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A paradigm-shifting design strategy is demonstrated that unifies the treatment of electronic and conformational properties of polymer dielectrics for concurrent high electric field and elevated temperature harsh conditions.

Flexible polymer dielectrics tolerant to electric field and temperature extremes are urgently needed for a spectrum of electrical and electronic applications. Given the complexity of the dielectric breakdown mechanism and the vast chemical space of polymers, the discovery of suitable candidates is nontrivial. We have laid the foundation for a systematic search of the polymer chemical space, which starts with "gold-standard" experimental measurements and data on the temperature-dependent breakdown strength (Ebd) for a benchmark set of commercial dielectric polymer films. Phenomenological guidelines are derived from this data set on easily accessible properties (or "proxies") that are correlated with Ebd. Screening criteria based on these proxy properties (e.g., band gap, charge injection barrier, and cohesive energy density) and other necessary characteristics (e.g., a high glass transition temperature to maintain the thermal stability and a high dielectric constant for high energy density) were then setup. These criteria, along with machine learning models of these properties, were used to screen polymers candidates from a candidate list of more than 13 000 previously synthesized polymers, followed by experimental validation of some of the screened candidates. These efforts have led to the creation of a consistent and high-quality data set of temperature-dependent Ebd, and the identification of screening criteria, chemical design rules, and a list of optimal polymer candidates for high-temperature and high-energy-density capacitor applications, thus demonstrating the power of an integrated and informatics-based philosophy for rational materials design.

PURPOSE: To analyze the clinical profile of patients with posterior lenticonus and their surgical, visual, and refractive outcomes. RESULTS: Retrospective interventional case series of 84 eyes of 63 patients with posterior lenticonus. The incidence of posterior lenticonus was 3.98% during a study period of 5 years. One-third of cases had bilateral posterior lenticonus. The mean age was 4.78 ± 4.28 years (unilateral cases were significantly older than bilateral, P = 0.0001). Males were 54%. Mean axial length and keratometry were 21.49 mm and 44.88 D, respectively. Eyes with the bilateral disease were significantly shorter (axial length, P = 0.0012) and smaller (horizontal corneal diameter, P

Polymer dielectrics essentially revolutionized the electrical power system, pervasively used in nearly all the key electronic and electrical devices, due mainly to their suitably large bandgaps. However, insufficient attention has been paid to the bandgap in the design of new polymer dielectrics for high temperatures. In this paper, we present a unified principle for the design of flexible, high temperature polymer dielectrics. As exemplified by our recently discovered poly(oxa)norbornenes (POFNB), saturated bicyclics with varying carbonyl and ether groups in the bicyclic repeat units, connected by unconjugated alkenes and freely rotatable single bonds in conjunction with freely rotating fluorinated benzene ring side-groups, can impart flexibility yet retain thermal stability while providing large bandgaps to olefinic polymers. The results indicate that POFNB has stably low conduction current under concurrent high electric field and elevated temperatures beneficial from its large band gap of ∼5 eV and high glass transition temperature of 186 °C.

Purpose: To study interobserver variability for measurement of grating acuity in preverbal and nonverbal children with developmental delay using Lea Grating Paddles (Lea Hyvärinen). Methods: In this prospective study, preverbal patients younger than 3 years and older nonverbal patients (with developmental delay) were included. Those with poor neck holding were excluded. Binocular and monocular visual acuity assessment was done simultaneously using Lea Grating Paddles by two examiners who were blinded from each other's results. Results: Thirty-one children were tested (19 [61.29%] males and 12 [38.71%] females). The mean age was 28.5 months (range: 4 to 44 months). A total of 92% of the observations showed interobserver agreement of 0.5 octave or better in binocular testing. Results for monocular testing showed interobserver agreement (0.5 octaves or better) in 95.65% and 95.23% of right and left eyes, respectively. Combined results showed agreement better than 0.5 octaves in 94.20%. The mean binocular visual acuity was 2.07 and 2.14 cycles per degree (cpd) for the first and second observer, respectively ( P = .59). Similarly, the mean monocular visual acuity for the right and left eyes was 0.98 and 0.97 cpd for observer 1 and 0.89 and 0.79 cpd for observer 2, respectively ( P = .91 and .14, for the right and left eyes, respectively). Conclusions: Interobserver variability for grating acuity measurement using Lea Grating Paddles is minimal, signifying it to be a reliable and reproducible alternative to conventional preferential looking testing procedures. [ J Pediatr Ophthalmol Strabismus . 2020;57(5):305–308.]

