Spin disorder control of topological spin texture

Stabilization of topological spin textures in layered magnets has the potential to drive the development of advanced low-dimensional spintronics devices. However, achieving reliable and flexible manipulation of the topological spin textures beyond skyrmion in a two-dimensional magnet system remains challenging. Here, we demonstrate the introduction of magnetic iron atoms between the van der Waals gap of a layered magnet, Fe3GaTe2, to modify local anisotropic magnetic interactions. Consequently, we present direct observations of the order-disorder skyrmion lattices transition. In addition, non-trivial topological solitons, such as skyrmioniums and skyrmion bags, are realized at room temperature. Our work highlights the influence of random spin control of non-trivial topological spin textures.

A substitutional quantum defect in WS2 discovered by high-throughput computational screening and fabricated by site-selective STM manipulation

Point defects in two-dimensional materials are of key interest for quantum information science. However, the parameter space of possible defects is immense, making the identification of high-performance quantum defects very challenging. Here, we perform high-throughput (HT) first-principles computational screening to search for promising quantum defects within WS2, which present localized levels in the band gap that can lead to bright optical transitions in the visible or telecom regime. Our computed database spans more than 700 charged defects formed through substitution on the tungsten or sulfur site. We found that sulfur substitutions enable the most promising quantum defects. We computationally identify the neutral cobalt substitution to sulfur (CoS 0 ) and fabricate it with scanning tunneling microscopy (STM). The CoS 0 electronic structure measured by STM agrees with first principles and showcases an attractive quantum defect. Our work shows how HT computational screening and nanoscale synthesis routes can be combined to design promising quantum defects.

Integration of transcriptomics and long-read genomics prioritizes structural variants in rare disease

Rare structural variants (SVs) - insertions, deletions, and complex rearrangements - can cause Mendelian disease, yet they remain difficult to accurately detect and interpret. We sequenced and analyzed Oxford Nanopore long-read genomes of 68 individuals from the Undiagnosed Disease Network (UDN) with no previously identified diagnostic mutations from short-read sequencing. Using our optimized SV detection pipelines and 571 control long-read genomes, we detected 716 long-read rare (MAF < 0.01) SV alleles per genome on average, achieving a 2.4x increase from short-reads. To characterize the functional effects of rare SVs, we assessed their relationship with gene expression from blood or fibroblasts from the same individuals, and found that rare SVs overlapping enhancers were enriched (LOR = 0.46) near expression outliers. We also evaluated tandem repeat expansions (TREs) and found 14 rare TREs per genome; notably these TREs were also enriched near overexpression outliers. To prioritize candidate functional SVs, we developed Watershed-SV, a probabilistic model that integrates expression data with SV-specific genomic annotations, which significantly outperforms baseline models that don't incorporate expression data. Watershed-SV identified a median of eight high-confidence functional SVs per UDN genome. Notably, this included compound heterozygous deletions in FAM177A1 shared by two siblings, which were likely causal for a rare neurodevelopmental disorder. Our observations demonstrate the promise of integrating long-read sequencing with gene expression towards improving the prioritization of functional SVs and TREs in rare disease patients.

Interlayer Coupling Controlled Ordering and Phases in Polar Vortex Superlattices

The recent discovery of polar topological structures has opened the door for exciting physics and emergent properties. There is, however, little methodology to engineer stability and ordering in these systems, properties of interest for engineering emergent functionalities. Notably, when the surface area is extended to arbitrary thicknesses, the topological polar texture becomes unstable. Here we show that this instability of the phase is due to electrical coupling between successive layers. We demonstrate that this electrical coupling is indicative of an effective screening length in the dielectric, similar to the conductor-ferroelectric interface. Controlling the electrostatics of the superlattice interfaces, the system can be tuned between a pure topological vortex state and a mixed classical-topological phase. This coupling also enables engineering coherency among the vortices, not only tuning the bulk phase diagram but also enabling the emergence of a 3D lattice of polar textures.

Multi-omic identification of key transcriptional regulatory programs during endurance exercise training

Transcription factors (TFs) play a key role in regulating gene expression and responses to stimuli. We conducted an integrated analysis of chromatin accessibility, DNA methylation, and RNA expression across eight rat tissues following endurance exercise training (EET) to map epigenomic changes to transcriptional changes and determine key TFs involved. We uncovered tissue-specific changes and TF motif enrichment across all omic layers, differentially accessible regions (DARs), differentially methylated regions (DMRs), and differentially expressed genes (DEGs). We discovered distinct routes of EET-induced regulation through either epigenomic alterations providing better access for TFs to affect target genes, or via changes in TF expression or activity enabling target gene response. We identified TF motifs enriched among correlated epigenomic and transcriptomic alterations, DEGs correlated with exercise-related phenotypic changes, and EET-induced activity changes of TFs enriched for DEGs among their gene targets. This analysis elucidates the unique transcriptional regulatory mechanisms mediating diverse organ effects of EET.

