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The flexibility, durability, and lightweight offered by plastic displays have not been accomplished commercially, despite years of research. However, significant commercial progress of a bistable nematic liquid crystal display (LCD) did not occur until the invention of the Zenithal Bistable Display (ZBD) in 1995. Thermotropic liquid crystal behavior occurs in rigid, anisotropic organic molecules, with the degree of order being related to the temperature of the material. Compared with other LCD alignment surfaces, either rubbed or photoaligned polymers, the ZBD surface requires considerable engineering to achieve consistent device operation. Surface bistability in ZBD is realised using a surface grating as one of the liquid crystal alignment layers. Although it is possible to create a scattering mode ZBD LCD, this technology is usually configured to operate by modulating polarized light. As well as a two-polariser fully reflective LCD mode, the ZBD technology can be deployed in other configurations, which can have merits for particular applications.

Individual instances of the knock resonant response are easy to acquire but these are subject to noise and vary considerably from cycle to cycle due to random variations in the knock process. This work provides a new way to quantify and model the stochastic properties of knock signals, capturing both the time domain resonant characteristics within a cycle as well as the random variations from cycle to cycle. A new phase alignment method enables the ensemble mean knock waveform to be identified from the data which also removes noise components without the need for narrowband filtering. This ensemble waveform shows the empirical characteristics of knock onset, decay, and frequency slurring within the cycle as the gas expands and cools. The phase-aligned cyclic variations of the knock waveform are also shown to approximate a (time-varying) dual-Gaussian distribution, and fitting such a model to the data enables the statistical properties of the dataset as a whole to be decomposed into separate knocking and non-knocking populations providing further insight into the knock process. The technique is applied both to filtered cylinder pressure signals and to accelerometer-based knock signals, and the results are compared and contrasted.

Ferroelectric liquid crystals remain of interest for display and spatial light modulators because they exhibit significantly faster optical response times than nematics. However, smectic layers are sensitive to shock-induced flow and are usually permanently displaced once a well-aligned sample is disrupted, rendering such devices inoperable. We introduce a vertical alignment geometry combined with a surface-relief grating to control both the smectic layer and director orientations. This mode undergoes “self-healing” of the smectic layers after disruption by shock-induced flow. Sub-millisecond switching between optically distinct states is demonstrated using in-plane electric fields. Self-healing occurs within a second after being disrupted by shock, wherein both the layer and director realign without additional external stimulus. The route to material improvements for optimised devices is discussed, promising faster spatial light modulators for high-speed adaptive optics, micro-displays for virtual/augmented reality and telecommunications with inherent shock stability.

We describe a modified microfluidic method for making Giant Unilamellar Vesicles (GUVs)viawater/octanol-lipid/water double emulsion droplets. At a high enough lipid concentration we show that thede-wetting of the octanol from these droplets occurs spontaneously (off-chip) without the need to useshear to aid the de-wetting process. The resultant mixture of octanol droplets and GUVs can beseparated by making use of the buoyancy of the octanol. A simpler microfluidic device and pumpsystem can be employed and, because of the higher flow-rates and much higher rate of formation ofthe double emulsion droplets (B1500 s 1compared to up toB75 s 1), it is easier to make largernumbers of GUVs and larger volumes of solution. Because of the potential for using GUVs thatincorporate lyotropic nematic liquid crystals in biosensors we have used this method to make GUVs thatincorporate the nematic phases of sunset yellow and disodium chromoglycate. However, the phasebehaviour of these lyotropic liquid crystals is quite sensitive to concentration and we found that there isan unexpected spread in the concentration of the contents of the GUVs obtained.

In liquid crystal (LC) droplets, small changes in surface anchoring energy can produce large changes in the director field which result in readily detectable optical effects. This makes them attractive for use as biosensors. Coating LC droplets with a phospholipid monolayer provides a bridge between the hydrophobic world of LCs and the water-based world of biology and makes it possible to incorporate naturally occurring biosensor systems. However, phos-pholipids promote strong perpendicular (homeotropic) anchoring that can inhibit switching of the director field. We show that the tendency for phospholipid layers to promote perpendicular anchoring can be suppressed by using syn-thetic phospholipids in which the acyl chains are terminated with bulky tert-butyl or ferrocenyl groups; the larger these end-group(s), the less likely the system is to be perpendicular/radial. Additionally, the droplet director field is found to be dependent on the nature of the LC, particularly its intrinsic surface properties; but not (apparently) on the sign of the dielectric anisotropy, the proximity to the melting/isotropic phase transition, the surface tension (in air) or the values of the Frank elastic constants.

