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The main two optical aberrations seen in any imaging system are defocus and astigmatism. Traditionally, the approaches to correct both aberrations utilize the mechanical movement of fixed power spherical and cylindrical lenses. In this report, we have proposed a non-mechanical, electrically tunable optical system that can provide both focus and astigmatism power correction with an adjustable axis. The concept device is comprised of stripe electrodebased gradient refractive index liquid crystal lens. Dynamic astigmatism and focus correction are demonstrated upon application of electric field on the designed device. Unlike complex, bulky, and curved shape lens systems, the proposed device is flat, low cost, and low voltage driven.

For the correction of defocus and astigmatism, mechanical approaches are well known, but there is a need for a non-mechanical, electrically tunable optical system that could provide both focus and astigmatism power correction with an adjustable axis. The optical system presented here is composed of three liquid-crystal-based tunable cylindrical lenses that are simple, low cost, and having a compact structure. Potential applications of the concept device include smart eyeglasses, virtual reality (VR)/ augmented reality (AR) head-mounted displays (HMDs), and optical systems subject to thermal or mechanical distortion. Details of the concept, design method, numerical computer simulations of the proposed device, as well as characterization of a prototype, are provided in this work.

Pancharatnam Phase Devices (PPDs) are an exciting new area for optical component development. Single layer active devices that provide optical beam steering over a range of several degrees will be discussed. The devices considered here use a comb electrode structure to provide an in-plane electric field to control the optical axis orientation of the liquid crystal director to have the desired spiral pattern of a PPD device. Two basic concepts will be discussed: one that used the in-plane fields to “pin” the only the ends of the spiral pattern; and another that uses sub elements to defines the desired director orientation at several locations in the spiral. The concepts, design details, and modeling results are shown.

Rootless plants in the genus Wolffia are some of the fastest growing known plants on Earth. Wolffia have a reduced body plan, primarily multiplying through a budding type of asexual reproduction. Here, we generated draft reference genomes for Wolffia australiana (Benth.) Hartog & Plas, which has the smallest genome size in the genus at 357 Mb and has a reduced set of predicted protein-coding genes at about 15,000. Comparison between multiple high-quality draft genome sequences from W. australiana clones confirmed loss of several hundred genes that are highly conserved among flowering plants, including genes involved in root developmental and light signaling pathways. Wolffia has also lost most of the conserved nucleotide-binding leucine-rich repeat (NLR) genes that are known to be involved in innate immunity, as well as those involved in terpene biosynthesis, while having a significant overrepresentation of genes in the sphingolipid pathways that may signify an alternative defense system. Diurnal expression analysis revealed that only 13% of Wolffia genes are expressed in a time-of-day (TOD) fashion, which is less than the typical ∼40% found in several model plants under the same condition. In contrast to the model plants Arabidopsis and rice, many of the pathways associated with multicellular and developmental processes are not under TOD control in W. australiana, where genes that cycle the conditions tested predominantly have carbon processing and chloroplast-related functions. The Wolffia genome and TOD expression data set thus provide insight into the interplay between a streamlined plant body plan and optimized growth.

Cerebral autoregulation (CA) refers to the ability of the brain vasculature to control blood flow in the face of changing blood pressure. One of the methods commonly used to assess cerebral autoregulation, especially in participants at rest, is the analysis of phase derived from transfer function analysis (TFA), relating arterial blood pressure (ABP) to cerebral blood flow (CBF). This and other indexes of CA can provide consistent results when comparing groups of subjects (e.g. patients and healthy controls or normocapnia and hypercapnia) but can be quite variable within and between individuals. The objective of this paper is to present a novel parametric bootstrap method, used to estimate the sampling distribution and hence confidence intervals (CIs) of the mean phase estimate in the low-frequency band, in order to optimise estimation of measures of CA function and allow more robust inferences on the status of CA from individual recordings. A set of simulations was used to verify the proposed method under controlled conditions. In 20 healthy adult volunteers (age 25.53.5 years), ABP and CBF velocity (CBFV) were measured at rest, using a Finometer device and Transcranial Doppler (applied to the middle cerebral artery), respectively. For each volunteer, five individual recordings were taken on different days, each approximately 18 min long. Phase was estimated using TFA. Analysis of recorded data showed widely changing CIs over the duration of recordings, which could be reduced when noisy data and frequencies with low coherence were excluded from the analysis (Wilcoxon signed rank test p = 0.0065). The TFA window-lengths of 50s gave smaller CIs than lengths of 100s (p < 0.001) or 20s (p < 0.001), challenging the usual recommendation of 100s. The method adds a much needed flexible statistical tool for CA analysis in individual recordings.