Non-local dielectric effects in nanoscience

The physical properties of charges and excitations in nanoscale materials are influenced both by the dielectric properties of the material itself and the surrounding environment. This non-local dielectric effect was first discussed in the context of molecules in solvents over a century ago. In this perspective, we discuss non-local dielectric effects in zero-dimensional, one-dimensional, and two-dimensional nanoscale systems.

Near-Field Coupling with a Nanoimprinted Probe for Dark Exciton Nanoimaging in Monolayer WSe2

Tip-enhanced photoluminescence (TRPL) is a powerful technique for spatially and spectrally probing local optical properties of 2-dimensional (2D) materials that are modulated by the local heterogeneities, revealing inaccessible dark states due to bright state overlap in conventional far-field microscopy at room temperature. While scattering-type near-field probes have shown the potential to selectively enhance and reveal dark exciton emission, their technical complexity and sensitivity can pose challenges under certain experimental conditions. Here, we present a highly reproducible and easy-to-fabricate near-field probe based on nanoimprint lithography and fiber-optic excitation and collection. The novel near-field measurement configuration provides an ∼3 orders of magnitude out-of-plane Purcell enhancement, diffraction-limited excitation spot, and subdiffraction hyperspectral imaging resolution (below 50 nm) of dark exciton emission. The effectiveness of this high spatial X_D mapping technique was then demonstrated through reproducible hyperspectral mapping of oxidized sites and bubble areas.

Rotational and dilational reconstruction in transition metal dichalcogenide moiré bilayers

Lattice reconstruction and corresponding strain accumulation plays a key role in defining the electronic structure of two-dimensional moiré superlattices, including those of transition metal dichalcogenides (TMDs). Imaging of TMD moirés has so far provided a qualitative understanding of this relaxation process in terms of interlayer stacking energy, while models of the underlying deformation mechanisms have relied on simulations. Here, we use interferometric four-dimensional scanning transmission electron microscopy to quantitatively map the mechanical deformations through which reconstruction occurs in small-angle twisted bilayer MoS₂ and WSe₂/MoS₂ heterobilayers. We provide direct evidence that local rotations govern relaxation for twisted homobilayers, while local dilations are prominent in heterobilayers possessing a sufficiently large lattice mismatch. Encapsulation of the moiré layers in hBN further localizes and enhances these in-plane reconstruction pathways by suppressing out-of-plane corrugation. We also find that extrinsic uniaxial heterostrain, which introduces a lattice constant difference in twisted homobilayers, leads to accumulation and redistribution of reconstruction strain, demonstrating another route to modify the moiré potential.

Transferable nano-patterned ALD Membrane

We demonstrate fabrication of nano-patterned thin ALD (Atomic layer deposition) membrane (suspended/transferable) by using a bi-layer resist process where the bottom layer resist acts as a sacrificial layer. This method enables an all dry deterministic transfer of nano-patterned ALD membrane on desired substrate, allowing assembly of multitude of hetero-structures \& functionalities that are not yet accessible. Unlike conventional ways of achieving patterned alumina membrane reported in literature our technique requires significantly less fabrication steps and paves the way for novel ALD membrane-based technology.

Size-Induced Ferroelectricity in Antiferroelectric Oxide Membranes

Despite extensive studies on size effects in ferroelectrics, how structures and properties evolve in antiferroelectrics with reduced dimensions still remains elusive. Given the enormous potential of utilizing antiferroelectrics for high-energy-density storage applications, understanding their size effects will provide key information for optimizing device performances at small scales. Here, the fundamental intrinsic size dependence of antiferroelectricity in lead-free NaNbO₃ membranes is investigated. Via a wide range of experimental and theoretical approaches, an intriguing antiferroelectric-to-ferroelectric transition upon reducing membrane thickness is probed. This size effect leads to a ferroelectric single-phase below 40 nm, as well as a mixed-phase state with ferroelectric and antiferroelectric orders coexisting above this critical thickness. Furthermore, it is shown that the antiferroelectric and ferroelectric orders are electrically switchable. First-principle calculations further reveal that the observed transition is driven by the structural distortion arising from the membrane surface. This work provides direct experimental evidence for intrinsic size-driven scaling in antiferroelectrics and demonstrates enormous potential of utilizing size effects to drive emergent properties in environmentally benign lead-free oxides with the membrane platform.