Reactive mesogens (RMs) have been used in a wide variety of applications, from retardation plates for OLED screens, liquid crystal phase stabilisation, optical or electrically active elastomers to novel optic components. They can be processed as standard liquid crystals and subsequently polymerised to stabilise both shape and anisotropic properties. However, creating complex shapes while maintaining good alignment of the RM optical axis can be a challenge. In the present work, embossing is used to replicate a wide variety of RM structures in several electro-optic devices. A novel device geometry is proposed where a polarisation-independent lens is formed by opposing birefringent Fresnel zone plates embossed in aligned RM. The RM forms the optical elements and alignment layers for an index-matched liquid crystal, arranged to form the twisted nematic configuration. Low voltages switch the device between non-focusing and focusing states. After characterising lens efficiency and beam properties, the method is used to fabricate a switchable multi-level Fresnel zone plate with optical efficiencies beyond 50 %, and theoretically able to produce polarisation independent lenses with efficiencies approaching 100% from a single structure. Finally, manufactured polarisation-independent gratings and microlens arrays are presented using the method to illustrate the wide range of applicability.

A record is given of the special meeting organised by the UK&I Chapter of the Society of Information Display held at the Royal Academy of Engineering in London, to celebrate the 50th anniversary of the RCA announcement of the first Liquid Crystal Display on 28th May 1968. Coming exactly eighty years after the report of the first liquid crystal materials, this announcement sparked interest across the globe, and particularly in the UK, Switzerland and Japan. Presentations of the early LCD history from Hilsum, Schadt and Raynes give insights into both the science and also the process of invention itself. These early contributors are followed by a view from the USA from Bos and representation from the companies Sharp and Merck that helped shape the success of these fascinating and useful materials. Also reviewed are talks on the use of organic semiconductors to drive plastic LCD by Sirringhaus, reflective LCD of Folium Optics, retail signage of Displaydata, as well as a look to the future from LCD competitors from Bodle (Phase Change Material displays) and BOE (OLED).

A simple method for vapour-phase deposition of a silane surfactant is presented, which produces tuneable homeotropic anchoring in liquid crystals. Both the zenithal anchoring energy and surface slip are measured by fitting to the latching threshold versus pulse width characteristic of a zenithal bistable nematic liquid crystal device based on a deep, submicron grating. The method is shown to give microscopic anchoring strength between 5 × 10⁻⁵ and 2 × 10⁻⁴ J/m², with a surface slip of about 100 nm. The silanated surfaces are characterized using atomic force microscopy and X-ray photoelectron spectroscopy, which show a direct relationship between the surface coverage of silane groups and the resulting anchoring energy.

Nematic liquid crystals are anisotropic fluids that self-assemble into vector fields, which are governed by geometrical and topological laws. Consequently, particulate or droplet inclusions self-assemble in nematic domains through a balance of topological defects. Here, we use double emulsions of water droplets inside radial nematic liquid crystal droplets to form various structures, ranging from linear chains to three-dimensional fractal structures. The system is modeled as a formation of satellite droplets, distributed around a larger, central core droplet and we extend the problem to explain the formation of fractal structures. We show that a distribution of droplet sizes plays a key role in determining the symmetry properties of the resulting geometric structures. The results are relevant to a variety of inclusions, ranging from colloids suspensions to multi-emulsion systems. Such systems have potential applications for novel switchable photonic structures as well as providing wider insights into the packing of self-assembled structures., Topological defects in liquid crystals can drive the assembly of colloidal inclusions. Here the authors place water droplets of different sizes in a larger nematic liquid crystal drop and observe the formation and self-assembly of fractal colloidal structures.

Over the past half century, liquid crystal displays (LCDs) have grown to be one of the most successful optoelectronic technologies, becoming an integral part of communication devices and often an enabling technology. This success has required many adaptions to meet the requirements of everincreasing complexity and performance. Indeed, it is the adaptability of liquid crystal devices that grounds their success. After outlining the basic physics of liquid crystals and device construction, the various modes used in commercial displays will be reviewed, both for mainstream and niche markets, together with a summary of the important complimentary technologies. Finally, liquid crystal devices that have promise for future applications in optoelectronics will be discussed.