Controlling and optimising the alignment of liquid crystals is a crucial process for display application. Here, we investigate the effects of humidity and surface types on photoalignment of an azo-dye brilliant yellow (BY). Specifically, the effect of humidity on the photoalignment of BY was studied at the stage of substrate storage before coating, during the spin-coating process, between film coating and exposure, and after exposure. Surprising results are the drastic effect of humidity during the spin-coating process, the humidity annealing to increase the order of the BY layer after exposure and the dry annealing to stabilise the layer. Our results are interpreted in terms of the effect of water on the aggregation of BY. The type of surface studied had minimal effects. Thin BY films (about 3 nm thickness) were sensitive to the hydrophilicity of the surface while thick BY films (about 30 nm thickness) were not affected by changing the surface. The results of this paper allow for the optimisation...

Currently available head-mounted displays for virtual and augmented reality systems provide many of the visual cues that a viewer senses in the real world, but not the important accommodation cue. Approaches to solve this problem have been considered, but proposed solutions come at significant cost in terms of image quality and system complexity. In this paper we propose a simple system, based on electronic liquid crystal lenses. The design and performance of applicable electronic lenses are presented. A surprising result of the proposed design is the potential for a reduced system bandwidth.

Presbyopia is the failure of the eye lens to accommodate. The widely used presbyopia correction method involves wearing bi/trifocal or progressive glasses, which limits the field of view due to division of lens area into sections of different optical power. A large aperture focus tunable liquid crystal lens has the potential to correct human eye accommodation failure and provide a wide field of view. In this paper, we present characterization and demonstration of a segmented phase profile liquid crystal lens, which has the characteristics of a large area (diameter: 20 mm), being flat and thin (

Accommodation–convergence mismatch is still an unsolved issue within the field of augmented reality, virtual reality, and three-dimensional systems in general. Solutions suggested to correct the focus cue in recent years require additional bandwidth, or compromise the image resolution. Our simple approach to overcome this issue is by using an eye-tracking system and electronic lenses. We propose an electronic hybrid lens system composed of segmented phase profile liquid crystal and Pancharatnam phase lenses. For practical application, eye tracking is necessary for measuring the toe-in of the user’s pupil to calculate the object depth. This information is used to determine the required diopteric power of the hybrid system. The optical performance and imaging quality of the proposed hybrid system are evaluated.

“Lower lip shave” is the excision of the epithelium of the rmilion for treatment of dysplasia or superficial carcinoma situ. The lower lip is reconstructed by advancement of the cosa of the labia which is both functional and aesthetic.1 Serious haemorrhage from the branches of the arteries of labia is possible, which can make it difficult to check margins of the excision and recontour the border of the rmillion. We apply pressure with bowel clamps bilaterally t below both commissures (Fig. 1), which considerably uces bleeding. This also makes it easier to neatly excise the rest of the cosa, as it removes the need for digital pressure to the ial arteries, during which the assistant can inadvertently injured by sharps. Once haemorrhage is controlled, we can use diathermy to uterise localised bleeding points and this improves visibilwhilst the vermillion border is contoured and the lower reconstructed.