Non-volatile electric-field control of inversion symmetry

Competition between ground states at phase boundaries can lead to significant changes in properties under stimuli, particularly when these ground states have different crystal symmetries. A key challenge is to stabilize and control the coexistence of symmetry-distinct phases. Using BiFeO₃ layers confined between layers of dielectric TbScO₃ as a model system, we stabilize the mixed-phase coexistence of centrosymmetric and non-centrosymmetric BiFeO₃ phases at room temperature with antipolar, insulating and polar semiconducting behaviour, respectively. Application of orthogonal in-plane electric (polar) fields results in reversible non-volatile interconversion between the two phases, hence removing and introducing centrosymmetry. Counterintuitively, we find that an electric field 'erases' polarization, resulting from the anisotropy in octahedral tilts introduced by the interweaving TbScO₃ layers. Consequently, this interconversion between centrosymmetric and non-centrosymmetric phases generates changes in the non-linear optical response of over three orders of magnitude, resistivity of over five orders of magnitude and control of microscopic polar order. Our work establishes a platform for cross-functional devices that take advantage of changes in optical, electrical and ferroic responses, and demonstrates octahedral tilts as an important order parameter in materials interface design.

Bidirectional phonon emission in two-dimensional heterostructures triggered by ultrafast charge transfer

Photoinduced charge transfer in van der Waals heterostructures occurs on the 100 fs timescale despite weak interlayer coupling and momentum mismatch. However, little is understood about the microscopic mechanism behind this ultrafast process and the role of the lattice in mediating it. Here, using femtosecond electron diffraction, we directly visualize lattice dynamics in photoexcited heterostructures of WSe₂/WS₂ monolayers. Following the selective excitation of WSe₂, we measure the concurrent heating of both WSe₂ and WS₂ on a picosecond timescale-an observation that is not explained by phonon transport across the interface. Using first-principles calculations, we identify a fast channel involving an electronic state hybridized across the heterostructure, enabling phonon-assisted interlayer transfer of photoexcited electrons. Phonons are emitted in both layers on the femtosecond timescale via this channel, consistent with the simultaneous lattice heating observed experimentally. Taken together, our work indicates strong electron-phonon coupling via layer-hybridized electronic states-a novel route to control energy transport across atomic junctions.

Hyperspectral imaging of exciton confinement within a moiré unit cell with a subnanometer electron probe

Electronic and optical excitations in two-dimensional systems are distinctly sensitive to the presence of a moiré superlattice. We used cryogenic transmission electron microscopy and spectroscopy to simultaneously image the structural reconstruction and associated localization of the lowest-energy intralayer exciton in a rotationally aligned WS₂-WSe₂ moiré superlattice. In conjunction with optical spectroscopy and ab initio calculations, we determined that the exciton center-of-mass wave function is confined to a radius of approximately 2 nanometers around the highest-energy stacking site in the moiré unit cell. Our results provide direct evidence that atomic reconstructions lead to the strongly confining moiré potentials and that engineering strain at the nanoscale will enable new types of excitonic lattices.

First-in-man trial of b3-adrenoreceptor agonist treatment in chronic heart failure – impact on diastolic function

Background

Diastolic dysfunction (DD) in heart failure (HF) is associated with increased myocardial cytosolic calcium, and calcium-efflux via the sodium-calcium-exchanger depends on the sodium gradient. Beta-3-adrenoceptor (β3-AR)-agonist lowers cytosolic sodium and has been shown to reverse organ congestion.

Purpose

To assess whether β3-AR-agonist treatment improves DD.

Methods

In a first-in-man randomized controlled, double-blind trial, we assigned 70 patients with HF with reduced ejection fraction (HFrEF) (NYHA II–III) and LVEF &lt;40% to receive mirabegron (300 mg/day) or placebo for 6 months, in addition to recommended HF-therapy. Patients were assessed with echocardiography and cardiac computed tomography (CCT) at baseline and follow-up. DD was graded according to the current American/European guidelines.

Results

Baseline and follow-up echocardiographic data were available in 57 patients (59±11 years, 88% male, 49% ischemic heart disease). Baseline LVEF was 34%±8%. No significant change in DD grade was found between the groups at follow-up, p=0.72. Neither was there any clinical differences in any singular diastolic parameters within or between groups by echocardiography (E/e' placebo: 13.3±6.9 to 12.6±5.1, p=0.19 vs. mirabegron: 12.0±5.7 to 12.8±7.9, p=0.67, mean difference 1.12 [95% CI −1.68 to 4.3], p=0.37), or CCT (left atrial max volume index: between group mean difference 0.2 [95% CI −6.2 to 5.6] ml/m2, p=0.91).

