Realization of a Z-Classified Chiral-Symmetric Higher-Order Topological Insulator in a Coupling-Inverted Acoustic Crystal.

Higher-order topological band theory has transformed the landscape of topological phases in quantum and classical systems. Here, we experimentally demonstrate a two-dimensional higher-order topological phase, referred to as the multiple chiral topological phase, which is protected by a multipole chiral number (MCN). Our realization differs from previous higher-order topological phases in that it possesses a larger-than-unity MCN, which arises when the nearest-neighbor couplings are weaker than long-range couplings. Our phase has an MCN of 4, protecting the existence of 4 midgap topological corner modes at each corner. The multiple topological corner modes demonstrated here could lead to enhanced quantum-inspired devices for sensing and computing. Our study also highlights the rich and untapped potential of long-range coupling manipulation for future research in topological phases.

The molecular basis of how buried human leukocyte antigen polymorphism modulates natural killer cell function.

Micropolymorphisms within human leukocyte antigen (HLA) class I molecules can change the architecture of the peptide-binding cleft, leading to differences in peptide presentation and T cell recognition. The impact of such HLA variation on natural killer (NK) cell recognition remains unclear. Given the differential association of HLA-B*57:01 and HLA-B*57:03 with the control of HIV, recognition of these HLA-B57 allomorphs by the killer cell immunoglobulin-like receptor (KIR) 3DL1 was compared. Despite differing by only two polymorphic residues, both buried within the peptide-binding cleft, HLA-B*57:01 more potently inhibited NK cell activation. Direct-binding studies showed KIR3DL1 to preferentially recognize HLA-B*57:01, particularly when presenting peptides with positively charged position (P)Ω-2 residues. In HLA-B*57:01, charged PΩ-2 residues were oriented toward the peptide-binding cleft and away from KIR3DL1. In HLA-B*57:03, the charged PΩ-2 residues protruded out from the cleft and directly impacted KIR3DL1 engagement. Accordingly, KIR3DL1 recognition of HLA class I ligands is modulated by both the peptide sequence and conformation, as determined by the HLA polymorphic framework, providing a rationale for understanding differences in clinical associations.

Observation of Degenerate Zero-Energy Topological States at Disclinations in an Acoustic Lattice.

Building upon the bulk-boundary correspondence in topological phases of matter, disclinations have recently been harnessed to trap fractionally quantized density of states (DOS) in classical wave systems. While these fractional DOS have associated states localized to the disclination's core, such states are not protected from deconfinement due to the breaking of chiral symmetry, generally leading to resonances which, even in principle, have finite lifetimes and suboptimal confinement. Here, we devise and experimentally validate in acoustic lattices a paradigm by which topological states bind to disclinations without a fractional DOS but which preserve chiral symmetry. The preservation of chiral symmetry pins the states at the midgap, resulting in their protected maximal confinement. The integer DOS at the defect results in twofold degenerate states that, due to symmetry constraints, do not gap out. Our study provides a fresh perspective about the interplay between symmetry protection in topological phases and topological defects, with possible applications in classical and quantum systems alike.

A comparison study between acoustic topological states based on valley Hall and quantum spin Hall effects.

Over the past few years, the rapid development in the fields of condensed matter physics, electronic, and photonic systems have inspired the design and experimental demonstration of various acoustic topological insulators (TIs). Among these, the topologically protected one-way propagation is a phenomenon that is gaining increased attention. Pseudospin states, which is the analogue of the quantum spin Hall effect from electronic systems, has been proven to enable topological edge states in acoustics. Similarly, the valley Hall (VH) effect is also observed in acoustic systems and provides a pair of valley vortex states with opposite chirality. These valley vortex states can similarly form topologically protected edge states and, in turn, realize robust one-way propagation. However, the differences in the physics behind these acoustic systems give rise to distinct features such as different angle selections and immunization levels to various types of defects. This article conducts a comparison study between topological states in valley Hall phononic crystals and TIs that reveals the differences and similarities in several aspects. Both of them have topologically protected edge states and thus the robust one-way propagation. For the maximum transmission incident angle and defect immunization, however, VH topological waveguides and TI waveguides show different characteristics.