Next-generation wearable systems call for flexible, breathable, and skin-friendly wireless transmitters for realizing body area networks and the internet of things. This work presents the first fully functional, poly(3,4-ethylenedioxythiophene):polystyrene sulfonate (PEDOT:PSS) screen-printed fabric patch antenna for next-generation wearable antennas. This is an unparalleled milestone as prior conductive polymer based fabrics all demonstrated insufficient RF radiation due to skin effect loss, whereas here, an all-organic fabric RF transmitter is realized with the help of nanotemplate-assisted PEDOT:PSS conductive phase segregation on the surface of fabric fibers, forming a continuum coaxial structure with a conductive shell. This multi-strand wire structure endows the conductive fibers with a high surface area that is similar to high frequency Litz-wire, resulting in an extremely high RF conductivity. The fabricated patch antenna based on this conductive fabric shows an extremely low return loss of −50 dB and a satisfactory radiation efficiency of 28% at its resonant frequency of 2.35 GHz, and preserves its performance characteristics when bent over a representative phantom. In addition, the Doppler radar system based on the fabric patch antennas demonstrates satisfactory speed and distance detection with high precision, well suited for future application as a short-range sensing device for blind assistance. This development paves a new way to fabricate all-organic flexible RF devices for wireless communication with profound implications for the field of integrated wearable electronic networks.

Flexible large bandgap dielectric materials exhibiting ultra-fast charging-discharging rates are key components for electrification under extremely high electric fields. A polyoxafluoronorbornene (m-POFNB) with fused five-membered rings separated by alkenes and flexible single bonds as the backbone, rather than conjugated aromatic structure typically for conventional high-temperature polymers, is designed to achieve simultaneously high thermal stability and large bandgap. In addition, an asymmetrically fluorinated aromatic pendant group extended from the fused bicyclic structure of the backbone imparts m-POFNB with enhanced dipolar relaxation and thus high dielectric constant without sacrificing the bandgap. m-POFNB thereby exhibits an unprecedentedly high discharged energy density of 7.44 J/cm(3) and high efficiency at 150 °C. This work points to a strategy to break the paradox of mutually exclusive constraints between bandgap, dielectric constant, and thermal stability in the design of all-organic polymer dielectrics for harsh condition electrifications.

PReCIS:: In India, older drivers with glaucoma show greater driving difficulty but are not involved in higher number of on-road accidents. To achieve balance between safety aspects and independence for drivers with glaucoma is important. PURPOSE The purpose of this study was to analyze driving habits of patients with glaucoma and to compare their driving behavior, driving difficulties, and accident rates with nonglaucoma controls. PATIENTS Patients with glaucoma aged older than 40 years were recruited. Subjects with best-corrected visual acuity ≤6/24 in the better-seeing eye and those having primary eye disorder other than glaucoma were excluded. Age-matched nonglaucoma controls were recruited. Subjects with clinically significant cataract and/or with best-corrected visual acuity ≤6/24 in both eyes were excluded. All cases and controls were legally licensed to drive. MATERIALS AND METHODS In this study, Driving Habits Questionnaire was used. Collected data were statistically analyzed using SAS, version 9.2 (GLM procedure), and IBM SPSS, version 22. P-values

Purpose: Glaucoma affects different aspects of vision including visual field. This prospective observational study aims to collect details of driving license (DL) renewal procedure (in an urban metro in India) among patients with diagnosed glaucoma and the method of reporting of vision-related requirements during renewal. Methods: One-hundred patients with diagnosed glaucoma above 40 years, having valid DL (with at least one renewal cycle), were included. Patients with other ocular comorbidities were excluded. Driving Habits Questionnaire and a questionnaire about license renewal were administered. Driving eligibility was compared to international guidelines. Results: Study population included patients with 69% early, 29% moderate, and 2% advanced glaucoma. Sixteen percent of patients had stopped driving. Legal license renewal procedure was bypassed by 45%. Form-1 was not submitted by 43% and 49% did not submit Form-1A at the time of renewal. Only 7.01% mentioned about glaucoma in the self-declaration form. None were asked about their visual field during renewal. Among 61 patients who submitted a medical certificate, the undersigning doctor was an ophthalmologist in only six patients. Thirty percent patients with valid Indian DL would not have satisfied International College of Ophthalmologists guidelines. Driving difficulties were experienced by 44%, more so in advanced glaucoma (F (1, 82) = 22.12, P < 0.001). Conclusion: Vision-related testing at the time of renewal of DL is inadequate in India. Chronic eye diseases such as glaucoma are commonly not self-declared or detected at pre-renewal testing. Clear-cut guidelines about visual requirements and implementation are required to prevent road traffic events because of vision-related errors.

