A
bstract
The superconformal index of
N
= 4 super-Yang Mills theory with U(
N
) gauge group can be written as a matrix integral over the gauge group. Recently, Murthy demonstrated that this integral ...can be reexpressed as a sum of terms corresponding to a giant graviton expansion of the index, and provided an explicit formula for the case of a single giant graviton. Here we give similar explicit formulae for an arbitrary number,
m
≥ 1, of giant gravitons. We provide 1/2 and 1/16 BPS index examples up to the order where three giant gravitons contribute and demonstrate that the expansion of the matrix integral differs from the giant graviton expansion computed in the supergravity dual. This shows that the giant graviton expansion is not necessarily unique once two or more giant gravitons start appearing.
Aqueous organic redox flow batteries (AORFBs) have received increasing attention as an emergent battery technology for grid‐scale renewable energy storage. However, physicochemical properties of ...redox‐active organic electrolytes remain fine refinement to maximize their performance in RFBs. Herein, we report a carboxylate functionalized viologen derivative, N,N′‐dibutyrate‐4,4′‐bipyridinium, (CBu)2V, as a highly stable, high capacity anolyte material under near pH neutral conditions. (CBu)2V can achieve solubility of 2.1 M and display a reversible, kinetically fast reduction at −0.43 V vs NHE at pH 9. DFT studies revealed that the high solubility of (CBu)2V is attributed to its high molecular polarity while its negative reduction potential is benefitted from electron‐donating carboxylate groups. A 0.89 V (CBu)2V/(NH)4Fe(CN)6 AORFB demonstrated exceptional energy storage performance, specifically, 100 % capacity retention with a discharge energy density of 9.5 Wh L−1 for 1000 cycles, power densities of up to 85 mW cm−2, and an energy efficiency of 70 % at 60 mA cm−2. (CBu)2V not only represents the most capacity dense viologen with pendant ionic groups and also exhibits the longest (1200 hours or 50 days) and the most stable flow battery performance to date.
A carboxylate functionalized viologen is developed as a capacity dense, highly stable anolyte for aqueous organic redox flow batteries up to 50 days of stable cycling.
Deep learning (DL) used for discriminative tasks in ophthalmology, such as diagnosing diabetic retinopathy or age-related macular degeneration (AMD), requires large image data sets graded by human ...experts to train deep convolutional neural networks (DCNNs). In contrast, generative DL techniques could synthesize large new data sets of artificial retina images with different stages of AMD. Such images could enhance existing data sets of common and rare ophthalmic diseases without concern for personally identifying information to assist medical education of students, residents, and retinal specialists, as well as for training new DL diagnostic models for which extensive data sets from large clinical trials of expertly graded images may not exist.
To develop DL techniques for synthesizing high-resolution realistic fundus images serving as proxy data sets for use by retinal specialists and DL machines.
Generative adversarial networks were trained on 133 821 color fundus images from 4613 study participants from the Age-Related Eye Disease Study (AREDS), generating synthetic fundus images with and without AMD. We compared retinal specialists' ability to diagnose AMD on both real and synthetic images, asking them to assess image gradability and testing their ability to discern real from synthetic images. The performance of AMD diagnostic DCNNs (referable vs not referable AMD) trained on either all-real vs all-synthetic data sets was compared.
Accuracy of 2 retinal specialists (T.Y.A.L. and K.D.P.) for diagnosing and distinguishing AMD on real vs synthetic images and diagnostic performance (area under the curve) of DL algorithms trained on synthetic vs real images.