Conclusions

In patients with HFrEF, no improvement nor worsening in DD gradings or singular diastolic parameters after β3-AR stimulation compared to placebo were identified. The findings add to previous literature questioning the role of impaired Na+-Ca2+ mediated Ca2+ export as a major culprit in DD.

Funding Acknowledgement

Type of funding sources: Foundation. Main funding source(s): The Heart Centre Research Foundation, RigshospitaletThe Novo Nordic Foundation

Photocatalytic degradation effect of CdSe nanoparticles for textile wastewater effluents at low cost and proves to be efficient method

Semiconductor nanoparticles and nanocrystals have a great impact due to its contribution in the diverse fields including electronics, solar energy, biological imaging, and photonics. Among these semiconductor nanoparticles, cadmium selenide of II-VI group binary semiconductor nanoparticles were synthesized using solvothermal process for the different reaction temperatures. The XRD pattern of the synthesized samples confirms the crystalline nature of the samples and showed increase in its crystallite size with rise in temperature. The morphology of the samples was analysed with TEM images and found that the nanoparticles synthesized at different temperatures were varied in size and shape indicating the increase in the size of the particles with the raise in temperature. The optical properties of the samples pointed out that they exhibit a blue shift owing to quantum confinement. Photocatalytic activity was carried out for the synthesized samples under visible light radiation using methylene blue (MB) as a model pollutant and it proved to be a good photocatalyst achieving the efficiency of 75% which is promising for future application with good optimization. The efficiency could be increased when these semiconductor CdSe nanoparticles are doped with metal particles due to an increase in the absorption edge wavelength and a decrease in bandgap energy were reported in detail.

Enhancing the photocatalytic performance of surface - Treated SnO2 hierarchical nanorods against methylene blue dye under solar irradiation and biological degradation

Surfactant -treated tin oxide (SnO₂) hierarchical nanorods were successfully synthesized through hydrothermal technique. The X-ray diffraction analysis showed the prepared SnO₂ possesses tetragonal rutile structure having appreciable crystallinity with crystallite sizes in the range of 110 nm-120 nm. UV-visible diffuse reflectance absorption spectra confirm that the better visible light absorption band of SnO₂ hierarchical nanorods have red shift compared to the pure SnO₂. Fourier transform infrared spectroscopy (FTIR) study evident that the as-prepared SnO₂ nanorods encompass the characteristic bands of SnO₂ nanostructures. The morphological analyses of prepared materials were performed by FESEM, which shows that hierarchal nanorods and complex nanostructures. EDX analyses disclose all the samples are composed of Sn and O elements. The photocatalytic performance of the prepared surfactant treated SnO₂ hierarchical nanorods was evaluated using methylene blue (MB) dye removal under direct natural sunlight. Recycling experiment results of CTAB - SnO₂ nanorods and photocatalytic reaction mechanism also discussed in detail.

Optimizing cathodoluminescence microscopy of buried interfaces through nanoscale heterostructure design

Mapping the optical response of buried interfaces with nanoscale spatial resolution is crucial in several systems where an active component is embedded within a buffer layer for structural or functional reasons. Here, we demonstrate that cathodoluminescence microscopy is not only an ideal tool for visualizing buried interfaces, but can be optimized through heterostructure design. We focus on the prototypical system of monolayers of semiconducting transition metal dichalcogenide sandwiched between hexagonal boron nitride layers. We leverage the encapsulating layers to tune the nanoscale spatial resolution achievable in cathodoluminescence mapping while also controlling the brightness of the emission. Thicker encapsulation layers result in a brighter emission while thinner ones enhance the spatial resolution at the expense of the signal intensity. We find that a favorable trade-off between brightness and resolution is achievable up to about ∼100 nm of total encapsulation. Beyond this value, the brightness gain is marginal, while the spatial resolution enters a regime that is achievable by diffraction-limited optical microscopy. By preparing samples of varying encapsulation thickness, we are able to determine a surprisingly isotropic exciton diffusion length of >200 nm within the hexagonal boron nitride which is the dominant factor that determines spatial resolution. We further demonstrate that we can overcome the exciton diffusion-limited spatial resolution by using spectrally distinct signals, which is the case for nanoscale inhomogeneities within monolayer transition metal dichalcogenides.