A large aperture tunable lens based on liquid crystals, which is considered for near-to-eye applications, is designed, built, and characterized. Large liquid crystal lenses with high quality are limited by very slow switching speeds due to the large optical path difference (OPD) required. To reduce the switching time of the lens, the thickness is controlled through the application of several phase resets, similar to the design of a Fresnel lens. A main point of the paper is the design of the Fresnel structure to have a minimal effect on the image quality. Our modeling and experimental results demonstrate that minimal image degradation due to the phase resets is observable when the segment spacing is chosen by taking into account human eye resolution. Such lenses have applications related to presbyopia and, in virtual reality systems, to solve the well-known issue of accommodation-convergence mismatch.

E-type polarizers are now available for industrial applications. New polarizers are produced as submicron thin film polarizing coating. Glass and plastic (PET) TN LCDs were manufactured with Thin Film Polarizers replacing conventional polarizers. Another design uses new polarizers to replace the alignment layer and performs both functions: polarization and LC alignment. Optical characteristics of new LCD design are comparable (Contrast Ratio =60) or better (Viewing Angle Cone) than conventional technology.

Efalizumab was approved for psoriasis in 2003. In 2008, two cases of progressive multifocal leukoenecephalopathy (PML) were reported, and in 2009, a third case was confirmed in patients on efalizumab monotherapy for psoriasis. As a result, in Europe, efalizumab's marketing authorization was suspended by the European Medicines Agency. Shortly thereafter, Genentech announced plans to withdraw the drug from the U.S. The withdrawal, which was completed in June 2009, was the result of the risk of an infection that is often fatal, with three confirmed PML cases out of the approximately 2,000 patients treated with efalizumab for more than three years. Efalizumab was one of the first biologics approved by the U.S. Food and Drug Administration for the treatment of moderate to severe plaque psoriasis. With the later approval of additional biologic agents for plaque psoriasis, prescribers had additional treatment options with improved efficacy and safety. The risks associated with efalizumab for its relatively low efficacy made it unattractive compared to other biologic product treatment options, ultimately leading to its withdrawal.

In the past, ecological risk assessments (ERAs) have generally overlooked the soil microbial community when evaluating the impacts of contaminants in soil. However, the soil microbial community, which includes bacteria and fungi, performs functions necessary for overall ecosystem health, including nitrogen fixation, nutrient cycling, and even degradation of contaminants. The incorporation of the soil microbial community into ERA requires the compilation of adequate toxicity data to complete the hazard assessment phase of the risk assessment. A variety of soil microbial toxicity tests exist that provide rapid and inexpensive results. Surveys of the microbial community at a contaminated site may also provide insight as to their functioning in the presence of contaminants. This paper explores the use of toxicity tests and surveys to evaluate chemical toxicity to microbes. However, many questions related to the best methodological approach to an ERA of the soil microbial community have yet to be answered.

Purpose: The authors determine if specific features of the clinical presentation of acute postoperative endophthalmitis correlate with the microbiologic culture results. Methods: A total of 420 patients who had clinical evidence of endophthalmitis within 6 weeks after cataract surgery or secondary intraocular lens implantation were evaluated as part of a randomized clinical trial. Results of cultures performed on aqueous and vitreous specimens obtained at presentation were categorized as follows: gram-positive coagulase-negative micrococci, "other" gram-positive, gram-negative, and equivocal/no growth. Results: Eleven features of the initial clinical presentation were associated with significant differences in the microbiologic spectrum ( P Conclusions: The presenting characteristics of acute endophthalmitis after cataract surgery may be helpful in predicting the most likely culture results. Such predictions do not appear sufficiently strong to guide the initial empiric choice of intravitreal antibiotics.

In Appl. Phys. Lett. 67, 1990 (1995), we proposed a particularly simple four‐domain (4‐D) twisted nematic(TN) liquid crystal display(LCD) device, which is composed of two left‐handed and two right‐handed TN subpixels. The two members of each pair of same handedness subpixels are rotated 180° with respect to each other, resulting in four domains that spatially average one another optically to provide a wide angle of viewing with no gray scale inversion. The optical performance of the 4‐D TN LCD was confirmed by studies of a test cell fabricated by a two‐step SiOx oblique evaporation technique. In this article, we report the realization of our four‐domain TN display by a reverse rubbing technique that should be suitable for mass production in the display industry. The optical simulation of our 4‐D TN cell was performed and the effect of disclinations at subpixel boundaries on display contrast investigated. A simple model was developed to evaluate the stability of our 4‐D structure.

