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We present a new integrated experimental and modeling effort that assesses the intrinsic sensitivity of energetic materials based on their reaction rates. The High Explosive Initiation Time (HEIT) experiment has been developed to provide a rapid assessment of the high-temperature reaction kinetics for the chemical decomposition of explosive materials. This effort is supported theoretically by quantum molecular dynamics (QMD) simulations that depict how different explosives can have vastly different adiabatic induction times at the same temperature. In this work, the ranking of explosive initiation properties between the HEIT experiment and QMD simulations is identical for six different energetic materials, even though they contain a variety of functional groups. We have also determined that the Arrhenius kinetics obtained by QMD simulations for homogeneous explosions connect remarkably well with those obtained from much longer duration one-dimensional time-to-explosion (ODTX) measurements. Kinetic Monte Carlo simulations have been developed to model the coupled heat transport and chemistry of the HEIT experiment to explicitly connect the experimental results with the Arrhenius rates for homogeneous explosions. These results confirm that ignition in the HEIT experiment is heterogeneous, where reactions start at the needle wall and propagate inward at a rate controlled by the thermal diffusivity and energy release. Overall, this work provides the first cohesive experimental and first-principles modeling effort to assess reaction kinetics of explosive chemical decomposition in the subshock regime and will be useful in predictive models needed for safety assessments.

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Supplemental Digital Content is Available in the Text.This study uses custom-designed automated software to explore both established and new metrics of choroidal structure in patients with and without central serous chorioretinopathy. It not only confirms the significance of choroid vascular index and automated choroid thickness measures but also demonstrates the use and utility of new and novel measures.

IMPORTANCE: Poor adherence or persistence to treatment can be a barrier to optimizing clinical practice (real-world) outcomes to intravitreal injection therapy in patients with neovascular age-related macular degeneration (nAMD). Currently, there is a lack of consensus on the definition and classification of adherence specific to this context. OBJECTIVE: To describe the development and validation of terminology on patient nonadherence and nonpersistence to anti–vascular endothelial growth factor therapy. DESIGN, SETTING, AND PARTICIPANTS: Following a systematic review of currently used terminology in the literature, a subcommittee panel of retinal experts developed a set of definitions and classification for validation. Definitions were restricted to use in patients with nAMD requiring intravitreal anti–vascular endothelial growth factor therapy. Validation by the full nAMD Barometer Leadership Coalition was established using a modified Delphi approach, with predetermined mean scores of 7.5 or more signifying consensus. Subsequent endorsement of the definitions was provided from a second set of retinal experts, with more than 50% members agreeing or strongly agreeing with all definitions. MAIN OUTCOMES AND MEASURES: Development of consensus definitions for the terms adherence and persistence and a classification system for the factors associated with treatment nonadherence or nonpersistence in patients with nAMD. RESULTS: Nonadherence was defined as missing 2 or more treatment or monitoring visits over a period of 12 months, with a visit considered missed if it exceeded more than 2 weeks from the recommended date. Nonpersistence was defined by nonattendance or an appointment not scheduled within the last 6 months. The additional terms planned discontinuation and transfer of care were also established. Reasons for treatment nonadherence and nonpersistence were classified into 6 dimensions: (1) patient associated, (2) condition associated, (3) therapy associated, (4) health system and health care team associated, (5) social/economic, and (6) other, with subcategories specific to treatment for nAMD. CONCLUSIONS AND RELEVANCE: This classification system provides a framework for assessing treatment nonadherence and nonpersistence over time and across different health settings in the treatment of nAMD with current intravitreal anti–vascular endothelial growth factor treatments. This may have additional importance, given the potential association of the coronavirus pandemic on adherence to treatment in patients with nAMD.

