of the dye molecules in these simulations provides calculated molecular order parameters, which are combined with calculated order parameters for the alignment of the transition dipole moments within the dyes, reported previously, to give calculated dichroic order parameters. The trend in the calculated dichroic order parameters between the dyes shows a good match with the trend in the experimental values, enabling the observed variation to be rationalised primarily by changes in the alignment of the calculated transition dipole moments within the dyes; the calculated molecular order parameters show a relatively small variation between the dyes. The results indicate that this computational approach may be used generally to rationalise trends in the alignment of guest molecules in liquid crystal hosts, suggesting that it may also be able to provide a predictive aid in the design of guest dyes

An Evaluation of Community Assessment Tools (CATs) in Predicting Use of Clinical Interventions and Severe Outcomes during the A(H1N1)pdm09 Pandemic

During severe influenza pandemics healthcare demand can exceed clinical capacity to provide normal standards of care. Community Assessment Tools (CATs) could provide a framework for triage decisions for hospital referral and admission. CATs have been developed based on evidence that supports the recognition of severe influenza and pneumonia in the community (including resource limited settings) for adults, children and infants, and serious feverish illness in children. CATs use six objective criteria and one subjective criterion, any one or more of which should prompt urgent referral and admission to hospital. A retrospective evaluation of the ability of CATs to predict use of hospital-based interventions and patient outcomes in a pandemic was made using the first recorded routine clinical assessment on or shortly after admission from 1520 unselected patients (800 female, 480 children <16 years) admitted with PCR confirmed A(H1N1)pdm09 infection (the FLU-CIN cohort). Outcome measures included: any use of supplemental oxygen; mechanical ventilation; intravenous antibiotics; length of stay; intensive or high dependency care; death; and “severe outcome” (combined: use of intensive or high dependency care or death during admission). Unadjusted and multivariable analyses were conducted for children (age <16 years) and adults. Each CATs criterion independently identified both use of clinical interventions that would in normal circumstances only be provided in hospital and patient outcome measures. “Peripheral oxygen saturation ?92% breathing air, or being on oxygen” performed well in predicting use of resources and outcomes for both adults and children; supporting routine measurement of peripheral oxygen saturation when assessing severity of disease. In multivariable analyses the single subjective criterion in CATs “other cause for clinical concern” independently predicted death in children and in adults predicted length of stay, mechanical ventilation and “severe outcome”; supporting the role of clinical acumen as an important independent predictor of serious illness

Heliophysics and Amateur Radio:Citizen Science Collaborations for Atmospheric, Ionospheric, and Space Physics Research and Operations

The amateur radio community is a global, highly engaged, and technical community with an intense interest in space weather, its underlying physics, and how it impacts radio communications. The large-scale observational capabilities of distributed instrumentation fielded by amateur radio operators and radio science enthusiasts offers a tremendous opportunity to advance the fields of heliophysics, radio science, and space weather. Well-established amateur radio networks like the RBN, WSPRNet, and PSKReporter already provide rich, ever-growing, long-term data of bottomside ionospheric observations. Up-and-coming purpose-built citizen science networks, and their associated novel instruments, offer opportunities for citizen scientists, professional researchers, and industry to field networks for specific science questions and operational needs. Here, we discuss the scientific and technical capabilities of the global amateur radio community, review methods of collaboration between the amateur radio and professional scientific community, and review recent peer-reviewed studies that have made use of amateur radio data and methods. Finally, we present recommendations submitted to the U.S. National Academy of Science Decadal Survey for Solar and Space Physics (Heliophysics) 2024–2033 for using amateur radio to further advance heliophysics and for fostering deeper collaborations between the professional science and amateur radio communities. Technical recommendations include increasing support for distributed instrumentation fielded by amateur radio operators and citizen scientists, developing novel transmissions of RF signals that can be used in citizen science experiments, developing new amateur radio modes that simultaneously allow for communications and ionospheric sounding, and formally incorporating the amateur radio community and its observational assets into the Space Weather R2O2R framework. Collaborative recommendations include allocating resources for amateur radio citizen science research projects and activities, developing amateur radio research and educational activities in collaboration with leading organizations within the amateur radio community, facilitating communication and collegiality between professional researchers and amateurs, ensuring that proposed projects are of a mutual benefit to both the professional research and amateur radio communities, and working towards diverse, equitable, and inclusive communities

Rethinking capital mobility, re‐regulating financial markets

The globalisation hypothesis has altered many of the common-sense ‘truths’ around which the social world is organised.* In particular, globalisation is thought to restrict the parameters of the politically and economically possible. Indeed, the notion of constrained choice is so pronounced that we are increasingly confronted with the image of globalisation’s ‘logic of no alternative’; an image which is predicated on the assumption of perfect capital mobility. Capital is considered to be sufficiently rational to take advantage of enhanced exit options from the national economy in circumstances in which its interests are served by moving off-shore. Moreover, global markets are also assumed to have exploited contemporary technological developments to such an extent that they now clear instantaneously; consequently, allowing capital to further its interests wherever in the world new profit opportunities arise. Thus, we are presented with the fundamental ‘reality’ of globalisation as currently narrated throughout much of the west: unless the market can be allowed to restore a competitive global equilibrium, capital will exit high-wage, high-cost western economies and re-locate in lower-wage, lower-cost, newly industrialising economies. Under the auspices of ever more hostile wage competition from the newly industrialising economies, globalisation is commonly presumed to act as a trigger for an ‘inevitable’ job displacement effect as capital deserts the advanced industrialised economies

Selective Microwave-Assisted Pyrolysis of Cellulose towards Levoglucosenone with Clay Catalysts

Levoglucosenone (anhydrosugar) is one of the most promising chemical platforms derived from the pyrolysis of biomass. It is a chiral building block for pharmaceuticals as well as an intermediate in the production of solvents and polymers. Therefore, the development of cost-efficient, low-energy production methods is vital for a future sustainable biorefinery. Here, a novel, green approach to the production of levoglucosenone was developed by using a microwave (MW)-assisted pyrolysis of cellulose in the presence of readily available clays. It was shown that natural and pillared clays in the presence of MW irradiation significantly increase the yield of levoglucosenone from cellulose. Both the water content and the presence of acid centres are critical characteristics that influence the yield and distribution of catalysed products. A unique experiment was designed by using a synergetic effect between different types of catalysts, which enhanced the levoglucosenone yield to 12.3 wt % with 63 % purity