The zenithal bistable display (ZBD) was the first liquid crystal device mode to be commercialised that uses nematic disclinations in a constructive fashion, to use the flexoelectric effect inherent to all liquid crystals but at the time was considered too weak an effect to be useful, and to transfer nano-replication methods to the LCD manufacturing environment. The genesis of the invention and spin-out company ZBD Displays Limited will be described, and the evolution of that company from licensing model, through fabless manufacturer to display provider and finally to a system provider for the retail sector. The story may be useful not just to those interested in the science behind a rather unusual LCD, but also those involved in taking technology from laboratory to manufacturing, from idea to commercial success.

Highly first order silane end-group difluoroterphenyl liquid crystal was added to trifluoroterphenyl host with a nematic to smectic-C phase transition to increase its first order nature, achieve a higher cone angle and reduce its temperature dependence. Increasing concentration of the additive, caused a linear decrease and eventual disappearance of the nematic phase. A smectic-A phase was injected at 35 % concentration, making the transition second order. Optical studies of the mixtures showed little dependence of the highest value of cone angle on concentration. The original host showed first order cone angle behavior and was used to fabricate a twisted FLC device.

Polarized Raman Spectroscopy (PRS) is used to quantify the orientational order in the conventional (N) and twist-bend (NTB) nematic phases of a homologous series of liquid crystalline dimers. The dimers investigated have 7, 8, 9 and 11 methylene groups connecting two cyanobiphenyl mesogens and data for 4-pentyl-4'-cyanobiphenyl (5CB) and 4-octyl-4'-cyanobiphenyl (8CB) are included for comparison. Simulated and measured Raman spectra for the materials are compared. PRS is used to determine both (P2) and (P4) order parameters across the nematic temperature range and immediately below the NTB–N phase transition using a model that takes into account the molecular bend of the odd dimers, which is described in detail. In the nematic phase, the odd dimers are found to exhibit rather low order parameters with hP2i taking values between 0.3 and 0.5 and (P4) about 0.25. In contrast, the even dimer shows extremely high values of the order parameters with (P2) taking values between 0.7 and 0.8 and (P4) between 0.4 and 0.45. For the odd dimers, the values of (P2) in the NTB phase are similar to those of the N phase, whereas (P4) jumps by approximately 5–10% and then decreases with temperature. On comparing the experimental data with the theoretical predictions, we find reasonable qualitative agreement for all materials with molecular field theory. The odd dimers, however, show higher (P4) values than obtained from theoretical models, a factor attributed to the neglect of molecular flexibility and biaxiality in the PRS analysis.

Ferroelectric liquid crystals (FLCs) were a major topic for research in the 1980s and 1990s, to which George Gray and his research family played a fundamental role in developing the field. The famous symbiotic relationship between the chemists at Hull University and device physicists at the Royal Signals and Radar Establishment (RSRE) continued throughout this period, providing the basis for the τVmin mode of FLC operation. The principal of this mode relies on the dielectric biaxiality inherent to the smectic C and ferroelectric smectic C* liquid crystal phases. As with nematics before, new materials and device physics developed hand-in-hand, allowing materials to be formulated with addressing times of 12μs at voltages below 30 V. After reviewing the material physics behind these devices, new measurements of the biaxial refractive indices and permittivities are presented, from which the biaxial order parameter C is determined.

The term Energy-Return-On-Energy-Invested (EROEI) is self-explanatory and this topic has been the author’s primary research interest since about 2007. Many publications in journals including ‘Fuel’ (an Elsevier journal) have resulted. This paper comprises a synthesis and analysis of this work together with some new ideas.