To link to full-text access for this article, visit this link: http://dx.doi.org/10.1016/j.ajo.2006.10.031 Byline: Tariq M. Aslam (a), Manish Gupta (a), David Gilmour (b), Niall Patton (a), Baljean Dhillon (a) Abstract: To describe the types and prevalence of long-term, established pseudophakic dysphotopsia in a typical population more than a year after cataract extraction. Author Affiliation: (a) Princess Alexandra Eye Pavilion, Edinburgh, United Kingdom (b) St James University Hospital, Leeds, United Kingdom Article History: Accepted 14 October 2006

•The current study reviews the literature on psychosocial and psychological interventions to prevent and treat depression and anxiety in patients with age-related macular degeneration (AMD).•Studies suggested that tailored interventions using group self-management techniques, and individual behavioural activation plus low vision rehabilitation can be effective to treat and prevent depression in AMD patients. One study suggested that a stepped-care intervention using cognitive-behavioural techniques can be effective to manage anxiety and depression over time.•Clinical practice with AMD patients can rely on some tailored cognitive-behavioural therapeutic protocols to improve patients’ mental health, but further clinical trials will generate the necessary evidence-based knowledge to improve those therapeutic techniques and offer additional tailored interventions for AMD patients.

PurposeMucopolysaccharidoses (MPSs) are a heterogeneous group of lysosomal storage disorders. Ocular complications (such as corneal clouding, retinopathy and optic neuropathy) are common. Notably, there is a paucity of data on the effect of genotype and systemic treatments (enzyme replacement therapy or haematopoietic stem cell transplantation) on the ocular phenotype in MPS. We prospectively studied the ocular features of patients with MPSI (Hurler/Hurler-Scheie/Scheie), MPSIV (Morquio) and MPSVI (Maroteaux-Lamy), to evaluate the effect of different therapeutic interventions and to correlate the findings with genetic and biomarker data.MethodsProspective observational cohort study. Study participants underwent detailed ocular examination including visual acuity; assessment of corneal clouding (Iris camera Corneal Opacification Measure score and Pentacam densitometry) and retinal and optic nerve imaging (optical coherence tomography and wide-field fundus imaging). Data on genotype, biomarkers and delivered therapies (type and length of treatment) were also collected for each patient where available.ResultsOverall, 21 patients with MPSI, 4 patients with MPSIV and 3 patients with MPSVI were recruited. Corneal clouding scores were higher in MPSI compared with MPSIV and MPSVI. Retinopathy was evident in patients with MPSI only. Association was observed between corneal clouding and biomarkers in MPSI, MPSIV and MPSVI. However, no clear association was seen between genotype or treatment type and ocular phenotype.ConclusionsThe ocular phenotype in MPS is variable, with corneal clouding occurring in MPSI, MPSIV and MPSVI, and retinopathy in MPSI only. There was an association between corneal clouding and efficacy of systemic treatment as measured by biomarkers.

Torpedo maculopathy is a rare congenital anomaly of the retinal pigment epithelium (RPE). Various imaging modalities have been used to assess cases of torpedo maculopathy, including optical coherence tomography (OCT) and fundus autofluorescence (FAF). OCT angiography (OCTA) offers combined structural and flow characteristics of imaged lesions. The authors present OCTA findings in two cases of torpedo maculopathy. Common features include loss of RPE and choriocapillaris allowing greater visualization of larger vessels in the outer choroid. This confirms the potential of OCTA to provide greater detail of retinal and choroidal architecture and elucidate the histopathology of retino-choridal lesions.[[Ophthalmic Surg Lasers Imaging Retina. 2017;48:932–935.]

The detonation of carbon-rich high explosives yields solid carbon as a major constituent of the product mixture, and depending on the thermodynamic conditions behind the shock front, a variety of carbon allotropes and morphologies may form and evolve. We applied time-resolved small-angle X-ray scattering (TR-SAXS) to investigate the dynamics of carbon clustering during detonation of PBX 9502, an explosive composed of 1,3,5-triamino-2,4,6-trinitrobenzene (TATB) and 5 wt % fluoropolymer binder. Solid carbon formation was probed from 0.1 to 2.0 μs behind the detonation front and revealed rapid carbon cluster growth which reached a maximum after ∼200 ns. The late-time carbon clusters had a radius of gyration of 3.3 nm which is consistent with 8.4 nm diameter spherical particles and matched particle sizes of recovered products. Simulations using a clustering kinetics model were found to be in good agreement with the experimental measurements of cluster growth when invoking a freeze-out temperature, and temporal shift associated with the initial precipitation of solid carbon. Product densities from reactive flow models were compared to the electron density contrast obtained from TR-SAXS, and used to approximate the carbon cluster composition as a mixture of 20% highly ordered (diamond-like) and 80% disordered carbon forms, which will inform future product equation of state models for solid carbon in PBX 9502 detonation product mixtures.

