Do COVID-19 Infections Result in a Different Form of Secondary Hemophagocytic Lymphohistiocytosis.

The coronavirus disease 2019 (COVID-19) pandemic, caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), has resulted in significant morbidity and mortality across the world, with no current effective treatments available. Recent studies suggest the possibility of a cytokine storm associated with severe COVID-19, similar to the biochemical profile seen in hemophagocytic lymphohistiocytosis (HLH), raising the question of possible benefits that could be derived from targeted immunosuppression in severe COVID-19 patients. We reviewed the literature regarding the diagnosis and features of HLH, particularly secondary HLH, and aimed to identify gaps in the literature to truly clarify the existence of a COVID-19 associated HLH. Diagnostic criteria such as HScore or HLH-2004 may have suboptimal performance in identifying COVID-19 HLH-like presentations, and criteria such as soluble CD163, NK cell activity, or other novel biomarkers may be more useful in identifying this entity.

A surveillance method to identify patients with sepsis from electronic health records in Hong Kong: a single centre retrospective study.

BACKGROUND: Currently there are only two population studies on sepsis incidence in Asia. The burden of sepsis in Hong Kong is unknown. We developed a sepsis surveillance method to estimate sepsis incidence from a population electronic health record (EHR) in Hong Kong using objective clinical data. The study objective was to assess our method's performance in identifying sepsis using a retrospective cohort. We compared its accuracy to administrative sepsis surveillance methods such as Angus' and Martin's methods. METHOD: In this single centre retrospective study we applied our sepsis surveillance method on adult patients admitted to a tertiary hospital in Hong Kong. Two clinicians independently reviewed the clinical notes to determine which patients had sepsis. Performance was assessed by sensitivity, specificity, positive predictive value, negative predictive value and area under the curve (AUC) of Angus', Martin's and our surveillance methods using clinical review as "gold standard." RESULTS: Between January 1 and February 28, 2018, our sepsis surveillance method identified 1352 adult patients hospitalised with suspected infection. We found that 38.9% (95%CI 36.3-41.5) of these patients had sepsis. Using a 490 patient validation cohort, two clinicians had good agreement with weighted kappa of 0.75 (95% CI 0.69-0.81) before coming to consensus on diagnosis of uncomplicated infection or sepsis for all patients. Our method had sensitivity 0.93 (95%CI 0.89-0.96), specificity 0.86 (95%CI 0.82-0.90) and an AUC 0.90 (95%CI 0.87-0.92) when validated against clinician review. In contrast, Angus' and Martin's methods had AUCs 0.56 (95%CI 0.53-0.58) and 0.56 (95%CI 0.52-0.59), respectively. CONCLUSIONS: A sepsis surveillance method based on objective data from a population EHR in Hong Kong was more accurate than administrative methods. It may be used to estimate sepsis population incidence and outcomes in Hong Kong. TRIAL REGISTRATION: This study was retrospectively registered at clinicaltrials.gov on October 3, 2019 ( NCT04114214 ).

The effect of an on-site vision examination on adherence to vision screening recommendations.

Vision screenings are intended to efficiently identify students with possible visual impairment and initiate a referral for diagnosis and treatment. In many cases, at-risk students do not access the recommended care or experience delays in receiving care. The purpose of this article is to report the effect on adherence to vision screening recommendations by providing the eye examination at the students' school and at no cost. Of the 1,306 students screened, 382 (29.2%) were identified with possible visual impairment. Parental consent for examination was obtained for 198 (51.8%) students. Our vision screening and examination program yielded similar adherence to follow-up as stand-alone vision screening programs. Future program considerations should address perceptual barriers that may be contributing to parental nonadherence to vision screening recommendations.

Genetic association between germline JAK2 polymorphisms and myeloproliferative neoplasms in Hong Kong Chinese population: a case-control study.