Polymer dielectrics are key materials for capacitive energy storage in electrical and electronic systems owning to their ultra-high power density and high breakdown strength. However, the dramatically increased electrical conduction leads to poor energy storage performance under high electric fields, especially at elevated temperatures. Here we introduce structural defects into Polyetherimide (PEI) to modify the high-temperature dielectric properties. The polarization and conduction properties are investigated to reveal the effect of the structural defect. The modified PEI exhibits largely improved charge-discharge efficiency at elevated temperatures due to the suppressed electrical conduction, e.g., 91 % under ~400 MV/m at 200°C. The modification of PEI through a high-throughput facile process exhibited an enormous potential in capacitive energy storage under harsh conditions. The strategy demonstrated here unveils an unexplored space for modifying established polymers by introducing local structural defects.

The dielectric constant (ϵ) is a critical parameter utilized in the design of polymeric dielectrics for energy storage capacitors, microelectronic devices, and high-voltage insulations. However, agile discovery of polymer dielectrics with desirable ϵ remains a challenge, especially for high-energy, high-temperature applications. To aid accelerated polymer dielectrics discovery, we have developed a machine-learning (ML)-based model to instantly and accurately predict the frequency-dependent ϵ of polymers with the frequency range spanning 15 orders of magnitude. Our model is trained using a dataset of 1210 experimentally measured ϵ values at different frequencies, an advanced polymer fingerprinting scheme and the Gaussian process regression algorithm. The developed ML model is utilized to predict the ϵ of synthesizable 11,000 candidate polymers across the frequency range 60–1015 Hz, with the correct inverse ϵ vs. frequency trend recovered throughout. Furthermore, using ϵ and another previously studied key design property (glass transition temperature, Tg) as screening criteria, we propose five representative polymers with desired ϵ and Tg for capacitors and microelectronic applications. This work demonstrates the use of surrogate ML models to successfully and rapidly discover polymers satisfying single or multiple property requirements for specific applications.

We piloted an innovation in teaching by conducting live virtual bedside clinics and evaluated the effectiveness compared to conventional bedside clinics. The purpose is to report the methodology and survey results of this innovation in teaching. A virtual bedside clinic was set up utilizing multiple audio-visual aids at a tertiary eye care facility. The bedside clinic was conducted and streamed live to pre-registered participants across the globe using the Zoom platform. The online survey was conducted comparing its effectiveness with conventional bedside clinics. A total of five sessions were conducted. A total of 2058 participants registered (411/session), of which 938 (45.57%) attended (187/session). A total of 287 participants (30.6%) responded to the survey. The respondents included ophthalmology residents (43.4%), fellows (19%), sub-specialty ophthalmologists (15.4%), general ophthalmologists (12%), and optometrists (9%). More than 95% of the respondents felt that these clinics were equally effective/better in imparting the following: physical examination 97%, clinical knowledge 99.3%, clinical reasoning 98.3%, procedural skills 95%, and communication skills 96.5%. Respondents suggested that these clinics were better/equally effective in the following techniques: general examination (96%), ocular motility (93.3%), nystagmus evaluation (93.3%), and anterior (80%) and posterior segment examination (73.3%). The hybrid mode presentation (97.3%) and discussion with the panel (100%) were reported to be equally effective/much better. Live virtual bedside clinics are a novel and effective way of continuing quality teaching and impactful learning. Most of the bedside manners, procedural skills, and examination techniques can be effectively taught through this virtual platform with a scope to improve anterior and posterior segment examination skills.

The next generation electrical-power and electronic systems with wide band gap semiconductors require thin dielectric films operating under the extreme electric field at elevated temperatures. Here we investigated the conduction properties under high electric field up to 450 MV/m for biaxially oriented polypropylene (BOPP), which is the state-of-the-art commercially available polymer for capacitive applications, as well as three high-temperature polymers poly(ether ether ketone)(PEEK), poly(etherimide)(Ultem) and polyimide(Kapton). Further analysis was performed based on the hopping conduction mechanism. At elevated temperature, the increased thermally-assisted excitation energy gave rise to an increase of the hopping distance. It is argued that the large band gap provided a higher energy barrier to the charge hopping. If the band gap is large enough, the tunneling process dominated the charge transport, i.e., the case of BOPP. For high-temperature applications, both the thermal stability and large band gap are required in order to suppress the temperature and electric field dependent conduction.