Effect of Ag doped MnO2 nanostructures suitable for wastewater treatment and other environmental pollutant applications

A modest sol-gel method has been employed to prepare the pure and Ag doped MnO₂ nanoparticles and methodologically studied their physical, morphological, and photosensitive properties through XRD, TEM, EDAX, Raman, UV, PL and N₂ adsorption - desorption study. Tetragonal crystalline arrangement with spherical nanoparticles was found out through XRD and TEM studies. The EDAX studies further supported that formation Ag in the MnO₂ crystal matrix. The bandgap energy of Ag doped MnO₂ was absorbed through UV spectra. Photo -generated recombination process and surface related defects were further recognized by PL spectra. Through visible light irradiation, the photo - degradation of methyl orange (MO) and phenol dye solutions were observed. The optimum condition of (10 wt% of Ag) Ag doped MnO₂ catalyst showed tremendous photocatalytic efficiency towards MO than phenol under same experimental study.

131 The Health-Related Quality of Life of Patients Waiting for Anterior Cruciate Ligament Reconstruction Is Worse Than an Age and Sex Match Population: Increasing Time on Waiting List Was Independently Associated With a Worse Quality of Life

Aim

To assess the health-related quality of life (HRQoL) of patients waiting for an anterior cruciate ligament (ACL) reconstruction compared to the population at risk, and whether knee specific function was predictive of HRQoL and to identify factors associated with a worse HRQoL.

Method

Sixty-seven patients (male n = 50, female n = 17, mean age 29) identified from the surgical waiting list completed a questionnaire that included demographics, BMI, time of injury, EuroQol 5-demension (EQ-5D), short-form (SF-)36 and International Knee Documentation Committee (IKDC) scores. Age and sex matched HRQoL data were obtained from population level data.

Results

The mean EQ-5D score for the study cohort was significantly worse than the matched score (difference 0.367, p&lt;0.001), and the same trend was observed for all eight dimensions of the SF-36 score. Thirty-three (49%) patients felt their health in general was somewhat or much worse compared to one-year ago. There was a correlation between the IKDC and EQ-5D scores (r = 0.540, p&lt;0.001), and linear regression was used to formulate the EQ-5D score: EQ-5D = (IKDCx0.013)–0.015(constant). The SF-36 physical component and the length of time on the waiting list were independently associated the HRQoL, with each 14-point drop or for every 200-days a clinically significant deterioration in a patients HRQoL occurred, respectively.

Conclusions

Patients had a significantly worse HRQoL when compared to age and sex match population, which deteriorates with worsening physical function and increasing length of time on the waiting list. The knee specific IKDC correlated with HRQoL and could be used to estimate the EQ-5D score.

Ferroelectricity in a semiconducting all-inorganic halide perovskite

Ferroelectric semiconductors are rare materials with both spontaneous polarizations and visible light absorptions that are promising for designing functional photoferroelectrics, such as optical switches and ferroelectric photovoltaics. The emerging halide perovskites with remarkable semiconducting properties also have the potential of being ferroelectric, yet the evidence of robust ferroelectricity in the typical three-dimensional hybrid halide perovskites has been elusive. Here, we report on the investigation of ferroelectricity in all-inorganic halide perovskites, CsGeX3, with bandgaps of 1.6 to 3.3 eV. Their ferroelectricity originates from the lone pair stereochemical activity in Ge (II) that promotes the ion displacement. This gives rise to their spontaneous polarizations of ~10 to 20 μC/cm2, evidenced by both ab initio calculations and key experiments including atomic-level ionic displacement vector mapping and ferroelectric hysteresis loop measurement. Furthermore, characteristic ferroelectric domain patterns on the well-defined CsGeBr3 nanoplates are imaged with both piezo-response force microscopy and nonlinear optical microscopic method.

Electric field control of chirality

Polar textures have attracted substantial attention in recent years as a promising analog to spin-based textures in ferromagnets. Here, using optical second-harmonic generation–based circular dichroism, we demonstrate deterministic and reversible control of chirality over mesoscale regions in ferroelectric vortices using an applied electric field. The microscopic origins of the chirality, the pathway during the switching, and the mechanism for electric field control are described theoretically via phase-field modeling and second-principles simulations, and experimentally by examination of the microscopic response of the vortices under an applied field. The emergence of chirality from the combination of nonchiral materials and subsequent control of the handedness with an electric field has far-reaching implications for new electronics based on chirality as a field-controllable order parameter.

Electrical Injuries and Neurosurgery: A Case Report and Review of Literature

Introduction Electrical injuries account for 5 to 27% of admissions to burn units. The nervous system is affected in as much as 21% of nervous injuries, with reported mortality.