Online Circular Contrast Perimetry: A Comparison to Standard Automated Perimetry.

PURPOSE: The aim was to validate and compare the diagnostic accuracy of a novel 24-degree, 52-loci online circular contrast perimetry (OCCP) application to standard automated perimetry (SAP). DESIGN: Prospective cohort study. METHODS: Two hundred and twenty participants (125 normal controls, 95 open angle glaucoma patients) were included. Agreement, correlation, sensitivity, specificity, and area under receiver operating curves (AUC) were compared for parameters of OCCP, SAP, and optical coherence tomography (OCT) for the retinal nerve fiber layer and macular ganglion cell complex inner plexiform layer. RESULTS: Pointwise sensitivity for OCCP was greater than SAP by 1.02 log units (95% CI: 0.95-1.08); 95% limits of agreement 0.860 to 1.17. Correlation and agreement for global indices and regional zones between OCCP and SAP were strong. OCCP mean deviation (MD) AUC was 0.885±0.08, similar to other instruments' parameters with the highest AUC: SAP MD (0.851±0.08), OCT retinal nerve fiber layer inferior thickness (0.908±0.07), OCT ganglion cell complex inner plexiform layer inferior thickness (0.849±0.08), P>0.05. At best cutoff, OCCP MD sensitivity/specificity were comparable to SAP MD (90/74 vs 94/65%). CONCLUSIONS: OCCP demonstrates similar perimetric sensitivities to SAP and similar AUC to SAP and OCT in distinguishing glaucoma patients from controls. OCCP holds promise as a glaucoma surveillance and screening tool, with the potential to be utilized for in-clinic and at-home perimetry and expand community testing.

Circular Contrast Perimetry via Web Application: A Patient Appraisal and Comparison to Standard Automated Perimetry.

Purpose: The purpose of the study was to compare a novel, 24°, 52-locus online circular contrast perimetry (OCCP) application against standard automated perimetry (SAP) in terms of both diagnostic accuracy and patient attitudes. Design: This was a cross-sectional study. Subjects: Ninety-five participants (42 controls and 53 open-angle glaucoma patients) were included. Methods: Participants performed both perimetry tests and then completed an online survey. Subjective feedback responses were collected. Main Outcome Measures: Agreement, sensitivity, specificity, and area under receiver operating curves (AUCs) were compared for the parameters of OCCP, SAP, and OCT for the retinal nerve fiber layer (RNFL) and macular ganglion cell complex inner plexiform layer (GCC + IPL). Participant attitudes toward the OCCP test versus the SAP test, in both glaucoma patients and controls, were compared. Rasch analysis assessed the psychometric properties of the survey and intergroup variability. Results: The AUC for OCCP mean deviation (MD) was 0.959 ± 0.02. Compared with other instruments' parameters with the highest AUC, it was superior to SAP MD (0.871 ± 0.04, P = 0.03) and OCT GCC + IPL (0.871 ± 0.04, P = 0.03) and similar to OCT RNFL inferior thickness (IT) (0.917 ± 0.03, no significance). Online circular contrast perimetry pointwise sensitivity was less than SAP by 4.30 dB (95% confidence interval = 4.02-4.59); 95% limits of agreement ranged from -6.28 to -2.33 dB. At the best cutoff, the OCCP MD had a sensitivity of 98% and specificity of 85% for detecting glaucoma. Cohen's kappa demonstrated good agreement with SAP MD (0.69) and OCT RNFL IT (0.62) and moderate agreement with OCT GCC + IPL IT (0.57). Participants preferred OCCP across most survey parameters (P < 0.0001). Rasch analysis demonstrated no differential item functioning for clinical group, gender, or age. Conclusions: With similar diagnostic metrics to SAP, OCCP offers an improved user experience with the potential to increase the provision of care and improve disease surveillance outcomes.