Highly conductive, metal-like poly(ethylene terephthalate) (PET) nonwoven fabric was prepared by coating poly(3,4-ethylenedioxythiophene):poly(4-styrenesulfonate) (PEDOT:PSS) containing dimethyl sulfoxide (DMSO) onto PET nonwoven fabric previously coated with graphene/graphite. The sheet resistance of the original nonwoven fabric decreases from80 MΩ□

Herein, we present a facile method for color-tuning an electrochromic device that switched between two neutral colors through simple color mixing of a conjugated polymer, poly(2,2-dimethyl-3,4-propylenedioxythiophene) and an electrochromic small molecule aromatic diester, diethyl-4,4′-biphenyldicarboxylate. The resulting device had a photopic contrast of ca. 57% across the visible spectrum. In addition, the device exhibited color uniformity and stability over 2,000 switches. Using these mixed coloring materials, a large area electrochromic device of 140 cm2 was fabricated, exceeding the size of ophthalmic lenses and small displays.

Flexible dielectrics operable under simultaneous electric and thermal extremes are critical to advanced electronics for ultrahigh densities and/or harsh conditions. However, conventional high-performance polymer dielectrics generally have conjugated aromatic backbones, leading to limited bandgaps and hence high conduction loss and poor energy densities, especially at elevated temperatures. A polyoxafluoronorbornene is reported, which has a key design feature in that it is a polyolefin consisting of repeating units of fairly rigid fused bicyclic structures and alkenes separated by freely rotating single bonds, endowing it with a large bandgap of ≈5 eV and flexibility, while being temperature-invariantly stable over -160 to 160 °C. At 150 °C, the polyoxafluoronorbornene exhibits an electrical conductivity two orders of magnitude lower than the best commercial high-temperature polymers, and features an unprecedented discharged energy density of 5.7 J cm-3 far outperforming the best reported flexible dielectrics. The design strategy uncovered in this work reveals a hitherto unexplored space for the design of scalable and efficient polymer dielectrics for electrical power and electronic systems under concurrent harsh electrical and thermal conditions.

A 10-year-old boy admitted for high-grade fever and pneumonia developed left preseptal and early orbital cellulitis, unresponsive to higher intravenous antibiotics. He received oseltamivir, on testing positive for H1N1 virus on the nasopharyngeal and throat swabs. There was dramatic improvement with resolution of orbital cellulitis within 24 h of starting oseltamivir. We report a very rare presentation of pediatric orbital cellulitis secondary to systemic H1N1 infection. Prompt investigations and timely treatment with oseltamivir aided in complete resolution, avoiding vision and life-threatening complications.

High performance computing (HPC) facilities consist of a large number of computer servers, which dissipate thermal energy in a data center. Efficient heat dissipation of these high density servers is a major concern to increase the life of electronic devices. Cooling of these devices involve thermal management strategies based on energy efficient cooling in a raised floor configuration, which depends on proper air flow distribution in an under-floor plenum, configuration of perforated tiles and arrangement of servers in racks. The current investigation was carried out with an objective to study air flow pattern inside plenum and to find out a better predictive tile model for air flow distribution through perforated tile. The full scale Computational Fluid Dynamics (CFD) model was used to predict flow over perforated tiles and temperature distribution over server racks inlet at different cold aisles. The governing equations (mass, momentum and energy) were solved to compute flow and temperature distribution in the computational domain. The RANS based k–e turbulence model was used for estimating turbulent kinetic energy (k) and turbulence dissipation rate (e). The under-floor blockages and CRAC locations were found to be significant parameters influencing flow distribution in different cold aisles. The CFD model was validated by carrying out experimental works. The deviation in flow rates obtained by CFD model was within 15 % with respect to experimental values for different rows in cold aisle. Cold aisle containment for over provisioned case of data centre was studied using modified body force model, which predicted better hot air entrainment and momentum rise of cold air as compared to porous jump model. The root mean square error (RMSE) of the temperature predicted by the modified body force model was 1.68 °C, whereas the RMSE predicted by porous jump model was 1.72 °C. Based on the CFD simulation studies, some energy saving opportunities were suggested for improving the thermal performance of the HPC facility.