BACKGROUND: Myeloproliferative neoplasms (MPNs) are a group of haematological malignancies that can be characterised by a somatic mutation (JAK2V617F). This mutation causes the bone marrow to produce excessive blood cells and is found in polycythaemia vera (~95%), essential thrombocythaemia and primary myelofibrosis (both ~50%). It is considered as a major genetic factor contributing to the development of these MPNs. No genetic association study of MPN in the Hong Kong population has so far been reported. Here, we investigated the relationship between germline JAK2 polymorphisms and MPNs in Hong Kong Chinese to find causal variants that contribute to MPN development. We analysed 19 tag single nucleotide polymorphisms (SNPs) within the JAK2 locus in 172 MPN patients and 470 healthy controls. Three of these 19 SNPs defined the reported JAK2 46/1 haplotype: rs10974944, rs12343867 and rs12340895. Allele and haplotype frequencies were compared between patients and controls by logistic regression adjusted for sex and age. Permutation test was used to correct for multiple comparisons. With significant findings from the 19 SNPs, we then examined 76 additional SNPs across the 148.7-kb region of JAK2 via imputation with the SNP data from the 1000 Genomes Project. RESULTS: In single-marker analysis, 15 SNPs showed association with JAK2V617F-positive MPNs (n = 128), and 8 of these were novel MPN-associated SNPs not previously reported. Exhaustive variable-sized sliding-window haplotype analysis identified 184 haplotypes showing significant differences (P < 0.05) in frequencies between patients and controls even after multiple-testing correction. However, single-marker alleles exhibited the strongest association with V617F-positive MPNs. In local Hong Kong Chinese, rs12342421 showed the strongest association signal: asymptotic P = 3.76 × 10-15, empirical P = 2.00 × 10-5 for 50,000 permutations, OR = 3.55 for the minor allele C, and 95% CI, 2.59-4.87. Conditional logistic regression also signified an independent effect of rs12342421 in significant haplotype windows, and this independent effect remained unchanged even with the imputation of additional 76 SNPs. No significant association was found between V617F-negative MPNs and JAK2 SNPs. CONCLUSION: With a large sample size, we reported the association between JAK2V617F-positive MPNs and 15 tag JAK2 SNPs and the association of rs12342421 being independent of the JAK2 46/1 haplotype in Hong Kong Chinese population.

A painful squat test provides limited diagnostic utility in CAM-type femoroacetabular impingement.

PURPOSE: The purpose of this study is to determine the relationship between a symptomatic maximal squat and the presence of radiographic CAM-type femoroacetabular impingement (FAI) on magnetic resonance imaging (MRI) and to determine the sensitivity and specificity of a maximal squat test for the presence of radiographic CAM-type femoral deformity in an adult population. METHODS: In this pilot study, 76 consecutive patients were recruited from an outpatient clinic at McMaster University. All patients presented with pre-arthritic hip pain and were asked to perform a maximal squat. The results of this test were compared to magnetic resonance imaging and magnetic resonance angiographic (MRI and MRA) findings evaluating and characterizing CAM-type FAI deformity. RESULTS: The sensitivity and specificity of the maximal squat test were 75 % (56.6-88.5 %) and 41 % (27.0-56.8 %), respectively, for CAM-type FAI deformity. The positive and negative likelihood ratios were modest at 1.3 (0.9-1.7) and 0.6 (0.3-1.2), respectively. This means that a 30 % pre-test probability is improved to 36 % following a positive squat test and reduced to 20 % with a negative squat test. CONCLUSION: The maximal squat test was found to have marginal incremental diagnostic ability for CAM-type FAI. Its utility in the diagnostic evaluation of FAI remains limited. This survey elucidates areas of research for future studies relevant to the clinical diagnosis of FAI.

Feasibility of a clinical trial of vision therapy for treatment of amblyopia.