Case Report The authors report a case of a patient presenting to the neurosurgical service with a traumatic brain injury (TBI) caused due to an electrical burn. Available data was reviewed through a PubMed search of literature, with special attention to the nature of presentation, classification of such injuries, the pathophysiology of the events that arise, complications to be expected, and the guidelines for management.

Conclusion It is possible for electrical injuries to cause TBIs requiring neurosurgical intervention.

Mono- and Biallelic Protein-Truncating Variants in Alpha-Actinin 2 Cause Cardiomyopathy Through Distinct Mechanisms

BACKGROUND

ACTN2 (alpha-actinin 2) anchors actin within cardiac sarcomeres. The mechanisms linking ACTN2 mutations to myocardial disease phenotypes are unknown. Here, we characterize patients with novel ACTN2 mutations to reveal insights into the physiological function of ACTN2.

METHODS

Patients harboring ACTN2 protein-truncating variants were identified using a custom mutation pipeline. In patient-derived iPSC-cardiomyocytes, we investigated transcriptional profiles using RNA sequencing, contractile properties using video-based edge detection, and cellular hypertrophy using immunohistochemistry. Structural changes were analyzed through electron microscopy. For mechanistic studies, we used co-immunoprecipitation for ACTN2, followed by mass-spectrometry to investigate protein-protein interaction, and protein tagging followed by confocal microscopy to investigate introduction of truncated ACTN2 into the sarcomeres.

RESULTS

Patient-derived iPSC-cardiomyocytes were hypertrophic, displayed sarcomeric structural disarray, impaired contractility, and aberrant Ca2+-signaling. In heterozygous indel cells, the truncated protein incorporates into cardiac sarcomeres, leading to aberrant Z-disc ultrastructure. In homozygous stop-gain cells, affinity-purification mass-spectrometry reveals an intricate ACTN2 interactome with sarcomere and sarcolemma-associated proteins. Loss of the C-terminus of ACTN2 disrupts interaction with ACTN1 (alpha-actinin 1) and GJA1 (gap junction protein alpha 1), 2 sarcolemma-associated proteins, which may contribute to the clinical arrhythmic and relaxation defects. The causality of the stop-gain mutation was verified using CRISPR-Cas9 gene editing.

CONCLUSIONS

Together, these data advance our understanding of the role of ACTN2 in the human heart and establish recessive inheritance of ACTN2 truncation as causative of disease.

Facile synthesis of sphere-like structured ZnIn2S4-rGO-CuInS2 ternary heterojunction catalyst for efficient visible-active photocatalytic hydrogen evolution

Photocatalysis is a promising approach for generating hydrogen, an eco-friendly and cost-effective fuel. It is hypothesized that the ternary catalyst ZnIn₂S₄-rGO-CuInS₂, prepared by ultrasonication method, should be effective for optimized photocatalytic hydrogen generation in a Na₂S/Na₂SO_3-water mixture. The as-synthesized catalyst was characterized using various surface analytical and optical techniques. Field-emission scanning electron microscopy and high-resolution transmission electron microscopy analyses revealed that marigold-like structured ZnIn₂S₄ and layer-structured CuInS₂ were dispersed on the reduced graphene oxide sheets. The ternary ZnIn₂S₄-rGO-CuInS₂ system showed enhanced photocatalytic H₂ production compared to pure ZnIn₂S₄, CuInS₂, ZnIn₂S₄-rGO, CuInS₂-rGO, and ZnIn₂S₄-CuInS₂ catalysts under visible light illumination. The fabricated ZnIn₂S₄-rGO-CuInS₂ catalyst afforded hydrogen generation of 2531 μmol/g after 5 h. The enhanced performance of the ZnIn₂S₄-rGO-CuInS₂ catalyst originates from the synergetic effect with rGO as the electron transfer medium, and is confirmed by photocurrent density and photoluminescence measurements that indicate reduced recombination between the excited electron and hole pairs, and fast electron transfer in the ternary composite. The excellent performance of the ZnIn₂S₄-rGO-CuInS₂ catalyst for up to three consecutive cycles was demonstrated in cyclic stability tests under visible-light illumination.