In this consecutive case series, reduction in pigment epithelial detachment height and volume and increase in pigment epithelial detachment reflectivity were more pronounced on treatment with aflibercept and were influenced by severity of disease at baseline. Aflibercept treatment achieves greater and faster improvement in quantifiable pigment epithelial detachment metrics at 3 months and 1 year from treatment onset.

The purpose of the current study was to examine the painful elbow, and in particular enthesitis, in psoriatic arthritis (PsA) and rheumatoid arthritis (RA) using clinical examination, ultrasonography (US) and magnetic resonance imaging (MRI). Patients with elbow pain (11 with PsA and 9 with RA) were recruited. Clinical examination, US and MRI studies were performed on the same day. For enthesitis, the common extensor and flexor insertions and the triceps insertion were imaged (20 patients, giving a total of 60 sites with comparative data). Imaging was performed with the radiologists blinded to the diagnosis and clinical findings. US was used to assess ‘inflammatory activity’ (Power Doppler signal, oedema, tendon thickening and bursal swelling) and ‘damage’ (erosions, cortical roughening and enthesophytes). MRI was used to assess ‘inflammation’ (fluid in paratenon, peri-entheseal soft-tissue oedema, entheseal enhancement with gadolinium, entheseal oedema and bone oedema) and ‘damage’ (erosion, cortical roughening and enthesophyte). Complete scan data were not available for all patients as one patient could not tolerate the MRI examination. No significant differences in imaging scores were found between PsA and RA. Analysis of damage scores revealed complete agreement between US and MRI data in 43/55 (78%) comparisons; in 10/55 (18%) cases the US data were abnormal but the MRI data normal; in 2/55 (4%) cases, the MRI data were abnormal and the US data normal. Analysis of the inflammation scores revealed complete agreement between US and MRI data in 33/55 (60%) comparisons; in 3/55 (5%) cases US data were abnormal but MRI data normal; in 19/55 (35%) cases the MRI data were abnormal and the US data normal. There was a poor relationship between assessments based on clinical examination and imaging studies. Readers could not accurately identify the disease from imaging findings. Based on our results, at the elbow, US and MR have different roles in assessing enthesitis, with US apparently the better diagnostic tool for assessing damage and MR the better tool for assessing inflammation. In this study enthesitis and synovitis in the painful elbow were found equally in cases of established RA and PsA.

The correct use of inhaler devices with facemasks and spacers in young children can be difficult for both children and parents, resulting in distress for both, poor adherence and ineffective drug delivery. The aim of this study was to develop and assess the utility and impact of an interactive electronic game designed to improve the experience of spacer devices in young asthmatic children. The Respiratory Aid For Inhaler (RAFIhaler) technology consists of a smartphone mounted on a metered dose inhaler with a valved holding chamber device (spacer) and connected to an electronic sensor adjacent to the outflow valve of the spacer. A custom-designed android application on the smartphone derives the child’s breathing patterns from the sensor, translating this information into visible effects on on-screen cartoon characters. After a period of iterative development, the final structure and software design was tested on children at Royal Manchester Children’s Hospital who had been admitted with acute wheeze. A survey, including open-ended questions, was administered to assess the parent and child’s reaction to the RAFIhaler. A total of 14 children (age range 2–7 years; 7 boys) participated in the study and used the RAFIhaler, of whom 13 completed the final survey; all 14 parents completed the survey. All 13 children reported they enjoyed playing the game. Ten of these children (91%) felt that the RAFIhaler helped them in taking their medication, and 13 of the 14 parents felt that RAFIhaler helped their children use their spacer. The one parent who felt that the RAFIhaler was not of any benefit felt his/her child already used the inhaler well. Some of the benefits of the RAFIhaler specifically voiced by parents were “enjoyable” (n= 3), “good distraction” (n= 3), “made child calmer” (n= 2), “helped in breathing/inhalation technique” (n= 3) and “would be useful in home setting” (n= 1). Young children may benefit from the incorporation of devices and game applications with use of their inhalers. Feedback from children and parents suggests potential benefits to children may include learning correct use, reducing distress and anxiety and improving overall adherence.