The diagnostic accuracy of 2 retinal specialists on real vs synthetic images was similar. The accuracy of diagnosis as referable vs nonreferable AMD compared with certified human graders for retinal specialist 1 was 84.54% (error margin, 4.06%) on real images vs 84.12% (error margin, 4.16%) on synthetic images and for retinal specialist 2 was 89.47% (error margin, 3.45%) on real images vs 89.19% (error margin, 3.54%) on synthetic images. Retinal specialists could not distinguish real from synthetic images, with an accuracy of 59.50% (error margin, 3.93%) for retinal specialist 1 and 53.67% (error margin, 3.99%) for retinal specialist 2. The DCNNs trained on real data showed an area under the curve of 0.9706 (error margin, 0.0029), and those trained on synthetic data showed an area under the curve of 0.9235 (error margin, 0.0045).
Deep learning-synthesized images appeared to be realistic to retinal specialists, and DCNNs achieved diagnostic performance on synthetic data close to that for real images, suggesting that DL generative techniques hold promise for training humans and machines.
Coronavirus disease 2019 (COVID-19), caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), is a new human disease with few effective treatments
. Convalescent plasma, donated by ...persons who have recovered from COVID-19, is the acellular component of blood that contains antibodies, including those that specifically recognize SARS-CoV-2. These antibodies, when transfused into patients infected with SARS-CoV-2, are thought to exert an antiviral effect, suppressing virus replication before patients have mounted their own humoral immune responses
. Virus-specific antibodies from recovered persons are often the first available therapy for an emerging infectious disease, a stopgap treatment while new antivirals and vaccines are being developed
. This retrospective, propensity score-matched case-control study assessed the effectiveness of convalescent plasma therapy in 39 patients with severe or life-threatening COVID-19 at The Mount Sinai Hospital in New York City. Oxygen requirements on day 14 after transfusion worsened in 17.9% of plasma recipients versus 28.2% of propensity score-matched controls who were hospitalized with COVID-19 (adjusted odds ratio (OR), 0.86; 95% confidence interval (CI), 0.75-0.98; chi-square test P value = 0.025). Survival also improved in plasma recipients (adjusted hazard ratio (HR), 0.34; 95% CI, 0.13-0.89; chi-square test P = 0.027). Convalescent plasma is potentially effective against COVID-19, but adequately powered, randomized controlled trials are needed.
Purpose of Review
Diabetic retinopathy (DR) is one of the leading causes of vision loss worldwide. Although screening and early treatment guidelines for DR have significantly reduced the disease ...burden, restrictions related to the COVID-19 pandemic have changed real-world practice patterns in the management of DR. This review summarizes evolving guidelines and outcomes of the treatment of DR in the setting of the pandemic.
Recent Findings
Intravitreal injections for DR have decreased significantly globally during the pandemic, ranging from approximately 30 to nearly 100% reduction, compared to corresponding timepoints in 2019. Most studies on functional outcomes show a decrease in visual acuity on delayed follow-up.
Summary
Changing practice patterns in the management of DR has led to fewer intravitreal injections and overall reduction in visual acuity on follow-up. As COVID variants emerge, it will be necessary to continue evaluating practice guidelines.
Spatial genome organization and its effect on transcription remains a fundamental question. We applied an advanced chromatin interaction analysis by paired-end tag sequencing (ChIA-PET) strategy to ...comprehensively map higher-order chromosome folding and specific chromatin interactions mediated by CCCTC-binding factor (CTCF) and RNA polymerase II (RNAPII) with haplotype specificity and nucleotide resolution in different human cell lineages. We find that CTCF/cohesin-mediated interaction anchors serve as structural foci for spatial organization of constitutive genes concordant with CTCF-motif orientation, whereas RNAPII interacts within these structures by selectively drawing cell-type-specific genes toward CTCF foci for coordinated transcription. Furthermore, we show that haplotype variants and allelic interactions have differential effects on chromosome configuration, influencing gene expression, and may provide mechanistic insights into functions associated with disease susceptibility. 3D genome simulation suggests a model of chromatin folding around chromosomal axes, where CTCF is involved in defining the interface between condensed and open compartments for structural regulation. Our 3D genome strategy thus provides unique insights in the topological mechanism of human variations and diseases.