BackgroundAnimal pigmentation has received much attention in evolutionary biology research due to its strong implications for adaptation and speciation. However, apart from a few cases the genetic changes associated with these evolutionary processes remain largely unknown. The Midas cichlid fish from Central America are an ideal model system for investigating pigmentation traits that may also play a role in speciation. Most Midas cichlids maintain their melanophores and exhibit a grayish (normal) color pattern throughout their lives. A minority of individuals, however, undergo color change and exhibit a distinctive gold or even white coloration in adulthood. The ontogenetic color change in the Midas cichlids may also shed light on the molecular mechanisms underlying pigmentation disorders in humans.ResultsHere we use next-generation sequencing (Illumina) RNAseq analyses to compare skin transcriptome-wide expression levels in three distinct stages of color transformation in Midas cichlids. cDNA libraries of scale tissue, for six biological replicates of each group, were generated and sequenced using Illumina technology. Using a combination of three differential expression (DE) analyses we identified 46 candidate genes that showed DE between the color morphs. We find evidence for two key DE patterns: a) genes involved in melanosomal pathways are up-regulated in normally pigmented fish; and b) immediate early and inflammatory response genes were up-regulated in transitional fish, a response that parallels some human skin disorders such as melanoma formation and psoriasis. One of the DE genes segregates with the gold phenotype in a genetic cross and might be associated with incipient speciation in this highly “species-rich” lineage of cichlids.ConclusionsUsing transcriptomic analyses we successfully identified key expression differences between different color morphs of Midas cichlid fish. These differentially expressed genes have important implications for our understanding of the molecular mechanisms underlying speciation in this lineage of extremely young species since they mate strongly assortatively, and new species may arise by sexual selection due to this color polymorphism. Some of the human orthologues of the genes identified here may also be involved in pigmentation differences and diseases and therefore provide genetic markers for the detection of human pigmentation disorders.

Spinal dysraphism is a congenital defect of the vertebral column and spinal cord secondary to imperfect closure of the caudal neuropore of the developing neural tube. This report describes computed tomographic myelography (Myelo-CT) characteristics of spina bifida occulta, spinal cord aplasia/hypoplasia and split cord malformation type II (diplomyelia) in the caudal lumbar area of a 2 month old mixed breed dog. &nbsp, La disrafia espinal es un defecto congénito de la columna vertebral y la médula espinal secundaria a un cierre imperfecto del neuroporo caudal del tubo neural en desarrollo. Este reporte describe las características observadas en una mielografía por tomografía computarizada (mielo-TC) de una espina bífida oculta, aplasia/hipoplasia segmentaria de médula espinal y duplicación de médula espinal tipo II (diplomielia) en el segmento lumbar caudal de un perro mestizo de dos meses de edad. &nbsp

The PLoS Medicine Editors' individual competing interests are at http://www.plosmedicine.org/static/editorsInterests.action. PLoS is funded partly through manuscript publication charges, but the PLoS Medicine Editors are paid a fixed salary (their salary is not linked to the number of papers published in the journal). The PLoS Medicine Editors are each paid a salary by the Public Library of Science, and they wrote this editorial during their salaried time. No specific funding was received for this paper. Provenance: Written by editorial staff; not externally peer reviewed.

A randomized, controlled, parallel-group study was undertaken to assess the clinical efficacy of a new elbow support ('Epitrain') compared with a standard elasticated tubular stockinette support ('Tubigrip') in 35 patients with acute painful elbow disorders. On entry, patients had a clinical examination, including measurement of the range of active and passive movement of the affected joint, and were allocated to one or other treatment group (19 to 'Epitrain', 16 to control). All patients were allowed to take 1g paracetamol up to 4-times daily if necessary for the control of pain. Assessments were made daily by patients, using visual analogue scales, of their pain levels at rest, at night and on activity, and of the limitation of their activity. Details were also recorded of their ability to work normally. At the end of the 14-day study period, patients were re-examined by the doctor and were asked for an overall assessment of their response to treatment. Analysis of data from the daily diary records showed progressive, significant reductions to zero in scores for all the pain and the activity criteria in the 'Epitrain' group during the first 7 to 9 days; thereafter, this improvement was maintained. In contrast, the reductions in symptom scores in the control group were much smaller, confined to the first 3 to 5 days, with little further improvement. The median times taken for reduction of symptom scores to 10% of initial levels were at least 14 days for all four visual analogue scale assessments in the control group. In contrast, a 90% reduction occurred in the 'Epitrain' group in a median time of 6.5 days for rest pain (p less than 0.01), 7 days for night pain (p less than 0.01), 8 days for pain on activity (p less than 0.01) and 9 days for limitation of activity (p less than 0.02). The mean range of active joint movement improved from 80 degrees to 141 degrees in the 'Epitrain' group, but only from 83 degrees to 98 degrees in the control group (p less than 0.0002). Similar results were obtained for passive joint movement. Overall, 13 (68%) of the 19 patients in the 'Epitrain' group were described as 'cured' as compared with 2 (13%) of the 16 patients in the control group (p less than 0.02).(ABSTRACT TRUNCATED AT 400 WORDS)