PURPOSE: We conducted a pilot randomized clinical trial of office-based active vision therapy for the treatment of childhood amblyopia to determine the feasibility of conducting a full-scale randomized clinical trial. METHODS: A training and certification program and manual of procedures were developed to certify therapists to administer a standardized vision therapy program in ophthalmology and optometry offices consisting of weekly visits for 16 weeks. Nineteen children, aged 7 to less than 13 years, with amblyopia (20/40-20/100) were randomly assigned to receive either 2 hours of daily patching with active vision therapy or 2 hours of daily patching with placebo vision therapy. RESULTS: Therapists in diverse practice settings were successfully trained and certified to perform standardized vision therapy in strict adherence with protocol. Subjects completed 85% of required weekly in-office vision therapy visits. Eligibility criteria based on age, visual acuity, and stereoacuity, designed to identify children able to complete a standardized vision therapy program and judged likely to benefit from this treatment, led to a high proportion of screened subjects being judged ineligible, resulting in insufficient recruitment. There were difficulties in retrieving adherence data for the computerized home therapy procedures. CONCLUSIONS: This study demonstrated that a 16-week treatment trial of vision therapy was feasible with respect to maintaining protocol adherence; however, recruitment under the proposed eligibility criteria, necessitated by the standardized approach to vision therapy, was not successful. A randomized clinical trial of in-office vision therapy for the treatment of amblyopia would require broadening of the eligibility criteria and improved methods to gather objective data regarding the home therapy. A more flexible approach that customizes vision therapy based on subject age, visual acuity, and stereopsis might be required to allow enrollment of a broader group of subjects.

Comparison of COVID-19 with influenza A in the ICU: a territory-wide, retrospective, propensity matched cohort on mortality and length of stay.

OBJECTIVES: Direct comparisons between COVID-19 and influenza A in the critical care setting are limited. The objective of this study was to compare their outcomes and identify risk factors for hospital mortality. DESIGN AND SETTING: This was a territory-wide, retrospective study on all adult (≥18 years old) patients admitted to public hospital intensive care units in Hong Kong. We compared COVID-19 patients admitted between 27 January 2020 and 26 January 2021 with a propensity-matched historical cohort of influenza A patients admitted between 27 January 2015 and 26 January 2020. We reported outcomes of hospital mortality and time to death or discharge. Multivariate analysis using Poisson regression and relative risk (RR) was used to identify risk factors for hospital mortality. RESULTS: After propensity matching, 373 COVID-19 and 373 influenza A patients were evenly matched for baseline characteristics. COVID-19 patients had higher unadjusted hospital mortality than influenza A patients (17.5% vs 7.5%, p<0.001). The Acute Physiology and Chronic Health Evaluation IV (APACHE IV) adjusted standardised mortality ratio was also higher for COVID-19 than influenza A patients ((0.79 (95% CI 0.61 to 1.00) vs 0.42 (95% CI 0.28 to 0.60)), p<0.001). Adjusting for age, PaO2/FiO2, Charlson Comorbidity Index and APACHE IV, COVID-19 (adjusted RR 2.26 (95% CI 1.52 to 3.36)) and early bacterial-viral coinfection (adjusted RR 1.66 (95% CI 1.17 to 2.37)) were directly associated with hospital mortality. CONCLUSIONS: Critically ill patients with COVID-19 had substantially higher hospital mortality when compared with propensity-matched patients with influenza A.

Return to preinjury activity levels after surgical management of femoroacetabular impingement in athletes.

PURPOSE: A systematic review was conducted to identify, assess, and summarize the available evidence pertaining to surgical intervention for femoroacetabular impingement (FAI) in athletes. Summary estimates of treatment effect (proportion with 95% confidence interval [CI]) were calculated specifically for the rate of return to sport. METHODS: Electronic databases (Medline, Embase, and Cochrane Library) were searched from inception to November 2011. The references of included articles were reviewed for eligible studies. The inclusion criteria were clinical studies, studies involving humans, minimum 6 months' follow-up, exclusive FAI treatment, and focus on athletes. Exclusion criteria were review articles, basic science investigations, radiologic studies, arthroplasty, and nonathlete clinical studies. A quality assessment of the included articles was conducted by 2 reviewers using a quality assessment tool developed by Yang et al. We used a random-effects model (DerSimonian-Laird method) to calculate weighted proportions. Percentages with 95% CIs are reported. RESULTS: Nine articles met the inclusion and exclusion criteria in this review. There was 72% agreement (95% CI, 0% to 94%) between the 2 independent reviewers for inclusion and quality assessment of the studies. A total of 418 athletes were surgically treated for FAI and were available for assessment. The rate of return to sport was 92% (95% CI, 87% to 96%), and the rate of return to the previous level of competition was 88% (95% CI, 80% to 94%). CONCLUSIONS: Despite the limitations of our systematic review, the findings suggest that surgical treatment for FAI resulted in a high return to preinjury activity levels of sports. LEVEL OF EVIDENCE: Level IV, systematic review of Level IV studies (case series).