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•ChIA-PET is inclusive in mapping 3D genome at multi-scale and nucleotide resolution•CTCF foci spatially arrange RNAPII transcription concordant in CTCF-motif direction•SNPs alter haplotype chromatin topology and function that link to disease risks•3D genome models elucidate topological framework for transcriptional regulation
Advanced ChIA-PET shows that CTCF/cohesin and RNA polymerase II arrange spatial organization for coordinated transcription. Haplotype variants exhibit allelic effects on chromatin topology and transcription that link disease susceptibility.
Within the past 20
years, depression research has given increasing consideration to the possibility of complex and reciprocal relations between stress and depression. Not only does stress increase ...risk for depression (i.e., a stress exposure model of depression), but depression, or depressogenic vulnerabilities, in turn, also increases susceptibility to stressful events that are at least in part influenced by the individual (i.e., stress generation; Hammen, 1991). The present review provides a systematic examination of the stress generation literature to date, with specific focus given to depression and depressogenic risk factors (i.e., past stress, negative cognitive styles, and personality and interpersonal vulnerabilities) as predictors of the stress generation effect, as well as gender differences in stress generation, the sequelae of generated stress, and the relative specificity of this phenomenon to depression. The research thus far appears most consistent in supporting the role of depression in predicting generated stress, although more research is still required. In addition to highlighting these findings, methodological limitations and conceptual gaps in the literature are discussed with the view of informing future research in this area.
Histone modifications are key regulators of chromatin function. However, little is known to what extent histone modifications can directly impact on chromatin. Here, we address how a modification ...within the globular domain of histones regulates chromatin function. We demonstrate that H3K122ac can be sufficient to stimulate transcription and that mutation of H3K122 impairs transcriptional activation, which we attribute to a direct effect of H3K122ac on histone-DNA binding. In line with this, we find that H3K122ac defines genome-wide genetic elements and chromatin features associated with active transcription. Furthermore, H3K122ac is catalyzed by the coactivators p300/CBP and can be induced by nuclear hormone receptor signaling. Collectively, this suggests that transcriptional regulators elicit their effects not only via signaling to histone tails but also via direct structural perturbation of nucleosomes by directing acetylation to their lateral surface.
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► H3K122ac is a conserved modification on the lateral surface of the histone octamer ► Enrichment of H3K122ac at gene promoters correlates with transcriptional output ► H3K122ac stimulates histone eviction from and transcription of chromatin ► High levels of H3K122ac are a signature of active gene enhancers
Acetylation of histone H3 at lysine 122 (H3K122ac) is found to be catalyzed by p300/CBP and to mark transcriptionally active chromatin genome wide. H3K122ac likely promotes transcription directly by weakening histone-DNA interactions rather than indirectly by recruiting an effector.
Tanking up energy through atypical charging Hu, Bo; Liu, T Leo
Science (American Association for the Advancement of Science),
2021-May-21, 2021-05-21, 20210521, Volume:
372, Issue:
6544
Journal Article
Peer reviewed
Designed ketone molecules can undergo two-electron charge storage in aqueous solutions
Aqueous redox flow batteries could provide viable grid-scale electrochemical energy storage for renewable energy ...because of their high-power performance, scalability, and safe operation (
1
,
2
). Redox-active organic molecules serve as the energy storage materials (
2
,
3
), but only very few organic molecules, such as viologen (
4
,
5
) and anthraquinone molecules (
6
), have demonstrated promising energy storage performance (
2
). Efforts continue to develop other families of organic molecules for flow battery applications that would have dense charge capacities and be chemically robust. On page 836 of this issue, Feng
et al.
(
7
) report a class of ingeniously designed 9-fluorenone (FL) molecules as high-performance, potentially low-cost organic anode electrolytes (anolytes) in aqueous organic redox flow batteries (see the figure, top). These FL anolytes not only display exceptional energy storage performance but also exhibit an unprecedented two-electron storage mechanism.
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