Outdoor surveillance systems that involve farfield operations often encounter atmospheric turbulence perturbations due to a series of randomized reflections and refraction effecting incoming light rays. The resulting distortions make it hard to discriminate between true moving objects and turbulence induced motion. Current algorithms are not effective in detecting true moving objects in the scene and also rely on computationally complex warping methods. In this paper, we describe a real time embedded solution connected with traditional cameras to both rectify turbulence distortions and reliably detect and track true moving targets. Our comparisons with other methods shows better turbulence rectification with less false and miss detections. FPGADSP based embedded realization of our algorithm achieves nearly 15x speed-up along with lesser memory requirement over a quad core PC implementation. The proposed system is suitable for persistence surveillance systems and optical sight devices.

In this paper, we present a hierarchical spatiotemporal blur-based approach to automatically detect contaminants on the camera lens. Contaminants adhering to camera lens corresponds to blur regions in digital image, as camera is focused on scene. We use kurtosis for a first level analysis to detect blur regions and filter them out. Next level of analysis computes lowpass energy and singular values to further validate blur regions. These analyses detect blur regions in an image efficiently and temporal consistency of blur is additionally incorporated to remove false detections. Once the presence of a contaminant is detected, we use an appearance-based classifier to categorize the type of contaminant on the lens. Our results are promising in terms of performance and latency when compared with state-of-the-art methods under a variety of real-world conditions.

The quality of an outdoor image is often degraded due to inevitable atmospheric weather conditions such as fog, haze, low light, etc. Existing quality measurement indices fail to produce accurate no-reference scores that correspond to conditions present in images of complex natural scenes. In this paper, we propose a novel approach that can reliably measure the amount of degradation introduced in the image without the dependency on a clean reference ground truth image. In addition, region level histogram calculations and maximum bin criteria make the proposed algorithm robust to a variety of conditions. As a byproduct, fog and low light maps are also generated and can be used to visually validate the amount of fog or low light present in the scene. Analytical and qualitative results prove that our proposed approach has wide applicability to a variety of foggy and low light scenarios.

Long range surveillance videos are often distorted by random perturbations of the optical pathways caused by atmospheric turbulence. While humans can easily perceive and separate the moving objects from the turbulent motion, it is still a challenge for vision systems. In this paper, we present a near real-time approach to detecting moving objects in the presence of turbulence. As a first step, our method learns the dynamics of the latent turbulence and extracts an approximate foreground. Statistical analysis of the foreground object properties is used to eliminate noise due to turbulence preserving only the true moving objects. Our approach also results in a stable background with minimal turbulence. We tested our method on a wide range of scenarios corrupted by various levels of turbulence. Compared with state of the art, our results are quite promising.

Image super resolution attempts to extract high-resolution image using one or more corrupted low resolution images. Typical patch-wise sparse dictionary based super resolution reconstruction methods remove undesired effects but sometimes lead to blurring due to averaging of many high resolution (HR) patches. On the other hand, local self-similarity based super resolution (SR) suffers from insufficient number of HR patches and can result in distorted and unnatural SR images. In this paper, we propose a novel single image super resolution approach that reconstructs high resolution images by leveraging direct mapping i.e. one-to-one mapping between low resolution and high resolution patches. In addition, high frequency content is separated and preserved in the SR reconstructed image. Further, a K-D tree classification and knn-search algorithm is used for fast and robust search by dimensions. Incorporation of Non-Local Means filtering reduces unwanted noise as well as undesired artifacts. Finally, the proposed Gaussian weighting scheme reduces error in HR patch reconstruction process. The proposed approach is also robust for larger magnification factor beyond 2.

Atmospheric turbulence degrades images by causing non-uniform geometric deformations and distortions due to the random fluctuations of refractive index over air media. In this paper, a new approach based on hierarchical layer parsing is developed. Each frame from a set of temporal frames is decomposed into a collection of isoplanatic space-time patches. Thereafter, each of temporal patches is parsed hierarchically to separate layers corresponding to, low rank background, sparse turbulence errors, and moving objects, using low rank matrix decomposition. In order to remove redundant blur that remains after local hierarchical parsing blind de-convolution procedure is applied. Finally, the stable background component and the one or more moving object components are fused to reconstruct the turbulence mitigated content.

Atmospheric turbulence degrades image with nonuniform geometric deformations and distortions, due to random fluctuations of refractive index over air media. Typical approaches to turbulence removal do not consider moving objects of interest. We propose a method that combines two independent approaches, non-rigid image registration and background subtraction using Gaussian mixture modeling (GMM), to detect moving objects in turbulent conditions. Nonrigid image registration removes geometric distortions and stabilizes overall scene. Then GMM based background subtraction technique is used to detect moving objects. We demonstrate robustness of our proposed approach under varying turbulence conditions using qualitative and quantitative comparisons with existing methods.