Managing dental erosion.

The clinical signs of dental erosion are initially subtle, yet often progress because the patient remains asymptomatic, unaware and uninformed. Erosion typically works synergistically with abrasion and attrition to cause loss of tooth structure, making diagnosis and management complex. The purpose of this article is to outline clinical examples of patients with dental erosion that highlight the strategy of early identification, patient education and conservative restorative management. Dental erosion is defined as the pathologic chronic loss of dental hard tissues as a result of the chemical influence of exogenous or endogenous acids without bacterial involvement. Like caries or periodontal disease, erosion has a multifactorial etiology and requires a thorough history and examination for diagnosis. It also requires patient understanding and compliance for improved outcomes. Erosion can affect the loss of tooth structure in isolation of other cofactors, but most often works in synergy with abrasion and attrition in the loss of tooth structure (Table 1). Although erosion is thought to be an underlying etiology of dentin sensitivity, erosion and loss of tooth structure often occurs with few symptoms. The purpose of this article is threefold: first, to outline existing barriers that may limit early management of dental erosion. Second, to review the clinical assessment required to establish a diagnosis of erosion. And third, to outline clinical examples that review options to restore lost tooth structure. The authors have included illustrations they hope will be used to improve patient understanding and motivation in the early management of dental erosion.

Mechanical Properties of Injection Molded PP/PET-Nanofibril Composites and Foams.

The creation and application of PET nanofibrils for PP composite reinforcement were studied. PET nanofibrils were fibrillated within a PP matrix using a spunbond process and then injection molded to test for the end-use properties. The nanofibril reinforcement helped to provide higher tensile and flexural performance in solid (unfoamed) injection molded parts. With foam injection molding, the nanofibrils also helped to improve and refine the microcellular morphology, which led to improved performance. Easily and effectively increasing the strength of a polymeric composite is a goal for many research endeavors. By creating nanoscale fibrils within the matrix itself, effective bonding and dispersion have already been achieved, overcoming the common pitfalls of fiber reinforcement. As blends of PP and PET are drawn in a spunbond system, the PET domains are stretched into nanoscale fibrils. By adapting the spunbonded blends for use in injection molding, both solid and foamed nanocomposites are created. The injection molded nanocomposites achieved increased in both tensile and flexural strength. The solid and foamed tensile strength increased by 50 and 100%, respectively. In addition, both the solid and foamed flexural strength increased by 100%. These increases in strength are attributed to effective PET nanofibril reinforcement.

Electrospun polyethylene oxide/cellulose nanocrystal composite nanofibrous mats with homogeneous and heterogeneous microstructures.

An electrospinning process was successfully used to fabricate polyethylene oxide/cellulose nanocrystal (PEO/CNC) composite nanofibrous mats. Transition of homogeneous to heterogeneous microstructures was achieved by tailoring the concentration of PEO/CNC mixture in the solution from 5 to 7 wt %. Morphology investigation of the obtained nanofibers demonstrated that rod-shaped CNCs were well-dispersed in the as-spun nanofibers and highly aligned along the nanofiber long-axis. PEO/CNC nanofibers became more uniform and smaller in diameter with increased CNC-loading level. The heterogeneous composite mats were composed of rigid-flexible bimodal nanofibers. Results of structure characterization indicated that the incorporated CNCs interacted strongly with the PEO matrix through hydrogen bonding. Mechanical properties of both types of mats were effectively improved by using CNCs, with heterogeneous mats being stronger than their homogeneous counterparts for all compositions (0-20 wt % CNC contents). When a smaller diameter needle was used to form homogeneous mats, enhanced thermal and mechanical properties were obtained.