A specialized hydrodynamic simulation code has been developed and verified for the simulation of one-dimensional unsteady problems involving the detonation and deflagration of high explosives. To model all the relevant physical processes in these problems, a code is required to simulate compressible hydrodynamics, unsteady thermal conduction, and chemical reactions with complex rate laws. Several verification exercises are presented which test the implementation of these capabilities. The code also requires models for physics processes such as equations of state and conductivity for pure materials and mixtures as well as rate laws for chemical reactions. Additional verification tests are required to ensure that these models are implemented correctly. Though this code is limited in the types of problems it can simulate, its computationally efficient formulation allows it to be used in calibration studies for reactive burn models for high explosives. This study demonstrates how a series of verification tests can be used to ensure that the various physics processes needed to simulate complex phenomenon can be tested to ensure that they are correctly implemented.

Purpose Wet age-related macular degeneration (ARMD) is a leading cause of visual impairment. Anti-vascular endothelial growth factor (VEGF) injections are the mainstay of treatment but require monthly injections and frequent hospital visits. A novel approach to treatment with the use of stereotactic radiotherapy (Oraya IRay) as an adjunct to ranibizumab injections has shown promising results. We explored patients’ experiences of receiving Oraya therapy for wet ARMD.Methods We present a consecutive case series with objective and detailed reporting of the personal experiences of 5 patients with active wet ARMD treated with Oraya radiotherapy in our unit. We provided all patients who had received one Oraya treatment with a standardized survey composed of 10 questions addressing the experience of receiving this treatment.Results Generally, patients reported positive experiences of receiving Oraya treatment and perceived this treatment as a better option in comparison with anti-VEGF injections. However, the patients’ perceptions of Oraya treatment varied according to patients’ previous experiences of anti-VEGF injections and expectations of treatment.Conclusions Patients mainly justified their decision to receive Oraya treatment by expecting fewer intravitreal injections, but more research on this topic is needed to suggest new evidence-based treatment protocols for patients with wet ARMD.

Iris recognition systems are among the most accurate of all biometric technologies with immense potential for use in worldwide security applications. This study examined the effect of eye pathology on iris recognition and in particular whether eye disease could cause iris recognition systems to fail. The experiment involved a prospective cohort of 54 patients with anterior segment eye disease who were seen at the acute referral unit of the Princess Alexandra Eye Pavilion in Edinburgh. Iris camera images were obtained from patients before treatment was commenced and again at follow-up appointments after treatment had been given. The principal outcome measure was that of mathematical difference in the iris recognition templates obtained from patients' eyes before and after treatment of the eye disease. Results showed that the performance of iris recognition was remarkably resilient to most ophthalmic disease states, including corneal oedema, iridotomies (laser puncture of iris) and conjunctivitis. Problems were, however, encountered in some patients with acute inflammation of the iris (iritis/anterior uveitis). The effects of a subject developing anterior uveitis may cause current recognition systems to fail. Those developing and deploying iris recognition should be aware of the potential problems that this could cause to this key biometric technology.

Disability glare describes the loss of retinal image contrast as a result of intraocular light scatter, or straylight. It has increasingly important modern implications such as with cataract and refractive surgery or high-intensity lighting. However, its measurement has proven difficult despite many varying approaches. This article aims to explain the principles and problems associated with glare testing that are important for assessment and use of glare measures. After defining disability glare, this article discusses the importance of its measurement to current clinical practice. It explains the principles and mechanisms that underlie disability glare and its measurement. Finally, some examples of available glare tests are described to illustrate the principles discussed.

As ophthalmic science develops, the expectations of surgeons and patients undergoing cataract or refractive surgery also advance. Good Snellen visual acuity is not always an indicator for patient satisfaction, and the surgeon must understand the nature and pathogenesis of problems with other less recognised visual functions. This paper discusses the phenomenon of unwanted light images that may occur after surgery due to optical media imperfections, termed pseudophakic photic phenomena. It covers definitions, assessment, high-risk groups and possible explanations for the occurrence of such phenomena.