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A particularly simple four‐domain (4‐D) twisted nematic (TN) liquid crystal display (LCD) device is proposed, which is composed of two left‐handed TN and two right‐handed TN subpixels. One of each pair of same handedness subpixels is rotated 180° with respect to the other, resulting in four domains that spatially average one another optically to provide a wide angle of viewing with no gray scale inversion. The detailed fabrication process is presented for a two step SiOx oblique evaporation technique used to realize this 4‐D TN LCD. A reverse rubbed polyamide fabrication process has also been successfully used and will be presented in the full length article. Here we present the complete viewing angle and contrast ratio data for a simple and successful 4‐D TN LCD cell.

A near-diffraction-limited, low-haze and tunable liquid crystal (LC) lens is presented. Building on an understanding of the key factors that have limited the performance of lenses based on liquid crystals, we show a simple design whose optical quality is similar to a high quality glass lens. It uses 'floating' electrodes to provide a smooth, controllable applied potential profile across the aperture to manage the phase profile.

A comprehensive analysis of fundamental factors and their effects on the performance of liquid crystal (LC)-based lenses is given. The analysis adopts numerical LC director and electric field simulation, as well as scalar diffraction theory for calculating the lens performance considering different variable factors. A high-efficiency LC lens with concentric electrode rings is fabricated for verifying and enriching the analysis. The measurement results are in close agreement with the analysis, and a summary of key factors is given with their quantitative contributions to the efficiency.

A high-efficiency tunable refractive lens based on liquid crystals with concentric electrode rings and a simple unique design of a resistor network is reported, and used to assess the performance of an optimized electrically tunable lens. It has a large number of phase control points to be able to accurately control the phase profile and produce high efficiency. The lens design uses resistors between neighboring electrodes to minimize external connections. The lens optical path difference is measured as a near perfect parabolic shape and the Strehl ratio of about 80% is obtained (comparing to a high-quality glass lens). Image evaluations show a good image quality with diffraction limited resolution, but the contrast is lowered by a large-area haze. The lens design also shows a good switching speed, and adjustable power, allowing it to be used in many applications. An example lens with a diameter of 2.4 mm and a 5 diopter tunable range is used in the evaluations.

We consider the dynamics of a variable optical prism based on Pancharatnam phase. The device basics, using liquid crystals (LCs) as the electro-optical material, have been previously proposed. In this paper, we study the dynamics of discrete changes in the phase profile, and also continuous changes in the phase profile through acquired data and numerical modeling. We show that a design based on LCs whose dielectric anisotropy can change sign (as a function of frequency) allows continuous tuning with reasonable response times.

Vast amounts of evolving data are created in the design of hard real-time software systems. This data must be managed so that it can be stored and retrieved according to the needs of design engineers. In the Computer-Aided Prototyping System (CAPS), a Design Database (DDB) must manage the storage and retrieval of the entire Prototype System Description Language (PSDL) program. This thesis presents a conceptual design and initial implementation of a Design Database (DDB) for the Computer-Aided Prototyping System (CAPS). http://archive.org/details/aconceptuallevel1094524279 Lieutenant, United States Navy Approved for public release; distribution is unlimited.

— The experimental demonstration of a polarization-independent high-transmission field-sequential liquid-crystal-etalon modulator for portable projection-display application is presented. Polarization independence allows for high transmission efficiency for laser illumination sources using the polarization diversity method of speckle reduction. These devices can also be considered for LED illumination sources; however, the spectral width of current LEDs does not allow for high efficiency, especially for the green channel. These devices demonstrate millisecond switching needed for field-sequential-color generation.

Niccolò Fausti, master of ceremonies at St Mark's Venice from 1576 to 1598, in one of his several additions at the back of a manuscript ceremoniale of 1564, lists the days on which Vespers in the ducal basilica were performed by two choirs of singers.