Decision-making in the management of the patient with dental erosion.

The clinical signs of dental erosion are initially subtle; yet they often progress because the patient remains asymptomatic, unaware, and uninformed. Erosion typically works synergistically with abrasion and attrition to cause loss of tooth structure, making diagnosis and management complex. The purpose of this article is to outline clinical examples of patients with dental erosion that highlight the strategy of early identification, patient education, and conservative restorative management.

Myopia Progression as a Function of Sex, Age, and Ethnicity.

Purpose: To model juvenile-onset myopia progression as a function of race/ethnicity, age, sex, parental history of myopia, and time spent reading or in outdoor/sports activity. Methods: Subjects were 594 children in the Collaborative Longitudinal Evaluation of Ethnicity and Refractive Error (CLEERE) Study with at least three study visits: one visit with a spherical equivalent (SPHEQ) less myopic/more hyperopic than -0.75 diopter (D), the first visit with a SPHEQ of -0.75 D or more myopia (onset visit), and another after myopia onset. Myopia progression from the time of onset was modeled using cubic models as a function of age, race/ethnicity, and other covariates. Results: Younger children had faster progression of myopia; for example, the model-estimated 3-year progression in an Asian American child was -1.93 D when onset was at age 7 years compared with -1.43 D when onset was at age 10 years. Annual progression for girls was 0.093 D faster than for boys. Asian American children experienced statistically significantly faster myopia progression compared with Hispanic (estimated 3-year difference of -0.46 D), Black children (-0.88 D), and Native American children (-0.48 D), but with similar progression compared with White children (-0.19 D). Parental history of myopia, time spent reading, and time spent in outdoor/sports activity were not statistically significant factors in multivariate models. Conclusions: Younger age, female sex, and racial/ethnic group were the factors associated with faster myopic progression. This multivariate model can facilitate the planning of clinical trials for myopia control interventions by informing the prediction of myopia progression rates.

Association of HLA-B22 serotype with SARS-CoV-2 susceptibility in Hong Kong Chinese patients.

The coronavirus disease 2019 (COVID-19) is a highly infectious disease caused by SARS-CoV-2. Since its first report in December 2019, COVID-19 has evolved into a global pandemic causing massive healthcare and socioeconomic challenges. HLA system is critical in mediating anti-viral immunity and recent studies have suggested preferential involvement of HLA-B in COVID-19 susceptibility. Here, by investigating the HLA-B genotypes in 190 unrelated Chinese patients with confirmed COVID-19, we identified a significant positive association between the B22 serotype and SARS-CoV-2 infection (p = 0.002, Bonferroni-corrected p = 0.032). Notably, the B22 serotype has been consistently linked to susceptibility to other viral infections. These data not only shed new insights into SARS-CoV-2 pathogenesis and vaccine development but also guide better infection prevention/control.

Optimal length and usefulness of temporal artery biopsies in the diagnosis of giant cell arteritis: a 10-year retrospective review of medical records.