Abstract Background. This study explores the relative influence of fibrosis and pearl-type posterior capsule opacification (PCO) on visual function. It also examines the relevance of analyzing different central areas of posterior capsule on visual function. Methods. Thirty-eight eyes of 33 patients had their vision tested and posterior capsules photographed digitally. Each patient then underwent Nd:YAG laser capsulotomy. Patients returned 1 week later for repeat vision tests and photography. Analyses of areas of pearls and fibrosis were performed using the EPCO software system. The difference in these values before and after Nd:YAG laser capsulotomy was compared to change in vision for each patient. The effect of analyzing the central 1.5-, 2.5- and 3.5-mm zones was studied. Results. Stepwise multiple linear regression analysis shows that improvements in distance and near acuity are most strongly related to the central 1.5-2.5 mm of fibrosis and the central 3.5 mm of pearls. Improvements in contrast sensitivity are most strongly related to the central 1.5 mm of both fibrosis and pearls. Conclusion. In the assessment of PCO, the location and morphology of opacification correlate with visual function. Central fibrosis and paraxial pearls are important determinants of visual dysfunction.

Abstract Background. There are no prospective controlled trials comparing methods of capsulotomy or patterns of capsulotomy openings in similarly graded opacified posterior capsules. This paper aims to investigate the effect of various forms of posterior capsular opacification (PCO) capsulotomy openings on visual function Methods. Thirty-six eyes of 34 patients had vision tested and posterior capsules were digitally photographed. Each patient then underwent Nd:YAG laser capsulotomy. Patients returned 1 week later for repeat vision tests and photography. Analyses of areas of pearls and fibrosis were performed using the EPCO software system. Analyses of size and shape of capsulotomy was also done with image analysis software. The capsulotomy characteristics were analysed with respect to improvements in vision, taking into consideration the PCO scores. Results. No correlation was found between capsulotomy dimensions and visual function improvement, even when PCO details were included in the analyses. Neither capsulotomy area, eccentricity, nor shape irregularity in the ranges measured was found to correlate significantly with eventual visual outcome in terms of contrast sensitivity, near and distance visual acuity, or glare readings. Conclusion. Performing a small capsulotomy (at least 1.5 mm in diameter), even if decentred up to 1 mm, may allow for satisfactory visual performance as long as the aperture is clear and not obscured by residual strands.

A level-set algorithm for tracking discontinuities in hyperbolic conservation laws is presented. The algorithm uses a simple finite difference approach, analogous to the method of lines scheme presented in C.-W. Shu and S. Osher (1988, J. Comput. Phys.77, 439). The zero of a level-set function is used to specify the location of the discontinuity. Since a level-set function is used to describe the front location, no extra data structures are needed to keep track of the location of the discontinuity. Also, two solution states are used at all computational nodes, one corresponding to the “real” state, and one corresponding to a “ghost node” state, analogous to the “Ghost Fluid Method” of R. P. Fedkiw et al.(1999, J. Comput. phys.154, 459). High-order pointwise convergence is demonstrated for linear and nonlinear conservation laws, even at discontinuities and in multiple dimensions. The solutions are compared to standard high-order shock-capturing schemes. This paper focuses on scalar conservation laws. An example is given for shock tracking in the one-dimensional Euler equations. Level-set tracking for systems of conservation laws in multidimensions will be presented in future work.

While Eulerian schemes work well for most gas flows, they have been shown to admit nonphysical oscillations near some material interfaces. In contrast, Lagrangian schemes work well at multimaterial interfaces, but suffer from their own difficulties in problems with large deformations and vorticity characteristic of most gas flows. We believe that the most robust schemes will combine the best properties of Eulerian and Lagrangian schemes. In this paper, we propose a new numerical method for treating interfaces in Eulerian schemes that maintains a Heaviside profile of the density with no numerical smearing along the lines of earlier work and most Lagrangian schemes. We use a level set function to track the motion of a multimaterial interface in an Eulerian framework. In addition, the use of ghost cells (actually ghost nodes in our finite difference framework) and a new isobaric fix technique allows us to keep the density profile from smearing out, while still keeping the scheme robust and easy to program with simple extensions to multidimensions and multilevel time integration, e.g., Runge–Kutta methods. In contrast, previous methods used ill-advised dimensional splitting for multidimensional problems and suffered from great complexity when used in conjunction with multilevel time integrators.