Enhanced nonlinear interaction of polaritons via excitonic Rydberg states in monolayer WSe2

Strong optical nonlinearities play a central role in realizing quantum photonic technologies. Exciton-polaritons, which result from the hybridization of material excitations and cavity photons, are an attractive candidate to realize such nonlinearities. While the interaction between ground state excitons generates a notable optical nonlinearity, the strength of such interactions is generally not sufficient to reach the regime of quantum nonlinear optics. Excited states, however, feature enhanced interactions and therefore hold promise for accessing the quantum domain of single-photon nonlinearities. Here we demonstrate the formation of exciton-polaritons using excited excitonic states in monolayer tungsten diselenide (WSe2) embedded in a microcavity. The realized excited-state polaritons exhibit an enhanced nonlinear response ∼[Formula: see text] which is ∼4.6 times that for the ground-state exciton. The demonstration of enhanced nonlinear response from excited exciton-polaritons presents the potential of generating strong exciton-polariton interactions, a necessary building block for solid-state quantum photonic technologies.

Hierarchical porous CeO2 micro rice-supported Ni foam binder-free electrode and its enhanced pseudocapacitor performance by a redox additive electrolyte

A hierarchical porous CeO₂ micro rice/NF binder free electrode was fabricated via a facile hydrothermal method and the electrochemical performances were enhanced by the addition of 0.2 M K₄[Fe(CN)₆] redox additive in a 3 M KOH electrolyte.

High-throughput SARS-CoV-2 and host genome sequencing from single nasopharyngeal swabs

During COVID19 and other viral pandemics, rapid generation of host and pathogen genomic data is critical to tracking infection and informing therapies. There is an urgent need for efficient approaches to this data generation at scale. We have developed a scalable, high throughput approach to generate high fidelity low pass whole genome and HLA sequencing, viral genomes, and representation of human transcriptome from single nasopharyngeal swabs of COVID19 patients.

Emergence of variant avian infectious bronchitis virus in India

BACKGROUND

Infectious bronchitis virus (IBV) is the etiological agent of an acute and highly contagious disease. Infectious bronchitis (IB) affects chicken of all ages and poses major economic loses to the poultry industry worldwide. The continuous evolution of the spike protein (S1) of IBV is responsible for the prevalence of many serotypes/genotypes around the world. Multiple lineages of IBV strains have been detected in chicken flocks in India since 2003.

AIMS

To detect IBV genotypes prevalent in India.

METHODS

Organ samples from 20 IBV-positive flocks with variable clinical signs were used for the amplification of the S1 gene of IBV by reverse transcriptase-polymerase chain reaction (RT-PCR).

RESULTS

Positive PCR amplicons were sequenced. Sequence analysis showed that 14 field isolates belonged to the GI-1 genetic lineage (Mass 41 serotype), two field isolates belonged to the GI-13 (UK 4/91 variant IBV strain), one field isolate grouped with GIII, GV, and GVI genetic lineage and three belonged to a variant genotype unique to India (GI-24). Phylogenetic analysis also showed a similar type of grouping within the field isolates. Among the fourteen GI-1 isolates, 12 were isolated between 2003 and 2006 and only two were isolated between 2009 and 2011. The two field isolates belonging to GI-13 were isolated in 2007, another one belonging to GIII, GV, and GVI was isolated in 2010 and three field isolates were not close to any reference IBV sequences isolated in 2006 (IND-TN-168-06), 2010 (IND-TN-280-10) and 2011 (IND-TN-290-11).

CONCLUSION

A unique variant of IBV is emerging in India (GI-24). Our findings will have important implications for future vaccine intervention.

Rigid Band Shifts in Two-Dimensional Semiconductors through External Dielectric Screening

We investigate the effects of external dielectric screening on the electronic dispersion and the band gap in the atomically thin, quasi-two-dimensional (2D) semiconductor WS_{2} using angle-resolved photoemission and optical spectroscopies, along with first-principles calculations. We find the main effect of increased external dielectric screening to be a reduction of the quasiparticle band gap, with rigid shifts to the bands themselves. Specifically, the band gap of monolayer WS_{2} is decreased by about 140 meV on a graphite substrate as compared to a hexagonal boron nitride substrate, while the electronic dispersion of WS_{2} remains unchanged within our experimental precision of 17 meV. These essentially rigid shifts of the valence and conduction bands result from the special spatial structure of the changes in the Coulomb potential induced by the dielectric environment of the monolayer.

Dielectric disorder in two-dimensional materials

Understanding and controlling disorder is key to nanotechnology and materials science. Traditionally, disorder is attributed to local fluctuations of inherent material properties such as chemical and structural composition, doping or strain. Here, we present a fundamentally new source of disorder in nanoscale systems that is based entirely on the local changes of the Coulomb interaction due to fluctuations of the external dielectric environment. Using two-dimensional semiconductors as prototypes, we experimentally monitor dielectric disorder by probing the statistics and correlations of the exciton resonances, and theoretically analyse the influence of external screening and phonon scattering. Even moderate fluctuations of the dielectric environment are shown to induce large variations of the bandgap and exciton binding energies up to the 100 meV range, often making it a dominant source of inhomogeneities. As a consequence, dielectric disorder has strong implications for both the optical and transport properties of nanoscale materials and their heterostructures.