BACKGROUND: In giant cell arteritis, temporal artery biopsies often show vasculitis with giant cell formation, but optimal biopsy length for diagnosis is debated. We reviewed temporal artery biopsies from a 10-year period in the province of Alberta, Canada, to identify an ideal biopsy length in the diagnostic process for giant cell arteritis. METHODS: We retrospectively reviewed electronic medical records of patients who had undergone a temporal artery biopsy procedure in Alberta between Jan 1, 2008, and Jan 1, 2018, as reported in the Data Integration and Management Repository of Alberta Health Services. We extracted data on baseline demographic characteristics (sex and age), inflammatory markers (erythrocyte sedimentation rate [ESR] and C-reactive protein [CRP]), temporal artery biopsy characteristics (side of biopsy and postfixation length), and final pathological diagnoses. All positive biopsies were reviewed by a single pathologist to ensure uniformity of pathological interpretation, with subsequent discordant results removed from analysis. Predictors of positive pathological diagnosis of giant cell arteritis were modeled by logistic regression, and the Akaike information criterion was used to compare logistic regression models with varying biopsy length cutoffs (0·5, 1·0, 1·5, 2·0, and 2·5 cm) to determine a change point for diagnostic sensitivity in postfixation length. FINDINGS: We extracted data on 1203 temporal artery biopsies; after removal of 13 discordant biopsies, 1190 biopsies from 1163 patients were reviewed. The mean age of patients was 72·0 years (SD 10·3) and 799 (68·7%) patients were women. 222 (18·7%) temporal artery biopsies were positive for giant cell arteritis. In univariable analysis, increases in age (71·3 years [SD 10·6] in negative biopsies vs 75·3 years [8·3] in positive biopsies; odds ratio [OR] 1·04 [95% CI 1·02-1·06]; p<0·0001)), ESR (36 mm/h [IQR 18-62] in negative biopsies vs 57 [31-79] in positive biopsies; 1·01 [1·01-1·02]; p<0·0001), CRP (12·1 mg/L [IQR 3·3-35·1] in negative biopsies vs 41·8 [14·6-82·4] in positive biopsies; 1·01 [1·01-1·01]; p<0·0001), and biopsy length (1·2 cm [IQR 0·9-1·7] in negative biopsies vs 1·6 [1·1-2·0] in positive biopsies; 1·28 [1·09-1·51]; p=0·0025) were associated with a positive pathological diagnosis. In multivariable analysis adjusted for age, ESR, and CRP, age (adjusted OR 1·04 [95% CI 1·02-1·05]; p=0·0001), CRP (1·01 [1·00-1·01]; p=0·0006), and biopsy length (1·22 [1·00-1·49]; p=0·047) remained statistically significant predictors. The Akaike information criterion determined a change point of 1·5 cm for diagnostic sensitivity. INTERPRETATION: Accounting for postfixation shrinkage, our findings suggest a 1·5-2·0 cm prefixation length as the optimal biopsy length to diagnose patients with giant cell arteritis, with greater lengths unlikely to provide significant additional diagnostic yield to justify risks associated with surgery. FUNDING: None.

Scalable Fabrication of Thermally Insulating Mechanically Resilient Hierarchically Porous Polymer Foams.

The requirement of energy efficiency demands materials with superior thermal insulation properties. Inorganic aerogels are excellent thermal insulators, but are difficult to produce on a large-scale, are mechanically brittle, and their structural properties depend strongly on their density. Here, we report the scalable generation of low-density, hierarchically porous, polypropylene foams using industrial-scale foam-processing equipment, with thermal conductivity lower than that of commercially available high-performance thermal insulators such as superinsulating Styrofoam. The reduction in thermal conductivity is attributed to the restriction of air flow caused by the porous nanostructure in the cell walls of the foam. In contrast to inorganic aerogels, the mechanical properties of the foams are less sensitive to density, suggesting efficient load transfer through the skeletal structure. The scalable fabrication of hierarchically porous polymer foams opens up new perspectives for the scalable design and development of novel superinsulating materials.

Enhanced Thermal Conductivity of Graphene Nanoplatelet-Polymer Nanocomposites Fabricated via Supercritical Fluid-Assisted in Situ Exfoliation.