The level set method for multiphase compressible flows is simple to implement, especially in the presence of topological changes. However, this method was shown to suffer from large spurious oscillations. A new Ghost Fluid Method (GFM) was developed to remove these spurious oscillations by minimizing the numerical smearing in the entropy field with the help of an Isobaric Fix technique. The GFM was designed for traditional contact discontinuities where the interface moves with the fluid velocity only. In this paper, the GFM is extended to treat multimaterial interfaces where the interface velocity includes a regression rate due to the presence of chemical reactions converting one material into another. Specifically, interface models for deflagration and detonation discontinuities are considered. The resulting numerical method is robust and easy to implement.

A detonation shock-evolution equation that predicts both pulsating and cellular detonation has been derived in the limit of near-Chapman-Jouguet detonation, weak curvature, slow temporal variation, and large activation energy with a newly applied technique of the method of successive approximation. The evolution equation describes a wave hierarchy that is consistent with the linear stability theory of the evolution equation. We define the parameter regime for which the equation applies. The transverse wave instability, as indicated from analysis, leads to cellular detonation. Triple-points tracks correspond to shock-shock intersections of the dynamic solution of smooth portions of the front. The dynamics of the cellular solution are consistent with the notion that the power of the detonation front is derived from the normal reaction zone and the triple points are generated as the interaction of the independently propagating fronts and the consequent shock-shock intersections, not as the centers of blast waves. Explicit criteria for prediction of cell widths and cell aspect ratios are given.

We give an extension of the level set formulation of Osher and Sethian, which describes the dynamics of surfaces that propagate under the influence of their own curvature. We consider an extension of their original algorithms for finite domains that includes boundary conditions. We discuss this extension in the context of a specific application that comes from the theory of detonation shock dynamics (DSD). We give an outline of the theory of DSD which includes the formulation of the boundary conditions that comprise the engineering model. We give the formulation of the level set method, as applied to our application with finite boundary conditions. We develop a numerical method to implement arbitrarily complex 2D boundary conditions and give a few representative calculations. We also discuss the dynamics of level curve motion and point out restrictions that arise when applying boundary conditions.

We present details of 'Mercury', a high-speed downhole communications system that utilizes the (metallic) wall of a gas or oil pipeline or a drill 'string' as the communications 'channel' to control or monitor equipment or sensors used in the oil industry. Conventional downhole communication systems typically use 'mud pulse' telemetry for 'Measurement While Drilling' (MWD) operations. Current mud pulse telemetry technology offers bandwidths of up to 40 bit/s. However the data rate drops with increasing length of the wellbore and is typically as low as 1.5 bit/s - 3.0 bit/s at a depth of 35,000 ft. - 40,000 ft. The system described, by contrast, offers data rates of several megabits per second over distances of many kilometres and uses Orthogonal Frequency Division Multiplexing (OFDM) coupled with Wideband Frequency Division Multiple Access (W-CDMA). This paper presents details of our system; results of several trials undertaken on actual gas pipelines in the UK will be presented at the Conference.

There are a multitude of applications using modern tablet computers for vision testing that are accessible to ophthalmology patients. While these may be of potential future benefit, they are often unsupported by scientific assessment. This report investigates the pertinent physical characteristics behind one of the most common highest specification tablet computers with regard to its capacity for vision testing. We demonstrate through plotting of a gamma curve that it is feasible to produce a precise programmable range of central luminance levels on the device, even with varying background luminance levels. It may not be possible to display very low levels of contrast, but carefully using the gamma curve information allows a reasonable range of contrast sensitivity to be tested. When the screen is first powered on, it may require up to 15 min for the luminance values to stabilize. Finally, luminance of objects varies towards the edge of the screen and when viewed at an angle. However, the resulting effective contrast of objects is less variable. Details of our assessments are important to developers, users and prescribers of tablet clinical vision tests. Without awareness of such findings, these tests may never reach satisfactory levels of clinical validity and reliability.