Intrinsic lifetime of higher excitonic states in tungsten diselenide monolayers

The reduced dielectric screening in atomically thin transition metal dichalcogenides allows to study the hydrogen-like series of higher exciton states in optical spectra even at room temperature. The width of excitonic peaks provides information about the radiative decay and phonon-assisted scattering channels limiting the lifetime of these quasi-particles. While linewidth studies so far have been limited to the exciton ground state, encapsulation with hBN has recently enabled quantitative measurements of the broadening of excited exciton resonances. Here, we present a joint experiment-theory study combining microscopic calculations with spectroscopic measurements on the intrinsic linewidth and lifetime of higher exciton states in hBN-encapsulated WSe₂ monolayers. Surprisingly, despite the increased number of scattering channels, we find both in theory and experiment that the linewidth of higher excitonic states is similar or even smaller compared to the ground state. Our microscopic calculations ascribe this behavior to a reduced exciton-phonon scattering efficiency for higher excitons due to spatially extended orbital functions.

Enhancement of Exciton-Phonon Scattering from Monolayer to Bilayer WS2

Layered transition metal dichalcogenides exhibit the emergence of a direct bandgap at the monolayer limit along with pronounced excitonic effects. In these materials, interaction with phonons is the dominant mechanism that limits the exciton coherence lifetime. Exciton-phonon interaction also facilitates energy and momentum relaxation, and influences exciton diffusion under most experimental conditions. However, the fundamental changes in the exciton-phonon interaction are not well understood as the material undergoes the transition from a direct to an indirect bandgap semiconductor. Here, we address this question through optical spectroscopy and microscopic theory. In the experiment, we study room-temperature statistics of the exciton line width for a large number of mono- and bilayer WS₂ samples. We observe a systematic increase in the room-temperature line width of the bilayer compared to the monolayer of 50 meV, corresponding to an additional scattering rate of ∼0.1 fs^-1. We further address both phonon emission and absorption processes by examining the temperature dependence of the width of the exciton resonances. Using a theoretical approach based on many-body formalism, we are able to explain the experimental results and establish a microscopic framework for exciton-phonon interactions that can be applied to naturally occurring and artificially prepared multilayer structures.

Genetic structure of a small closed population of the New Zealand white rabbit through pedigree analyses

The genetic structure of a small population of New Zealand White rabbits maintained at the Sheep Breeding and Research Station, Sandynallah, The Nilgiris, India, was evaluated through pedigree analyses. Data on pedigree information (n=2503) for 18 yr (1995-2012) were used for the study. Pedigree analysis and the estimates of population genetic parameters based on the gene origin probabilities were performed. The analysis revealed that the mean values of generation interval, coefficients of inbreeding and equivalent inbreeding were 1.49 yr, 13.23 and 17.59%, respectively. The proportion of population inbred was 100%. The estimated mean values of average relatedness and individual increase in inbreeding were 22.73 and 3.00%, respectively. The percentage increase in inbreeding over generations was 1.94, 3.06 and 3.98 estimated through maximum generations, equivalent generations and complete generations, respectively. The number of ancestors contributing the majority of 50% genes (f_a50) to the gene pool of reference population was only 4, which might have led to reduction in genetic variability and increased the amount of inbreeding. The extent of genetic bottleneck assessed by calculating the effective number of founders (f_e) and the effective number of ancestors (f_a), as expressed by the f_e/f_a ratio was 1.1, which is indicative of the absence of stringent bottlenecks. Up to 5th generation, 71.29% pedigree was complete, reflecting the well maintained pedigree records. The maximum known generations were 15, with an average of 7.9, and the average equivalent generations traced were 5.6, indicating a fairly good depth in pedigree. The realized effective population size was 14.93, which is very critical, and with the increasing trend of inbreeding the situation has been assessed as likely to become worse in future. The proportion of animals with the genetic conservation index (GCI) greater than 9 was 39.10%, which can be used as a scale to use such animals with higher GCI to maintain balanced contribution from the founders. From the study, it was evident that the herd was completely inbred, with a very high inbreeding coefficient, and the effective population size was critical. Recommendations were made to reduce the probability of deleterious effects of inbreeding and to improve genetic variability in the herd. The present study can help in carrying out similar studies to meet the demand for animal protein in developing countries.