As electronic devices become increasingly miniaturized, their thermal management becomes critical. Efficient heat dissipation guarantees their optimal performance and service life. Graphene nanoplatelets (GnPs) have excellent thermal properties that show promise for use in fabricating commercial polymer nanocomposites with high thermal conductivity. Herein, an industrially viable technique for manufacturing a new class of lightweight GnP-polymer nanocomposites with high thermal conductivity is presented. Using this method, GnP-high-density polyethylene (HDPE) nanocomposites with a microcellular structure are fabricated by melt mixing, which is followed by supercritical fluid (SCF) treatment and injection molding foaming, which adds an extra layer of design flexibility. Thus, the microstructure is tailored within the nanocomposites and this improves their thermal conductivity. Therefore, the SCF-treated HDPE 17.6 vol % GnP microcellular nanocomposites have a solid-phase thermal conductivity of 4.13 ± 0.12 W m-1 K-1. This value far exceeds that of their regular injection-molded counterparts (2.09 ± 0.03 W m-1 K-1) and those reported in the literature. This dramatic improvement results from in situ GnPs' exfoliation and dispersion, and from an elevated level of random orientation and interconnectivity. Thus, this technique provides a novel approach to the development of microscopically tailored structures for the production of lighter and more thermally conductive heat sinks for next generations of miniaturized electronic devices.

Ultralight Microcellular Polymer-Graphene Nanoplatelet Foams with Enhanced Dielectric Performance.

Dielectric polymer nanocomposites with high dielectric constant (ε') and low dielectric loss (tan δ) are extremely desirable in the electronics industry. Percolative polymer-graphene nanoplatelet (GnP) composites have shown great promise as dielectric materials for high-performance capacitors. Herein, an industrially-viable technique for manufacturing a new class of ultralight polymer composite foams using commercial GnPs with excellent dielectric performance is presented. Using this method, the high-density polyethylene (HDPE)-GnPs composites with a microcellular structure were fabricated by melt-mixing. This was followed by supercritical fluid (SCF) treatment and physical foaming in an extrusion process, which added an extra layer of design flexibility. The SCF treatment effectively in situ exfoliated the GnPs in the polymer matrix. Moreover, the generation of a microcellular structure produced numerous parallel-plate nanocapacitors consisting of GnP pairs as electrodes with insulating polymer as nanodielectrics. This significantly increased the real permittivity and decreased the dielectric loss. The ultralight extruded HDPE-1.08 vol % GnP composite foams, with a 0.15 g·cm-3 density, had an excellent combination of dielectric properties (ε' = 77.5, tan δ = 0.003 at 1 × 105 Hz), which were superior to their compression-molded counterparts (ε' = 19.9, tan δ = 0.15 and density of = 1.2 g·cm-3) and to those reported in the literature. This dramatic improvement resulted from in situ GnP's exfoliation and dispersion, as well as a unique GnP parallel-plate arrangement around the cells. Thus, this facile method provides a scalable method to produce ultralight dielectric polymer nanocomposites, with a microscopically tailored microstructure for use in electronic devices.

Stability of visual acuity improvement following discontinuation of amblyopia treatment in children aged 7 to 12 years.

OBJECTIVE: To assess the stability of visual acuity improvement during the first year after cessation of amblyopia treatment other than spectacle wear in children aged 7 to 12 years. METHODS: At the completion of a multicenter randomized trial during which amblyopia treated with patching and atropine improved by at least 2 lines on the electronic Early Treatment of Diabetic Retinopathy Study testing protocol, 80 patients aged 7 to 12 years were followed up while not receiving treatment (other than spectacle wear) for 1 year. MAIN OUTCOME MEASURE: Ten letters or more (> or =2 lines) worsening of visual acuity (measured using the electronic Early Treatment of Diabetic Retinopathy Study testing protocol) during the year following treatment discontinuation. RESULTS: During the year following cessation of treatment, the cumulative probability of worsening visual acuity (> or =2 lines) was 7% (95% confidence interval, 3%-17%); 82% of patients maintained an increase in visual acuity of 10 letters or more compared with their visual acuity before starting treatment. CONCLUSION: Visual acuity improvement occurring during amblyopia treatment is sustained in most children aged 7 to 12 years for at least 1 year after discontinuing treatment other than spectacle wear. TRIAL REGISTRATION: ClinicalTrials.gov identifier: NCT00094692.